Invar 36 Forging Parts | Alloy 36 | UNS K93600 | China Professional ISO 9001 Manufacturer

Jiangsu Liangyi Co., Limited is a leading China ISO 9001:2015 certified manufacturer of Invar 36 forging parts, with over 25 years of specialized experience in custom open die forging and seamless rolled ring production. Our Invar 36 (also known as Alloy 36, UNS K93600, and commercially marketed as Nilo 36®) forged products are manufactured to ASTM, AMS, DIN, EN, JIS, ASME, API and NORSOK international standards, and are widely supplied to industrial buyers in more than 50 countries across Europe, North America, the Middle East, Southeast Asia, Oceania and East Asia.

This page is written by our senior nickel alloy forging engineering team with 25+ years of hands-on experience. Beyond product specifications, we share unique proprietary insights into Invar 36's physics, forging challenges, material selection pitfalls, machining recommendations, and real-world engineering case studies — information that goes far beyond typical supplier datasheets and is not available elsewhere.

About Jiangsu Liangyi — Our Invar 36 Forging Factory

Established in 1997 in Jiangyin City, Jiangsu Province, China, our factory covers 80,000 square meters with an original fixed asset of over 40 million USD. We are equipped with advanced production and inspection facilities, including 2000T–6300T hydraulic forging presses, 1–5T electro-hydraulic forging hammers, 1M and 5M seamless rolling machines, ten heat treatment furnaces with precise atmosphere and temperature control, and a full range of NDT, chemical composition, mechanical property and metallographic testing equipment.

Our annual manufacturing capacity reaches 120,000 tons. Our technical team consists of 15+ senior nickel alloy forging engineers, and our quality team includes 5+ ASNT Level III inspectors. We have built a dedicated Invar 36 production knowledge base from over 2,000 completed projects, allowing us to predictively resolve the specific challenges this alloy presents — narrow forging temperature windows, work hardening behavior, grain coarsening sensitivity, and post-forge dimensional stabilization requirements that most general forging shops cannot manage.

The Invar Effect: Why Invar 36 Has Ultra-Low CTE — Physics Explained

Most industrial buyers know that Invar 36 has a very low coefficient of thermal expansion. Very few datasheets explain why — and understanding the mechanism is essential for engineering correctly with this alloy and avoiding costly mistakes.

The Magnetovolume Effect: The True Origin of Low CTE

Invar 36's low CTE is not a coincidence of composition — it is the result of a fundamental quantum mechanical phenomenon called the magnetovolume effect (also referred to as magnetostriction-driven volume anomaly or spontaneous volume magnetostriction). Here is the mechanism:

1. Normal thermal expansion: Like all metals, the iron-nickel lattice naturally expands when heated, driven by increased atomic vibration amplitude. This positive thermal expansion would, in a non-magnetic material, produce a CTE of approximately 12–14 × 10⁻⁶/°C.
2. Spontaneous volume magnetostriction: In the ferromagnetic state (below the Curie temperature), the magnetic exchange interaction between neighboring Fe atoms causes a spontaneous volume expansion of the crystal lattice. This magnetically driven volume change is strongly temperature-dependent — as temperature increases, the spontaneous magnetization decreases, and with it the magnetostriction volume expansion.
3. Compensation: The decrease in magnetic volume expansion with temperature precisely offsets the normal positive thermal expansion. At the specific composition of approximately 36% Ni, these two effects cancel almost exactly in the temperature range of 20°C–200°C, resulting in a net CTE of only ~1.2 × 10⁻⁶/°C. Charles Édouard Guillaume discovered this in 1897 and was awarded the Nobel Prize in Physics in 1920.

Why 36% Nickel is the "Magic" Composition

The magnetovolume compensation is extremely sensitive to nickel content. Reducing the nickel content below ~34% shifts the Curie temperature below room temperature, eliminating the compensation effect. Increasing nickel above ~40% shifts the magnetic ordering in ways that reduce the compensation magnitude. The 35.5%–36.5% Ni range (as specified in UNS K93600) is the narrow "sweet spot" where the two effects cancel most completely across the industrially useful temperature range. This is why our internal nickel control range is precisely 35.5%–36.5% — slightly tighter than the ASTM F1684 standard specification — and is verified by direct-reading spectrometer on every single melt.

