1.3964 (X2CrNiMnMoNNb21-16-5-3) Forging Parts | Custom Stainless Steel Forgings from Jiangyin Jiangsu China

Jiangsu Liangyi Co., Limited is a vertically integrated ISO 9001:2015 certified 1.3964 forging parts manufacturer with 25+ years of uninterrupted production experience in Chengchang Industry Park, Jiangyin, Jiangsu, China. We are one of the very few facilities in China that controls every step of the X2CrNiMnMoNNb21-16-5-3 forging supply chain in-house: from EAF/LF/VOD melting and optional ESR remelting, through open die forging on 2000–6300 ton hydraulic presses, seamless ring rolling on 1–5 meter CNC mills, precision CNC machining (±0.05mm), heat treatment with ±5°C furnace accuracy, and full NDT — all within our 80,000 ㎡ Jiangsu facility. Single-piece weights range from 30 kg to 30,000 kg. Annual capacity reaches 120,000 tons. We export to 50+ countries with EN 10204 3.1/3.2 Mill Test Certificates, and have delivered 1.3964 stainless steel forgings to nuclear power, oil & gas, offshore, marine, turbomachinery, valve manufacturing, and chemical process customers across Europe, North America, Asia-Pacific, and the Middle East.

What Makes 1.3964 (X2CrNiMnMoNNb21-16-5-3) Different: A Metallurgical Engineering Perspective

1.3964, designated X2CrNiMnMoNNb21-16-5-3 under EN 10088-3, belongs to a specialized class of high-nitrogen austenitic stainless steels that exploit a "dual-hardening" mechanism unavailable in conventional 300-series alloys. Understanding this mechanism is essential for engineers making material selection decisions — and it is why Jiangsu Liangyi's Jiangsu factory applies stricter process controls for this alloy than for any other stainless steel in our portfolio.

The Nitrogen + Niobium Synergy: How 1.3964 Achieves Twice the Yield Strength of 316L

In conventional 316L, strengthening is limited to solid-solution hardening from Mo and Ni, and the resulting yield strength plateaus at around 170 MPa. In 1.3964 (X2CrNiMnMoNNb21-16-5-3), two separate mechanisms operate simultaneously: (1) Nitrogen (N at 0.20–0.35 wt%) pins mobile dislocations through interstitial solid-solution strengthening — nitrogen atoms occupy octahedral sites in the FCC lattice, creating asymmetric stress fields that impede dislocation glide far more effectively than substitutional atoms like Mo or Mn. Each 0.1 wt% N addition contributes approximately 85–95 MPa to yield strength in austenite. (2) Niobium (Nb up to 0.25 wt%) precipitates fine NbC and NbN particles along grain boundaries and within grains during controlled cooling after forging, providing a secondary precipitation-hardening contribution while simultaneously pinning austenite grain boundaries during hot working. The result: yield strength of ≥ 370 MPa (EN minimum) with Jiangsu Liangyi's factory-guaranteed ≥ 380 MPa — achieved entirely without cold work or aging, making the forging dimensionally stable under service conditions.

Manganese (4.00–6.00 wt%) serves a dual purpose that is often overlooked in standard datasheets: it expands the austenite phase field, which allows a higher nitrogen solubility limit in the melt (approximately 0.30 wt% at atmospheric pressure vs. only 0.06 wt% in Mn-free austenite). This is critical because Jiangsu Liangyi achieves the target N range of 0.25–0.30% without pressurized nitrogen gas injection — a simpler and more reproducible process than some competing methods. Mn also partially replaces Ni as an austenite stabilizer, reducing raw material cost while maintaining the fully austenitic (FCC) microstructure required for non-magnetic behavior and superior toughness.

