1.4571 (X6CrNiMoTi17-12-2) Forging Parts | Complete Material & Manufacturing Guide | Jiangsu Liangyi
Product Overview & Key Performance Facts
Jiangsu Liangyi, an ISO 9001:2015 (opens in new tab) certified China manufacturer established in 1997, specializes in heavy-duty 1.4571 (X6CrNiMoTi17-12-2) open die forgings, seamless rolled rings, and precision-machined components. With 28+ years of experience, 120,000 tons annual capacity, and an 80,000 m² fully integrated facility, we supply certified 1.4571 forged parts to customers in 50+ countries — including major oil companies, global valve manufacturers, nuclear power operators, and leading European chemical engineering firms.
1.4571 is the European DIN EN designation (full name: X6CrNiMoTi17-12-2) for titanium-stabilized austenitic stainless steel. Its AISI equivalent is 316Ti (UNS S31635). It is alloyed with 16.5–18.5% chromium, 10.5–13.5% nickel, 2.0–2.5% molybdenum, and titanium ≥5×C% — the defining characteristic separating it from standard 316 and 316L.
(Oxidizing)
(Solution Annealed)
(Solution Annealed)
Temperature
The pitting resistance of 1.4571 is quantified by the Pitting Resistance Equivalent Number (PREN): PREN = %Cr + 3.3×%Mo + 16×%N. Using mid-specification values (Cr 17.5%, Mo 2.25%, N ~0.10%), 1.4571 yields PREN ≈ 26.5 — clearly outperforming 316L (PREN ~24) and substantially above 304 or 321 (PREN ~19–21). In practical terms, each additional PREN unit represents measurable improvement in resistance to localized pitting in chloride-containing media such as seawater, brine, and acidic process fluids.
1.4571 vs 316/316L: Six Performance Dimensions
| Index | 1.4571 (X6CrNiMoTi17-12-2) | 316/316L |
|---|---|---|
| Intergranular Corrosion (Post-Weld) | Excellent: Ti permanently binds C as TiC, preventing Cr₂₃C₆ grain-boundary precipitation | 316L uses low C (≤0.03%) to slow sensitization; offers no protection during prolonged service >400°C |
| High-Temp Structural Stability | Stable microstructure to 850°C; TiC precipitates thermally stable throughout service range | Sensitization risk above 450°C (316) / 550°C (316L) in sustained service; not EN 10302 listed |
| Creep & Rupture Strength | Covered by EN 10302 (Creep-Resisting Steels); tabulated design values to 700°C | Not listed in EN 10302; no certified creep design values above 550°C |
| PREN | ~26–27 (Cr17.5 + 3.3×Mo2.25 + 16×N0.1) | ~24 (316L); both carry similar Mo, but sensitized grain-boundary zones lose Cr below 12%, reducing local PREN to zero |
| Post-Weld Heat Treatment | Not required — Ti stabilization is permanent regardless of welding heat input | Not required for 316L welds, but prolonged high-temp service still sensitizes the HAZ over time |
| Applicable Standards | DIN EN 10088-3, EN 10302, ASTM A182 F316Ti; material compatible with PED 2014/68/EU and API 6A/6D component requirements | DIN EN 10088-3, ASTM A182 F316L — not covered by EN 10302 for creep design |
Explore our complete range of forged products and forging material grades.
Metallurgical Science: How Titanium Stabilization Eliminates Sensitization
Most material datasheets describe what 1.4571 does. This section explains why — the underlying metallurgy that makes titanium stabilization superior to low-carbon grades for high-temperature and welded applications.
The Sensitization Problem in Unstabilized Austenitic Steels
Austenitic stainless steels derive corrosion resistance from the passive chromium oxide (Cr₂O₃) film that forms when surface chromium concentration exceeds approximately 12 wt%. This film is self-healing in most environments. However, when an unstabilized grade such as 316 is exposed to temperatures between 425°C and 800°C — the “sensitization zone” — carbon dissolved in the austenite matrix migrates to grain boundaries and combines with chromium to form chromium carbides (Cr₂₃C₆). This consumes chromium from the grain-boundary-adjacent zone, creating chromium-depleted regions below 12 wt%. These depleted zones lose passive film protection and become vulnerable to preferential corrosive attack — the failure mode called intergranular corrosion (IGC) or “weld decay.”
This sensitization window is unavoidable in practice: weld heat-affected zones (HAZ) routinely pass through 425–800°C during multi-pass welding; process equipment operating at 450–700°C enters it in normal service; and even solution-annealed material can sensitize during slow cooling through this range. Any material that cannot chemically suppress Cr₂₃C₆ formation in this window carries a latent structural integrity risk.
🔬 Critical Engineering Insight: Sensitization Is Not Always Visible
Sensitized stainless steel components can appear visually identical to unsensitized ones — same surface finish, same color, same dimensional integrity. Failure by intergranular corrosion can be sudden and catastrophic in pressurized service. This is why material stabilization, not post-installation inspection, is the correct engineering control. Once 1.4571 with proper Ti/C ratio is forged and solution-annealed, its immunity to sensitization is permanent and unconditional throughout the service life.
How Titanium Permanently Solves Sensitization
1.4571 exploits a fundamental thermodynamic difference: titanium carbide (TiC) has a significantly more negative free energy of formation than chromium carbide (Cr₂₃C₆) at all temperatures relevant to forging and heat treatment. Titanium therefore preferentially combines with all available carbon in the melt and during solution annealing at 1050–1100°C — before chromium has any thermodynamic opportunity to form carbides. The DIN EN 10088-3 specification encodes this directly: Ti ≥5×C minimum, guaranteeing sufficient titanium to bond every carbon atom as TiC. Once bound at high temperature, TiC remains thermodynamically stable throughout the full service temperature range, including the 425–800°C sensitization zone. With zero free carbon available, Cr₂₃C₆ cannot form. Grain boundaries remain chromium-rich. The passive film remains intact.