Critical Warning: The Curie Temperature Trap at 230°C

What Happens at the Curie Transition

Below ~230°C, Invar 36 is ferromagnetic. Above ~230°C, thermal energy overcomes the magnetic exchange coupling, and the alloy transitions to a paramagnetic state. When this transition occurs:

• The spontaneous volume magnetostriction collapses to zero
• The thermal expansion compensation mechanism disappears entirely
• CTE rises to 12–14 × 10⁻⁶/°C within a temperature band of approximately 10–20°C above the Curie point
• Upon cooling back below the Curie temperature, the low CTE is recovered — but dimensional changes during the high-CTE excursion remain

Implications for Post-Forge Heat Treatment

One of the most common mistakes made by buyers purchasing Invar 36 forgings from suppliers without specialized experience is requesting a stress relief heat treatment at temperatures above the Curie point. Standard stress relief temperatures for nickel alloys (450°C–600°C) are far above the Invar 36 Curie temperature. At these temperatures, Invar 36 behaves as a normal high-CTE alloy, and any residual stress relief also causes macro-scale dimensional changes that cannot be corrected by subsequent cooling. Our proprietary stress relief protocol for Invar 36 keeps temperatures at 150°C–180°C and uses extended time (4–8 hours per inch of section thickness) to achieve effective stress reduction without compromising CTE performance.

Welding Heat-Affected Zone Considerations

The weld heat-affected zone (HAZ) of Invar 36 inevitably exceeds the Curie temperature during welding. After welding, it is essential to perform a post-weld solution annealing treatment (850°C–900°C, followed by rapid controlled cooling) to re-homogenize the HAZ microstructure and restore low-CTE performance. Welded assemblies that are not properly post-weld heat treated may show localized CTE anomalies of 3–8 × 10⁻⁶/°C in the HAZ region, leading to unexpected dimensional drift in precision applications.

Invar 36 vs. Kovar, Super Invar, Invar 42, and CFRP — Material Selection Guide

Invar 36 is the most popular low CTE metallic material but it is not the ideal solution for all applications. Based on more than 25 years of application engineering experience, this guide assists engineers in selecting the appropriate low-CTE material for their particular needs.

Why Forged Invar 36 Outperforms Cast Invar 36: A Technical Comparison

Not all Invar 36 components are equal. The manufacturing route — forging versus casting — profoundly affects the material's actual performance in service. Based on our 25 years of comparative production data, here is the definitive technical case for choosing forged Invar 36 for demanding applications:

Grain Structure and Homogeneity

In cast Invar 36, solidification produces a coarse dendritic grain structure with significant nickel segregation between dendrite cores and interdendritic regions. Dendrite cores typically contain 33–34% Ni while interdendritic zones reach 37–39% Ni. This chemical inhomogeneity causes local CTE variations of up to 0.8 × 10⁻⁶/°C within the same casting. In precision applications, this means the actual dimensional behavior of the part may deviate from calculated values, causing assembly errors that are difficult to trace and impossible to correct after installation.

Forging, combined with our ESR/VAR remelting process, breaks down the dendritic structure. The combination of controlled deformation and diffusion homogenization during forging and annealing reduces nickel segregation to <0.5% variation across the section, delivering a uniform CTE distribution verified by our in-house dilatometer on sectional test coupons.

Porosity, Inclusions, and Structural Integrity

Cast Invar 36 commonly contains shrinkage porosity (volumetric shrinkage during solidification is approximately 3–4%), gas porosity (from dissolved hydrogen and nitrogen), and oxide inclusion clusters from the casting process. These defects degrade fatigue life, create leak paths in pressure-containing components, and provide sites for stress concentration in precision structures. Forging — especially with our ESR pre-treatment — achieves a virtually pore-free, inclusion-minimized microstructure with ultrasonic testing cleanliness ratings to SEP 1921 Class C/C or better.