Sigma Phase Risk: The Critical Temperature Window Every Engineer Must Know

One underappreciated risk with high-Cr, high-Mo austenitic grades is sigma (σ) phase precipitation, which occurs in the temperature range of approximately 650–950°C during slow cooling or prolonged exposure. Sigma phase is an Fe-Cr-Mo intermetallic compound that is both brittle and highly corrosion-susceptible; even 1–2 vol% precipitation can reduce impact toughness by 50% or more and dramatically lower PREN in the affected zones. In 1.3964 forgings, the elevated Cr (20.5–21.0%) and Mo (3.2–3.4%) content means the sigma nose on the TTT diagram is particularly prominent. Jiangsu Liangyi's solution: all 1.3964 forgings are water-quenched immediately from the annealing temperature (1065°C or 1121°C), bypassing the 650–950°C danger zone in under 3 minutes for forgings up to 300 mm section thickness. For very heavy sections (>400 mm), we use our high-flow-rate quench tank (water flow ≥ 800 L/min, inlet temperature maintained ≤ 40°C) to guarantee the cooling rate stays above the critical 2°C/s threshold throughout the cross-section. Every batch includes a post-quench sensitization check per ASTM A262 Practice E to confirm sigma-free structure before shipment.

Physical & Thermal Properties of 1.3964 Steel (Jiangsu Liangyi Reference Data)

The physical properties of 1.3964 (X2CrNiMnMoNNb21-16-5-3) are directly relevant to design calculations for pressure vessels, heat exchangers, and rotating machinery. The following values are based on our in-house measurements and cross-referenced with EN 10088-1 and published metallurgical literature for this alloy class:

The notably low magnetic permeability (≤ 1.005 at all temperatures and in deformed condition) makes 1.3964 forgings uniquely suitable for applications requiring non-magnetic structural components, such as nuclear instrumentation housings, MRI-related equipment frames, and electromagnetic flow meter bodies.

1.3964 Corrosion Resistance: PREN Calculation, Critical Pitting Temperature & SCC Performance

PREN ≥ 40: Calculation, Context, and What It Means in Practice

The Pitting Resistance Equivalent Number (PREN) is the single most widely referenced corrosion-screening parameter for stainless steels in chloride environments. The formula is:

PREN = %Cr + 3.3 × %Mo + 16 × %N

Using Jiangsu Liangyi's guaranteed composition midpoint (Cr = 20.75%, Mo = 3.30%, N = 0.275%), the calculated PREN = 20.75 + (3.3 × 3.30) + (16 × 0.275) = 20.75 + 10.89 + 4.40 = 36.0 minimum, typically 38–42 depending on actual heat chemistry. This significantly outperforms 316L (PREN ≈ 22–26) and is comparable to or better than 2205 duplex (PREN ≈ 33–38), while maintaining a fully austenitic — and therefore non-magnetic — microstructure.

The critical advantage of 1.3964 forgings over 2205 duplex in offshore and subsea applications is immunity to Hydrogen-Induced Stress Cracking (HISC). The fully austenitic microstructure of 1.3964 has no ferrite phase to act as a hydrogen diffusion pathway, making it the preferred choice for CP-protected subsea connectors and riser clamps where duplex requires design restrictions per DNV-RP-F112.

1.3964 (X2CrNiMnMoNNb21-16-5-3) Global Standards Cross-Reference Table

One of the most frequent challenges for procurement engineers is identifying the correct designation across different national and international standards. 1.3964 does not have a direct, identical equivalent in ASTM, UNS, or JIS — a fact that creates significant confusion and occasionally results in incorrect material substitutions. The table below reflects Jiangsu Liangyi's 25+ years of cross-standard sourcing and export experience:

Jiangsu Liangyi recommendation: For the order of 1.3964 forging parts  for EN projects always specify EN material number 1.3964 and specify that the MTC should explicitly list C, N and Nb analysis values. Specifications that merely specify “high-nitrogen austenitic stainless” or “XM-19 equivalent” without verifying Nb content risk accepting non-conforming material that can pass tensile testing but fail intergranular corrosion testing per ASTM A262.

