Last reviewed: · EN 10083-3 · 1.7707 / 30CrMoV9 · © 2026 Jiangsu Liangyi Co., Limited
Article Summary
30CrMoV9 (1.7707) is a high-performance chromium-molybdenum-vanadium nitriding steel specified under EN 10083-3. Key facts engineers need to know:
- Surface hardness 700–1,000 HV after gas, salt bath, or plasma nitriding
- Tensile strength >800 MPa in quench and temper condition (section size and heat treatment dependent)
- Contains 2.3–2.7% Cr, 0.15–0.25% Mo, 0.10–0.20% V as principal alloying additions
- Heat treatment route: anneal 650–720°C → harden 870–930°C → temper 580–700°C → nitride 500–580°C
- Applications: automotive powertrains, steam turbines, oil & gas drilling tools, mining equipment, wind turbine gearboxes
- Welding is not recommended without specialist engineering controls
- Manufactured by Jiangsu Liangyi Co., Limited, ISO 9001:2015 certified, established 1997, Jiangyin, China
The Engineering Case for 30CrMoV9
Not every alloy steel earns the title of a benchmark material. 30CrMoV9 has. Across automotive powertrain engineering, turbine manufacturing, oil and gas drilling tool design, wind energy gearboxes, and heavy mining machinery, this chromium-molybdenum-vanadium alloy occupies a performance envelope that simpler grades cannot reach.
Its defining advantage is a combination of properties that are rarely achieved simultaneously: after nitriding, the surface hardness reaches 700–1,000 HV, yet the core remains tough and ductile enough to absorb dynamic shock loads without fracture. It can be quenched and tempered to tensile strengths above 800 MPa, with precise properties achievable through controlled heat treatment — giving engineers and application engineers significant flexibility to optimize for their specific load case.
This guide is written for engineers making material selection decisions. We cover chemical composition, mechanical properties, heat treatment, nitriding performance, applications across six industries, grade comparisons, and complete sourcing guidance.
Designation Reference: 30CrMoV9 appears under multiple naming conventions: 1.7707 (EN material number), 30CrMoV9 (DIN/EN chemical designation). These refer to the same steel grade. It is broadly comparable in application scope — though not in exact composition or nitriding performance — to AISI 4130/4140 class alloys. Always verify the exact grade against your procurement specification.
Chemical Composition of 30CrMoV9 (1.7707)
30CrMoV9's engineering performance originates at the alloy chemistry level. Its elemental additions are balanced to deliver surface hardenability, core toughness, elevated-temperature creep resistance, and dimensional stability after heat treatment. The full composition is governed by EN 10083-3:
| Element | Symbol | Range (wt%) | Engineering Role |
|---|---|---|---|
| Carbon | C | 0.26 – 0.34 | Base hardness and tensile strength through martensite formation |
| Chromium | Cr | 2.30 – 2.70 | Primary hardenability; forms CrN / Cr₂N nitrides for surface hardness; wear and corrosion resistance |
| Molybdenum | Mo | 0.15 – 0.25 | Elevates creep strength; suppresses temper embrittlement; improves deep hardenability |
| Vanadium | V | 0.10 – 0.20 | Grain refinement; secondary hardening during tempering; improves fatigue strength |
| Manganese | Mn | 0.40 – 0.70 | Enhances hardenability; deoxidizer; sulfide morphology control |
| Silicon | Si | Max 0.40 | Deoxidizer; raises elastic limit |
| Nickel | Ni | Max 0.60 | Residual element; controlled impurity |
| Phosphorus | P | Max 0.035 | Controlled impurity — excess promotes grain boundary embrittlement |
| Sulfur | S | Max 0.035 | Controlled impurity — MnS inclusions degrade toughness if uncontrolled |
Why Chromium Content Is the Defining Factor
The 2.3–2.7% chromium specification distinguishes 30CrMoV9 from lower-alloy nitriding steels. During gas or plasma nitriding, chromium reacts preferentially with nitrogen to form a dense network of chromium nitride precipitates (CrN and Cr₂N) throughout the diffusion zone. These precipitates are thermally stable and extremely hard — producing surface hardness of 700–1,000 HV depending on nitriding method and process parameters.
Vanadium acts as a grain boundary pin during austenitizing, preventing austenite grain coarsening and maintaining a fine, homogeneous grain structure — directly improving impact toughness and high-cycle fatigue resistance in the finished component.