Mechanical Property Comparison

The Charpy impact values at -196°C are particularly critical for LNG applications, where cryogenic toughness determines whether a structural component survives sudden pressure fluctuations or thermal shock during LNG loading/unloading operations. Our forged Invar 36 routinely achieves ≥ 80 J at -196°C — more than double the typical cast value — providing a substantial safety margin against brittle fracture in LNG service.

Our Full Range of Custom Invar 36 Forged Products

We manufacture a complete portfolio of custom Invar 36 forging parts with strict dimensional tolerance control (standard ±0.5 mm for rough machined; up to ±0.02 mm for precision finish machined parts), adaptable to your specialized industrial applications:

All Alloy 36 forged parts can be supplied in rough machined, semi-finish machined, or fully precision machined condition with complete heat treatment and testing certificates included.

Specialized Melting & Forging Process for Invar 36

Invar 36 is one of the most technically demanding alloys to forge correctly. Its narrow forging temperature window, strong work hardening tendency, extreme sensitivity to nickel content uniformity, and the requirement that its unique CTE property be preserved through every production step place it in a category that requires dedicated expertise. Our approach — developed and refined over 2,000+ Invar 36 projects — differs fundamentally from standard nickel alloy forging practice in the following ways:

Why Invar 36 is Difficult to Forge (and What We Do About It)

• Narrow temperature window: Forging must be performed between 900°C and 1,200°C. Above 1,200°C, austenite grain growth accelerates exponentially (grain size can increase 3× in 30 minutes at 1,250°C), degrading mechanical properties and CTE uniformity. Below 900°C, work hardening increases rapidly and the risk of internal tearing and surface cracking rises. Our proprietary in-forge pyrometric monitoring system tracks surface temperature continuously throughout the forging sequence, triggering an automatic reheating alarm if any zone drops below 920°C.
• Work hardening behavior: Invar 36 has a high work hardening rate (n-value ~0.3–0.35), meaning each forging pass significantly increases flow stress. Inexperienced forging shops attempting to take excessive reduction per heat create adiabatic shear bands and internal cracking — defects that may only be revealed by ultrasonic testing and are not recoverable. Our pass reduction schedule is derived from 25 years of flow stress modeling data, using incremental 15–25% reduction per heating cycle with intermediate reheats.
• Post-forge grain size control: Achieving ASTM grain size 5–8 in the annealed condition requires precise control of total deformation ratio, final forging temperature, and annealing temperature. Insufficient total deformation (<3:1 reduction ratio) results in unrecrystallized coarse grain areas. Insufficient annealing temperature (<820°C) leaves residual deformation energy. Excessive annealing temperature (>950°C) triggers grain growth. Our recipe targets 850°C–880°C for 1 hour per 25 mm of section thickness, consistently achieving grain size 5–7 across the full section.

Premium Melting & Refining Routes

Standard Industrial Grade Route (LNG, Oil & Gas, General Industrial)

1. Primary melting via 30T Electric Arc Furnace (EF)
2. Secondary refining via Argon Oxygen Decarburization (AOD), Vacuum Oxygen Decarburization (VOD), or Vacuum Degassing — controls dissolved H to < 2 ppm, O to < 20 ppm, N to < 80 ppm
3. Final refining via Electroslag Remelting (ESR) — breaks up dendritic segregation, removes oxide inclusions, improves surface quality; typical sulfur reduction from 0.004% to ≤ 0.002%
4. Optional secondary Vacuum Arc Remelting (VAR) for high-demand cryogenic applications requiring ASTM A484 Class 1 cleanliness

Aerospace & High-Precision Grade Route (Aerospace, Satellite, Laser)

1. Primary melting via Vacuum Induction Melting (VIM) — prevents atmospheric contamination during primary melt, achieves H < 1 ppm, O < 10 ppm
2. Secondary refining via Electroslag Remelting (ESR) or Vacuum Arc Remelting (VAR)
3. Optional double VAR process for critical aerospace satellite structural applications — achieves the highest achievable isotropy and the most uniform Ni distribution, CTE variability within ±0.03 × 10⁻⁶/°C across section

