2.4643 (NiCr33Mo8) Forging Parts | China Jiangsu Jiangyin ISO 9001:2015 Certified Open Die Forging Manufacturer
Quick Buyer's Guide for 2.4643 (NiCr33Mo8) Forgings
- Best For: Wet process phosphoric acid, nuclear power, sour oil and gas, hot sodium hydroxide environments
- Main Advantage: 2x longer service life than G-30 alloy, superior chloride SCC resistance
- Certifications: ISO 9001:2015, PED CE, NACE MR0175
- Lead Time: 15-30 days for standard products, 30-45 days for custom
- Request a Quote: Send your 2D or 3D drawings, material specs, quantity to sales@jnmtforgedparts.com
Product Overview of 2.4643 (NiCr33Mo8) Nickel Alloy Forgings
Jiangsu Liangyi Co., Limited, a top ISO 9001:2015 certified open die forging manufacturer located in Jiangyin City, Jiangsu Province, China – the core high-end forging industry cluster in the Yangtze River Delta, specializes in custom 2.4643 (NiCr33Mo8) forgings and seamless rolled steel forged rings. With over 25 years of nickel alloy forging experience, we provide a full range of service from steel melting, open die forging, seamless ring rolling, heat treatment, CNC machining to full non-destructive testing (NDT).All parts fully meet ASTM, EN, API, ASME international standards and client custom drawings.
Our 2.4643 (NiCr33Mo8) forging parts are widely used in harsh industrial applications across the United States, Europe, the Middle East, Southeast Asia, and Australia, including wet process phosphoric acid production, nuclear power generation, onshore and offshore sour oil and gas, petrochemical processing, and power generation industries. This high-nickel chromium-molybdenum alloy delivers exceptional corrosion resistance, superior mechanical stability, and outstanding anti-dealloying performance in extreme environments that conventional stainless steel and other nickel alloys cannot withstand.
Core Material Advantages & Competitive Performance of 2.4643 (NiCr33Mo8)
2.4643 (NiCr33Mo8) is a high-chromium nickel-molybdenum alloy with a unique formula design.It has excellent performance in both oxidizing and reducing corrosive environments. Following are its main advantages :
Exceptional Acid Corrosion Resistance
It has excellent corrosion resistance in wet process phosphoric acid production environments that contain fluoride impurities. In fertilizer manufacturing scenarios, its lifetime is twice as long as G-30 alloy and five times as long as 316L stainless steel. Its high chromium content guarantees great resistance to nitric acid and mixtures containing nitric acid, while its high molybdenum content gives it moderate resistance to reducing acids such as sulfuric acid.
Superior Chloride Corrosion Resistance
It has great resistance to localized corrosion (pitting, crevice corrosion)and chloride stress corrosion cracking (SCC) in environments with high chloride levels. This gets rid of the common problems that stainless steel often has—like breaking or failing—in marine, offshore, and chemical processing settings. It also fully meets the NACE MR0175 standard for use in sour oil and gas operations.
Unique Hot Alkali Corrosion Resistance
Unlike other common nickel-chromium-molybdenum alloys (such as Hastelloy C276), 2.4643 (NiCr33Mo8) is better at resisting dealloying elemental corrosion in hot sodium hydroxide environments. So that it is the best choice material for caustic soda production and alkaline chemical processing.
All our 2.4643 forgings undergo standard solution heat treatment at 1140-1175°C followed by rapid water quenching, to fully release the material's corrosion resistance and ensure stable mechanical properties in long-term extreme service.
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Jiangsu Liangyi Exclusive: PREN Index Benchmark for 2.4643 vs Competing Alloys
The Pitting Resistance Equivalent Number (PREN = %Cr + 3.3×%Mo + 16×%N) quantifies an alloy's localized corrosion threshold in chloride-bearing media. Using typical composition mid-values, 2.4643 (NiCr33Mo8) achieves a PREN of approximately 60–62 — calculated as 33.3 + 3.3×8.3 = 60.7 — substantially outperforming G-30 alloy (~46–50), Hastelloy C-276 (~72 but with lower Cr), and by a wide margin exceeding 316L stainless steel (PREN ~24–26). This index directly correlates with safe operating temperature in seawater: alloys with PREN >40 are considered suitable for offshore service; 2.4643 exceeds this threshold by over 50%, making it a dependable choice for NACE Zone 2 and Zone 3 sour environments.
Quantified Corrosion Rate Comparison: 2.4643 vs Competing Alloys in Key Industrial Media
The following corrosion rate data shows the typical performance ranges we recorded during our factory’s material qualification tests and from published industrial case studies for these alloy types. The actual corrosion rate will change depending on the exact acid concentration, temperature, types of impurities, and flow conditions. For advice tailored to your specific application, please contact our technical team.
| Corrosive Medium & Condition | 2.4643 NiCr33Mo8 | G-30 (N06030) | C-276 (2.4819) | 316L SS |
|---|
| Wet Process H₃PO₄ 50–55%, 85°C, with HF impurities | <0.05 mm/yr | 0.08–0.12 mm/yr | 0.15–0.25 mm/yr | >2.0 mm/yr |
| 50% NaOH, 120°C (hot caustic soda) | <0.02 mm/yr | 0.05–0.10 mm/yr | 0.30–0.60 mm/yr ⚠ dealloying risk | >1.5 mm/yr |
| 3.5% NaCl seawater, 60°C (chloride pitting) | No pitting (PREN ≈61) | No pitting (PREN ≈48) | No pitting (PREN ≈70) | Active pitting (PREN ≈25) |
| H₂S + CO₂ sour gas, NACE TM0177 SSC test | Pass (NACE MR0175 compliant) | Pass | Pass | Fail (SCC susceptible) |
| Nitric acid 65%, 80°C (oxidizing acid) | <0.10 mm/yr ✓ High Cr advantage | <0.15 mm/yr | 0.50–1.20 mm/yr ⚠ Low Cr limit | 0.30–0.80 mm/yr |
⚠ Data sourced from Jiangsu Liangyi's in-house material qualification records and referenced industry alloy performance studies. Rates are indicative; consult our engineering team for site-specific assessment.
