Overview of Surface Hardness for 200 Common Types of Steel (Translated & Humanized)

Steel is a foundational material across industries, and different types of steel offer varying levels of hardness, strength, and wear resistance. This guide provides a detailed overview of surface hardness values for 200 common steel types, including carbon steel, alloy steel, stainless steel, tool steel, and others. These values serve as useful references for mechanical design, manufacturing, and material selection.

1. Carbon Steel

- General Carbon Structural Steel:

• Q195 / Q215 / Q235 / Q275: Widely used in construction, bridges, and automotive parts. Surface hardness typically ranges from HRC 22–25.

• 08F / 10F: Suitable for body panels and stamped parts (e.g., in automotive or appliances), HRC 22–24.

• 20 / 20F: Often used for gears, shafts, and structural components, HRC 24–26.

- Medium Carbon Steel:

• 35 / 45 / 50 / 55 / 60: Ideal for medium-duty parts such as axles, bolts, and gears. Hardness ranges from HRC 25–33 depending on the grade and treatment.

- Carbon Tool Steel:

• T8 / T10 / T12: Used for tools like chisels and cutting blades. Typically hardened to HRC 58–66 for high wear resistance.

2. Alloy Steel

- Structural Alloy Steel:

• 40Cr / 42CrMo / 35CrMo / 30CrMo: Common in automotive and machinery applications. Heat-treated hardness generally falls in the HRC 40–48 range.

- Spring Steel:

• 60Si2Mn / SUP10 / 55Si2Mn / 50CrVA: Known for high elasticity and fatigue strength, suitable for springs and suspension components. HRC 44–50.

- Alloy Tool Steel:

• Cr12 / Cr12MoV / 9SiCr / 5CrMnMo: Used for dies, punches, and molds. Hardness after heat treatment usually falls between HRC 58–65.

3. Stainless Steel

- Austenitic Stainless Steel:

• 304 / 316 / 321: Known for corrosion resistance and good formability. Surface hardness ranges from HRB 70–95, depending on cold working.

- Ferritic Stainless Steel:

• 430 / 409 / 446: Used in decorative panels, exhaust systems, and heat-resistant components. Hardness is usually HRB 70–90.

- Martensitic Stainless Steel:

• 1Cr13 / 2Cr13 / 3Cr13 / 4Cr13 / 9Cr18 / 9Cr18MoV / X50CrMoV15: Suitable for blades, shafts, and high-strength parts. Hardness typically ranges from HRC 40–50.

4. High-Speed Steel (HSS)

• M2 / M35 / M42 / W9Mo3Cr4V: Used for drill bits, cutters, and other high-speed tools. These steels maintain hardness at high temperatures, typically HRC 63–68.

5. Bearing Steel

• GCr15 / GCr9 / G20CrMo: Designed for high wear resistance and dimensional stability, commonly used in rolling bearings. Hardness is usually HRC 60–65.

6. Mold Steel

- Hot-Work Tool Steel:

• H13 / H21 / 3Cr2W8V: Suitable for die casting, forging dies, and hot shear blades. Typical hardness: HRC 44–54.

- Cold-Work Tool Steel:

• CrWMn / 7CrSiMnMoV: Used for blanking, punching, and forming dies. Hardness often in the range of HRC 58–63.

7. Specialty Steel

• NM400 / HARDOX500: Wear-resistant steels used in mining and heavy-duty machinery. Surface hardness typically HRC 40–55.

• Mn13: High-manganese steel that hardens with use. Base hardness is low (~HB 220) but can reach HRC 45 after cold work.

• T91 / P91: Alloy steels for pressure vessels and high-temperature pipelines. Hardness usually between HRC 23–30.