Precision Forging & Heat Treatment Process

With our 2000T–6300T hydraulic forging presses, 1–5T electro-hydraulic forging hammers and 5M seamless rolling machines, we strictly control the forging temperature window of Invar 36 (900°C–1,200°C). Our proprietary heat treatment process — solution annealing at 850°C–900°C followed by controlled cooling — fully stabilizes the face-centered cubic (FCC) austenitic microstructure and ensures the ultra-low CTE performance and mechanical properties meet the requirements of extreme operating conditions from -270°C to 200°C.

Invar 36 (UNS K93600) Standard Chemical Composition

Our Invar 36 (UNS K93600) forging parts strictly adhere to the following composition limits. These products meet the same specification as materials commercially marketed under trade names such as Nilo 36® — and meet UNS K93600 and ASTM F1684 chemical composition standards. Every single melt is verified by our in-house direct-reading optical emission spectrometer (OES) and carbon-sulfur combustion analyzer. Our internal control limits are tighter than the published standard to ensure CTE performance and inter-batch consistency:

Mechanical Properties & CTE Data Across Temperature Range

All Invar 36 forging parts from Jiangsu Liangyi are supplied in solution annealed (+AT) condition with the following guaranteed properties, based on our continuous in-house testing database of 2,000+ production batches:

CTE Performance Across the Full Operating Temperature Range

The CTE of Invar 36 is not constant — it varies with temperature and magnetic state. The table below, based on our in-house dilatometer database and published literature, provides a reliable engineering reference for design calculations:

Physical Properties Reference

• Density: 8.05 g/cm³
• Elastic Modulus (E): ~141 GPa at 20°C
• Thermal Conductivity: 10.5 W/(m·K) at 20°C
• Electrical Resistivity: ~0.82 µΩ·m at 20°C
• Specific Heat Capacity: 515 J/(kg·K) at 20°C
• Curie Temperature: ~230°C (variable ±20°C depending on exact Ni content and trace element levels)
• Melting Range: 1,430°C–1,450°C

Magnetic Properties of Invar 36 & Electromagnetic Considerations

Invar 36 is ferromagnetic at room temperature — a direct consequence of its nickel-iron composition and the same magnetic exchange interaction that gives it the low CTE property. This magnetic behavior has important implications for design, material handling, and certain application categories that are rarely discussed in supplier datasheets.

Main Magnetic Parameters

• Relative magnetic permeability (µr): 2,000–3,000 at room temperature (soft magnetic material, easily magnetized and demagnetized)
• Coercive force (Hc): 15–25 A/m (very magnetically soft — low residual magnetism after removal of external field)
• Saturation magnetization: ~1.26 Tesla at 20°C
• Curie temperature: ~230°C (transition to paramagnetic)

Design Implications of Invar 36 Ferromagnetism

• MRI and sensitive electromagnetic equipment: Invar 36 components should not be used in or near strong magnetic field environments (e.g., MRI machines, Hall effect sensors, particle accelerator beam guides) without magnetic shielding or substitution with a non-magnetic low-CTE alternative. The high permeability will distort local magnetic fields.
• Eddy current testing (ET): The ferromagnetic nature makes eddy current NDT more complicated. Our NDT team uses specialized low-frequency probes and flux saturation techniques for eddy current inspection of Invar 36 forgings where required.
• Machining with magnetic chucks: The ability to firmly clamp Invar 36 on electromagnetic chucks during surface grinding and high-precision machining makes it superior to austenitic stainless steel. For high-accuracy optical and instrument-grade applications, residual magnetism after machining must be strictly controlled. Our workshop is capable of providing professional demagnetization treatment to satisfy such technical requirements.
• Material traceability and sorting: Unlike austenitic stainless steel, Invar 36 responds strongly to a permanent magnet — a useful quick-check for material identification in mixed alloy environments. However, this does not replace chemical composition verification.

