| Jiangsu Liangyi Technical Team | ⏱ ~12 min read
31CrMo12 (1.8515) Forging Parts | ISO Certified Custom Alloy Steel Forgings Manufacturer
📌Summary: 31CrMo12 (1.8515) Forging Parts
- Material: 31CrMo12 (EN material number 1.8515) — high-performance chromium-molybdenum (Cr: 2.80–3.30%, Mo: 0.30–0.50%) alloy steel according to EN 10083-3:2006.
- Manufacturer: Founded in 1997, Jiangsu Liangyi Co. is located in Jiangyin City, Jiangsu Province, China, and our company is ISO 9001:2015 certified
- Products: Open die forgings, seamless rolled rings (OD up to 5000mm), gear shafts, round bars (Ø up to 1200mm), hollow parts — 30kg to 30,000kg per piece.
- Tensile Strength (Q&T, 40–100mm): 980–1180 MPa | Yield Strength: ≥785 MPa | Impact Energy: ≥20J at 20°C.
- Standards: EN 10083-3, ASTM A788, ASTM A29, PED 2014/68/EU, EN 10228, ISO 6336-5.
- Certification: EN 10204 Type 3.1 standard (3.2 with third-party available). Full traceability for 10+ years.
- Lead Time: 20–35 working days | Delivery: 50+ countries worldwide | Contact: [email protected]
📋 Table of Contents
With over 25 years of industry experience, an 80,000 ㎡ modern production base, and an annual manufacturing capacity of 120,000 tons, we supply high-performance quenched and tempered 31CrMo12 alloy steel forgings to customers in more than 50 countries across Europe, North America, Australia, the Middle East, Southeast Asia, South America and Africa.
This high-grade chromium-molybdenum alloy steel meets EN 10083-3:2006 and has good hardenability (even for large-section components up to 250mm thick), high surface wear resistance, good toughness, great fatigue strength, and stable mechanical properties under extreme heavy loads and high pressure. → Jump to: Chemical Composition | Mechanical Properties | Applications | FAQ
Full Customization Capability
We can make custom 31CrMo12 forgings based on your drawings, with weights ranging from 30 kg to 30,000 kg for a single piece. We support small quantity orders and mass production orders.
One-Stop Full-Process Service
One-stop service From steel melting to open die forging, CNC machining, heat treatment, strict quality control, and global delivery.
Strictly Meet International Standard
All forgings strictly meet EN, ASTM, DIN, ISO standards, we provide full traceability and complete material certification for every batch.
Advanced Production & Inspection
We have a 6300T hydraulic forging press, a 5M ring rolling machine, and a full set of NDT testing tools to make sure our parts are of high quality.
Main Advantages of 31CrMo12 (1.8515) Steel
Good Through-Hardenability
It has consistent mechanical properties even in parts up to 250 mm thick. This solves the main softness problem that often exists in low alloy steel.
High Wear & Fatigue Resistance
Its surface is very hard after heat treatment, so it can work well in heavy machinery's long-term cyclic loads without breaking.
Better Toughness & Strength Balance
It has a high tensile and yield strength while still being very tough on impact, even at low temperatures.
Good Elevated Temperature Performance
It keeps stable mechanical properties at moderately high temperatures, so it is good for power transmission and industrial equipment use.
Full Range of Custom 31CrMo12 (1.8515) Forging Parts
We make all kinds of 31CrMo12 (1.8515) forged parts as below but not limited:
- Forged Bars and Rods: Round, square, flat, rectangular, solid, and stepped bars and rods, with a maximum diameter of 1200 mm and a maximum length of 12000 mm.
- Seamless Rolled Rings: Gear rings, riding rings, slewing bearing races, contoured rolled rings — OD up to 5000mm, wall thickness 50mm to 800mm.
- Shafts & Gear Components: Gear shafts, pinion shafts, spindles, crankshafts, rotary kiln shafts, turbine shafts, gear wheels, and pinions, they all meet ISO 6336-5 MQ quality grade.
- Hollow & Casing Parts: Forged sleeves, bushings, housings, shells, cases, hollow bars, pipe tubes, barrels, and hydraulic honed cylinders, and they are used for heavy machinery.
- Custom Shaped Forgings: Discs, disks, blocks, plates, flanges, valve bodies, and custom-shaped forgings fully based on clients' drawings and technical requirements.
All forged parts can be provided under forging, normalizing, quenching and tempering (Q&T), rough-machining, or finish-machined conditions. Custom surface treatments such as nitriding and quenching are also acceptable.
