AISI 431 (UNS S43100 / Grade 431 / SUS 431) Forged Forging Parts | China ISO 9001:2015 Certified Manufacturer Since 1997

AISI 431 Martensitic Stainless Steel: Material Science, Global Standards & Manufacturer Overview

Established in 1997, Jiangsu Liangyi Co., Limited is a vertically integrated open die forging and seamless ring rolling manufacturer with 27+ years of dedicated experience in producing high-performance AISI 431 (UNS S43100, Grade 431, SUS 431, DIN 1.4057) forged steel parts. With an 80,000 m² modern production base in Jiangyin City, Jiangsu Province — strategically positioned at the heart of China's Yangtze River Delta industrial corridor — we supply premium custom AISI 431 forged parts to 50+ countries across North America, Europe, the Middle East, Asia Pacific, and Australia.

The Metallurgical Logic Behind AISI 431: Why Nickel Changes Everything

Most engineers encounter AISI 431 as simply "the corrosion-resistant version of 410," but the metallurgical reality is more nuanced and worth understanding in depth — because it directly determines why AISI 431 forgings outperform competing grades in specific applications.

Standard AISI 410 is a lean 12% chromium martensitic steel with no deliberate nickel addition. When solidifying from the melt, 410 traverses a phase field where delta-ferrite is thermodynamically stable alongside austenite. In large ingots and heavy forgings, this can produce residual delta-ferrite bands that act as crack initiation sites under cyclic loading — a serious concern in pump shafts, valve stems, and marine propeller shafts.

The 1.25–3.00% nickel addition in AISI 431 fundamentally rebalances this phase diagram. Nickel is a strong austenite stabilizer: it narrows the delta-ferrite stability field and drives solidification more completely through the austenitic phase before martensite transformation. The practical results, demonstrated across our 27 years of production experience with this alloy, include:

• Near-zero delta-ferrite in properly forged cross-sections, confirmed by metallographic examination at 400× magnification in our in-house laboratory
• Significantly improved Charpy V-notch impact energy at sub-zero temperatures — typically 40–80 J at −40°C in Q&T condition, vs. 15–25 J for standard 410
• Higher corrosion potential (Ecorr) in NaCl solutions — our corrosion testing records show AISI 431 in Q&T condition achieves approximately 3–4× better general corrosion resistance than 410 in 3.5% NaCl at 25°C
• Broader heat treatment window — the reduced delta-ferrite content means AISI 431 responds more predictably to austenitizing heat, giving tighter mechanical property scatter across large cross-sections

Global Standard Cross-Reference for AISI 431

When procuring Grade 431 stainless steel forgings for multinational projects, correct standard cross-referencing is critical to avoid specification errors and customs compliance issues. The following table provides the complete official cross-reference for AISI 431 across all major national and regional standards:

Our AISI 431 forged parts are produced to match customer-specified standards from all the above standard systems. All requirements for chemical composition, mechanical performance and non-destructive testing are verified strictly in line with the specification version stated in the purchase order. You can check our full range of  forging materials for complete cross-reference support covering all alloy grades.

Complete Physical, Thermal & Corrosion Properties of AISI 431 (UNS S43100)

Comprehensive engineering design of components in AISI 431 stainless steel requires accurate physical and thermal property data beyond the basic mechanical values. The tables below present verified reference data for AISI 431 in the normalized and tempered (N+T) condition, drawn from our in-house material database accumulated over 27 years of production and quality testing. These values reflect our own measurement records and published ASTM/ASM data.

Physical Properties at Room Temperature (20°C)

Thermal Properties at Various Temperatures

Corrosion Resistance Data: Where AISI 431 Performs — and Where It Doesn't

Unlike generic material datasheets that simply label AISI 431 as "good" or "moderate" for corrosion resistance, our 27 years of real-world supply experience allows us to provide specific, environment-based guidance. AISI 431's corrosion performance is highly dependent on heat treatment condition, surface finish, and the specific chemical environment. The following data reflects verified field feedback from our global clients:

Strictly Controlled Chemical Composition of AISI 431 (UNS S43100) Forged Steel

Every heat of AISI 431 forged steel produced at Jiangsu Liangyi begins with chemical composition verification in our in-house OES (Optical Emission Spectrometry) laboratory — a step that occurs before a single kilogram of steel enters our forging press. This pre-forging spectrometric verification, combined with incoming mill certificate review, forms the first of our five quality control gates and is non-negotiable for every batch we produce.