Why Low Carbon (316L) Is an Incomplete Solution
316L reduces carbon to ≤0.03%, limiting the amount of Cr₂₃C₆ that can form during welding. This is sufficient for short-duration welds where HAZ exposure time above 425°C is brief. However, during sustained service at 400–600°C over months or years — typical in heat exchangers, reactor vessels, and power plant pipework — even the trace carbon in 316L will gradually migrate to grain boundaries and form enough Cr₂₃C₆ to measurably reduce corrosion resistance. 316L’s approach delays sensitization; 1.4571’s approach eliminates it. For long design-life equipment above 400°C in corrosive service, the distinction is the difference between a calculated risk and an engineering guarantee.
Complete Material Specifications: Chemical, Mechanical & Physical Properties
Chemical Composition — DIN EN 10088-3
| Element | Symbol | Content (wt%) | Metallurgical Role |
|---|---|---|---|
| Iron | Fe | Balance (~61–71%) | Base austenitic matrix |
| Chromium | Cr | 16.5 – 18.5 | Primary corrosion resistance; passive Cr₂O₃ film formation |
| Nickel | Ni | 10.5 – 13.5 | Austenite phase stabilizer; improves ductility, toughness, and stress-corrosion resistance |
| Molybdenum | Mo | 2.0 – 2.5 | Pitting and crevice corrosion resistance; +3.3× weighting in PREN formula |
| Titanium | Ti | ≥5×C, ≤0.70 | Carbon stabilizer; forms stable TiC above sensitization range, preventing Cr₂₃C₆ grain boundary precipitation |
| Manganese | Mn | 0 – 2.0 | Austenite former; improves hot workability and deoxidation |
| Silicon | Si | 0 – 1.0 | Deoxidizer; moderate high-temperature oxidation resistance |
| Carbon | C | 0 – 0.080 | Controls minimum Ti requirement (Ti ≥5×C); kept low to minimize free C available for sensitization |
| Phosphorus | P | 0 – 0.045 | Residual; controlled for weldability and hot ductility |
| Sulfur | S | 0 – 0.015 | Residual; low S maximizes ductility, toughness, and intergranular corrosion resistance |
Mechanical Properties — Solution Annealed (+A) Delivery Condition
All 1.4571 forgings from Jiangsu Liangyi are delivered in the solution annealed and water-quenched condition (+A) as standard. Tensile, hardness, and impact properties are verified by testing on specimens machined from the forging body per EN ISO 6892-1 and EN ISO 148-1.
| Property | Min. Required | Typical Range | Test Standard |
|---|---|---|---|
| Tensile Strength (Rm) | 500 MPa | 500 – 700 MPa | EN ISO 6892-1 |
| 0.2% Proof Strength (Rp0.2) | 200 MPa | 200 – 280 MPa | EN ISO 6892-1 |
| Elongation at Fracture (A5) | 30% | 35 – 50% | EN ISO 6892-1 |
| Reduction of Area (Z) | — | 55 – 70% | EN ISO 6892-1 |
| Brinell Hardness (HB) | — | ≤215 HB | EN ISO 6506-1 |
| Charpy V-Notch (KV at +20°C) | 60 J | 100 – 220 J | EN ISO 148-1 |
| Charpy V-Notch (KV at −196°C) | — | ≥40 J (typical) | EN ISO 148-1 (specify for cryogenic/LNG) |
Cryogenic impact testing at −196°C is available on request for LNG and industrial gas applications. Please specify requirement when enquiring.
Physical Properties at Various Temperatures
The following physical properties are critical for thermal design calculations, fatigue analysis, and thermal expansion management in equipment design. Note that 1.4571’s thermal conductivity (~15 W/m·K) is approximately one-third that of carbon steel (~50 W/m·K) — engineers designing heat exchangers and thermally cycled equipment must use temperature-corrected values, not room-temperature constants.
| Physical Property | 20°C | 200°C | 400°C | 600°C | Unit |
|---|---|---|---|---|---|
| Density | 7.95 | 7.87 | 7.74 | 7.60 | g/cm³ |
| Modulus of Elasticity (E) | 200 | 190 | 178 | 163 | GPa |
| Thermal Conductivity (λ) | 15.1 | 16.5 | 18.0 | 19.8 | W/(m·K) |
| Mean Thermal Expansion Coeff. (α, vs 20°C) | — | 16.5 | 17.0 | 17.5 | 10⁻⁶ m/(m·K) |
| Specific Heat Capacity (cₚ) | 500 | 530 | 560 | 590 | J/(kg·K) |
| Electrical Resistivity (ρ) | 0.75 | 0.90 | 1.05 | 1.15 | μΩ·m |
Values represent typical material behavior for guidance. Verify critical design parameters with the Jiangsu Liangyi technical team for your specific heat number and application.
🔬 Design Note: Thermal Expansion vs Carbon Steel
1.4571’s thermal expansion coefficient (16.5–17.5 × 10⁻⁶ m/(m·K)) is approximately 40% higher than carbon steel (~12 × 10⁻⁶). For mixed-material assemblies, thermally cycled flanged joints, and large nozzle-to-shell connections, this differential expansion must be accounted for in gasket selection, bolt load calculations, and pipe stress analysis. Ignoring differential expansion in stainless-to-carbon-steel mixed systems is a common source of flange leakage and bolt fatigue in petrochemical installations.