Industrial Uses & Global Cases
31CrMo12 (1.8515) forged parts are widely used in heavy-duty industries, and they have good performance under harsh working conditions.
Wind & Hydro Renewable Energy Industry
31CrMo12 steel is the industry-standard material for critical transmission parts in renewable energy equipment, it has great fatigue resistance, surface durability, and long-term reliability in different load conditions.
- Main applications: Mainly used gear shafts of wind turbine gearbox gear shafts, annular gears, pinion shafts, planet gears, main shafts of water turbines, rotor shafts of generators and parts of tidal energy equipment.
We provided custom 31CrMo12 forged gear shafts and ring gears for the 8MW offshore wind turbine gearboxes of the North Sea project (Germany and the Netherlands).
Mining & Heavy Engineering Industry
Our 1.8515 alloy steel forgings are ideal for high-impact, heavy-load equipment in mining and construction, with good strength and toughness to reduce downtime under continuous working condition.
- Main uses: Mainly used in the shafts of crushers, rotary crushers, rotary bearings, mine hoists, conveyor pulleys, excavators, crusher pulleys, drag cables, etc.
Supplied large forged eccentric shafts (>2.5 tons) for gyratory crushers in iron ore mines in Western Australia. All of them meet ASTM A788, and they are hard enough to withstand impact.
Cement & Building Materials Industry
31CrMo12 forged parts are widely used in large-scale cement production lines, supporting the stable operation of heavy-duty rotary kilns, grinding mills, and drying equipment.
- Main Uses: Mainly used for pinion shafts of cement grinding rotary kilns, riding gear rings, tension and torsion rods, bearing wheels of rotary dryers, gear shafts of granulators and parts of drying and coating machines.
We provided case-hardened ground pinion shafts for a 5000t/d cement production line in the UAE. They all meet DIN 3990-5 gear quality standards and have stable transmission and long wear life under continuous high-load, high-temperature operation.
Oil & Gas Exploration & Production Industry
1.8515 alloy steel is widely used in onshore and offshore oil and gas drilling and production equipment, and it has good hardenability and mechanical stability even under high pressure, alternating loads, and corrosive environments.
- Main Uses: They are used for Oil drilling tool gear shafts, mud pump herringbone gear shafts, winch stub shafts, hydraulic honed cylinders, wellhead components, valve bodies and subsea equipment parts.
We provide custom 31CrMo12 forged herringbone gear shafts for land drilling rig mud pumps in the Texas shale gas field, USA. They have high tensile strength and fatigue resistance, and all meet strict NDT requirements and API related standards.
General Mechanical Engineering & Transportation Industry
31CrMo12 is used in general machinery, automotive, locomotive, heavy truck, power transmission and other industries.
- Main Uses: They are used for gas compressor crankshafts, mechanical press crankshafts, pump crankshafts, gearbox gear wheels, reducer pinion shafts, locomotive transmission shafts, crane wheels, heavy truck ring gears, concrete mixer bearing rings, and gear couplings.
We provided 1.8515 forged crankshafts for large reciprocating gas compressors for a well-known German industrial equipment manufacturer. And they all passed strict mechanical property testing and full UT flaw detection, with EN 10204 3.1 certificates provided for each batch.
Other Industrial Uses
We also customize 31CrMo12 (1.8515) forgings for sugar factories, flue gas desulfurization (FGD) systems, shipbuilding, metallurgical cold rolling mills and offshore engineering projects.
Manufacturing Process of 31CrMo12 Steel and Precision Forging Process
We follow strict and standardized manufacturing processes that are in accordance with the international standard EN 10083-3 to make sure that each batch of 31CrMo12 (1.8515) forgings has high quality and stable performance.
- Steel Melting: We use a 30-ton EAF, LF ladle refining furnace and VD vacuum degassing process to produce 31CrMo12 ingots, and these parts have high-purity, low impurities and consistent chemical composition.
- Precision Open Die Forging: This is done on hydraulic forging presses with a capacity of 2000T to 6300T and a minimum forging ratio of ≥3:1. It breaks down the cast structure, refines the grain size, increases the internal density, and improves the mechanical properties.
- Seamless Ring Rolling: We use CNC seamless ring rolling machines with a range of 1M to 5M to produce parts, so that they have stable internal structure and correct sizes, which prevents welding defects and increases load-bearing capacity and fatigue life.
- Controlled Heat Treatment: We use our computer-controlled heat treatment furnaces to perform quenching and tempering, case hardening, normalizing or annealing, so that the parts have stable properties all the time.
- Good Machining: Using large CNC lathes, milling machines, grinding machines, gear hobbing machines, and other tools to do rough machining, semi-finish machining and finish machining.