Our Premium Melting Route: Why Melt Quality Determines Forging Quality

Unlike manufacturers who simply purchase commercially available bar stock and call it a "forging," Jiangsu Liangyi operates its own steel melting and refining facility — a critical differentiation that gives us direct control over the melt chemistry that determines the final properties of your AISI 431 forged component.

Our standard production route for AISI 431 follows a triple-process melting sequence that we have refined over 27 years:

Explore our full forging materials capability to understand how our melting routes apply across our full alloy portfolio.

Mechanical Properties of AISI 431 Forging Parts: Delivery Conditions, Heat Treatment Variants & Size Effects

Specifying mechanical properties for AISI 431 (UNS S43100) forgings requires understanding how properties vary with heat treatment condition, cross-section size, and test location. The values below represent our standard guaranteed minimums from our production records, with practical commentary on what drives the variation — information that most datasheets omit.

Standard Delivery Condition: Normalized and Tempered (N+T)

Heat Treatment Variants: Tailoring Properties to Your Application

One of the key engineering advantages of AISI 431 stainless steel is the wide range of mechanical properties achievable through heat treatment — from soft, machinable annealed condition to ultra-high-strength quench and temper condition. The following table shows our achievable property ranges across all standard heat treatment conditions, which we verify for every production batch:

Cross-Section Size Effect on Mechanical Properties: What Engineers Must Know

A technically critical factor that is almost universally absent from supplier datasheets — but is essential for heavy forging engineering — is the size / cross-section effect on mechanical properties. AISI 431, like all hardenable steels, shows a systematic decrease in mechanical properties with increasing cross-section diameter, because thicker sections cool more slowly during quenching, producing a softer, coarser martensitic structure at the center.

Based on our production and testing records across 27 years of manufacturing, we have compiled the following property reduction factors for AISI 431 Q+T forgings. These are the actual values we use internally when setting heat treatment parameters for client orders:

AISI 431 Heat Treatment: Process Parameters, Temper Embrittlement Avoidance & Cryogenic Treatment

Heat treatment of AISI 431 stainless steel forgings is more nuanced than for standard carbon steels, and incorrect heat treatment is one of the two most common causes of AISI 431 component premature failure in service (the other being incorrect surface condition leading to pitting corrosion). Based on our 27 years of production experience, we document here the critical parameters, pitfalls, and advanced techniques that distinguish a quality AISI 431 heat treatment from a mediocre one.

The Temper Embrittlement Trap: A Critical Warning for AISI 431

One of the most technically important — and most commonly ignored — aspects of heat treating martensitic stainless steels including AISI 431 is temper embrittlement. This phenomenon, also called "475°C embrittlement" or "secondary hardening embrittlement" in this context, occurs when AISI 431 is tempered or cooled slowly through the temperature range of approximately 370–560°C (700–1,040°F).

At these temperatures, impurity elements — primarily phosphorus (P) and sulfur (S) — that have been dissolved in the martensite matrix during austenitizing begin to segregate to prior austenite grain boundaries. This grain boundary enrichment dramatically reduces grain boundary cohesion and causes a sharp drop in Charpy impact energy, sometimes reducing toughness by 50–70% versus properly treated material — without any change in hardness or tensile strength. This is why hardness testing alone cannot detect temper embrittlement.

Cryogenic Treatment Protocol for LNG / Low-Temperature Applications

Standard Q+T heat treatment of AISI 431 invariably leaves a small percentage (typically 3–12% by volume) of untransformed retained austenite in the microstructure. While this retained austenite is not harmful for room-temperature applications, it can become problematic in two scenarios: (1) cryogenic applications where it may transform to martensite spontaneously, causing dimensional instability, and (2) high-cycle fatigue applications where retained austenite at inclusion boundaries can initiate fatigue cracks.

