Hardness Profile
A hardness profile shows the hardness readings along a line or matrix on the material surface. It visualizes local property changes, like at welds.
Physical-Chemical Mechanism
A hardness profile shows how hardness changes over a distance or area. This can be influenced by factors like welding, heat treatment, or mechanical stress.
Metallurgical Relevance & Welding Risks
An uneven hardness profile can create local stress zones, leading to cracks or wear issues. In welds, a steep hardness gradient (e.g., from fast cooling) can cause brittle martensite, hurting toughness and formability.
Workshop Practice & Action Points
To ensure a uniform hardness profile, use controlled cooling. This can be done by choosing the right welding process (e.g., TIG) and managing cooling paths or shielding gas. For heavy sections or high-stress areas, plan and control cooling carefully.