Machining, Welding & Surface Treatment Guidance for Invar 36 Forgings

Successfully working with Invar 36 in your facility requires understanding its specific machining, welding, and surface treatment characteristics. Based on feedback from our global customers over 25 years, the following guidance addresses the most common challenges encountered when processing Invar 36 forged components:

Machining Invar 36: Key Challenges and Solutions

Invar 36 is a moderately difficult material to machine due to its combination of high ductility, significant work hardening tendency, and low thermal conductivity. Built-up edge on cutting tools, poor surface finish, introduction of residual stress and unexpected dimensional changes after machining are the result of poor machining practice.

• Cutting tool selection: Carbide tools (K05–K15 grade, uncoated or TiN coated) preferred over high-speed steel. Positive rake angle geometry (8°–15°) essential to minimize work hardening. Avoid conventional carbide grades with high cobalt binder, which adhere to Invar 36 chips.
• Cutting speed and feed: Recommended cutting speed: 60–100 m/min for turning; 40–80 m/min for milling. Feed rate: 0.1–0.2 mm/rev for roughing, 0.05–0.08 mm/rev for finishing. Do not dwell or rub the tool on the surface — this immediately work hardens the surface and degrades subsequent cut quality.
• Coolant: Flood cooling essential. Neat cutting oil provides better surface finish; water-soluble coolant (8–10% concentration) acceptable for roughing. Never dry machine — the low thermal conductivity of Invar 36 concentrates heat at the cutting edge, accelerating tool wear and inducing thermal residual stresses.
• Dimensional stability after machining: For precision parts requiring tolerances tighter than ±0.05 mm, a stress relief heat treatment at 150°C–180°C for 4–8 hours per 25 mm section thickness (below the Curie temperature) is recommended after rough machining and before final finish machining. This releases machining-induced residual stresses that would otherwise cause slow dimensional drift over weeks to months in service.
• Magnetic chuck use: Effective and recommended for surface grinding. After grinding, demagnetize parts to residual field < 5 Gauss for sensitive applications.

Welding Invar 36 Forged Components

Invar 36 is weldable by TIG (GTAW), MIG (GMAW), plasma arc, and electron beam welding. Resistance welding is also applicable for thin-section joining. Key requirements for successful Invar 36 welding:

• Filler material: Use Invar 36 matching filler (e.g., AWS ERNi-1, ER36 grade Invar filler wire). Do not use austenitic stainless steel or regular nickel alloy fillers — they will cause CTE mismatch at the weld joint.
• Preheat: Sections under 10 mm — no preheat required. Sections 10–50 mm — preheat to 80°C–120°C. Sections over 50 mm — preheat to 120°C–150°C. Interpass temperature should not exceed 150°C to keep the HAZ below the Curie point during welding.
• Post-weld heat treatment (PWHT): Required for structural assemblies requiring uniform CTE. PWHT, 1 hour for each 25 mm section thickness, at 850°C–900°C, followed by rapid cooling. This re-solutionizes the HAZ microstructure and restores CTE to ≤ 1.5 × 10⁻⁶/°C. Note: Standard PWHT temperatures used for carbon steel (600°C–650°C) are above the Invar 36 Curie point and must NOT be used.
• Shielding gas: 100% argon or Ar/He mixture for TIG. CO₂-containing shielding gases should be avoided as carbon pickup in the weld pool increases weld bead hardness and reduces ductility.

Surface Treatment & Corrosion Protection

Invar 36 has moderate corrosion resistance — better than carbon steel but inferior to austenitic stainless steel. In clean, dry industrial environments, Invar 36 forms a stable passive layer and requires no surface treatment. For more aggressive environments, the following surface treatments are compatible:

• Electroless nickel plating (EN): Recommended for improved corrosion resistance and wear resistance. Thickness 25–75 µm. Note: the plating CTE is ~13 × 10⁻⁶/°C, so thermal cycling may cause cracking in thick coatings on thin-wall parts.
• Hard chrome plating: Applicable for wear-resistant surfaces on valve stems and actuator components. Thickness 10–50 µm.
• Passivation (nitric acid): Suitable for general corrosion protection in mild environments. Does not significantly affect dimensional tolerance.
• Physical Vapor Deposition (PVD) coatings: TiN, TiCN coatings for precision instrument surfaces requiring both wear resistance and low CTE base material. PVD process temperatures (< 200°C) safely below the Curie point.
• Avoid: Hot-dip galvanizing (> 400°C process) and phosphating at high temperatures — both exceed the Curie temperature and will disturb the microstructural CTE properties.

