The hardness of a material refers to its ability to resist the intrusion of external mechanical forces (such as indentation, scratching, and abrasion) or the occurrence of permanent deformation. It is one of the core indicators for measuring the mechanical properties of materials.
I. Core Hardness Testing Methods (Results Are Not Directly Interchangeable)
Different methods correspond to different scales and are suitable for different materials. The common classifications are as follows:
Testing Method
Core Principle
Common Scale
Suitable Materials
Brinell Hardness
Apply pressure with a cemented carbide ball indenter and calculate by measuring the indentation diameter
HBW
Low-hardness metals such as mild steel, cast iron, and non-ferrous metals
Rockwell Hardness
Use a diamond cone/cemented carbide ball indenter and measure the indentation depth difference
HRC (for hard metals), HRB (for soft metals)
Metals ranging from soft to hard, such as quenched steel and copper alloys
Vickers Hardness
Apply pressure with a square pyramid diamond indenter and calculate by measuring the indentation diagonal
HV
Almost all materials including metals, ceramics, thin films, and micro-components
Shore Hardness
Apply pressure with an elastic stylus and measure the rebound depth of the stylus
Shore A (for soft rubber), Shore D (for hard plastics)
Non-metallic materials such as rubber, plastics, and elastomers
II. Key Characteristics and Applications
Property Correlation: Hardness is usually positively correlated with wear resistance (the higher the hardness, the better the wear resistance), but negatively correlated with toughness (e.g., quenched steel has high hardness but is prone to brittleness).
Typical Application Scenarios:
Mechanical parts (gears, bearings): Measured by HRC/HV, requiring high hardness to ensure wear resistance.