Our proprietary cryogenic treatment protocol, developed specifically for AISI 431 cryogenic valve components supplied to European and Asian LNG projects, consists of the following sequence:

• Step 1: Standard austenitizing at 980°C and oil quenching to room temperature
• Step 2: Immediate controlled cooling to −196°C in liquid nitrogen at ≤ 5°C/min rate, holding for 4–8 hours (depending on section thickness)
• Step 3: Controlled warm-up to room temperature at ≤ 2°C/min — rapid warm-up can cause thermal shock cracking
• Step 4: High tempering at 620–680°C for 3+ hours to restore toughness in the newly transformed martensite
• Step 5: Charpy V-notch impact testing at −196°C to verify minimum 27 J per specimen, per EN ISO 148-1

This protocol has been validated across over 500 AISI 431 cryogenic component production batches supplied to European LNG projects since 2010, with zero reported in-service failures related to cryogenic material performance.

The Science of Forging AISI 431: Process Engineering, Challenges & Our Solutions

Most suppliers describe their forging process in generic terms. At Jiangsu Liangyi, we believe that transparent, detailed disclosure of our process engineering — including the specific challenges of forging AISI 431 and how we solve them — is what differentiates a genuine specialist manufacturer from a commodity supplier. The following section documents our production knowledge accumulated over 27 years and tens of thousands of AISI 431 forgings.

Why AISI 431 Is More Demanding to Forge Than Carbon Steel

AISI 431 presents the following specific forging challenges that do not exist — or exist at much lower severity — in conventional carbon or low-alloy steels:

Grain Flow Engineering: The Value That Only Forging Delivers

When an engineer specifies a forged AISI 431 shaft rather than a machined bar, they are purchasing not just a shape but a specific internal grain flow architecture that provides mechanical properties unattainable in any other manufacturing route. Here is the technical explanation of what grain flow means and why it matters for AISI 431 forged shafts and rings:

During open die forging, the austenite grains in the billet are elongated and refined by compressive deformation. After heat treatment, the martensite laths that form from these refined grains are aligned with the forging direction. In a properly forged AISI 431 shaft, this alignment means:

• Fatigue crack propagation resistance is maximized in the transverse direction — where rotating bending fatigue stresses are highest. Cracks attempting to propagate perpendicular to the shaft axis must cross aligned grain boundaries, requiring significantly higher energy than propagating parallel to grain boundaries in a machined-from-bar component.
• Impact energy in the longitudinal direction (along the shaft axis) is 20–35% higher than in the transverse direction for the same heat treatment condition. This anisotropy is a feature, not a defect: for shafts, it means maximum toughness is aligned with the primary loading direction (axial tension/compression).
• Charpy specimen orientation must be specified correctly in procurement documents. "Longitudinal Charpy" and "Transverse Charpy" specimens from the same forging can differ by 40–80 J in impact energy. Our MTCs clearly state the specimen extraction orientation, which clients should verify against their design specification.

Complete AISI 431 Forged Product Range & Dimensional Capabilities

Our manufacturing capabilities for AISI 431 (UNS S43100, Grade 431, SUS 431) forgings cover the full spectrum from small precision components to large-scale heavy industrial forgings, all produced from our own melted and refined steel. Every product line below is available with full machining, heat treatment, NDT, and certification from our single integrated facility — eliminating the supply chain fragmentation and quality handoff risks of multi-supplier sourcing.

AISI 431 Forged Round Bars, Flat Bars & Step Shafts

We produce AISI 431 forged round bars from Ø 50 mm to Ø 2,000 mm, and flat / rectangular bars from 50×50 mm to 800×2,000 mm cross-section, in lengths up to 15 meters for shafts. Our step shaft capability covers up to 8 distinct diameter steps in a single forging, eliminating weld-on collar joints that introduce corrosion risk and fatigue initiation points. Step shafts for pump motor applications are produced with transitions designed per your shaft drawing to minimize stress concentration factor (Kt) at diameter changes — a detail most suppliers' forging engineers overlook.

