Surface Roughness Comparator
A surface roughness comparison specimen is a standard tool for visual and tactile evaluation of workpiece surface condition before non-destructive testing. It helps classify roughness into different grades.
Physical-Chemical Mechanism of Action
A surface roughness comparator consists of a series of surfaces with different roughness. These patterns are produced by a special manufacturing process or by mechanical machining and serve as a reference.
Metallurgical Relevance & Risks in Welding
Correct assessment of surface condition is crucial for the quality of the welding process. Too high roughness can lead to uneven stresses and thus cracks, while too low roughness can make welding more difficult. An incorrect comparison can lead to wrong test results.
Workshop Practice & Instructions
Use a microscope or an optical comparator to compare the surface of the workpiece with the roughness comparator. Classification is done in steps (e.g., Ra 0.63 µm to Ra 125 µm). Make sure the comparator and the workpiece are viewed under the same lighting conditions.