1. test principle
Webster hardness testers are the basic principles of using certain shape of quenching pressure needle, standard springs into the surface of the sample under test force, meaning the indentation depth of the 0.01mm as a Vickers hardness units. Inversely proportional to the material hardness and indentation depth. Less indentation hardness higher hardness lower pushed deeper and deeper.
2. test equipment
Copper alloys Webster hardness tester-W-B75 (United States B-75) and W-BB75 (United States BB-75). W-B75 and W-BB75 and W-20 series aluminum alloys Webster hardness meter, finished its structure are the same, only W-B75 and W-BB75 choose the dropper on the cylinder, and W-20 series cone-shaped pressure-PIN. Difference between W-B75 and W-BB75, both types of model structure and dropper were the same, just W-B75 the use of a stiffer test of spring and, therefore, W-B75 are suitable for measuring hard and half-hard copper alloys, and W-BB75 type is suitable for measurement of pure copper and copper alloys of soft state. Because differences in test spring, so Wei after hardness measurements of different types of copper alloys, hardness results may differ. Conversion of hardness values of the different types of relationships are different.
Specimen thickness shall be not more than 6 mm, when the specimen thickness greater than 0.5 mm, with less than 1 mm, to compensate for lack of thickness errors, should take multiple pieces of the same closely after the folding of the sample for testing. Napkin size about 25 mmx25 mm. Tubular specimens should be less than φ 6 mm inner diameter.
Samples of the test surface should be smooth and clean, there should be no mechanical damage, the specimen should be thoroughly cleared face coating; if there are minor scratches or wear, needs polishing.