All forged bars and shafts are 100% ultrasonically tested per ASTM A388 or EN 10228-3 using angle beam and straight beam probes, with scan coverage of 100% of the forging volume. Any indication exceeding the reference reflector size (typically Ø 2mm flat-bottom hole equivalent) results in automatic rejection and material review, not rework.

UNS S43100 Seamless Rolled Forged Rings

Our ring rolling capability uses 1M and 5M CNC seamless ring rolling machines to produce Grade 431 seamless rolled rings in rectangular, contoured (L-shaped, T-shaped), and near-net-shape profiles. Key dimensional capabilities:

• Outer diameter: 200 mm – 6,000 mm
• Ring height: 50 mm – 1,500 mm
• Wall thickness: 50 mm – 800 mm (depending on OD)
• Single-piece weight: 10 kg – 30 tons
• Concentricity tolerance: ≤ 1 mm TIR for machined rings
• Out-of-roundness: ≤ 0.5% of OD for machined rings

Contoured ring profiles (flange rings, stepped rings) reduce final machining material removal by 35–60% versus rectangular-profile rings machined to shape, providing significant cost savings to clients for large-diameter rings. Share your ring drawing with our engineering team and we will advise on the optimal pre-form profile to minimize your total procurement cost.

Grade 431 Hollow Forgings: Housings, Shells & Cylinders

We manufacture SUS 431 seamless hollow forgings by a combined punching and mandrel drawing process on our open die press, producing hollow cylinders, pressure vessel shells, pump casings, and valve housings with superior wall integrity compared to any machined-from-solid or welded approach. Our hollow forging capability:

• Outside diameter: 200 mm – 3,000 mm
• Wall thickness: 50 mm – 500 mm
• Length: up to 4,000 mm
• Bore surface: rough-bored to H11 tolerance, or fine-bored to H7 tolerance on request

Custom AISI 431 Machined Forged Components

For clients requiring finished or semi-finished machined components, our in-house CNC machining facility — equipped with CNC lathes (swing Ø 2,000 mm × 8,000 mm between centers), horizontal boring mills, CNC milling centers, gear hobbing machines, and jig boring machines — provides complete machining services to finish tolerance. We routinely supply:

• Valve bodies, bonnets, and seat rings machined to final dimensions per client drawings and to meet API 6A dimensional requirements where specified
• Pump shafts machined to bearing journal tolerances (typically k6, m6, or n6 shaft fits for interference bearing mounting), keyway slots milled to DIN 6885 tolerances
• Flanges machined to ASME B16.5, EN 1092-1, or custom drilling patterns
• Marine propeller shafts with taper cone machined to ISO 484-1 cone angle tolerances and keyway milled to Lloyd's Register dimensional requirements
• Disc-shaped components (tube sheets, baffle plates, nozzles) with hole patterns drilled and reamed to H8 tolerance

View our complete forged product catalog and full equipment list for complete capability details.

Machining AISI 431 Forgings: Cutting Parameters, Tool Selection & Surface Treatment Options

For engineers and procurement specialists who will machine AISI 431 (UNS S43100) forgings in their own facilities — or who need to specify machined components — understanding the machinability characteristics and surface treatment options for this alloy is essential for cost-effective manufacturing and optimized component performance.

Machinability of AISI 431 vs. Other Stainless Grades

AISI 431 in the annealed condition (185–220 HB) has a machinability rating of approximately 45–55% relative to AISI 1212 free-machining carbon steel (rated 100%). In the Q+T condition at 280–320 HB, machinability drops to approximately 30–40%. By comparison, austenitic 316L — which work-hardens rapidly — has a machinability rating of only 35–45%, making AISI 431 in annealed condition notably easier to machine than 316L despite its higher strength potential. This counterintuitive advantage comes from the martensitic structure of 431, which does not work-harden as aggressively as austenitic grades under cutting tool contact.