High-Temperature Mechanical Properties of 1.4571 Forgings
Most supplier datasheets report only room-temperature mechanical properties. For engineers designing pressure vessels, heat exchangers, piping, or rotating machinery operating at elevated temperature, the degradation of yield and tensile strength with temperature is essential design input. The following values are consistent with EN 10302 and established high-temperature behavior of the X6CrNiMoTi17-12-2 alloy class.
| Temperature | Rp0.2 (MPa) | Rm (MPa) | Elongation A (%) | Design Note |
|---|---|---|---|---|
| 20°C (RT) | ≥200 | 500–700 | ≥30 | Reference condition |
| 100°C | ~175 | ~460 | ≥30 | Minor strength reduction |
| 200°C | ~153 | ~435 | ≥30 | Typical upper process temp for many chemical applications |
| 300°C | ~131 | ~413 | ≥35 | Steam sterilization (SIP) and autoclave range |
| 400°C | ~120 | ~393 | ≥35 | Where 316L sensitization risk begins in long-term service |
| 500°C | ~110 | ~368 | ≥35 | EN 10302 creep data applies from this range upward |
| 600°C | ~102 | ~340 | ≥40 | Elevated elongation; reduced Rm; creep governs long-term design |
High-temperature values are indicative for design guidance only. Actual heat-specific values per EN ISO 6892-2 are available on request with test certificates for critical applications.
Creep Rupture and Long-Term Strength
1.4571 is specifically listed in DIN EN 10302 (opens in new tab), the European standard for creep-resisting steels, nickel alloys, and cobalt alloys. EN 10302 provides tabulated 1% creep strength (Rp1,0) and rupture strength values for design at temperatures up to 700°C. When designing pressure equipment to EN 13480 (Metallic Industrial Piping) or EN 13445 (Unfired Pressure Vessels) for service above 500°C, the engineer must use EN 10302 creep data for allowable stress values — and 1.4571 is one of the few austenitic stainless steels with certified data in this standard. 316L does not appear in EN 10302 and therefore cannot be used for creep-controlled design under European pressure equipment codes without additional qualification testing.
Full Product Range & Dimensional Capability Matrix
Jiangsu Liangyi manufactures custom 1.4571 (X6CrNiMoTi17-12-2) forged components across a complete range of geometries, tailored to client engineering drawings. Our integrated facility — equipped with advanced hydraulic presses and ring rolling machines — produces forgings from 30 kg to 30,000 kg single-piece weight, 120,000 tons annual capacity.
Dimensional Capability Matrix by Product Type
| Product Type | OD / Width Range | Length / Height | Single-Piece Weight | Rough Tolerance (typical) | NDT Standard |
|---|---|---|---|---|---|
| Forged Rounds / Bars / Shafts | Ⅲ50 – Ⅲ2,000 mm | Up to 15,000 mm | 1 – 30,000 kg | +5/−0 mm (OD); +50/−0 mm (L) | EN 10228-3 / ASTM A388 |
| Seamless Rolled Rings | Ⅲ300 – Ⅲ6,000 mm OD | H: 50 – 2,500 mm | 10 – 30,000 kg | +5/−0 mm OD/ID; +10/−0 mm H | EN 10228-3 / ASTM A388 |
| Hollow Forgings / Sleeves | OD Ⅲ150 – Ⅲ3,000 mm | Up to 8,000 mm | 30 – 20,000 kg | +5/−0 mm OD/ID; wall ±10% | EN 10228-3 |
| Forged Discs / Plates / Blocks | Ⅲ100 – Ⅲ3,000 mm or W up to 2,000 mm | T: 20 – 1,500 mm | 1 – 20,000 kg | +5/−0 mm all directions | EN 10228-3 |
| Custom-Profile Forgings (valve bodies, step shafts, pump casings) | Per client drawing | Per client drawing | 1 – 30,000 kg | Per drawing + forging allowance | EN 10228-3 / client spec |
Precision-machined finish dimensions available for all product types. Tolerances to ISO 2768 medium or finer achievable. Submit engineering drawings for a tailored quotation.
Forged Bars, Rounds & Custom Shafts
X6CrNiMoTi17-12-2 forged round bars, square bars, flat bars, step shafts, gear shafts, and transmission shafts from Ⅲ50 mm to Ⅲ2,000 mm, length up to 15 m, single piece up to 30 t. Available with 100% UT per EN 10228-3 and EN 10204 3.1/3.2 certification. Used in oil & gas, power generation, chemical, and marine industries.
Seamless Rolled Forged Rings
Custom 1.4571 seamless rolled rings, contoured rings, and flange blanks from Ⅲ300 mm to Ⅲ6,000 mm OD. Ring rolling delivers continuous circumferential grain flow providing superior fatigue resistance vs flame-cut rings from plate — critical for rotating equipment and pressure-cycling service. Maximum 30 t per piece.
Seamless Hollow Forgings & Sleeves
1.4571 forged hubs, shells, sleeves, bushes, and casings with OD up to 3,000 mm. The mandrel forging process eliminates longitudinal weld seams entirely — the single most critical structural risk in high-pressure hollow components. Mandatory specification for downhole tools, pump barrels, and subsea pressure-containing components.
Forged Discs, Plates & Tube Sheets
X6CrNiMoTi17-12-2 forged discs and blocks for valve bonnets, pump covers, and heat exchanger tube sheets. Tube sheet OD up to 3,000 mm, thickness up to 1,500 mm. Controlled forging ratio ensures uniform through-thickness properties — tensile and toughness specifications met at section center, not just surface test pieces. Flatness to ±0.5 mm over full face achievable on precision-machined tube sheets.
Custom Piping & Pressure Vessel Components
1.4571 forged steel pipes, nozzles, channel flanges, baffle plates, and custom pressure vessel components. Compliant with ASME BPVC, EN 13445, and PED 2014/68/EU. Full integration of forging, heat treatment, machining, and NDT under one quality system ensures seamless traceability from heat number to final certificate.
Forging Process & Grain Flow Advantage vs Cast or Plate-Cut
Two components with identical 1.4571 chemical composition can perform dramatically differently in service — depending entirely on whether they were forged, cast, or machined from plate. Understanding this distinction is essential for engineers specifying critical pressure-containing and rotating components.