- Strict Quality Inspection: Each batch is checked, including the chemical composition, the forging process, the mechanical properties after heat treatment, the size, and NDT.
31CrMo12 (1.8515) Chemical Composition (EN 10083-3 Standard)
We strictly control the chemical composition of each heat of 31CrMo12 steel, with full traceability and third-party inspection results.
| Chemical Element | Standard Content Range (Weight %) |
|---|---|
| Carbon (C) | 0.28 – 0.35 % |
| Silicon (Si) | Max 0.40 % |
| Manganese (Mn) | 0.40 – 0.70 % |
| Phosphorus (P) | Max 0.025 % |
| Sulfur (S) | Max 0.035 % |
| Chromium (Cr) | 2.80 – 3.30 % |
| Molybdenum (Mo) | 0.30 – 0.50 % |
Mechanical Properties of 31CrMo12 (1.8515) Forged Steel
After standard quenching and tempering (Q&T) heat treatment, the mechanical properties are checked. All properties meet or exceed what EN 10083-3 requires.
| Section Diameter / Thickness | Tensile Strength (Rm) | Yield Strength (Re) | Elongation (A) | Impact Energy (KV at 20°C) |
|---|---|---|---|---|
| 16 – 40 mm | 1030 – 1230 MPa | ≥ 835 MPa | ≥ 10 % | ≥ 20 J |
| 40 – 100 mm | 980 – 1180 MPa | ≥ 785 MPa | ≥ 11 % | ≥ 20 J |
| 100 – 160 mm | 930 – 1130 MPa | ≥ 735 MPa | ≥ 12 % | ≥ 20 J |
| 160 – 250 mm | 880 – 1080 MPa | ≥ 675 MPa | ≥ 12 % | ≥ 20 J |
For custom heat treatment requirements (surface hardening or nitriding), we can adjust the process to meet specific hardness and mechanical property requirement. A Full set of mechanical property test reports are provided for each batch.
Inspection Standards & Strict Quality Control System
The quality control laboratory is equipped with one direct reading spectrometer, one universal mechanical property testing machine, one impact testing machine, one hardness tester, one metallographic microscope and a full set of non-destructive testing tools.
- General Standards for Steel Forgings: ASTM A788, ASTM A29, EN 10250, and other standards for steel forgings.
- Chemical Composition Analysis: ASTM A751, EN 10083-3. Complete element analysis is performed for each heat of steel.
- Mechanical Property Testing: ASTM A370, ISO 6892-1 (tensile test), ISO 148-1 (Charpy impact test). Test samples are taken from the same heat-treated batch.
- Hardness Testing: ASTM E18, ASTM E10, and ASTM E110. You can test hardness with Brinell, Rockwell, or Leeb methods.
- Metallographic Testing: ASTM E112 is used for testing grain size, non-metallic inclusion grade, microstructure analysis and decarburization layer testing.
- Non-Destructive Testing (NDT): ISO 9712/EN 10228 for Ultrasonic Test (UT); ISO 9934 for Magnetic Particle Test (MT); ISO 3452 for Penetrant Test (PT). Radiographic testing (RT) is available on request.
- NDT Personnel Qualification: All NDT operators are certified at Level 2 and Level 3 according to ISO 9712 and SNT-TC-1A standards.
Material Certification & Full Traceability System
We provide a full set of material certificate for each batch of finished 31CrMo12 (1.8515) forged parts. The certificate includes:
- Customer order number, item number, and drawing reference
- Material grade names: 31CrMo12 / 1.8515, with steel heat number and batch number
- Full chemical composition analysis results of the steel heat
- Heat treatment method record, including heat treatment type, temperature and holding time
- Full mechanical properties test results, including tensile strength, yield strength, elongation, impact energy and hardness
- Non-destructive testing (NDT) qualification certificate and test results
- Size inspection report, statement that are in accordance with relevant standards and customer requirements
EN 10204 Type 3.2 certificate with third-party inspection (BV, SGS, TUV, etc.) is also available upon request. Every production is traceability from original steel melting to final shipment.
Global Clients & Industry References
Since 1997, Jiangsu Liangyi has supplied 31CrMo12 (1.8515) forging parts to over 50 countries, building long-term partnerships with leading industrial companies worldwide.
🌍 Europe
Long-term supply to wind turbine gearbox manufacturers and industrial equipment companies in Germany, Netherlands, UK, Italy, France, Spain, Poland. EN 10083-3 and PED 2014/68/EU accordance.