Recommended Cutting Parameters for AISI 431

Surface Treatment Options for AISI 431 Forgings

The surface condition of a finished AISI 431 forged component directly determines its corrosion resistance in service — sometimes more significantly than the alloy composition itself. AISI 431 relies on a thin (2–5 nm) Cr₂O₃ passive film for corrosion protection; anything that disrupts or contaminates this film — iron contamination from tooling, heat tint from welding, or mechanical damage — can initiate localized corrosion. The following surface treatment options, all available from our machining facility, address different service requirements:

AISI 431 vs. Competing Grades: A Practical Engineering Selection Guide for Forgings

Selecting the right stainless steel grade for a forged component requires weighing mechanical performance, corrosion resistance, heat treatment response, weldability, machinability, and cost. The following comparison is drawn from our direct manufacturing experience producing all five grades listed — not from generic published datasheets — and reflects the real-world tradeoffs our clients encounter when making grade selection decisions.

Jiangsu Liangyi Engineering Verdict: AISI 431 occupies an irreplaceable engineering niche — it is the only standard stainless steel grade that simultaneously offers: heat-treatable high strength (up to 1,100 MPa), NACE MR0175 sour service qualification, excellent cryogenic toughness to −196°C, good UT inspectability in heavy sections, full magnetic permeability for magnetic detection applications, and moderate procurement cost. No other single grade delivers all five of these attributes. This is why, despite being a grade that dates to the early 20th century, AISI 431 remains the dominant material in marine propeller shafts, wellhead valve stems, and LNG cryogenic valve components globally.

AISI 431 Forgings in Service: Global Industries, Regional Projects & Documented Client Outcomes

The following application documentation is drawn directly from Jiangsu Liangyi's own production and client feedback records. We resist the temptation to generalize or exaggerate — these case studies reflect actual components we manufactured, actual client challenges, and actual verified outcomes. We believe this level of transparency is what genuine expertise looks like.

Oil & Gas: Wellhead Equipment & Downhole Drilling Components

AISI 431 combines the three properties most demanded by oil & gas engineers: high tensile strength for pressure containment, H₂S sour service qualification per NACE MR0175, and good corrosion resistance in CO₂-bearing produced water. In our 27 years, oil & gas accounts for approximately 38% of our total AISI 431 production volume by weight.

Marine & Shipbuilding: Propeller Shafts, Rudder Stocks & Offshore Components

AISI 431 has been the dominant material for commercial marine propeller shafts since the 1970s, and for good reason: it offers 3–4× better saltwater corrosion resistance than plain carbon steel, higher fatigue strength (important for the torsional-flexural combined loading of propeller shafts), and is readily available in forged form at diameters up to 2,000 mm. Marine applications account for approximately 28% of our AISI 431 production volume.

Valve & Flow Control: Cryogenic, High-Pressure & Subsea Applications

The valve and flow control industry is the third-largest consumer of AISI 431 forgings globally, accounting for approximately 22% of our production volume. AISI 431 is uniquely suited for valve applications because it combines heat-treatable strength (for pressure containment), excellent dimensional stability after heat treatment (critical for tight valve seat leakage class), wear resistance (for ball valve balls and seat surfaces), and corrosion resistance in the transported media.

High-Specification Power Plant: Reactor Coolant System Forged Components

Our UNS S43100 stainless steel forgings have been supplied for demanding power plant applications requiring the highest level of chemical composition control, full material traceability, comprehensive NDT, and complete documentation packages.

Pump, Turbomachinery & Power Generation Industry

Pressure Vessel & Petrochemical Industry

 Our SUS 431 forged components are used in the global petrochemical industry in applications ranging from crude oil distillation towers to fertilizer plant heat exchangers. They include tube sheets, nozzle forgings, baffle plates and pressure vessel heads. The moderate corrosion resistance and high strength of AISI 431 allows somewhat thinner wall designs compared to austenitic 316L in certain applications, thus reducing the capital cost while maintaining the integrity of pressure containment.

In-House Production Equipment & Heat Treatment Capabilities for AISI 431 Forgings

At Jiangsu Liangyi, vertical integration is not a marketing phrase — it is the operational reality that underpins our quality consistency and lead time predictability. From steel melting to CNC machining to NDT, every step of the value chain for your AISI 431 forged component occurs within our 80,000 m² production base in Jiangyin, Jiangsu Province. This means we do not subcontract heat treatment to external vendors, we do not use outside NDT services, and we do not depend on spot-market bar stock for our forging raw material.