Forged vs Cast vs Plate-Machined: Structural Comparison
| Attribute | Open Die Forged (Jiangsu Liangyi) | Investment Cast | Machined from Plate / Bar Stock |
|---|---|---|---|
| Microstructure | Refined, equiaxed grain structure; continuous fiber flow aligned to component geometry by forging direction control | Coarse dendritic solidification structure; directional grain growth; potential shrinkage porosity at section centers | Grain flow from rolling is interrupted and cut perpendicular to final shape; anisotropic properties in transverse direction |
| Tensile Strength (Relative) | 100% (reference baseline) | 75–85% of forged values typical | 90–95% in rolling direction; 75–80% transverse |
| Fatigue Strength | 100% — continuous grain flow resists crack initiation and propagation at stress concentrations | 50–65% — inclusions and porosity act as fatigue crack nucleation sites | 70–85% — interrupted fiber flow creates stress concentrations at machined grain boundaries |
| Internal Soundness | No voids, no centerline porosity; 100% UT verified per EN 10228-3 / ASTM A388 | Inherent risk of shrinkage cavity and gas porosity at thick sections; RT preferred over UT for cast components | Dependent on source mill quality; laminations and inclusions possible in transverse direction |
| Anisotropy | Minimal — grain flow designed to align with principal stress directions of the finished component | Moderate — equiaxed dendrites have random orientation but casting defects create unpredictable weak planes | High — transverse mechanical properties (Z-direction) can be 20–30% below longitudinal (L-direction) |
| NDT Reliability | Excellent — dense, continuous structure with predictable, uniform UT wave velocity and attenuation | Limited — dendritic structure scatters ultrasound; deep defects in thick sections difficult to detect reliably | Good in rolling direction; UT limitations transverse; laminations may not be detectable unless specifically targeted |
Jiangsu Liangyi Four-Stage 1.4571 Forging Process
Premium Melting & Refining
EAF primary melting + AOD/VOD refining. Optional ESR for ultra-critical applications. S ≤0.015%, P ≤0.045%. Ti/C ratio confirmed spectroscopically before casting. Inclusion rating per EN 10247 available.
Controlled Temperature Forging
Forging window: 950–1150°C. Finish temperature ≥900°C maintained via infrared pyrometry with automatic press interlock. Minimum 3:1 forging ratio; 5:1+ available for maximum grain refinement. 2,000–6,300-ton hydraulic presses.
Solution Annealing Heat Treatment
1050–1100°C soak, calculated per section thickness (min 1 hr per 25 mm). Rapid water quench within 60 s of furnace exit. Fully dissolves Cr₂₃C₆; restores corrosion resistance and ductility. Temperature uniformity ±5°C verified.
100% NDT + Precision Machining
100% UT per EN 10228-3 / ASTM A388. Liquid penetrant testing (PT) per EN ISO 3452-1. CNC machining to client drawings. CMM dimensional verification. EN 10204 3.1 or 3.2 MTC issued per batch.
🔬 Why Finish Forging Temperature Matters for Ti-Stabilized Grades
For 1.4571, maintaining the finish forging temperature above 900°C is metallurgically mandatory. Below this temperature, austenite work-hardens too rapidly, increasing forging force and risking surface cracking. More critically, low finish temperatures can cause TiC precipitates to partially dissolve back into solution under non-equilibrium conditions, requiring extended solution annealing soak time to fully restore the stabilized structure. At Jiangsu Liangyi, infrared pyrometry with automatic press interlock stops forging if temperature drops below threshold, and the workpiece is reheated before continuing. This process discipline is not verifiable from a material test certificate; it requires supplier audit of manufacturing procedures — which we welcome and facilitate for key customers.
Grade Selection Guide: 1.4571 vs Five Alternative Alloys
Material selection for corrosion-resistant forged components is one of the highest-stakes engineering decisions in chemical, oil & gas, and power generation projects. Over-specifying drives unnecessary cost; under-specifying risks catastrophic failure. The following comparison is based on 28 years of manufacturing and customer feedback across 50+ countries, reflecting real-world selection decisions — not generic alloy tables.
| Grade (DIN / AISI) | Ti-Stabilized? | Mo Content | PREN (Approx.) | Max Continuous Service Temp. | Best Application | Cost vs 1.4571 |
|---|---|---|---|---|---|---|
| 1.4571 (X6CrNiMoTi17-12-2 / 316Ti) | Yes (Ti ≥5×C) | 2.0 – 2.5% | ~26–27 | 850°C oxidizing; 450°C corrosive | Welded assemblies in corrosive high-temp service; oil & gas; chemical; pharmaceutical; nuclear; power generation | Reference (1.0×) |
| 1.4404 (X2CrNiMo17-12-2 / 316L) | No | 2.0 – 2.5% | ~24 | 550°C intermittent; risk above 400°C sustained | Non-welded or short-term welded service below 400°C; food, pharma, architecture | ~0.95× (similar) |
| 1.4541 (X6CrNiTi18-10 / 321) | Yes (Ti ≥5×C) | None | ~17–18 | 850°C oxidizing | High-temp non-corrosive environments; no chloride or acid exposure; aerospace; furnace parts; food without CIP cleaning | ~0.90× |
| 1.4539 (X1NiCrMoCuN25-20-5 / 904L) | No | 4.0 – 5.0% | ~34–36 | 400°C (sensitization risk above this) | Concentrated H₂SO₄, H₃PO₄, seawater, wet chlorine; phosphoric acid production; FGD systems | ~2.5–3.0× |
| 1.4462 (X2CrNiMoN22-5-3 / 2205 Duplex) | No | 3.0 – 3.5% | ~33–35 | 300°C max (475°C embrittlement risk above 300°C) | High-strength + moderate corrosion below 280°C; seawater piping; desalination; structural components; where SCC of austenitic grades is a concern | ~1.5× |
| Alloy 825 (UNS N08825) | No | 2.5 – 3.5% | ~38–40 | 500°C | Extreme environments: concentrated H₂SO₄ at temperature, sour gas with high H₂S & CO₂ partial pressure, hot phosphoric acid; CRA-lined tubulars | ~4–6× |
Five Practical Selection Rules from Jiangsu Liangyi Technical Team
- Choose 1.4571 over 316L when the component will be welded, operates continuously above 400°C, has a design life exceeding 10 years in corrosive service, or the specification references EN 10302 for creep-controlled design.