Mechanical Properties of 30CrMoV9 (1.7707)
Mechanical properties depend on heat treatment condition, section diameter, and specific heat treatment parameters. The values below represent minimum achievable properties in the quench and temper (+QT) condition. Custom properties can be developed by our metallurgical engineers to match your specific operating conditions:
Section Size Effect: Mechanical properties decrease with increasing section diameter due to hardenability limits. For large sections or special property requirements, our metallurgical engineers can develop a customized heat treatment program. Contact us with your section size and required property levels for a technical assessment.
Physical Properties Reference
| Property | Typical Value | Notes |
|---|---|---|
| Density | 7.83 g/cm³ | Room temperature |
| Thermal Conductivity | ~33 W/m·K | At 20°C |
| Thermal Expansion Coeff. | 11.7 × 10⁻⁶ /°C | Range 20–100°C |
| Specific Heat Capacity | 0.46 J/g·K | Room temperature |
| Elastic Modulus | ~210 GPa | Standard for alloy steels |
| Max Service Temperature | 540 °C | For power generation applications |
Complete Heat Treatment Guide for 30CrMoV9
Jiangsu Liangyi performs all heat treatment in-house using ten computer-controlled furnaces, with precise temperature control to achieve the required mechanical properties. The four heat treatment routes below can be applied individually or in sequence:
Soft Annealing — Maximum 248 HB
Heat to 650–720°C, hold at temperature, then slow-cool in the furnace to a maximum hardness of 248 HB. Significantly improves machinability, eliminates residual hot-work stress, and prepares the material for precision machining before the hardening cycle.
Hardening — Austenitize at 870–930°C
Austenitize at 870–930°C until the microstructure is fully homogeneous, then quench in oil or polymer solution. Converts austenite to a fully martensitic structure for maximum hardness prior to tempering.
Tempering — 580–700°C
Temper immediately after hardening at 580–700°C. Temperature is precisely adjusted to achieve the best balance of tensile strength, toughness, and ductility for each customer's application requirements. Cannot be reversed without full re-hardening.
Nitriding — 500–580°C, 700–1,000 HV Surface
Gas nitriding, salt bath nitriding at 570–580°C, or plasma (ion) nitriding at approximately 500–530°C after final tempering. Produces a surface case depth of 0.3–0.6 mm with hardness of 700–1,000 HV. Dimensional change is less than 0.01 mm, compatible with finished precision components.
⚠ Welding Not Recommended: Due to its carbon content and high hardenability, 30CrMoV9 is not suitable for welding without specialist engineering controls including pre-heat, controlled inter-pass temperature, post-weld heat treatment, and full re-qualification of mechanical properties. Design components to avoid welded joints wherever possible.
Why 30CrMoV9 Is an Outstanding Nitriding Steel
Nitriding is a thermochemical surface-hardening process conducted below the austenitizing range. Because the bulk microstructure is not transformed, core mechanical properties and component dimensions remain essentially unchanged — critical for precision components with tight tolerances that have already been finish-machined.
The 2.3–2.7% chromium in 30CrMoV9 forms a dense network of chromium nitride precipitates (CrN, Cr₂N) during nitriding. These precipitates are thermally stable and maintain hardness in service up to 400°C, making nitrided 30CrMoV9 parts highly suitable for high-temperature wear applications.
Gas Nitriding vs Plasma Nitriding — Which to Specify?
Gas nitriding (ammonia atmosphere, 570–580°C) and salt bath nitriding are the standard industrial methods — economical, proven, and scalable for large-batch production. Plasma (ion) nitriding (~500–530°C) offers finer process control, selective surface treatment through masking, and a more uniform compound layer with reduced white layer thickness. For precision aerospace or high-cycle fatigue components, plasma nitriding is often the preferred specification. Jiangsu Liangyi performs all three methods in-house.
Industrial Applications of 30CrMoV9 Forged Parts
The combination of high post-nitriding surface hardness, excellent core toughness, and dimensional stability makes 30CrMoV9 the preferred grade across multiple demanding industries. Below are the principal application sectors and specific component types that Jiangsu Liangyi regularly produces in this grade:
Automotive & Powertrain
Crankshafts, camshafts, gearbox shafts, piston pins, transmission gears, and clutch hubs. The nitrided surface resists fretting and adhesive wear under high-cycle contact loading.
