Vickers Hv	HB	Rockwell				Rockwell Superficial			Shore Hs	Temsile Stemgth KG/mm2
Vickers Hv	HB	HRA	HRB	HRC	HRD	15-N	30-N	45-N	Shore Hs	Temsile Stemgth KG/mm2
940		85.6		68.0	76.9	93.2	84.4	75.4	97
920		85.3		67.5	76.5	93.0	84.0	74.8	96
900		85.0		67.0	76.1	92.9	83.6	74.2	95
880		84.7		66.4	75.7	92.7	83.1	73.6	93
860		84.4		65.9	75.3	95	82.7	73.1	92
840		84.1		65.3	74.8	92.3	82.2	72.2	91
820		83.8		64.7	74.3	92.1	81.7	71.8	90
800		83.4		64.0	73.8	91.8	81.1	71.0	88
780		83.0		63.3	73.3	91.5	80.4	70.2	87
760		82.6		62.5	72.6	91.2	79.7	69.4	86
740		82.2		61.8	72.1	91.0	79.1	68.6	84
720		81.8		61.0	71.5	90.7	78.4	67.7	83
700		81.3		60.1	70.8	90.3	77.6	66.7	81
690		81.1		59.7	70.5	90.1	77.2	66.2
680		80.8		59.2	70.1	89.8	76.8	65.7	80
670		80.6		58.8	69.8	89.7	76.4	65.3
660		80.3		58.3	69.4	89.5	75.9	64.7	79
650		80.0		57.8	69.0	89.2	75.5	64.1
640		79.8		57.3	68.7	89.0	75.1	63.5	77
630		79.5		56.8	68.3	88.8	74.6	63.0
620		79.2		56.3	67.9	88.5	74.2	62.4	75
610		78.9		55.7	67.5	88.2	73.6	61.7
600		78.6		55.2	67.0	88.0	73.2	61.2	74
590		78.4		54.7	66.7	87.8	72.7	60.5		210
580		78.0		54.1	66.2	87.5	72.1	59.9	72	206
570		77.8		53.6	65.8	87.2	71.7	59.3		202
560		77.4		53.0	65.4	86.9	71.2	58.6	71	199
550	(505)	77.0		52.3	64.8	86.6	70.5	57.8		194
540	(496)	76.7		51.7	64.4	86.3	70.0	57.0	69	190
530	(488)	76.4		51.1	63.9	86.0	69.5	56.2		186
520	(480)	76.1		50.5	63.5	85.7	69.0	55.6	67	183
510	(473)	75.7		49.8	62.9	85.4	68.3	54.7		179
500	(465)	75.3		49.1	62.2	85.0	67.7	53.9	66	174
490	456	74.9		48.4	61.6	84.7	67.1	53.1		169
480	448	74.5		47.7	61.3	84.3	66.4	52.2	64	165

Material hardness is a measure of a material’s resistance to deformation, particularly permanent indentation, scratching, cutting, or abrasion. It’s a critical property in selecting materials for engineering, tooling, gears, and wear-resistant applications. There are different types of hardness depending on what kind of resistance you’re measuring:

Types of Hardness

Scratch Hardness
- Resistance to being scratched or cut.
- Measured by the Mohs scale (used for minerals).
Indentation Hardness
- Resistance to permanent deformation from a fixed load.
- Most common in metals and industrial components.
- Measured by:
  - Brinell Hardness (HBW)
  - Rockwell Hardness (HRC, HRB, etc.)
  - Vickers Hardness (HV)
Rebound Hardness
- Measures elasticity by how high a dropped object bounces off the material.
- Measured by Shore scleroscope (used less commonly).

Common Hardness Testing Methods

Method	Application	Typical Scale	How It Works
Brinell (HBW)	Soft–medium metals	100–600 HBW	A steel ball is pressed into the material; a large indent = softer
Rockwell (HRC/HRB)	General metals	20–70 HRC	Cone or ball indenter; depth of penetration is measured
Vickers (HV)	Thin or small parts	100–1000+ HV	Diamond pyramid indenter; very precise
Mohs	Minerals, coatings	1–10	Scratching test using standard reference minerals

Comparison Example

Material	Brinell (HB)	Rockwell (HRC)	Vickers (HV)	Mohs
Soft steel	~120	—	~130	~4
Hardened tool steel	~600	60–65 HRC	~800	~8.5
Titanium	~200	30–40 HRC	~300–400	~6
Glass	—	—	—	~6.5
Diamond (hardest)	—	—	—	10

Why Hardness Matters

Wear resistance: Harder materials resist wear better (critical for gears, dies, cutting tools).
Machinability: Very hard materials are difficult to cut or drill.
Fatigue and strength: Generally, higher hardness can correlate with higher tensile strength.
Heat treatment effect: Many metals (like steel) are heat-treated to raise hardness via surface or through-hardening.

Hardness in Gears and Mechanical Parts

Gear teeth are often surface-hardened (e.g., via carburizing, nitriding, or induction hardening) to combine a hard, wear-resistant surface with a tough, ductile core.
Typical gear surface hardness:
- Carburized steel: 58–62 HRC
- Induction hardened: 50–60 HRC
- Nitrided steel: ~1000–1200 HV

Material hardness is not the same as strength, toughness, or brittleness, but it’s closely related. The proper hardness depends on what your part needs to do — whether it must resist wear, endure impact, or tolerate bending.