Full Alloy Selection Matrix: 2.4643 (NiCr33Mo8) vs Major Nickel Alloys for Industrial Forgings
Choosing the right nickel alloy for your forged part means balancing four key factors: corrosion resistance, mechanical performance, machinability, and total lifecycle cost. The table below shows Jiangsu Liangyi's engineering evaluation of these four aspects for the five most commonly specified alloys in our global order portfolio.
| Performance Dimension | 2.4643 NiCr33Mo8 | G-30 N06030 | C-276 2.4819 | Alloy 625 2.4856 | 316L SS |
|---|
| Chromium Content | 33% (Highest) | 30% | 16% | 22% | 17% |
| Molybdenum Content | 8.3% | 5.5% | 16% (Highest) | 9% | 2% |
| PREN Index (approx.) | ~61 | ~48 | ~70 | ~52 | ~24 |
| Wet H₃PO₄ Resistance | ★★★★★ Best | ★★★☆☆ Good | ★★★☆☆ Moderate | ★★☆☆☆ Limited | ★☆☆☆☆ Poor |
| Hot NaOH Resistance | ★★★★★ Unique | ★★★☆☆ | ★☆☆☆☆ Dealloying | ★★☆☆☆ | ★☆☆☆☆ Poor |
| HNO₃ Oxidizing Acid | ★★★★★ High Cr | ★★★★☆ | ★★☆☆☆ Low Cr limit | ★★★☆☆ | ★★★☆☆ |
| Chloride SCC Resistance | ★★★★★ Excellent | ★★★★☆ | ★★★★★ Excellent | ★★★★☆ | ★☆☆☆☆ SCC failure risk |
| High-Temp Strength (>500°C) | ★★★★☆ | ★★★☆☆ | ★★★☆☆ | ★★★★★ Nb-strengthened | ★★☆☆☆ |
| Machinability (forged) | ★★★★☆ Good | ★★★★☆ | ★★★☆☆ | ★★★☆☆ | ★★★★★ Easiest |
| Relative Material Cost | $$$ Mid-high | $$$ Mid-high | $$$$ High (16% Mo) | $$$$ High (Nb) | $ Low |
| Best For | Phosphoric acid, NaOH, nuclear, sour gas | Phosphoric acid (budget) | Reducing acids, HCl, mixed acids | High-temp, seawater, fatigue | Mild environments, cost-sensitive |
★ Rating based on Jiangsu Liangyi's 25-year engineering experience and cross-application performance data from 50+ countries. Ratings are comparative within this alloy group.
Material Grade, Equivalent Specifications & Applicable Product Standards
Our 2.4643 (NiCr33Mo8) forging material strictly meets global mainstream material standards, and they are fully traceable from raw material to finished products. The equivalent grade specifications are as below:
- European Standard (EN/DIN): 2.4643, NiCr33Mo8
- Unified Numbering System (UNS):
- Common Trade Names: Alloy 35, Nickel Alloy 35
ASTM / ASME Product Form Standards for (2.4643 NiCr33Mo8)
When you source 2.4643 forged parts, it’s important to specify the correct product form standard in your purchase order. This is important for compliance audits, third-party inspections, and meeting regulatory requirements. Jiangsu Liangyi manufactures and tests these parts in line with all the following standards — note that ASME SB-series specifications are the ASME-approved equivalents of ASTM B-series specifications, and they are specifically used for pressure vessel and piping compliance under the ASME Boiler & Pressure Vessel Code (BPVC) and B31.3.
| Product Form | ASTM Standard | ASME Equivalent | Typical Application in 2.4643 Forgings |
|---|
| Forgings (all shapes) | ASTM B462 | ASME SB-462 | Flanges, fittings, valve bodies, rings, discs and pump casings |
| Rod & Bar (hot-finished) | ASTM B573 | ASME SB-573 | Shafts, drive spindles, bolting stock and machined valve stems |
| Seamless Pipe & Tube | ASTM B622 | ASME SB-622 | Heat exchanger tubes, reactor piping and pressure vessel nozzles |
| Plate, Sheet & Strip | ASTM B575 | ASME SB-575 | Tube sheets, baffle plates, saddle pads and liner plates |
| Welded Fittings | ASTM B366 | ASME SB-366 | Pipe elbows, tees and reducers for corrosive piping systems |
| Chemical Analysis | ASTM E8 / E38 / E1473 | ASME-referenced | Composition verification per MTC, incoming inspection |
All 2.4643 forged parts from Jiangsu Liangyi come with an EN 10204 3.1 Material Test Certificate (MTC) as standard. EN 10204 3.2 certificate with inspection by an accredited third party (such as SGS, BV, TÜV) is available per request. For nuclear and pressure vessel applications, we also offer ASME-code compliant documentation, including material certification letters.
Full Range of 2.4643 (NiCr33Mo8) Forging Products
We manufacture a full range of custom 2.4643 (NiCr33Mo8) forging products in all kinds of shapes and specifications, with single-piece weight capacity from 30kg to 30,000kg, maximum diameter up to 6 meters. Our main product lines fully cover the needs of global industrial clients, and you can explore our full forged product catalog for more details:
Forged Bars & Rotating Shafts
2.4643 forged steel round bars, square bars, flat bars, rectangular bars, hollow bars, step shafts, splined drive shafts, and turbine rotor shafts. The maximum forging diameter is up to 2 meters, the maximum length is up to 15 meters. We provide all parts with full mill test certificate (MTC) EN 10204 3.1 / 3.2.
Seamless Rolled Forged Rings
Custom NiCr33Mo8 seamless rolled rings, contoured forged rings, gear rings, flange blanks, and valve body rings. The maximum outer diameter is up to 6 meters, single-piece weight is up to 30 tons. They are the best choice material for high-pressure valve, pressure vessel, bearing, and rotating equipment applications, and all of them are provided with 100% ultrasonic testing (UT) before delivery.
Forged Hollow Parts& Pressure Parts
2.4643 (NiCr33Mo8) forged steel hubs, housings, shells, sleeves, bushes, casings, heavy-wall cylinders, seamless pipes, and tubings. Outer diameter capacity is up to 3000mm. They are used for reactor pressure vessels, heat exchangers, wellhead equipment, and high-pressure fluid handling applications.
Forged Discs, Plates & Block Forgings
NiCr33Mo8 forged discs, disks, blocks, plates, tube sheets, baffle plates, and flanged blanks. The maximum diameter is up to 3 meters, single-piece weight is up to 20 tons, They all meet ASTM, ASME and EN standards for pressure vessels, heat exchangers, valves, and turbomachinery applications.
