Vickershårdhedsprøvningen

Vickers hardness, also known as diamond pyramid hardness, is a method of measuring the hardness of materials. Developed by Robert L. Smith and George E. Sandland at Vickers Ltd. in England, it was introduced in 1925. The test involves impressing a square-based diamond pyramid indenter with a specific angle of 136 degrees into the surface of the material being tested. The indenter is pressed into the material with a known load for a set amount of time. After the load is removed, the diagonals of the resulting indentation are measured. The Vickers hardness number (HV) is then calculated by dividing the applied load by the surface area of the indentation. The formula is HV = 1.8544 * P / d^2, where P is the load in kilograms-force and d is the average length of the diagonals in millimeters. This test is widely used because it can be applied to a wide range of materials, from very soft metals to very hard ceramics, and can be used to measure hardness on a single grain of a metal. The Vickers hardness test is standardized by ISO 6507 and ASTM E384. It is a non-destructive test when performed with very low loads, allowing for microhardness testing.