Jiangsu Liangyi China — 1.3964 Forging Shapes & Full Dimensional Capability Matrix

Jiangsu Liangyi's Jiangyin production line manufactures 1.3964 (X2CrNiMnMoNNb21-16-5-3) forged parts across five primary product categories. Every product type is produced with a minimum forging ratio of 3:1 — our internal specification, stricter than the typical 2:1 minimum at many China forging facilities. The 3:1 minimum ensures complete break-up of the as-cast dendritic structure, closes micro-porosity, and aligns the austenite grain flow with the part geometry for maximum fatigue and fracture toughness.

1.3964 Forging Parts — Industry Applications: Engineering Reasons & Jiangsu Liangyi Case Studies

The following section goes beyond generic application lists to explain the specific engineering reasons why 1.3964 (X2CrNiMnMoNNb21-16-5-3) forged components are selected in each industry — and how Jiangsu Liangyi's Jiangsu factory has fulfilled these requirements for real customers. Design engineers, procurement teams, and project managers will find the technical context useful for material justification documentation.

1.3964 (X2CrNiMnMoNNb21-16-5-3) Chemical Composition — EN Standard vs. Jiangsu Liangyi Guaranteed Range

All 1.3964 forging parts produced at Jiangsu Liangyi's Jiangyin Jiangsu China factory are chemically analyzed by in-house OES (Optical Emission Spectrometer) and validated by wet chemistry for N and C before any forging begins. Each column below explains the engineering rationale for Jiangsu Liangyi's tighter control range:

1.3964 Forging Mechanical Properties — Delivery Condition (Solution Annealed + Water Quenched)

Jiangsu Liangyi supplies all 1.3964 (X2CrNiMnMoNNb21-16-5-3) forgings in the solution-annealed and water-quenched condition. Mechanical testing is performed on test coupons cut from the forging body — not from a separately forged test ring — per EN 10088-3 §8.5. All results are certified by Jiangsu Liangyi's laboratory; third-party witnessing by SGS/BV/TÜV available upon request:

Elevated-temperature note: At 300°C, 1.3964 Rp0.2 is approximately 270–290 MPa (vs. ~240 MPa for 316L at the same temperature), maintaining its strength advantage through the typical pressure vessel and heat exchanger operating range. Creep data at >400°C available from our engineering team on request.

Jiangsu Liangyi Jiangsu — 1.3964 Forging Manufacturing Process: The Details That Make the Difference

Most forging datasheets describe a generic process. Jiangsu Liangyi's engineering team shares the specific process parameters and decisions developed over 25+ years of producing 1.3964 (X2CrNiMnMoNNb21-16-5-3) forgings — knowledge that directly explains why our products consistently outperform competitors on mechanical testing and corrosion evaluation.

Step 1 — Melting & Nitrogen Control: The Hardest Part of 1.3964 Production

Achieving nitrogen content of 0.25–0.30 wt% reproducibly is the primary technical challenge in 1.3964 melting. In a standard EAF without atmosphere control, maximum soluble N in austenitic stainless melt is approximately 0.06–0.08 wt% at atmospheric pressure — far below target. Jiangsu Liangyi's approach uses a two-stage solution: (1) LF (Ladle Furnace) with nitrogen gas stirring — N₂ bubbles are injected through porous plugs at the ladle bottom under controlled partial pressure, progressively increasing N content to 0.20–0.25 wt% over 45–60 minutes. (2) VOD (Vacuum Oxygen Decarburization) at controlled pressure (150–300 mbar during N-addition phase), allowing additional N absorption while reducing C to ≤0.025%. The result: final N content controllable to ±0.02% of target, verified by inline OES sampling every 8 minutes during refining. For nuclear-grade orders requiring S ≤ 0.003%, an additional ESR (Electroslag Remelting) step further reduces S, O, and inclusion density by >50% compared to conventional melted material. Jiangsu Liangyi operates two ESR furnaces (300 kg and 5,000 kg capacity) dedicated to high-purity specialty forgings.

