Hardness Testing: Indentation, Scratch, and Method Selection Review
Hardness testing evaluates the ability of materials, coatings, platings, or rubber/plastic parts to resist localized deformation. Different materials and constructions require different methods. Before testing, companies should confirm material type, thickness, surface condition, test position, load, and acceptance requirement.
Common Test Items
| Item | Review focus | Common risk |
|---|---|---|
| Method selection | Select the method by metal, plastic, rubber, coating, or composite material | Inappropriate hardness scale is used to compare different materials |
| Sample preparation | Confirm thickness, flatness, surface roughness, and support method | Thin sample, uneven surface, or unstable backing affects results |
| Test position | Review edge distance, indentation spacing, coating area, and functional surface | Test points are too close to edge or defects, causing data deviation |
| Load and dwell time | Record indenter type, load, dwell time, and reading method | Parameters are not recorded, making the report difficult to reproduce |
| Result judgment | Check unit, scale, average, data spread, and abnormal point explanation | Only one value is provided without sample difference or test condition |
Report Boundaries
- The report should state hardness method, scale, indenter, load, sample position, and surface condition.
- After material grade, heat treatment, coating thickness, formula, or supplier changes, hardness data should be reviewed again.
- Different hardness scales should not be casually converted or directly compared.
- Customer-facing pages should avoid extending one hardness result to uncovered performance claims.
Green Ark's Recommendation
Green Ark (Shenzhen) Certification Co., Ltd. recommends managing hardness testing together with material specification, process batch, and functional-surface requirement. This helps reduce wrong method selection, inconsistent sample preparation, and report data misuse.