- Choose 1.4541 over 1.4571 only when the environment contains no significant chlorides or acids and the primary requirement is high-temperature oxidation resistance — typical in furnace components, atmospheric high-temperature structural parts, or food processing equipment without acid CIP cleaning cycles.
- Choose 1.4539 (904L) over 1.4571 when process media is concentrated sulfuric or phosphoric acid, or when PREN must exceed 30 for very high chloride environments. Note: 904L is significantly more difficult to forge and weld, and costs 2.5–3× more. Confirm that 1.4571 genuinely cannot meet the corrosion requirement before specifying 904L.
- Choose 2205 Duplex over 1.4571 when high mechanical strength combined with moderate corrosion resistance is needed, stress corrosion cracking (SCC) is a primary concern, and service temperature is below 280°C. Duplex grades are never suitable above 300°C due to 475°C embrittlement risk, and they require tighter welding parameter qualification than austenitic grades.
- Stay with 1.4571 when you need a cost-effective, field-proven, broadly certified material for welded corrosion-resistant equipment in oil & gas, chemical, pharmaceutical, or power generation service between 100–700°C. It is the optimal balance of corrosion performance, weldability, availability, certification coverage, and cost for the vast majority of industrial applications in this category.
Welding Guide for 1.4571 Fabricators
The following welding guidance is drawn from Jiangsu Liangyi’s experience supporting global customers who weld our 1.4571 forgings into pressure vessels, piping systems, and valve bodies. It is provided for technical reference; specific welding procedures must be qualified per AWS / EN ISO standards by the fabricating shop’s certified welding engineer.
Filler Material Selection
| Application | Recommended Filler | Standard | Notes |
|---|---|---|---|
| Critical welds: pressure-containing joints in high-temperature or corrosive service above 400°C | ER316LTi (Ti-stabilized) | AWS A5.9 / EN ISO 14343 | Maintains Ti stabilization in weld metal; preserves intergranular corrosion resistance across the full weld cross-section; mandatory for service above 400°C |
| General fabrication: non-pressure welds, ambient or short-term service below 400°C | ER316L (low carbon, non-stabilized) | AWS A5.9 ER316L | Widely available; acceptable for welds not exposed to prolonged elevated temperature; relies on low C rather than Ti stabilization |
| Submerged arc welding (SAW) for heavy sections | ER316LTi wire + matching neutral flux | AWS A5.9 / EN ISO 14343 | Confirm flux is neutral (not oxidizing) to avoid Ti burn-off from weld pool; use agglomerated flux preferred over fused for Ti-bearing wires |
| Dissimilar welds: 1.4571 to carbon steel or low-alloy steel | ERNiCr-3 (Alloy 82) or ER309Mo | AWS A5.14 / AWS A5.9 | Nickel-base filler (Alloy 82/182) preferred for thermally cycled or high-temperature service; ER309Mo suitable for ambient service |
Main Welding Parameters for 1.4571
- Pre-weld heat treatment: Not required. Austenitic stainless steels do not require preheating. Ensure joint area is clean, dry, and free of grease, scale, and chloride-containing compounds before welding.
- Post-weld heat treatment (PWHT): Not needed for 1.4571 in standard service conditions. This is a main economic and schedule advantage over ferritic, martensitic, and precipitation-hardening grades. If stress relief is considered for large, complex assemblies, consult a metallurgist: PWHT above 450°C on austenitic steels can induce sensitization if the thermal cycle is not precisely controlled.
- Interpass temperature: Maximum 150°C. Exceeding this increases heat input, promotes grain growth in the HAZ, and risks distortion in thin-section components. Monitor with contact thermometer or temperature-indicating crayons between passes.
- Delta ferrite in weld metal: Keep 5–10 FN (Ferrite Number) in austenitic weld deposits to prevent solidification hot cracking. Verify with WRC-1992 (Welding Research Council) diagram using actual filler wire and base metal compositions. Below 5 FN, hot cracking risk increases; above 12 FN, low-temperature toughness and corrosion resistance may decrease.
- Shielding gas: Pure argon or Ar + 2% O₂ for TIG/GTAW; Ar + 2–5% CO₂ for MIG/GMAW. Avoid high CO₂ mixtures (>5%) which can reduce corrosion resistance of the weld surface oxide. Back-purge with pure argon on all root passes and pipe bore welds to protect the root bead and prevent oxidation inside the pipe bore.
- Post-weld cleaning: Remove all heat tint (weld-area oxide discoloration) by pickling with mixed HNO₃/HF acid solution (passivation paste or spray) or by mechanical grinding, followed by chemical passivation. Unremoved heat tint represents a chromium-depleted surface layer that significantly reduces corrosion resistance in service — a frequently overlooked but critical step in field weld quality assurance.
Eliminating post-weld heat treatment from fabrication scope saves direct cost of heat treatment, furnace time, and fixture preparation — typically 8–15% of total fabrication cost on complex stainless steel assemblies. It also eliminates schedule risk from furnace availability delays and the risk of heat treatment-induced distortion requiring costly re-machining of precision surfaces. For large pressure vessel fabricators working to tight project schedules, this advantage of 1.4571 over ferritic and martensitic alternatives is often the deciding factor in material selection.