Step 2 — Ingot Homogenization: Critical for 1.3964 More Than Any Other Grade

Due to high Mn content (4.5–5.5%), 1.3964 ingots show pronounced Mn-rich dendritic segregation in the as-cast condition. Mn-enriched dendrite cores can contain locally up to 6.5% Mn — above the EN maximum — while inter-dendritic zones may fall below 4.5%, causing locally insufficient nitrogen solubility and micro-porosity. Jiangsu Liangyi's homogenization practice: 1,200–1,220°C for 8–16 hours (depending on ingot diameter), followed by slow furnace cool to 900°C before transfer to the forge press. This dedicated homogenization step — which many lower-cost suppliers skip — is non-negotiable in our 1.3964 process because it eliminates the segregation banding that otherwise causes scatter in mechanical test results across large forgings.

Step 3 — Hot Working Temperature Window: Why We Stop at 1,050°C

The hot working window for 1.3964 is narrower than for 316L. Upper limit: approximately 1,240°C — above this, austenite grain growth is rapid (grain size doubles every 10°C above 1,250°C in this alloy). Lower limit: approximately 1,050°C — below this, sigma phase precipitation risk rises sharply. Sigma nucleates at deformation shear bands within the austenite and is invisible to the forge operator, but detected as brittle zones in post-forging impact testing. Jiangsu Liangyi's process control response: all 1.3964 forging operations are monitored by infrared pyrometer with a 1,050°C interlock alarm. If surface temperature falls below 1,060°C, forging stops and the piece returns to the reheating furnace for a verified 20-minute soak at 1,150°C before resuming. Large rings and discs are reheated a maximum of 3 times; pieces requiring a 4th reheat undergo additional metallographic examination before release.

Step 4 — Seamless Ring Rolling: Managing High-N Steel Ductility

The hot ductility of high nitrogen steels at rolling temperatures is worse than that of common austenitic grades because of increased lattice friction stress due to interstitial N atoms. Too-rapid radial feed in ring rolling initiates surface cracking at OD or ID surfaces. Jiangsu Liangyi's ring rolling procedure for 1.3964 seamless rolled rings: controlled mandrel feed rate of 0.5–1.5 mm per revolution (30–50% slower than our 316L rate), continuous pyrometer monitoring, and a maximum rolling time of 18 minutes between reheats for rings larger than Ø1,500 mm. The slower feed rate also improves wall thickness uniformity — our OD tolerance after rolling is ±0.5% of nominal OD vs. the industry standard ±1.0%. Post-rolling, rings are leveled on a hydraulic press within 30 minutes to minimize ovality before solution annealing.

Step 5 — Solution Annealing & Quenching: Two Temperature Options Explained

Jiangsu Liangyi offers two standard annealing conditions for 1.3964 forgings:

• Option A — Standard: 1,065°C ± 10°C, hold 1 hour per 25mm section thickness, water quench to ≤50°C within 3 minutes. Meets EN 10088-3 minimum mechanical properties; produces ASTM grain size 5–7; balanced strength and toughness. Furnace atmosphere: slightly reducing (CO:CO₂ ≈ 0.02) to prevent surface Cr depletion.
• Option B — High Corrosion Resistance: 1,120°C ± 10°C, hold 1–2 hours, water quench. Higher temperature redissolves any residual sigma phase or carbides more completely, maximizing PREN. Results in ~10 MPa lower Rp0.2 than Option A. Recommended for chemical process and sea water immersion applications. Our quench tank: water flow ≥800 L/min, inlet water ≤40°C, and cooling rate >2°C/s even at heavy section cores >400 mm.