Custom Forged Valve & Pump Parts
Complete line of 2.4643 forged valve parts including valve balls, valve bonnets, valve bodies, valve stems, valve closures, valve seat rings, valve cores, and valve discs for ball valves, check valves, gate valves, globe valves, butterfly valves, and cryogenic service valves. We also supply forged pump parts including pump casings, covers, barrels, impellers, shafts, housings, and wear rings. All of the parts meet international API 6D and API 6A dimensional standards.
Industry-Specific Custom Forged Parts
Custom 2.4643 (NiCr33Mo8) forged parts for oil and gas, nuclear power, chemical processing, and power generation industries, including drilling pipes, drill rods, drilling collars, drilling tools, risers, connectors, flanges, gaskets, reactor coolant pump parts, turbine parts, pressure vessel nozzles, venturi cone meter bodies, and others.
2.4643 (NiCr33Mo8) Forging Dimension Capability — Jiangsu Liangyi Full Spec Sheet
The following table consolidates our complete dimensional manufacturing envelope for 2.4643 (NiCr33Mo8) forged products. All dimensions are achievable as-forged before final machining. Finished (post-machining) tolerances depend on part complexity; our engineering team will review your drawing and confirm feasibility within 48 hours.
| Product Form | OD / Width / Diameter Range | Length / Height / Thickness | Single-Piece Weight | Dimensional Tolerance |
|---|
| Round / Flat / Hex Bar | Ø50 – Ø2,000 mm | L ≤ 15,000 mm | 30 – 20,000 kg | EN 10243 / ASTM B462 or per drawing |
| Seamless Rolled Ring | OD Ø200 – Ø6,000 mm | H 50 – 3,000 mm | 50 – 30,000 kg | ASTM B247 or per drawing |
| Disc / Cake Forging | Ø200 – Ø3,000 mm | T 30 – 800 mm | 30 – 20,000 kg | ASTM B462 or per drawing |
| Hollow / Cylinder / Sleeve | OD Ø200 – Ø3,000 mm | L ≤ 8,000 mm; Wall ≥ 30 mm | 50 – 25,000 kg | Per drawing, UT 100% |
| Block / Slab Forging | W ≤ 2,500 mm | L ≤ 6,000 mm; T ≤ 1,200 mm | 100 – 25,000 kg | EN / ASTM or per drawing |
| Step Shaft / Rotor | Max OD Ø1,500 mm | L ≤ 12,000 mm | 50 – 15,000 kg | IT7–IT9 as-forged; IT6 post-CNC |
| Valve / Pump Body (custom shape) | Max envelope 2,000×2,000×1,500 mm | Per 3D model | 30 – 10,000 kg | Per API 6A/6D dimensional standard or customer drawing |
All as-forged dimensions subject to standard forging tolerances. CNC finish machining achieves IT6 dimensional accuracy and Ra 0.8 μm surface finish. Drawing review and DFM (Design for Manufacturability) analysis provided free of charge for qualified projects.
Chemical Composition of 2.4643 (NiCr33Mo8) Forging Steel
Our 2.4643 (NiCr33Mo8) forging material is smelted with advanced AOD/VOD refining process, with strict composition control to ensure material performance consistency. The precise chemical composition range is as below:
| Element | Content Range (Weight %) | Element | Content Range (Weight %) |
|---|
| Nickel (Ni) | 51.1 - 60.2 | Silicon (Si) | 0 - 0.6 |
| Chromium (Cr) | 32.3 - 34.3 | Tungsten (W) | 0 - 0.6 |
| Molybdenum (Mo) | 7.6 - 9.0 | Manganese (Mn) | 0 - 0.5 |
| Iron (Fe) | 0 - 2.0 | Aluminum (Al) | 0 - 0.4 |
| Cobalt (Co) | 0 - 1.0 | Copper (Cu) | 0 - 0.3 |
| Carbon (C) | 0 - 0.050 | Vanadium (V) | 0 - 0.2 |
| Phosphorus (P) | 0 - 0.030 | Sulfur (S) | 0 - 0.015 |
Mechanical Properties of 2.4643 (NiCr33Mo8) Forged Parts
All our 2.4643 forged parts is given strict solution heat treatment and mechanical property testing in our in-house laboratory, with delivery condition performance meeting and exceeding international standards. The main mechanical properties are as below:
| Mechanical Property | Standard Minimum Value | Typical Test Value |
|---|
| Tensile Strength (Rm) | 750 MPa | 760 MPa |
| Yield Strength (Rp0.2) | 310 MPa | 317 MPa |
| Elongation (A5) | 40% | 66% |
| Hardness (HB) | 140-220 HB (solution treated condition) |
Physical Properties of 2.4643 (NiCr33Mo8) — Engineering Reference Data
Physical properties govern thermal management, sealing design, and structural behavior in service. The following values apply to 2.4643 (NiCr33Mo8) in the solution-annealed condition. These figures are particularly critical for engineers designing heat exchangers (thermal conductivity, expansion coefficient) and pressure vessels (elastic modulus, density-based weight calculations):
| Physical Property | Value at 20°C | Value at 200°C | Value at 400°C | Unit |
|---|
| Density (ρ) | 8.10 | — | — | g/cm³ |
| Melting Range | 1,330 – 1,380°C (liquidus/solidus band) | °C |
| Thermal Conductivity (λ) | 11.5 | 14.2 | 17.8 | W/(m·K) |
| Coefficient of Thermal Expansion (α) | 12.1 (20–100°C) | 12.8 (20–200°C) | 13.5 (20–400°C) | × 10⁻⁶ /K |
| Specific Heat Capacity (Cp) | 430 | 455 | 490 | J/(kg·K) |
| Electrical Resistivity (ρₑ) | 1.18 | 1.22 | 1.27 | μΩ·m |
| Elastic Modulus (E) | 210 | 195 | 180 | GPa |
| Magnetic Permeability (μᵣ) | ≤ 1.01 (essentially non-magnetic) | — |
Physical property values represent typical midpoint figures for solution-annealed 2.4643 forgings. Density and expansion coefficient should be used for engineering calculations; confirm with our technical datasheet for design-critical applications.
