Indenter geometry
The shape and tip angle of the indenter affect the stress distribution and comparability of hardness test results.
Physical-Chemical Mechanism
The geometric shape (e.g., diamond or ball) and tip angle of the indenter determine how stress is distributed under the load. A finer tip angle leads to stronger local stress concentration.
Metallurgical Relevance & Risks in Welding
Incorrect indenter geometry can lead to inaccurate hardness test results. A too-large tip angle can reduce stress under the load, leading to lower hardness readings. A too-fine tip angle increases stress and can lead to too-high hardness readings.
Workshop Practice & Instructions
Use indenters with a standardized tip angle (e.g., 120° for diamond) and regularly check the integrity of the indenter for cracks or deformation. If results are inaccurate, check the geometric shape and tip angle of the indenter.