Step 6 — CNC Machining: Specific Challenges With 1.3964 and How Jiangsu Liangyi Handles Them

1.3964 is significantly more difficult to machine than 316L due to higher yield strength and work-hardening rate (approximately 1.8× that of 316L during cutting). Jiangsu Liangyi's CNC workshop has developed specific cutting parameters for this alloy: cutting speed 80–110 m/min (vs. 140–180 m/min for 316L), feed 0.20–0.35 mm/rev, TiCN-coated carbide inserts with 5° positive rake angle, continuous flood coolant at 8–10 bar. These parameters reduce tool consumption ~35% compared to standard speeds while achieving Ra 1.6 μm or better. Tight tolerances (bore H7, OD h6) are achievable in-house — no subcontracting of machining, which is a significant quality risk for traceability-critical forgings.

1.3964 Weldability Guide: Filler Selection, Procedure & Post-Weld Requirements

A key practical advantage of 1.3964 over duplex stainless steels is straightforward weldability: no preheat required, no PWHT required for most applications, and no phase balance concerns in the weld HAZ. The following table provides Jiangsu Liangyi engineering team guidance based on our experience qualifying WPS/WPQR for nuclear, offshore, and pressure vessel applications:

Jiangsu Liangyi Quality System — What "100% Inspection" Actually Means for 1.3964 Forgings

Incoming Raw Material Control

Before any 1.3964 heat is melted, every raw material charge component (ferro-chromium, ferro-manganese, ferro-molybdenum, pure Ni, Nb pellets, and base scrap) is sampled and analyzed by OES spectrometer. Charge materials failing Jiangsu Liangyi's trace element limits (Sn, Pb, As, Sb each ≤ 50 ppm) are rejected. This incoming control — which adds 4–6 hours to the pre-melt timeline and is skipped by many lower-cost Chinese suppliers — is the foundation of our superior final composition control.

Complete NDT Matrix for Every 1.3964 Forging

• Ultrasonic Testing (UT): 100% volumetric scan per ASTM A609 / EN 10228-3; acceptance to Level 3 (no relevant indications exceeding 50% of reference notch). Contact angle beam and immersion UT available for critical cross-sections. Jiangsu Liangyi's internal UT rejection rate for 1.3964 is <0.3% — one of the lowest for this alloy in China.
• Dye Penetrant Testing (PT): 100% of machined surfaces per ASTM E165 / EN 10228-2, Level 1 acceptance (no linear indications > 2 mm). Fluorescent PT available for nuclear components.
• Magnetic Particle Testing (MT): NOT applicable to 1.3964 (non-magnetic). Purchase orders requesting MT on 1.3964 are proactively flagged and corrected before production start — a common error Jiangsu Liangyi catches on multi-material orders.
• 100% Hardness Survey: Every piece measured on ≥ 3 locations per piece. Pieces exceeding HBW 280 are quarantined for investigation (indicative of incomplete solution annealing or localized sigma phase).
• 100% Dimensional Inspection: All important dimensions (bore diameter, OD, flange face flatness) measured using calibrated instruments traceable to NIST/NIM. CMM inspection of complicate profiles.

Certification & Traceability System

All 1.3964 stainless steel forgings  from Jiangsu Liangyi's Jiangsu China factory are supplied with Mill Test Certificate (MTC) EN 10204 3.1/3.2 with full Traceability from Raw Material Batch Number → Ingot Number → Forging Number → Heat Treatment Batch → Test Certificate → Piece Serial Number. Third-party inspection (SGS/BV/TÜV) is available on request. Each MTC includes: full chemical analysis (all 12 elements + trace elements on request), full mechanical test results, heat treatment record, NDT report numbers, dimensional inspection sign-off, and the authorizing inspector's name and stamp.

Total Cost of Ownership: Why 1.3964 Forgings Are Often More Economical Than 316L Over Equipment Lifecycle

The upfront material cost of 1.3964 forgings is 30–55% higher per kg than 316L. Here is why the lifecycle economics consistently favor 1.3964 in demanding service environments:

The economics are most favorable in marine, offshore, and chemical process environments where replacement and inspection access costs dominate the lifecycle cost model. Jiangsu Liangyi's engineering team is happy to assist customers build the business case for material upgrade from 316L to 1.3964 for specific applications — contact us with your service conditions and design parameters.