Elevated Temperature Mechanical Properties of 2.4643 (NiCr33Mo8) Forgings
Unlike austenitic stainless steels, which lose tensile strength sharply when the temperature goes above 400°C,2.4643 (NiCr33Mo8)keeps useful mechanical properties even up to 650°C. This is a main advantage when choosing materials for reactor pump casings, turbine valve bodies, and high-pressure steam equipment. The data below shows the typical minimum performance of solution-treated and water-quenched forgings produced by Jiangsu Liangyi, which meets the requirements of EN 10302 elevated temperature data.
| Test Temperature | Tensile Strength Rm (MPa) | 0.2% Proof Strength Rp0.2 (MPa) | Elongation A5 (%) | Reduction of Area Z (%) |
|---|
| RT (20°C) | ≥750 (min) / 760 typical | ≥310 (min) / 317 typical | ≥40 (min) / 66 typical | ≥45% |
| 100°C | ≥720 | ≥280 | ≥42 | ≥45% |
| 200°C | ≥680 | ≥235 | ≥40 | ≥43% |
| 300°C | ≥655 | ≥220 | ≥38 | ≥42% |
| 400°C | ≥640 | ≥210 | ≥36 | ≥40% |
| 500°C | ≥605 | ≥196 | ≥34 | ≥38% |
| 600°C | ≥578 | ≥185 | ≥32 | ≥36% |
| 650°C | ≥550 | ≥175 | ≥30 | ≥34% |
Elevated temperature mechanical properties represent typical minimum values for solution-annealed 2.4643 forgings per EN 10302 test methodology. Actual values may exceed these figures. Contact Jiangsu Liangyi for certified elevated-temperature test reports on specific heat lots.
Global Industrial Applications & Project Case Studies
Our 2.4643 (NiCr33Mo8) forging parts have been widely used in important projects across more than 50 countries in Europe, North America, the Middle East, Southeast Asia, and Australia, with proven long-term stable performance in harsh corrosive environments. Below are our core industry application cases:
Fertilizer & Wet Process Phosphoric Acid Industry
We have supplied over 3000 tons of 2.4643 (NiCr33Mo8) forged reactor nozzles, heat exchanger tube sheets, baffle plates, piping shells, and valve parts for 8 large-scale wet process phosphoric acid production plants in Thailand, Vietnam, and Malaysia. The material has excellent corrosion resistance in 85°C concentrated phosphoric acid with fluoride impurities, getting 2 times longer lifetime than G-30 alloy and significantly reducing unplanned shutdown and maintenance costs for our clients.
Nuclear Power Generation Industry
We provided custom NiCr33Mo8 forged casing shells, rotor impellers, containment seal chambers, and valve parts for reactor coolant pumps in 3 nuclear power plants in East Asia and Southeast Asia. Our 2.4643 forgings meet the strictest nuclear safety standards, with reliable structural stability, radiation resistance, and corrosion resistance in high-temperature, high-pressure long-term continuous operation.And they all meet ASME nuclear grade material requirements.
Onshore & Offshore Oil & Gas Industry
We delivered 2.4643 forged downhole drilling tools, mud motor splined drive shafts, electric submersible pump (ESP) parts, wellhead equipment (casing heads, tubing hangers, casing spools), valve bodies, double studded adapter flanges, and riser connectors for big onshore and offshore sour oilfield projects in Saudi Arabia, UAE, and Kuwait. The alloy has excellent resistance to chloride stress corrosion cracking and sour service corrosion, so that it is the best choice material for harsh downhole environments.And it fully meet NACE MR0175 standard.
Petrochemical & Chemical Processing Industry
We manufactured NiCr33Mo8 forged valve balls, stems, seat rings, bonnets, venturi cone meter bodies, and reactor parts for 12 petrochemical and fine chemical plants in Germany, Italy, and the United States. Our 2.4643 forgings withstand aggressive oxidizing acids, reducing acids, and hot sodium hydroxide environments, with great resistance to dealloying corrosion compared to other conventional nickel-chromium-molybdenum alloys,making sure they can work stably in important chemical processing systems.
Power Generation and Turbomachinery Industry
We supplied 2.4643 forged main steam valve seats, cores, sleeves, bonnets, gas and steam turbine parts, and centrifugal compressor impellers for 15 thermal power plants and combined-cycle power stations across China, Indonesia, and Pakistan. The material keeps stable mechanical properties at elevated temperatures up to 650°C, so that they can work reliably in high-pressure steam and extreme working conditions for rotating and static equipment.
Advanced Manufacturing Process & In-House Facility
Our company covers 80,000 ㎡ in Jiangyin, Jiangsu, China, and we have full production lines from steel melting to final inspection, guaranteeing full control over every production step of 2.4643 (NiCr33Mo8) forgings. Our main manufacturing process and equipment are as below:
Advanced Smelting Process
Our 2.4643 (NiCr33Mo8) material is smelted with advanced refining processes to guarantee ultra-low impurity content and uniform composition, including:
- 30t Electric Arc Furnace (EAF) + Ladle Refining Furnace (LF) + Vacuum Degassing (VOD)
- Induction furnace vacuum melting + Electro-Slag Remelting (ESR) for high-demand nuclear and aerospace applications
- Argon-Oxygen Decarburization (AOD) refining method for ultra-low carbon control
Forging & Heat Treatment Equipment
Our forging workshop is equipped with 2000T/4000T/6300T hydraulic forging presses, 1T/3T/5T electro-hydraulic forging hammers, 1-5 meter seamless ring rolling machines, and more than 10 heat treatment furnaces. We can get 30%+ forging ratio for all 2.4643 forgings, guarantee compact internal matrix and excellent mechanical properties, with no internal porosity, shrinkage, or other defects.
Precision Machining Capability
We provide a full range of CNC machining service for 2.4643 forgings, such as CNC lathes, milling machines, machining centers, and grinding machines, so we can get dimensional tolerance up to IT6 level, surface finish up to Ra 0.8μm,fully meeting the precision requirements of valve, pump, and rotating equipment parts.
Welding, Post-Weld Heat Treatment & Machining Guidelines for 2.4643 (NiCr33Mo8) Forgings
Correct welding and machining practice is important to preserving the corrosion resistance and mechanical integrity of 2.4643 (NiCr33Mo8) forgings in service. Based on Jiangsu Liangyi's more than 25 years of fabrication feedback from clients across more than 50 countries, the following practical guidelines reflect best-in-class field performance:
GTAW / TIG (preferred): ERNiCrMo-3 (AWS A5.14) — provides closely matched composition; suitable for all groove welding and root passes.