Rigorous Quality Control & International Certification

We operate a complete ISO 9001:2015 quality management system for all Alloy 36 forgings that we manufacture. Our quality system is not just certified, but also incorporates proprietary process controls and inspection protocols developed to address the unique metallurgical behavior of Invar 36:

Our Proprietary Three-Stage CTE Verification Protocol

Standard EN 10204 3.1 certificates do not require CTE verification — they only require chemical composition and room temperature mechanical properties. For precision applications, chemical compliance alone is insufficient: small variations in trace elements, residual stresses, and local deformation history can produce CTE deviations even within a chemically compliant forging. Our three-stage CTE verification protocol — unique in the China forging market — addresses this:

1. Stage 1 — Spectrometric Ni content control: Nickel verified to 35.5%–36.5% (±0.5% vs. ASTM's ±1%) immediately after each melt, before any further processing.
2. Stage 2 — Post-anneal dilatometer testing: Representative test coupons taken from each forging batch are tested on our precision dilatometer from -50°C to 250°C, generating a full CTE-vs-temperature curve. CTE at 20°C–100°C must confirm ≤ 1.5 × 10⁻⁶/°C before the batch proceeds to final machining.
3. Stage 3 — Section CTE uniformity check (for forgings > 5 tons): For large forgings, coupons from both ends of the forging are dilatometer-tested separately. Maximum permissible CTE difference between any two coupons from the same forging: 0.1 × 10⁻⁶/°C. Forgings exceeding this threshold are quarantined for investigation.

Full Testing Capabilities

• Chemical Analysis: Direct-reading OES spectrometer and carbon-sulfur combustion analyzer for full element verification per melt
• Mechanical Testing: Room temperature and low/high temperature tensile testing (-196°C to +200°C), Charpy impact testing (-196°C to +175°C), hardness testing (Brinell, Rockwell, Vickers), creep testing
• Metallographic Testing: Macro-etching inspection, ASTM E112 grain size analysis, ASTM E45 inclusion rating, SEP 1921 cleanliness rating, microstructure phase analysis
• Non-Destructive Testing (NDT): 100% ultrasonic testing (UT) per EN 10228-3/ASTM A388, liquid penetrant inspection (PT) per EN 10228-2, magnetic particle inspection (MT) per EN 10228-1
• Dimensional Inspection: CMM dimensional verification, surface roughness measurement (Ra 0.8–6.3 µm range), roundness and straightness per DIN 7151
• CTE Testing: precision dilatometer, -100°C to 300°C range, ±0.02 × 10⁻⁶/°C measurement accuracy
• Pressure Testing: Hydrostatic pressure testing to 1.5× design pressure for pressure-containing components

International Certifications & Compliance

• ISO 9001:2015 Quality Management System Certification
• EN 10204 3.1/3.2 Mill Test Certificate (MTC) for every batch
• PED 2014/68/EU — European Pressure Equipment Directive (Notified Body: TÜV/BV)
• ASME Section II Part B — North American Boiler & Pressure Vessel Code
• API 6A Product Specification Level (PSL) 1, 2, 3 — Oil & Gas Wellhead & Christmas Tree Equipment
• NORSOK MDS D46 — Norwegian Offshore Industry Material Data Sheet
• AMS 1444 — Products manufactured to this aerospace material specification
• JIS G 4901 / JIS G 3214 — Japanese Industrial Standards for Nickel Alloy

Global Industrial Applications & GEO-Targeted Project Cases

Our Invar 36 forging parts are proven across the world's most demanding industrial sectors. The following are real project case summaries from our production records (client identities protected per confidentiality agreements), representing the breadth and depth of our application expertise:

LNG Transport & Cryogenic Storage — European & Southeast Asian Market

The LNG industry is the single largest consumer of Invar 36 globally, with the alloy used in membrane-type LNG carrier tanks and onshore LNG storage tank inner membranes (GTT No. 96 and Mark III membrane systems). Beyond membrane sheet material, we supply custom Invar 36 forged pipes, seamless sleeves, valve seats, pump column connectors and transfer line components for LNG tanker construction and onshore LNG terminal projects in Germany, France, Netherlands, Singapore, Malaysia, and South Korea.