8-Point Buyer's Checklist: How to Specify & Verify 1.3964 Forging Parts from China

According to the experience of Jiangsu Liangyi to receive the purchase orders and quality non-conformances from global customers, the following eight specification points are the most neglected. Addressing them before placing the order can save you costly disputes and shipment delays:

Jiangsu Liangyi Jiangsu — Custom 1.3964 Forging Solutions: From Drawing to Delivery

 Jiangsu Liangyi, a fully integrated manufacturer of 1.3964 forging parts, is located in Jiangyin, Jiangsu, China and offers complete custom engineering support from the earliest design phase. We don’t just “manufacture to drawing” — we look at designs for forgeability, look for dimensions where requested tolerances require machining (rather than forging), and suggest forging shape optimizations that reduce machining cost without affecting function. This DFM (Design for Manufacturability) review is at no charge and typically results in 8-15% savings on the first order finished machining cost for customers.

Why Choose Jiangsu Liangyi as Your 1.3964 Forging Parts Manufacturer in China Jiangsu?

The China forging market offers many suppliers claiming capability for specialty grades like 1.3964 (X2CrNiMnMoNNb21-16-5-3). The ability to present a 1.3964 MTC does not mean a supplier truly controls the process. What genuinely differentiates Jiangsu Liangyi from most China-based competitors for this specific alloy:

• In-House LF/VOD + ESR Melting: Most Chinese forging suppliers purchase ingots from steel mills with no visibility or control over the melting process. Jiangsu Liangyi melts in-house, targeting N 0.25–0.30% with ±0.02% heat-to-heat consistency — the single most important factor for consistent yield strength and PREN in 1.3964.
• Documented Sigma Phase Controls: Our forging temperature floor of 1,050°C with infrared interlock, and our water quench protocol (800 L/min flow, ≤40°C water inlet) specifically address the sigma phase risk unique to this high-Cr, high-Mo alloy. Very few China suppliers have these documented controls.
• 25+ Years & Hundreds of 1.3964 Heats Produced: We are not learning on your order. We have dedicated forging parameters for every product shape in this alloy — developed through real production experience, not theoretical procedure.
• No Subcontracting Policy: 100% of operations (melting, forging, heat treatment, machining, NDT) performed within our Jiangyin facility. No raw material or semi-finished goods leave our site for external processing — the only way to guarantee true traceability.
• 120,000 Tons Annual Capacity, 80,000 ㎡ Facility: Production capacity for single prototype pieces through to annual supply programs of 5,000+ pieces without capacity conflicts.
• Factory Acceptance Testing (FAT) Support: Dedicated customer inspection room at our Jiangyin factory. Major international TPI agencies including SGS, Bureau Veritas (BV), and TÜV are welcome to conduct inspection; customers may also send their own authorized inspector. Advance scheduling is requested.
• Engineering-Level Technical Support: Our team includes metallurgical engineers who support material qualification documentation, PED compliance, ASME code data reports, and welding procedure qualification.
• Proven Track Record: References available from nuclear OEMs in China, offshore equipment manufacturers in Norway and UK, valve OEMs in USA, and turbomachinery OEMs in Germany and France — available under NDA on request.
• Competitive China Factory-Direct Pricing: No middleman; direct sales from our Jiangsu factory with transparent pricing and detailed cost breakdowns on request.
• On-Time Delivery: Lead time 15–45 days per order size; milestone tracking with customer portal access for large programs.

Frequently Asked Questions — 1.3964 (X2CrNiMnMoNNb21-16-5-3) Forging Parts

The following Q&A section addresses detailed technical and commercial questions that procurement engineers and design teams most frequently raise. For questions not covered here, contact our engineering team at sales@jnmtforgedparts.com — we respond within 24 hours.