9Cr18Mo steel is a Chinese GB standard martensitic stainless steel,After quenching, it has high hardness and wear resistance, and high dimensional stability at high and low temperature. 9Cr18Mo has the same characteristics and uses as 9Cr18 steel, but it has higher hardness and tempering stability after quenching. Molybdenum can increase the passivation effect of stainless steel

Worldwide equivalents of grade: 9Cr18Mo

Grade102Cr17Mo/9Cr18MoX105CrMo17 (1.4125)X105CrMo17(1.4125)SUS 440CX108CrMo17440C
Chemical Composition(%) of 9Cr18Mo Steel Material
CSi (≤)Mn (≤)P (≤)S (≤)Ni (≤)CrMo

Mechanical Properties of 9Cr18Mo

Material Rockwell hardness: ≥55 HRC (Quenching and tempering)

Material Brinell hardness: ≤269 HBW (steel bar after annealing)

Physical Properties of 9Cr18Mo

Density (g/cm3): 7.70

Specific heat capacity (J/Kg·K): 430 at 0-100℃

Thermal conductivity (W/m·K): 16.0 at 100℃

Electrical Resistivity (μΩ·m): 0.80 at 20℃

Longitudinal modulus of elasticity (kN/mm2): 215 at 20℃

Coefficients of linear thermal expansion:

Coefficients of linear thermal expansion (10-6/K)10.411.6

heat treatment

  1. 退火,800~920℃缓冷;
  2. 2)淬火,1000~1050℃油冷;
  3. 3)回火,200~ 300℃油、空冷。 

1、Annealing temperature of steel bars: 800-900℃ (Slow cooling)

2、Sample quenching temperature: 1000-1050℃ (Oil cooling)

3、Sample tempering temperature: 200-300℃ (Air cooling or Oil cooling)

9Cr18Mo Steel Application


29Cr18Mo钢适用于耐蚀性好(有磁性) 餐具(刀)、涡轮机叶片 淬火后,比440A钢硬度升高(有磁性),刀刃、管嘴、阀门、板尺、餐具(剪刀)。

1、 9Cr18Mo high carbon chromium stainless steel ball application: suitable for manufacturing bearings in corrosive media such as seawater, river water, nitric acid, steam and marine, such as bearings in ships and submersible pump parts, bearings in petroleum and chemical machinery, marine instrument bearings, etc

2、9cr18Mo steel is suitable for tableware (knife) with good corrosion resistance (magnetic). After quenching, the hardness of turbine blade is higher (magnetic) than that of 440A steel, including blade, nozzle, valve, plate ruler and tableware (scissors).

Products of 9Cr18Mo:

Product typeProductsDimensionProcessesDeliver Status
Plates / SheetsPlates / Sheets0.08-200mm(T)*W*LForging, hot rolling and cold rollingAnnealed, Solution and Aging, Q+T, ACID-WASHED, Shot Blasting
Steel BarRound Bar, Flat Bar, Square BarΦ8-1200mm*LForging, hot rolling and cold rolling, CastBlack, Rough Turning, Shot Blasting,
Coil / StripSteel Coil /Steel Strip0.03-16.0x1200mmCold-Rolled & Hot-RolledAnnealed, Solution and Aging, Q+T, ACID-WASHED, Shot Blasting
Pipes / TubesSeamless Pipes/Tubes, Welded Pipes/TubesOD:6-219mm x WT:0.5-20.0mmHot extrusion, Cold Drawn, WeldedAnnealed, Solution and Aging, Q+T, ACID-WASHED


9Cr18Mo steel is a Chinese GB standard martensitic stainless steel with high carbon and Chrome.
It has similar properties and uses as 9Cr18, but has a higher heat resistance and tempering resistance after quenching. Molybdenum (Mo) can increase the passivation effect of stainless steel.

It features of high hardness, heat resistance, tempering resistance, corrosion resistance and wonderful dimensional stability at elevated temperatures. It is widely used for plastic molds needed high load, nice wear resistance and sensible corrosion resistance.

9Cr18Mo’s new name is 02Cr17Mo.

9Cr18Mo is also a high-chrome and Mo alloy wear resistance and corrosion resistance plastic mold steel with high hardness.

Equivalent Grade

Chemical Composition

StandardSteel GradeCSi (≤)Mn (≤)P (≤)S (≤)Ni (≤)CrMo
GB/T 1220 – 2007 (year)9Cr18Mo

Mechanical Properties

Physical Properties

Heat Treatment Specification

  • Annealing: Heated uniformly to 1550/1600ºF (843/871ºC). Soak. Brinell hardness is close to 223. Intermediate or tempering treatment-heat uniformly to 1350/1400ºF (732/760 centigrade degree). Air cooling. Brinell hardness is 255.
  • Hardening:1850/1950ºF (1010/1066 centigrade degree). soak. quench in heat oil or air cooling
  • Tempering: 1850/1950ºF (1010/1066 centigrade degree). soak.quench in heat oil or air cooling.

Shapes and dimensions

Delivery Condition


  1. Plastic mold. Top-grade electrical switches, chargers and electrical kettle seat. Plugs and inserts mold. Such as laptops, cameras and preciseness instruments.
  2. For parts in friction and corrosive media. Such as cutting tools, knives, surgical blades, bearing rings and balls, valve parts. nozzles, measuring tools. high wear-resistant parts.