🌏 Asia-Pacific
Serving cement plant operators, mining equipment manufacturers and offshore energy companies in Australia, Japan, South Korea, India, Southeast Asia. Full ASTM A788 / EN document.
🌎 Americas & Middle East
Supplying oil & gas drilling equipment makers and heavy machinery OEMs in USA, Canada, Brazil, UAE, Saudi Arabia. API and ASME-compatible certification available.
📋 Other Regions
References are available. Qualified buyers can get detailed information about past projects, and sample EN 10204 3.1 certificates upon request.
Under the premise of abiding by the client's confidentiality agreement, we are more than willing to contact existing clients for potential clients and conduct background checks. Please contact [email protected] to request references or visit our Reference page for recorded project cases.
Why Choose Jiangsu Liangyi for 31CrMo12 (1.8515) Forgings?
Jiangsu Liangyi has focused on making alloy steel forgings for almost 30 years. We are a trusted partner for buyers, design teams and project managers all over the world.
⭐ Verified Reviews
We encourage clients to leave honest reviews on third-party platforms after project delivery. Verified reviews from our real customers can be found on Alibaba Trade Assurance, Google Business Profile, and SGS/BV inspection records. We do not publish unverified testimonials on this page in line with Google's review policies.
→ View our documented project references | Request client references by email
Our technical team consists of materials engineers, quality engineers and application specialists. They all have rich experience in chromium-molybdenum alloy steel. We work closely with our customers from the design stage all the way to final delivery. We offer full DFM checks, help you choose the right materials, and optimize the whole production process.
Other Alloy Steel Forging Products
In addition to 31CrMo12 (1.8515), we make a full range of alloy steel forgings. Check our other products for your engineering requirements:
Frequently Asked Questions (FAQ) About 31CrMo12 (1.8515) Forgings
31CrMo12 (material number 1.8515) is a high-performance chromium-molybdenum alloy steel that meets EN 10083-3:2006. It has good hardenability, high wear resistance after heat treatment, good toughness and fatigue strength, and it also has stable mechanical properties even under heavy loads and high pressure. It is used for heavy-duty forging parts in global industrial uses.
The main difference is the alloy content: 31CrMo12 has a much higher chromium content (2.8-3.3%) than 42CrMo4 (0.9-1.2%), which make sure it has better hardenability, wear resistance, and corrosion resistance. This means that 31CrMo12 is better for large parts which need higher surface hardness and wear resistance. On the other hand, 42CrMo4 is better for general medium-load uses because it costs less.
After standard quenching and tempering (Q&T) heat treatment, the hardness of 31CrMo12 steel ranges from 280 to 350 HB, depending on the size of the section and the temperature at which it was tempered. The surface hardness can be between 58 and 62 HRC for case hardening uses, and the depth of the hardened case can be changed.
Yes, we support both small sample production and large-volume mass production. For a single part, our minimum order weight is 30 kg. We can make custom parts for you once or for a long time with mass orders.
The standard lead time is 20-35 days. It always depends on part drawing, order quantity, processing steps, and heat treatment requirements. For urgent orders, expedited production can be arranged.
31CrMo12 steel is a little hard to weld because it has high chromium and carbon content. We need to preheat it to 200–350°C and apply heat treatment after welding to reduce stress to avoid cold cracking.
Yes, We can make our 31CrMo12 forgings in full accordance with the European Pressure Equipment Directive (PED 2014/68/EU). We offer full material traceability, certification, and test reports to help with pressure equipment projects in the EU market.
31CrMo12 (1.8515) is clearly better than 42CrMo4 (1.7225) in three main areas: (1) Hardenability: 31CrMo12 has uniform hardness up to a section thickness of 250 mm, while 42CrMo4 only has about 100 mm. (2) Surface wear resistance: After surface hardening, 31CrMo12 gets a surface hardness of 58–62 HRC. (3) Fatigue life: In wind turbine and industrial gearbox uses, higher alloy content leads to longer fatigue life under cyclic loading.
The price is different based on: part size (weight, diameter, length); supply condition (as-forged, heat treated Q&T, rough-machined, or finish-machined); order quantity; specific standard and certification requirements; and required NDT testing scope. As a direct manufacturer with capabilities in smelting, forging, heat treatment and mechanical processing, we offer competitive prices. We will provide a detailed quotation within 24 hours.
Get A Custom 31CrMo12 (1.8515) Forging Solutions for Your Project
We welcome you to send us your custom drawings, material requirements, quantity and uses details to get a detailed and competitive quotation. Our professional technical and sales team will provide you with professional forging solutions and full technical support within 24 hours.