GMAW / MIG: ERNiCrMo-3 wire — lower heat input variant; verify shielding gas mixture (Ar + 2–5% He recommended for better arc stability on thick sections).
SMAW / Stick: ENiCrMo-3 electrode for field repair welds; inter-run cleaning mandatory to avoid slag inclusion in corrosive service.
Important: Do NOT use carbon steel or austenitic SS filler; galvanic incompatibility accelerates localized corrosion at the weld toe in phosphoric acid service.
Preheat: None needed for section thickness <25 mm. For wall thickness >25 mm in ambient temperatures below 10°C, heat it to 50–80°C to get rid of surface moisture and reduce hydrogen risk.
Interpass temperature limit: <150°C — exceeding this threshold promotes sigma-phase precipitation in the heat-affected zone (HAZ), which degrades both toughness and corrosion resistance irreversibly.
Heat input control: Target 0.5–1.5 kJ/mm; avoid weave beads wider than 3× electrode diameter. Stringer bead technique preferred for HAZ grain control.
Standard PWHT for corrosion service: Full solution anneal at 1,150–1,175°C, minimum 30 minutes per 25 mm of section thickness, followed by rapid water quench (air cooling only acceptable for sections <3 mm).
Stress relief only (non-corrosive service): 850–900°C, 1–2 hours — acceptable where dimensional stability is the primary goal, but does NOT restore full corrosion performance.
Nuclear-grade PWHT: Must meet ASME Section III NB/NC/ND requirements; witness by AI (Authorized Inspector) mandatory; Jiangsu Liangyi can coordinate full ASME N-stamp sub-supplier documentation.
Cutting speed: 25–55 m/min (carbide inserts, CVD-coated preferred; avoid HSS tooling which work-hardens the surface).
Feed rate: 0.10–0.25 mm/rev for turning; 0.05–0.15 mm/tooth for milling. Aggressive feeds prevent rubbing-induced work hardening.
Depth of cut: Minimum 0.5 mm per pass to cut below the prior work-hardened layer; shallow "skimming" passes accelerate tool wear and surface deformation.
Coolant: Water-soluble emulsion at >80 bar flood pressure; high-pressure through-tool coolant mandatory for deep-hole drilling (>5×D). Dry machining is not acceptable for 2.4643.
2.4643 (NiCr33Mo8) Heat Treatment Regime Decision Matrix — Application-Specific Guide
Choosing the right heat treatment method for 2.4643 (NiCr33Mo8)forgings isn’t a one-size-fits-all choice. The method you need depends on how corrosive the medium is, how thick the part’s wall is, the type of weld joint, and whether you prioritize post-weld dimensional stability or full corrosion performance. Jiangsu Liangyi’s metallurgical team has put together the following decision matrix based on over 25 years of feedback from customer applications — this guidance is only for our engineering practice and isn’t found in any public alloy datasheets.
| Application Scenario | Recommended Regime | Temperature / Time | Cooling Method | Corrosion Performance After Treatment |
|---|
| Wet H₃PO₄ plant (primary service) | Full Solution Anneal ✓ | 1,150–1,175°C, 30 min/25 mm | Rapid water quench (<30 s to <400°C) | Maximum. Cr-rich passive film fully regenerated; corrosion rate <0.05 mm/yr in 85°C H₃PO₄ |
| Sour oil & gas (NACE MR0175 service) | Full Solution Anneal ✓ | 1,140–1,175°C, 30 min/25 mm | Water quench (mandatory for NACE compliance) | Maximum SCC resistance; HAZ sensitization zones eliminated |
| Nuclear reactor components (ASME Sec. III) | Full Solution Anneal + AI Witness ✓ | 1,150–1,175°C, per ASME NB/NC/ND | Water quench; cooling curve chart retained | Full property recovery; 100% traceability documentation for nuclear QA record |
| Non-corrosive structural service (dimensional-critical) | Stress Relief Only ⚠ | 850–900°C, 1–2 h | Air cool (slow furnace cool acceptable) | Reduces residual stress >60%; does NOT restore full corrosion performance — only acceptable in non-corrosive environments |
| Post-weld repair (in-situ field weld) | Local PWHT (if full anneal impractical) ⚠ | 900–950°C, 2–4 h, 300 mm band each side of weld | Controlled cool at <100°C/h to 300°C then air | Partial recovery only; acceptable for mechanical sealing surfaces; NOT recommended for primary corrosive fluid contact zones |
| Sensitization recovery (accidental overheating during fabrication) | Do NOT Stress Relieve — Must Full Anneal ✗ | Re-solution at 1,150°C minimum | Full water quench mandatory | Stress relief alone will not reverse Cr-carbide precipitation at grain boundaries. Component must be fully re-annealed or rejected |
⚠ This heat treatment decision matrix shows the special application engineering guidance from Jiangsu Liangyi. EN 10302 and ASTM B462 set the minimum requirements for solution annealing. The situations above go beyond the standard specifications, based on the feedback we got from actual use. For safety-critical parts, you should always check with your authorized materials engineer.
🔴 5 Critical Material Selection Failures in Phosphoric Acid & Chemical Processing — Why Projects Choose 2.4643 After Costly Mistakes
Jiangsu Liangyi's technical service team has found that there are repeated mistakes in choosing the right alloy for wet process phosphoric acid plants, caustic soda units, and chemical processing facilities around the world. The following five failure situations are based on real customer requests for part replacements we received between 2018 and 2025. These are the most common root causes that lead to emergency re-selection of the 2.4643 (NiCr33Mo8).. Understanding these failures will help engineers choose the correct alloy during the design phase — which avoids expensive unplanned factory shutdowns and part replacements.
① 316L SS Pitting Failure in Wet H₃PO₄
Root cause: 316L stainless steel (with a PREN of about 24) is basically not suitable for use in phosphoric acid that contains fluoride ions when the temperature is above 60°C. Fluoride ions will specifically attack the passive Cr₂O₃ film on the surface of the steel, causing pitting corrosion to start within a few weeks after the equipment is put into use. The typical time until failure is 3 to 18 months. This problem is often seen in reaction vessel nozzles, pump casings and heat exchanger tube sheets in SEA fertilizer plants.
2.4643 (NiCr33Mo8) with PREN ~61 and 33% Cr provides durable passive film stability in HF-contaminated phosphoric acid; documented service life >8 years at same plants.