Steel Melting & Refining Equipment

• 30T Electric Arc Furnace (EAF): Primary melting of stainless scrap and alloying additions; full decarburization and initial Cr/Ni chemistry control; capable of producing 30-ton heats per cycle
• 30T Ladle Refining Furnace (LRF): Precise final chemistry adjustment, temperature homogenization, and calcium treatment for inclusion shape modification; reduces sulfur to ≤ 0.015% routinely
• VOD (Vacuum Oxygen Decarburization) Furnace: Vacuum degassing to H₂ ≤ 2 ppm, N₂ ≤ 60 ppm; critical for hydrogen embrittlement prevention in heavy section forgings
• ESR (Electroslag Remelting) Furnaces: Available in 3T, 8T, and 20T ingot capacity; used for premium-grade AISI 431 for high-cleanliness, aerospace-adjacent, and high-cycle fatigue applications; reduces inclusion content by 70–80% versus conventional ingot
• Intermediate Frequency Induction Furnaces: For small-batch custom melts and fast-turnaround chemistry adjustments in quantities below 5 tons

Forging Equipment

• 6,300T Open Die Hydraulic Forging Press: Our largest press; used for AISI 431 shafts above 500 mm diameter and heavy plate forgings above 8 tons; provides the compressive stress necessary to close internal voids in large cross-sections
• 4,000T Open Die Hydraulic Forging Press: Medium-heavy forgings from 1–8 tons; ring preform preparation for ring rolling
• 2,000T Open Die Hydraulic Forging Press: Light-to-medium forgings from 100 kg–3 tons; fast-cycle production of small components
• 5M CNC Seamless Ring Rolling Machine: Rings up to Ø 6,000 mm outer diameter; axial and radial rolls independently CNC-controlled for precise dimensional control; contoured roll tooling for profile rings
• 1M CNC Seamless Ring Rolling Machine: Rings up to Ø 1,200 mm; high-speed production of smaller rings
• 0.75T – 9T Electro-Hydraulic Forging Hammers: Free-forming and die forging of small complex shapes; step shaft production
• Manipulators up to 60T lifting capacity: Paired with forging presses for safe and precise positioning of large ingots and workpieces during multi-step forging sequences
• Heating Furnaces (max 150T single piece): Gas-fired chamber furnaces with controlled atmosphere for pre-forging heating; PID-controlled to ±10°C for precise forging temperature entry

Heat Treatment Facilities

• Semi-Automatic Continuous Heat Treatment Furnaces (max 18m length): For long shafts and bar forgings; continuous conveyor feed with individually programmable temperature zones; avoids the distortion caused by manual handling of long workpieces in batch furnaces
• Quenching Tanks (depth up to 16m, oil and water): Deep-tank design ensures that long shafts can be quenched in a vertical orientation — the only correct method to prevent quench distortion in shafts above 3 meters; agitated oil quench for sections above 200 mm
• Hydrogen Bake-Out Furnaces (max 14m length): Operated at 200–250°C for 4–8 hours post-forging; mandatory protocol for all AISI 431 heavy section forgings to prevent hydrogen-induced delayed cracking
• Cryogenic Treatment System (−196°C LN₂): Liquid nitrogen immersion tank with programmable cooling and heating rate control (±2°C/min); used for LNG cryogenic valve components requiring −196°C toughness certification
• Tempering Furnaces (±5°C temperature control): Precision PID-controlled electric resistance tempering furnaces for tight hardness control; critical for NACE MR0175 components requiring ≤ 22 HRC max hardness consistency

CNC Machining Facilities

• CNC lathes with swing diameter up to Ø 2,000 mm and between-centers distance up to 8,000 mm
• Horizontal boring mills for large housing and casing bore machining
• CNC vertical and horizontal machining centers for multi-face milling and drilling
• Gear hobbing machines for spline shaft and gear forging finishing
• Jig boring machines for precision hole pattern drilling to ±0.02 mm positional tolerance
• Deep-hole drilling machines (gun drilling) for hollow shaft and nozzle bore finishing

See our complete equipment list for full specifications and capacity details.