Power Generation
Steam turbine shafts, valve stems, superheated steam valves, gate valves, and wind turbine gearbox shafts. Reliable performance at service temperatures up to 540°C.
Oil & Gas
Gear shafts for oil drilling tools, mud pump herringbone gear shafts for land and offshore rigs, anchor winch stub shafts for subsea offshore equipment.
Mining & Heavy Equipment
Eccentric shafts for gyratory crushers, conveyor pulley shafts, mine hoist spindles, heavy-load crane wheels, and slewing bearing races for excavators.
Sugar & Cement Industry
Pinion shafts and roller shafts for sugar mills and cement plant rotary kilns; riding gear rings for granulators, dryers, and coolers; high-strength pull torque rods.
General Mechanical Engineering
High-strength crankshafts for compressors and industrial pumps, gear couplings, hydraulic cylinder rods, and precision spindles requiring dimensional stability throughout service life.
30CrMoV9 vs 42CrMo4 vs 34CrNiMo6 — Steel Grade Comparison
When selecting a material grade, engineers most frequently compare 30CrMoV9 against 42CrMo4 and 34CrNiMo6. The table below provides a direct comparison across the properties that most influence selection decisions:
| Property | 30CrMoV9 / 1.7707 | 42CrMo4 / 1.7225 | 34CrNiMo6 / 1.6582 |
|---|---|---|---|
| Steel Type | Nitriding alloy steel | Cr-Mo steel | Ni-Cr-Mo steel |
| Tensile Strength Rm | >800 MPa | >900 MPa | >1,000 MPa |
| Surface Hardness (nitrided) | 700–1,000 HV (Excellent) | 400–600 HV (Moderate) | 500–700 HV (Good) |
| Nitriding Suitability | Excellent ✓✓ | Moderate | Moderate |
| Wear Resistance | Excellent ✓✓ | Good | Very Good ✓ |
| Core Toughness | Very Good ✓ | Very Good ✓ | Excellent ✓✓ |
| Dimensional Stability | Excellent ✓✓ | Moderate | Moderate |
| Standard | EN 10083-3 | EN 10083-3 | EN 10083-3 |
| Best For | Nitrided gear shafts, rings | Gears, crankshafts, axles | High-load turbine shafts |
When to choose 30CrMoV9: 30CrMoV9 is the best choice when your application requires high surface hardness with minimal dimensional distortion after heat treatment — such as precision gear shafts, wind turbine gearbox components, and mining equipment parts. Contact our engineers for a material recommendation tailored to your specific operating conditions.
Why Forging Is the Right Process for 1.7707 Components
The full mechanical potential of 30CrMoV9 is only realized through forging. Casting introduces porosity, segregation, and random grain structure — defects that degrade fatigue performance and toughness regardless of heat treatment quality. Forging eliminates these limitations by working the grain structure into alignment with the component's primary load direction.
Jiangsu Liangyi uses a 2,000–6,300-ton hydraulic press and 0.75–9-ton electro-hydraulic hammer to produce open die forged parts from 30 kg up to 30,000 kg. Our 5-meter seamless rolled ring machine produces rings with outer diameters up to 5,000 mm.
| Property | Forged 30CrMoV9 | Cast Equivalent |
|---|---|---|
| Grain Structure | Directional, fine, dense | Random, coarse, potentially porous |
| Fatigue Strength | +30–40% vs cast | Lower baseline |
| Impact Toughness | Significantly higher | Lower; brittle fracture risk |
| Dimensional Consistency | Excellent — controlled die process | Variable — solidification shrinkage |
| 100% UT Inspection | Fully achievable | Limited by internal porosity |
Jiangsu Liangyi's 30CrMoV9 (1.7707) open die forged parts are subject to 100% ultrasonic testing (UT) per agreed acceptance standards, with full triplicate inspection certification in accordance with EN 10204 3.1B as standard.