② Hastelloy C-276 Dealloying in Hot Caustic Soda
Root cause: C-276 alloy has a high molybdenum (Mo) content of 16%, which makes it easy to have selective molybdenum dissolution (dealloying) when used in NaOH (sodium hydroxide) solutions at temperatures above 80°C. This failure mode is not often mentioned in vendor datasheets. The parts affected include valve bodies and pump casings in caustic soda concentration units. The sign of this failure is that the parts suddenly lose their mechanical strength, and there is no visible damage on the surface before they break.
2.4643's balanced Cr/Mo ratio (33% Cr, 8.3% Mo) uniquely resists NaOH dealloying. No confirmed dealloying failures documented in Liangyi's NiCr33Mo8 reference installations in hot alkali service.
③ G-30 Alloy Premature Wear in HF-Rich H₃PO₄
Root cause: G-30 alloy (with 30% Cr and 5.5% Mo, and a PREN of about 48) works well in clean phosphoric acid. But when the HF (hydrofluoric acid) impurity content is more than 0.5 wt%, it is not as good as before. Its lower molybdenum content means it can’t protect against reducing acids well enough. In the same plant production process, its measured corrosion rate is 3 to 5 times higher than that of 2.4643 alloy.
Switching to 2.4643 (NiCr33Mo8) reduced corrosion rate by 55% in documented SEA plant upgrade case, extending maintenance interval from 24 months to >60 months.
④ Stress Corrosion Cracking in 904L Pump Shafts
Root cause: 904L (UNS N08904), though promoted as a "high-alloy" stainless steel, doesn’t have enough nickel content (around 25%) to reliably resist stress corrosion cracking (SCC) in brine containing hydrogen sulfide (H₂S) when the temperature is above 80°C. In offshore applications where 904L was incorrectly used as a substitute for nickel alloy, stress corrosion cracking failures of pump shafts were seen within 6 months.
2.4643 with >51% Ni base and NACE MR0175 compliance provides true SCC immunity in Cl⁻ + H₂S environments. Full nickel alloy — not a stainless steel substitute.
⑤ Alloy 625 Sensitization After Field Weld Repair
Root cause: Alloy 625 (UNS N06625) is prone to sensitization (δ-phase precipitation) in the heat-affected zone if it is welded without proper Post-Weld Heat Treatment (PWHT) in harsh corrosive environments. For example, in a refinery in the MENA region, a field repair weld was done on an Alloy 625 flange ring, but no full solution annealing was performed afterward. This led to intergranular corrosion failure within 4 months in an acidic gas environment containing hydrogen sulfide (H₂S) and carbon dioxide (CO₂).
2.4643 has lower susceptibility to HAZ sensitization vs. Nb-bearing Alloy 625, and its PWHT requirements are less demanding — full solution anneal at 1,150°C restores complete corrosion resistance. Liangyi provides pre-fabrication PWHT windows and certified heat treatment records with every delivery.
Full Material Traceability Chain: From Ingot to Delivered Forging — Jiangsu Liangyi's Heat Code Control System
For important service applications in oil and gas, nuclear, and chemical industries, full material traceability is not optional — it is a contractual and regulatory requirement. Jiangsu Liangyi operates a 7-stage heat code traceability system that provides unbroken documentation from raw nickel ingot to final delivered 2.4643 (NiCr33Mo8) forging, guaranteeing zero possibility of material mix-up or identity loss throughout the production chain:
Raw Nickel Ingot ReceiptMill cert + spectrometry verification
EAF/AOD/VOD SmeltingHeat number assigned; ladle cert generated
Ingot Casting & MarkingHeat # stamped on each ingot; weight recorded
Forging & Ring RollingHeat # transferred to each forging by stamp/tag
Heat TreatmentFurnace chart + time/temp curve archived per heat
NDT & Lab TestingUT/PT reports + mechanical/chemical test certs issued
Shipping & MTC IssueEN 10204 3.1/3.2 MTC with heat # cross-referenced to all test records
Every 2.4643 forging delivered by Jiangsu Liangyi carries a unique heat number that cross-references: (1) raw material certificate, (2) smelting record, (3) forging process log, (4) heat treatment chart, (5) NDT reports, (6) mechanical test results, (7) dimensional inspection record. Third-party witness by SGS, BV, or TÜV Rheinland can be arranged at any stage upon request. This traceability chain fully satisfies the requirements of API Q1, ISO 9001:2015, ASME NCA-3800, and nuclear grade QA programs.
Strict Quality Control System & Industry Certifications
Every batch of 2.4643 (NiCr33Mo8) forging parts is given full-process quality inspection from raw material incoming to finished product delivery, with 100% traceability for every production step. Our core inspection standards and certifications are as below:
Full-Process Quality Inspection
Raw Material Inspection
Spectral analysis for chemical composition, ultrasonic testing for internal defects, ensuring raw material fully meets 2.4643 material standards before production.
Forging and Heat Treatment Inspection
Real-time forging temperature monitoring, forging ratio control, heat treatment temperature curve recording, post-heat treatment mechanical property testing (tensile strength, yield strength, elongation, hardness) and metallographic analysis.
Non-Destructive Testing (NDT)
100% ultrasonic testing (UT), magnetic particle testing (MT), penetrant testing (PT) as per client requirements and international standards, with radiographic testing (RT) available for high-demand applications.
Final Inspection
Full dimension test, surface finish inspection, marking and packaging inspection, making sure finished products fully meet drawing requirements before delivery.
International Inspection Standards
- ASTM Standards: ASTM E8, ASTM E38, ASTM E112, ASTM A370 and ASTM A388
- EN and ISO Standards: EN 10204, EN 10302, EN ISO 6892-1/2, EN ISO 148-1 and EN ISO 6506-1
- Industry Standards: API 6A, API 6D, ASME Section VIII and NACE MR0175
Core Certifications
- ISO 9001:2015 Quality Management System Certification
- Pressure Equipment Directive (PED) CE Certification
- NACE MR0175 Compliance for Sour Service
- EN 10204 3.1 / 3.2 Mill Test Certificate Available
Custom Forging Capability & Global Service
As a professional China-based forging manufacturer, we provide full custom forging solutions for 2.4643 (NiCr33Mo8) parts according to client drawings and technical requirements, with flexible production capacity for both one sample orders and large-volume mass production.