Global Market Compliance & Localized Certifications
Our forged parts made of 1.4571 are produced and documented in accordance with the material standards and certification requirements of our main export markets with localized solutions tailored to the specific procurement and regulatory requirements of each region:
European Union (EU) Market
- Full compliance with DIN EN 10088-3, EN 10204, PED 2014/68/EU material requirements, and EN 10302 (creep)
- Materials fully compatible with PED 2014/68/EU; supporting documentation available for customer's CE conformity assessment
- Notified Body (NB) EN 10204 3.2 third-party inspection coordinated on request (TÜV, Bureau Veritas, Lloyd’s)
- Solutions for chemical, pharmaceutical (GMP), food processing, and nuclear industries
- Reference: Forged valve and pump components for German pharmaceutical manufacturers — 3,000+ SIP cycles verified, full PED and GMP certification
North America Market
- Compliant with ASTM A182 F316Ti and ASME BPVC Section II material requirements; material data suitable for API 6A/6D component manufacturers
- Full ASME-traceable material test reports; third-party inspection via SGS, Intertek, or Applus RTD
- Solutions for upstream & midstream oil & gas, LNG, power generation, and petrochemical
- Cryogenic impact testing at −196°C available for LNG valve and equipment applications
- Reference: Custom cryogenic valve stems and seat rings for US LNG plants — 50,000+ units delivered, zero field failures reported
Middle East & Africa Market
- Compliant with ARAMCO, ADNOC, KOC, and SABIC material and inspection specifications
- Material properties consistent with NACE MR0175 / ISO 15156 sour service material requirements; supporting data available on request
- Third-party inspection by major NOC-approved inspection bodies (SGS, Bureau Veritas, Intertek) coordinated on request
- Solutions for upstream oil & gas, LNG, sour crude refining, and desalination industries
- Reference: 120+ wellhead components for a major Middle East national oil company — H₂S partial pressure 0.08 MPa, zero field failures after 36 months continuous service
Asia Pacific Market
- Compliant with JIS G4303/G4312, GB/T 1220, and AS standards for Japan, South Korea, Southeast Asia, and Australia
- Classification society inspection witness services (KR, LR, DNV, ABS) coordinated on request for marine-certified components
- Direct Jiangyin port access for efficient shipping to Asia Pacific destinations
- Solutions for nuclear power, thermal power, marine, and petrochemical industries
- Reference: Nuclear reactor coolant pump components for 600 MW thermal power plant in Southeast Asia — EN 10204 3.2 TÜV witnessed, zero UT rejections across full supply
Industry Applications & Field Case Studies
The following field case studies are drawn from actual Jiangsu Liangyi project deliveries. Component details and client identities have been generalized per confidentiality agreements; technical specifications and performance outcomes are accurate as supplied.
Oil & Gas: Upstream, Midstream & Downhole
We produce 1.4571 forged components for onshore and offshore oil & gas operations: valve balls, bonnets, bodies, stems, and seat rings; downhole drilling tool drive shafts; electric submersible pump (ESP) motor shafts; Christmas tree wellhead spool bodies; casing heads, tubing heads, and tubing spools; double-studded adapter flanges and studded crosses.
Middle East Field Case: 120+ custom X6CrNiMoTi17-12-2 forged wellhead components for a major Saudi Arabia onshore sour crude oilfield (H₂S partial pressure 0.08 MPa, Zone 3 per NACE MR0175 / ISO 15156). All components passed 100% UT per API 6A material and documentation requirements. After 36 months of continuous operation, zero field failures or corrosion-related rejections were reported by the end-user inspection team.
Valve & Fluid Control Industry
X6CrNiMoTi17-12-2 forged valve spindles, butterfly valve main shafts, cryogenic HPBV (high-performance butterfly valve) shafts, and flow control internals are trusted by global valve OEMs. 1.4571’s titanium stabilization and PREN ~26–27 make it the standard specification for forged valve internals in chemical and oil & gas service. We also supply custom forged venturi cone meter bodies, oil measurement valve spools, and ultrasonic flow meter housings, with precision CNC machining to concentricity below 0.02 mm TIR for meter body requirements.
North America Field Case: Custom 1.4571 cryogenic valve stems and seat rings for a leading US valve OEM supplying LNG processing plants. Qualified to ASTM A182 F316Ti with Charpy impact at −196°C (≥40 J). Finished sealing surface tolerance ±0.05 mm; zero leakage verified in cryogenic proof pressure testing at 1.5× design pressure. 50,000+ units delivered; zero quality rejects or field failures reported to date.
Chemical & Pharmaceutical Industry
1.4571 stainless steel forgings are the global standard for fabricated chemical and pharmaceutical processing equipment. Applications include pump casings, impellers, shafts, and wear rings; reaction vessels and autoclave components; heat exchanger tube sheets and channel covers; and process equipment for cellulose, paper, pharmaceutical, textile, and food processing with CIP cleaning cycles.
European Union Field Case: 1.4571 forged valve bodies, pump casings, and pressure vessel nozzles for a German pharmaceutical API synthesis facility. Operating range 150–280°C with regular steam sterilization (SIP) at 135°C. After 3,000+ SIP cycles, post-service metallographic inspection confirmed zero sensitization or intergranular corrosion — fully meeting PED 2014/68/EU Module G certification and pharmaceutical GMP requirements for product-contact surface integrity.
Power Generation & Nuclear Industry
We manufacture 1.4571 forged components for nuclear reactor coolant pump (RCP) casings, seal chambers, and impellers; steam turbine components; and shaft elements for power-generation-coupled rotating machinery. These applications demand 20–40 year design life at 300–550°C — 1.4571’s EN 10302 creep certification and Ti-stabilized microstructure make it the specified material across all major power engineering codes.