Full-Process Quality Assurance for AISI 431 Forgings: From Melt Chemistry to Certified Delivery

The quality system governing our AISI 431 forged component production is designed around a fundamental principle: quality is built in at each process step, not inspected in at the end. Our 5-gate quality control system means that a forging that fails any intermediate gate is rejected or reworked before proceeding to the next step — not shipped and recalled later. This approach consistently delivers first-submission acceptance rates above 98% at client incoming inspection, and a zero field-return rate for quality-related failures over our last 5 years of production records.

The 5-Gate Quality Control System for AISI 431 Forgings

We welcome third-party inspection and client source inspection at any production stage. View our global project references for client testimonials and project documentation examples.

Packaging, Export Documentation & Global Logistics for AISI 431 Forgings

A forging delivered with surface damage, corrosion, or documentation errors creates real cost and schedule impact for global industrial projects. Jiangsu Liangyi treats packaging and logistics as integral parts of the quality system — not an afterthought. Our standard export packaging and documentation protocols for AISI 431 forged parts are designed for the specific transit risks of sea freight from China to destinations in North America, Europe, the Middle East, and Australia.

Standard Export Packaging Protocol

• Surface protection: All machined surfaces are coated with VCI anti-rust oil or protective wax. Rubber end caps are fitted to shaft journals and bore surfaces, and foam padding is used to cushion sealing faces and precision-machined surfaces.
• Wooden cases: All parts over 200 kg are packed in ISPM 15 heat-treated fumigation-free export wooden crates reinforced with steel strapping. Every shipment comes with standard fumigation-free certification to support customs clearance for the US, EU and Australia.
• Desiccants: Silica gel desiccant packs inside each sealed crate, calculated at 1 unit per 0.5 m³ of internal crate volume, to keep relative humidity below 40% during sea transit
• Marking: Heat number, part number, material designation (AISI 431 / UNS S43100 / DIN 1.4057), weight, dimensions, and country of origin (MADE IN CHINA) clearly marked on each crate with indelible marking fluid and metal tag
• Oversized freight: Components above 3,000 mm in length or above 10 tons are shipped in open-top flat rack containers with full engineering calculations for sea-fastening, reviewed and approved by the shipping line

Export Documentation Package

Every AISI 431 forging shipment from Jiangsu Liangyi includes the following standard export documentation:

• Commercial Invoice and Packing List (HS Code 7326.90 or 7228.60 as applicable)
• Certificate of Origin (FORM E for ASEAN countries; CO for all others)
• EN 10204 3.1 or 3.2 Mill Test Certificate (material-specific)
• NDT Reports (UT, MT, PT as applicable)
• Dimensional Inspection Report
• Heat Treatment Records (furnace chart recordings)
• ISPM 15 Fumigation Certificate for wooden packaging
• Dangerous Goods Declaration (if applicable, for VCI-treated components)

Strategic Location Advantage: Jiangyin, Jiangsu Province

Our production facility in Jiangyin City is located 80 km from Shanghai's Yangshan Deep-Water Port — China's largest container port and one of the world's top 3 busiest ports by TEU volume. This proximity provides:

• North America (US West Coast): Approximately 14–18 days sea transit from Yangshan Port
• European Union (Rotterdam, Hamburg): Approximately 28–35 days sea transit
• Middle East (Dubai, Dammam): Approximately 12–16 days sea transit
• Australia (Melbourne, Sydney): Approximately 12–18 days sea transit
• Southeast Asia (Singapore, Ho Chi Minh): Approximately 4–7 days sea transit

For time-critical air freight of small components (typically below 200 kg), we can arrange air cargo from Shanghai Pudong International Airport (PVG) for delivery within 2–4 business days to major global hubs.

Frequently Asked Questions: AISI 431 Forged Parts Technical & Commercial Guide

The following questions and answers are compiled from actual technical and commercial inquiries received by Jiangsu Liangyi's engineering and sales teams over 27 years of supplying AISI 431 (UNS S43100) forgings globally. These represent the most useful information for engineers and procurement professionals making material and supplier selection decisions.