Full-Cycle Custom Service
- Free drawing evaluation and material selection technical support
- Prototype development and small-batch trial production
- Mass production with strict quality consistency control
- Full heat treatment, machining, testing, and surface treatment services
- Third-party inspection service supported (SGS, BV, TUV, etc.)
- Download MTC Sample upon request
Global Export & Delivery Service
We export our 2.4643 forging parts to more than 50 countries across Europe, North America, the Middle East, Southeast Asia, Australia, and South America, with professional export service including:
- Different delivery terms: FOB, CIF, EXW, DDP and DDU
- Fast delivery time: 15-30 days for standard products, 30-45 days for custom products
- Professional shipping and customs clearance service
- 24/7 technical support and after-sales service
Export Packaging, Shipping Documentation & Payment Terms
Jiangsu Liangyi's logistics team manages every detail of export packaging, documentation, and clearance to make sure your 2.4643 (NiCr33Mo8) forged parts arrive on time, in perfect condition, and fully compliant with your local import regulations. Our standard export protocol is as follows:
| Category | Standard Specification | Optional Upgrade / Remarks |
|---|
| Rust Prevention | Anti-rust oil coating + VCI (Vapor Corrosion Inhibitor) film wrapping on all machined surfaces | Hermetic vacuum packaging for offshore or extended storage (>6 months transit) |
| Outer Packaging | ISPM-15 fumigated wooden crates with foam/rubber cushion lining; steel banding for heavy pieces (>2,000 kg) | Open steel pallet + chain lashing for OOG (out-of-gauge) forgings >3,000 kg; flat-rack container arrangement |
| Marking & Labelling | Heat number, material grade (2.4643/NiCr33Mo8), weight, gross/net, PO number, and country of origin stamped or stenciled on each piece and crate | Color-coded marking per client's material management system; RFID tagging available |
| Shipping Documents | Commercial Invoice, Packing List, Bill of Lading, Certificate of Origin (CO), EN 10204 3.1 MTC | EN 10204 3.2 MTC (with SGS/BV/TÜV), Form A (GSP), FORM E (ASEAN FTA), MSDS, ATA Carnet for sample shipments |
| Shipping Mode | FCL / LCL sea freight to major global ports (LA, Rotterdam, Jeddah, Singapore, Sydney, etc.) | Air freight for urgent samples (<500 kg); DDP door delivery available for US, EU, UAE |
| Payment Terms | T/T (wire transfer): 30% deposit upon order confirmation, 70% against copy of B/L | L/C at sight (for orders >USD 50,000); Western Union for small sample orders; discuss installment terms for annual framework contracts |
All export shipments meet China Customs HS Code 7326.90 (other articles of iron or steel), or HS Code 7228.60 (other bars and rods) as applicable. Our customs team provides HS code confirmation and duty rate pre-estimation for your destination country upon request.
📋 Complete RFQ Specification Checklist for 2.4643 (NiCr33Mo8) Forging Orders — What to Include in Your Inquiry
To get an accurate quotation and avoid revision cycles, Jiangsu Liangyi recommends including the following information when submitting your 2.4643 (NiCr33Mo8) forging inquiry. Our sales engineering team will respond with a detailed technical and commercial proposal within 24 hours for inquiries providing all checklist items. Missing information may extend the response cycle — this checklist is designed to eliminate that delay:
🔩 Material Specification
- Material grade: 2.4643 / NiCr33Mo8 / (confirm which standard governs)
- Applicable material standard: EN 10302, ASTM B462, or proprietary spec
- Required MTC type: EN 10204 3.1 or 3.2
- Special chemistry restrictions (e.g., C ≤ 0.02%, Co ≤ 0.1% for nuclear)
- Delivery condition: solution annealed + water quenched (standard) or other
📐 Geometry & Dimensions
- Product form: bar / ring / disc / hollow / step shaft / custom shape
- Key dimensions: OD × ID × H (rings), Ø × L (bars), W × L × T (discs)
- As-forged or finish machined? (provide machining drawing if machined)
- Dimensional tolerances needed (standard per ASTM/EN or per drawing)
- Surface finish requirement (as-forged / shot-blasted / machined Ra value)
- 2D drawing or 3D model (STEP/IGES preferred)
⚙️ Mechanical & Testing Requirements
- Minimum mechanical properties needed (Rm, Rp0.2, A5, HB) — state if standard minimum is sufficient
- NDT requirements: UT class, PT/MT acceptance criteria, reference standard (ASTM A388, EN 10228-3)
- Impact testing needed? (temperature, Charpy V-notch energy minimum)
- Elevated temperature tensile testing needed?
- Third-party inspection needed? (SGS / BV / TÜV / Intertek / LRQA)
- Corrosion testing required? (ASTM G28 Method A/B, ASTM G48)
🚢 Commercial & Logistics
- Quantity and unit (pieces / kg / sets)
- Required delivery date or project milestone
- Delivery terms: FOB Shanghai / CIF destination port / DDP destination
- Destination port or address (for freight pre-estimation)
- Preferred payment terms: T/T or L/C
- Is this a one-time purchase or blanket/annual order?
📁 Application Context (Optional but Helpful)
- Service medium / process fluid (e.g., 55% H₃PO₄ with HF, H₂S + CO₂ sour gas)
- Operating temperature and pressure
- Applicable industry standard (ASME VIII, NACE MR0175, API 6A/6D as design reference)
- End-user name (for EPC project tracking and previous supply history)
- Previous material used and reason for changing to 2.4643
🏭 What We Return to You (Within 24 h)
- Unit price and total commercial offer (USD, FOB Shanghai basis)
- Confirmed production lead time with milestone schedule
- Technical feasibility memo (weight estimate, forge-ability assessment)
- Applicable certifications confirmation
- Sample MTC from a previous similar heat (on request)
📩
Send your inquiry to: sales@jnmtforgedparts.com or WhatsApp
+86-135-8506-7993. Attach drawings in any format (PDF, DWG, STEP, DXF). Our engineering team responds in English, and quotes are valid for 30 days from issue date.
Frequently Asked Questions (FAQ) About 2.4643 (NiCr33Mo8) Forgings
What is 2.4643 (NiCr33Mo8) alloy equivalent grade?
2.4643 alloy is also known as NiCr33Mo8 under European DIN/EN standards, with its equivalent UNS number being , and it is also commonly referred to as Alloy 35 or Nickel Alloy 35 in the global market.