Asia Pacific Field Case: X6CrNiMoTi17-12-2 forged impellers, pump shafts, and seal chambers for nuclear RCP systems at a 600 MW thermal power plant. EN 10204 3.2 with TÜV-witnessed testing required. All forgings maintained Rm ≥500 MPa and Rp0.2 ≥200 MPa after 1,000-hour aging at 550°C. UT acceptance per EN 10228-3 Class 1 achieved; zero rejections across the entire supply batch.
Petrochemical: Heat Exchange & Pressure Vessels
Our 1.4571 forged tube sheets, baffle plates, nozzles, and channel flanges are widely used in shell-and-tube heat exchangers, reactors, and pressure vessels in petrochemical refining. Tube sheet flatness (±0.5 mm over full face) and tube hole positional tolerance (±0.1 mm) are consistently achieved in precision CNC machining, critical for proper tube expansion and sealing integrity over the full service life.
Southeast Asia Field Case: 80+ 1.4571 forged tube sheets and seamless rolled rings for a 200,000 BPD oil refinery in Malaysia. Tube sheet OD 850–1,650 mm, thickness 120–280 mm, with 6,000–12,000 tube holes per sheet at ±0.1 mm positional tolerance. Operating at 8.5 MPa / 420°C. a major NOC's approved third-party inspector witnessed all inspection stages. Full EN 10204 3.2 certification issued.
Quality Control, NDT & Certification Standards
At Jiangsu Liangyi, quality is built into every manufacturing stage via controlled procedures, calibrated equipment, and documented records. Our in-house inspection laboratory operates full NDT capability, OES chemical analysis, mechanical property testing (tensile, hardness, impact), and metallographic examination. Third-party inspection is coordinated on request with any major international inspection body.
Non-Destructive Testing (NDT) Scope
- 100% Ultrasonic Testing (UT) — per EN 10228-3 (Level 3 acceptance class standard; Level 4 available on request) and ASTM A388/388M. Applied after heat treatment on all forgings. Automated and manual UT for complex geometries.
- 100% Visual Inspection — per EN 13018. All forging surfaces inspected for cracks, laps, folds, seams, and mechanical damage. Acceptance criteria per EN ISO 11666 for machined surfaces.
- Liquid Penetrant Testing (PT) — per EN ISO 3452-1 / ASTM E165. Standard for surface and near-surface crack detection on austenitic stainless steel forgings. Fluorescent PT available for enhanced sensitivity on critical sealing surfaces.
- Dimensional Inspection — with calibrated Mitutoyo instruments and CMM (coordinate measuring machine). Full dimensional inspection reports issued for every order. All calibration equipment traceable to national measurement standards.
- Chemical Composition Analysis — OES (optical emission spectrometry) on every heat number before forging. Ti/C ratio specifically verified to confirm compliance with Ti ≥5×C specification.
Certification & Documentation Available
- EN 10204 3.1 Mill Test Certificate (MTC) — standard with every order; chemical composition, mechanical properties, NDT results, heat treatment records, signed by Jiangsu Liangyi QC Manager
- EN 10204 3.2 Third-Party Witness Certificate — independent inspector witnessing and countersigning all tests; coordinated with SGS, Bureau Veritas, Intertek, TÜV, Lloyd’s Register, DNV, Applus RTD, or client-nominated body
- ISO 9001:2015 Quality Management System Certification
- PED 2014/68/EU material compatibility — supporting documentation and material certification for customer's CE conformity assessment
- Material properties compliant with API 6A/6D and API 20A material requirements (product certification is the responsibility of the component manufacturer/end user)
- Material data package supporting NACE MR0175 / ISO 15156 sour service material selection (on request)
- DIN EN 10088-3 Stainless Steel Material Standard
- EN 10302 Creep-Resisting Steels Standard compliance documentation
- ASTM A182 F316Ti Forged Stainless Steel Compliance
- EN ISO 6892-1/2 Tensile Testing Standards
- EN ISO 9712 NDT Personnel Qualification Standard
About Jiangsu Liangyi — Your 1.4571 Forging Partner Since 1997
Established in 1997, Jiangsu Liangyi Co., Limited is a leading China-based manufacturer of open die forgings and seamless rolled rings, with an 80,000 m² fully integrated production facility and 40 million USD in fixed assets located in Jiangyin City, Jiangsu Province — one of China’s primary forging hubs, with direct logistics access to Yangtze River shipping and major international ports. We offer genuine end-to-end manufacturing: steel melting and refining, open die forging, ring rolling, heat treatment, precision CNC machining, and full NDT inspection — all under one roof, one quality system, one EN 10204 certificate chain.
Our production equipment includes 2,000–6,300-ton hydraulic forging presses, 0.75–9-ton electro-hydraulic forging hammers, 1–5-meter seamless ring rolling machines, and ten precision heat treatment furnaces with temperature uniformity ±5°C. Single-piece forging capacity: 30 kg to 30,000 kg. Annual output: 120,000 tons. Export destination: 50+ countries across North America, Europe, Middle East, Asia Pacific, and Africa. Customers include major oil companies, global valve and pump OEMs, nuclear power operators, EPC contractors, and trading companies serving all major industrial sectors.
We welcome factory audits by potential customers and new project partners. Our facility, quality system, and process controls are open for inspection at mutually agreed times. Contact sales@jnmtforgedparts.com to schedule a visit or video audit.
FAQ — 1.4571 (X6CrNiMoTi17-12-2) Forging Parts (9 Questions)
1.4571 (X6CrNiMoTi17-12-2) is the European DIN EN designation for titanium-stabilized molybdenum austenitic stainless steel. Equivalents: AISI 316Ti, UNS S31635, AFNOR Z6CNDTi17-12 (French), BS 320S31 (British). It is sometimes incorrectly described as equivalent to AISI 321 (1.4541), but 321/1.4541 contains no molybdenum and has a PREN of only ~17–18, compared to 1.4571’s ~26–27. Always confirm the full DIN/UNS designation in material specifications to prevent grade substitution errors during procurement.