At the -163°C boiling point of liquefied natural gas, carbon steel contracts by approximately 2 mm per meter of length — enough to break welds, crack flanges, and cause catastrophic leakage. Our Invar 36 valve seat forgings, with CTE ≤ 1.5 × 10⁻⁶/°C, contract by only 0.3 mm per meter over the same temperature drop — ensuring tight sealing and structural integrity over decades of thermal cycling in LNG service. All LNG components carry PED 2014/68/EU certification and EN 10204 3.2 third-party inspection by Bureau Veritas or TÜV Rheinland.

Aerospace Composite Mold Tooling — North American & European Market

The commercial aviation industry's adoption of carbon-fiber reinforced polymer (CFRP) structures for aircraft fuselage, wings, and nacelles requires autoclave tooling molds that maintain dimensional accuracy across the cure cycle (typically 180°C for 2 hours at 7–8 bar pressure). The CFRP layup and mold surface must have matched CTE to prevent spring-in deformation in the cured part. Our Invar 36 forged mold base and frame components have been supplied for large commercial aircraft and regional jet CFRP wing skin and fuselage panel tooling programs.

A key engineering challenge we solve in this application: at 180°C (above the Curie temperature's approach zone where Invar 36 CTE begins rising), standard Invar 36 shows CTE of approximately 2.5–4.0 × 10⁻⁶/°C. For critical autoclave tooling applications, we offer engineering support to select the optimal alloy (standard Invar 36 for 120°C cure cycles, Super Invar for room-temperature cure with high precision requirements) and produce tooling frames with verified CTE across the full cure temperature cycle. Flatness on finished mold frames: < 0.3 mm over 3 m length after final heat treatment and stabilization.

Oil & Gas Industry — Middle East & Nordic Market

LNG processing facilities, offshore FLNG (floating LNG) vessels, and deepwater subsea production systems operate liquefaction trains at temperatures reaching -162°C. We supply UNS K93600 forged valve bodies, bonnet forgings, valve stems, seats and wellhead components for oil and gas projects in Saudi Arabia (ARAMCO supply chain), UAE (ADNOC supply chain), Qatar (RasGas/QatarGas projects), and Norway (offshore North Sea platforms).

For Norway's NORSOK-regulated projects, all our Invar 36 forgings are manufactured to NORSOK MDS D46 specification requirements with full documentation, including supplementary charpy impact testing at -196°C (minimum 60J average, 45J single), HISC (Hydrogen Induced Stress Cracking) evaluation data, and cathodic protection compatibility assessment for subsea applications. This comprehensive documentation package is assembled by our dedicated NORSOK compliance team — an in-house capability that eliminates months of re-qualification work for our Nordic clients.

Satellite & Space Structural Components — Global Aerospace Market

Satellites experience temperature swings from +120°C (sun-facing) to -200°C (eclipse) within a single orbit. Structural components connecting electronic subsystems must maintain dimensional stability within ±0.05 mm over this full thermal cycle to prevent misalignment of optical sensors, antenna pointing systems, and solar panel deployment mechanisms. We manufacture precision Invar 36 forged satellite bus structural brackets, optical bench frames, and thermal compensation rod assemblies for European Space Agency (ESA) supply chain contractors and commercial satellite manufacturers.

For space applications, we offer the VIM+VAR double-remelt grade with helium leak testing at 10⁻⁹ mbar·L/s sensitivity, ASTM E1417 penetrant inspection to Class 4 sensitivity, and dimensional verification by CMM with traceable calibration to national standards (CNAS accredited).