What are the main advantages of 2.4643 alloy over G30 alloy?
2.4643 alloy has great corrosion resistance in wet process phosphoric acid with fluoride impurities, with 2 times longer lifetime than G-30 alloy. It also has better resistance to dealloying corrosion in hot sodium hydroxide environments, and more stable mechanical properties at elevated temperatures. So that is more cost-effective for long-term harsh service.
Can you produce custom 2.4643 forgings according to our drawings?
Yes, we specialize in custom open die forging of 2.4643 (NiCr33Mo8) parts according to client's 2D/3D drawings and technical requirements. We can produce custom parts with single-piece weight from 30kg to 30,000kg, maximum diameter up to 6 meters, with full CNC machining and testing services.
Is 2.4643 alloy resistant to chloride stress corrosion cracking?
Yes, 2.4643 (NiCr33Mo8) has excellent resistance to chloride stress corrosion cracking (SCC) and localized corrosion (pitting, crevice corrosion) in high-chloride media, which is far superior to conventional austenitic stainless steel. It fully meets NACE MR0175 standard for sour oil and gas service.
What is the delivery time for custom 2.4643 forging parts?
For standard 2.4643 forged bars and rings, the delivery time is 15-30 days. For custom parts with machining and testing requirements, the delivery time is 30-45 days, which can be adjusted according to your project schedule.
Do you provide EN 10204 3.2 MTC for 2.4643 forgings?
Yes, we provide EN 10204 3.1 mill test certificate for all 2.4643 forgings by default, and EN 10204 3.2 certificate with third-party inspection (SGS, BV, TUV, etc.) is available upon client's request.
What is the difference between 2.4643 (NiCr33Mo8) and Hastelloy C-276 (2.4819)?
The two alloys have different corrosion resistance properties. Hastelloy C-276 (2.4819)contains about 16% molybdenum and 16% chromium, which makes it perform well in strongly reducing acids like hydrochloric acid (HCl) and dilute sulfuric acid (H₂SO₄). However, its lower chromium content limits its performance in oxidizing environments such as nitric acid — and importantly, C-276 is prone to dealloying corrosion in hot sodium hydroxide (NaOH),a well-documented failure mode. 2.4643 (NiCr33Mo8) , which contains about 33% chromium, performs better than C-276 in all oxidizing acid environments, including wet-process phosphoric acid containing hydrofluoric acid (HF). It is also uniquely suitable for use in hot alkali environments. For most fertilizer, nuclear, and mixed oxidizing acid environments, 2.4643 is the best choice material in engineering and is more cost-effective. If you provide us with your specific process conditions, our team will offer a free comparative analysis of corrosion rates.
Can 2.4643 (NiCr33Mo8) forgings be used in ASME pressure vessel applications?
Yes. 2.4643 forgings are produced based on ASTM B462 / ASME SB-462 ,and they fully meet the pressure vessel design requirements of ASME Boiler and Pressure Vessel Code (BPVC) Section VIII Division 1 and Division 2. The allowable stress values (S-values) are listed in ASME BPVC Section II Part D — please confirm the applicable maximum design temperature with your Code Calculations team. Jiangsu Liangyi provides ASME material compliance documentation, including certified material test reports and chemical/mechanical conformance letters, to support your pressure vessel U-stamp or CE PED certification. For nuclear Class 1, 2, or 3 parts, we also meet the material documentation requirements of ASME Section III NCA/NB/NC.
What NDT (non-destructive testing) methods are applied to 2.4643 forgings at Jiangsu Liangyi?
Jiangsu Liangyi implements a comprehensive, multi-method Non-Destructive Testing (NDT) program for all 2.4643 (NiCr33Mo8) forgings. The program is customized according to the product form, wall thickness, and the criticality of its application. Our standard NDT scope includes the following: 100% Ultrasonic Testing (UT) in accordance with ASTM A388 or EN 10228-3 for all forgings with a section size greater than 50 mm, which can detect internal defects as small as 2 mm diameter flat-bottomed holes (FBH); Liquid Penetrant Testing (PT) in accordance with ASTM E165 or EN 10228-2 for all machined surfaces; Magnetic Particle Testing (MT) is not suitable for this alloy because it is non-magnetic (relative permeability μᵣ ≤ 1.01). For high-criticality applications such as nuclear reactor components or subsea wellhead equipment, we also provide Radiographic Testing (RT) in accordance with ASTM E94 and Eddy Current Testing (ET) for tube and bar products. All NDT work is carried out by our Level II and Level III certified technicians, and test reports are issued in line with the project specifications required by the client.
What is the minimum order quantity (MOQ) for 2.4643 forging parts?
Jiangsu Liangyi has a flexible MOQ policy for 2.4643 (NiCr33Mo8) forgings. For standard shapes such as bars, rings, and discs, the minimum order quantity is1 piece for prototype and R&D needs — we do not set minimum weight or value requirements for engineering samples. For volume production orders, we recommend a minimum of500 kg per heat / per specification. This ensures optimal smelting batch efficiency and better cost-per-kilogram performance. We also offer annual framework contracts (blanket purchase orders) for clients with recurring demand. These contracts provide priority scheduling, price locking, and reserved production capacity. Please contact our sales team to discuss your project’s volume and demand forecast.
How should 2.4643 (NiCr33Mo8) forged components be stored and handled on-site?
Proper on-site storage is essential to keep the surface integrity and corrosion resistance of 2.4643 forgings before installation. Below are the main guidelines:
(1)Store the forgings indoors in a dry, covered environment. Avoid direct contact with carbon steel racks or the floor — use rubber-lined or wooden support cradles to prevent iron contamination on the nickel alloy surface.
(2)Do not remove the VCI (Volatile Corrosion Inhibitor) packaging or anti-rust oil until right before installation or final machining.
(3)If the component surface is contaminated with carbon steel particles (iron transfer), restore its passivation by pickling it in a solution consisting of 15–20% nitric acid (HNO₃) and 1–3% hydrofluoric acid (HF) at 50°C for 10–30 minutes. After pickling, rinse thoroughly with water and dry it. Alternatively, contact Jiangsu Liangyi's after-sales team for guidance on surface restoration.
(4)Lifting precautions: Use nylon sling straps instead of bare wire ropes to avoid scratching the surface or damaging the precision-machined bores.