The Pitting Resistance Equivalent Number (PREN) of 1.4571 is approximately 26–27, calculated as: PREN = %Cr + 3.3×%Mo + 16×%N. Using mid-range composition (Cr 17.5%, Mo 2.25%, N ~0.10%): PREN ≈ 17.5 + 7.4 + 1.6 = 26.5. In practice, PREN quantifies resistance to localized pitting in chloride-containing media. 1.4571’s ~26–27 outperforms 316L (~24), clearly outperforms 304/321 (~19–21), and is suitable for moderate chloride environments including cooling water, process streams with up to several percent NaCl, and coastal atmospheric exposure. For severe chloride environments (seawater immersion, concentrated brine), consider 1.4539 (904L, PREN ~36) or duplex 1.4462 (2205, PREN ~34).
No. 1.4571 is a fully austenitic stainless steel and cannot be hardened by quenching or tempering — the austenite phase is not transformable to martensite at standard cooling rates. The only reliable hardening mechanism is cold working (work hardening by plastic deformation). The correct heat treatment is solution annealing at 1050–1100°C followed by rapid water quenching, which dissolves carbides, relieves residual stresses, and maximizes both corrosion resistance and ductility. Surface hardening by nitriding is possible but rarely specified for this grade.
1.4571 can be operated continuously up to 850°C in oxidizing environments without any structural degradation – TiC precipitates remain thermally stable and the austenitic matrix has adequate creep strength over the entire range. To prevent long-term localized corrosion at grain boundaries and precipitate interfaces the maximum recommended continuous service temperature in corrosive environments is 450°C. Generally short-term excursions to 900°C in oxidizing service are acceptable. For structural design above 500°C, the allowable stress values shall be taken from EN 10302 creep data.For temperatures above 850°C, look at higher-alloyed grades such as 310S or nickel-base superalloys.
The critical difference is the anti-sensitization mechanism: 1.4571 uses titanium stabilization (Ti ≥5×C%) to permanently bind all carbon as TiC, completely eliminating sensitization risk regardless of heat input or service temperature. 316L uses low carbon (≤0.03%) to slow the rate of chromium carbide formation, which reduces sensitization during short-duration welding but does not prevent it during prolonged service above 400°C. Both grades carry similar Mo content (2.0–2.5%) and broadly similar PREN. The choice rule: for welded assemblies and continuous service above 400°C or design lives exceeding 10 years in corrosive service, specify 1.4571. For non-welded or short-term applications below 400°C, 316L is acceptable at marginally lower cost.
Both 1.4571 (X6CrNiMoTi17-12-2) and 1.4541 (X6CrNiTi18-10 / 321) are titanium-stabilized austenitic stainless steels, but 1.4571 contains 2.0–2.5% molybdenum while 1.4541 contains none. This single compositional difference results in dramatically different PREN: 1.4571 ~26–27 vs 1.4541 ~17–18. In chloride-containing, acidic, or aggressive process media — which covers virtually all oil & gas, chemical, and pharmaceutical applications — 1.4571 offers far superior corrosion resistance. Choose 1.4541 only when the primary requirement is high-temperature oxidation resistance in environments genuinely free of significant corrosive media (e.g. furnace components, aerospace structures, food processing without acid CIP cleaning). For all other corrosive service, specify 1.4571.
For critical pressure-containing or high-temperature welds (service above 400°C), specify ER316LTi or a matching Ti-stabilized filler per AWS A5.9 / EN ISO 14343, which maintains titanium stabilization in the weld deposit and heat-affected zone. For general fabrication welds in ambient service (below 400°C), ER316L (non-stabilized, low carbon) is widely used and acceptable. No pre-weld heating or post-weld heat treatment is required for 1.4571 — a major cost and schedule advantage over ferritic and martensitic grades. Maintain delta ferrite in weld metal at 5–10 FN (Ferrite Number) to prevent solidification hot cracking. Remove all heat tint by pickling and passivation before placing assemblies into corrosive service.
Standard with every order: EN 10204 3.1 Mill Test Certificate (MTC) covering chemical composition (OES spectrometry), mechanical properties (tensile, hardness, impact), heat treatment records, and NDT results, signed by Jiangsu Liangyi QC Manager. Available on request: EN 10204 3.2 Third-Party Witness Certificate with independent inspector (SGS, Bureau Veritas, Intertek, TÜV, Lloyd’s, DNV, or client-specified body). Additional documentation: PED 2014/68/EU material compatibility, API 6A/6D material data, NACE MR0175 material selection data, ASME Section II compliance, and ISO 9001:2015 QMS certificate. Specify your full certification requirements when requesting a quotation.
Lead time depends on component geometry, weight, and required certification scope. Typical lead times: Standard forgings (bars, rings, discs) in solution annealed condition with EN 10204 3.1: 4–8 weeks from PO confirmation. Precision-machined components: 6–10 weeks. EN 10204 3.2 third-party inspection: add 1–2 weeks for inspector scheduling. Very large forgings (above 10 t, OD above 3 m) or complex custom profiles: 8–14 weeks. For urgent requirements, expedited scheduling on standard geometries may be available in 3–4 weeks — contact our sales team with your schedule requirements at the earliest stage. For repeat orders, we maintain material stock and standard forging blanks of common 1.4571 grades to reduce lead time.
Contact Us for Custom 1.4571 Forging Parts Quotation
Send us your engineering drawings, material specification, dimensions, required certifications, and target quantity. Our technical team reviews requirements and responds with a competitive, no-obligation quotation typically within 24–48 hours. We welcome enquiries from end users, EPC contractors, valve and pump OEMs, and distributor partners worldwide.
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