OLED & Semiconductor Manufacturing Equipment — Global Electronics Market

The production of OLED displays and advanced semiconductor devices requires vacuum deposition equipment with shadow mask frames that maintain precise alignment tolerances (< 5 µm over 1 m) during deposition cycles at 100°C–180°C. Invar 36 is the industry-standard material for large-generation OLED shadow mask frames, tension frames, and fine metal mask (FMM) support structures. We supply precision Invar 36 forged and machined frames to display manufacturing equipment suppliers in South Korea, Japan, and China for Gen 6, Gen 8, and Gen 10.5 OLED production lines.

Surface flatness requirements for these components are the most stringent in our product portfolio: flatness within 50 µm over 1,500 mm length, surface roughness Ra ≤ 0.4 µm, and residual magnetic flux density < 5 Gauss (to prevent interference with the electromagnetic shadow mask tensioning system). Our dedicated OLED component cell within our machine shop — with controlled temperature environment (22°C ± 1°C) — is set up specifically for these ultra-precision requirements.

Precision Instruments, Laser Systems & Thermostats — Global Market

We supply custom Invar 36 forgings and precision machined components to industrial automation, metrology, laser physics, and thermostatic control clients across 50+ countries. Representative applications include: optical bench frames and mirror mount housings for high-power industrial laser systems (Nd:YAG, CO₂, fiber laser), length standard bars for dimensional metrology laboratories, bi-metal thermostat passive elements (Invar 36 bonded to high-CTE copper or stainless steel), clock pendulum rods and balance wheel components for scientific clocks, and Fabry-Pérot interferometer spacer bars for spectroscopy applications.

For laboratory and instrumentation clients, we offer a Certificate of Conformance specific to dimensional metrology requirements, including material density verification, CTE per dilatometer over the specific service temperature range, Young's modulus, and specific heat capacity values from our in-house materials characterization laboratory.

Invar 36 Forging Procurement Checklist: What to Specify When Ordering

From our experience handling 2,000+ Invar 36 forging orders from buyers in 50+ countries, the most common source of delays, cost overruns, and non-conformances is incomplete or incorrect specifications at the point of ordering. This checklist — developed by our customer engineering team — ensures your order is processed correctly from the first interaction:

Essential Information to Provide with Your Enquiry

• Material designation: Specify at least one of: Invar 36 / Alloy 36 / UNS K93600. If special purity is needed, specify VIM, ESR, or VAR remelting route.
• Dimensions & weight: Provide a 2D drawing (PDF, DXF, DWG) or 3D model (STEP, IGES) with all tolerances. If only rough forging is needed, specify envelope dimensions and weight. If finish machined, specify all important dimensions and surface roughness (Ra).
• Heat treatment condition: Typically solution annealed (+AT). If you need a specific hardness or strength level outside standard +AT condition, specify this explicitly.
• Quantity and delivery schedule: Per piece and total quantity; required delivery date; whether expedited production is acceptable at premium cost if standard lead time is insufficient.
• Application service conditions: Minimum and maximum service temperature; working pressure (if pressure-containing component); exposure environment (LNG, seawater, corrosive gas, vacuum, etc.).
• Test and inspection requirements: Specify needed mechanical tests (tensile, impact, hardness), NDT methods (UT, PT, MT), chemical analysis reporting, and CTE verification if needed.
• Certification requirements: Specify EN 10204 level (3.1 standard; 3.2 if third-party inspection required and by which body: TÜV, SGS, BV, DNV, LLOYDS, etc.); applicable codes (PED, ASME, API 6A, NORSOK, AMS, JIS).
• Country of destination: Affects export documentation, customs HS code classification, and applicable import certifications.

Targeted Global Markets & Localized Services

We have built deep export expertise over 25 years, with mature logistics solutions, localized certification packages, and multilingual technical support for each of our main target markets:

Why Choose Jiangsu Liangyi as Your Invar 36 Forging Partner in China

Frequently Asked Questions (FAQ) About Invar 36 Forging Parts