How to Specify and Source 30CrMoV9 Forged Parts
Effective sourcing of forged 1.7707 components requires a complete technical inquiry. The checklist below covers everything needed for an accurate quotation from Jiangsu Liangyi:
| # | Specification Item | Why It Matters |
|---|---|---|
| 1 | Material standard — EN 10083-3 or DIN 17211 | Defines composition and acceptance criteria for material certification |
| 2 | Delivery condition: +QT, +A, or +N | Determines what mechanical properties are tested and certified |
| 3 | Required Rm / Rp0.2 / KV minimum values | Must correspond to your design load calculations |
| 4 | Section size and forging weight (30 kg–30 tons) | Controls achievable hardenability and resulting properties |
| 5 | Nitriding requirement (if applicable) | Affects surface finish specification and pre-nitriding machining allowance |
| 6 | UT inspection class (SEP 1921 or ASTM A388) | Defines acceptable ultrasonic indication limits |
| 7 | Engineering drawing or 3D model | Required for near-net shape forging to minimize machining cost |
| 8 | Material cert: EN 10204 3.1B (standard) or 3.2 (on request) | 3.1B is standard; 3.2 with Lloyd's/DNV/ABS available on request |
To request a 30CrMoV9 forging quotation, Jiangsu Liangyi provides free technical consultation, full material traceability from billet to finished part, and EN 10204 3.1B certification as standard. Our factory has been established since 1997, covers 80,000 m², and has an annual production capacity of 120,000 tons. Contact: sales@jnmtforgedparts.com | +86-135-8506-7993 (Phone/WhatsApp) | www.jnmtforgedparts.com | Chengchang Industry Park, Jiangyin City, Jiangsu Province, China.
Frequently Asked Questions about 30CrMoV9 (1.7707) Steel
30CrMoV9 (EN material number 1.7707) is a high-performance chromium-molybdenum-vanadium nitriding alloy steel specified under EN 10083-3. It contains 2.3–2.7% chromium, 0.15–0.25% molybdenum, and 0.10–0.20% vanadium. After nitriding it achieves surface hardness of 700–1,000 HV. In quench and temper condition, tensile strength is above 800 MPa. It is used in automotive powertrains (crankshafts, camshafts, gearbox shafts), power generation (turbine components, steam valves, wind turbine gearboxes), oil and gas (drilling tool components), mining (crusher shafts, bucket pins), and sugar and cement industry (gear shafts, riding rings).
There is no difference — 30CrMoV9 and 1.7707 are the same steel grade. 30CrMoV9 is the chemical composition designation (Carbon, Chromium, Molybdenum, Vanadium), while 1.7707 is the official material number (Werkstoffnummer) per DIN and EN standards. 30CrMoV9 is typically used in technical documentation; 1.7707 is used in material ordering and certification documents.
After gas nitriding or salt bath nitriding, 30CrMoV9 (1.7707) achieves surface hardness of 700–1,000 HV. Under optimized plasma (ion) nitriding conditions, hardness can reach up to 1,000 HV. The nitrided case depth is typically 0.3–0.6 mm with a dimensional change of less than 0.01 mm, making nitriding suitable for precision finished components.
Jiangsu Liangyi Co., Limited is ISO 9001:2015 certified and provides EN 10204 3.1B material test certificates as standard for all 30CrMoV9 forged parts. EN 10204 3.2 certification with independent third-party inspection — including Lloyd's Register, DNV, ABS, and others — is available upon request at no additional commitment during quoting.
No. AISI 4140 contains only 0.8–1.1% chromium and no vanadium, resulting in a much weaker nitriding response and significantly lower surface hardness after nitriding. 30CrMoV9 with 2.3–2.7% chromium is specifically designed for applications requiring high nitrided surface hardness. For non-nitrided structural applications under North American standards, 4140 may serve as a working substitute after engineering review.
30CrMoV9 is not recommended for welding. Due to its carbon content and high hardenability, the heat-affected zone is prone to martensite formation and cracking without pre-heat, controlled inter-pass temperature, and post-weld heat treatment. Any welded 30CrMoV9 assembly requires full re-qualification of mechanical properties. Components should be designed to avoid welded joints wherever possible.
Need Custom 30CrMoV9 Forged Parts?
Jiangsu Liangyi Co., Limited — established 1997, ISO 9001:2015 certified — manufactures 1.7707 forged components for global customers. Send your drawing for a free quotation with EN 10204 3.1B material certification.
✉ sales@jnmtforgedparts.com ·
📞 +86-135-8506-7993 ·
🌐 www.jnmtforgedparts.com
📍 Chengchang Industry Park, Jiangyin City, Jiangsu Province, China