Search results
Results from the WOW.Com Content Network
A Rockwell hardness tester. The Rockwell hardness test is a hardness test based on indentation hardness of a material. The Rockwell test measures the depth of penetration of an indenter under a large load (major load) compared to the penetration made by a preload (minor load). [1]
BHN = load in kilograms divided by the spherical area of the indentation in square millimetres (refer to Brinell scale for method of calculation) It is a rapid, non-destructive (except at the surface being tested) means of determining the hardness of metals. This area is a function of the ball diameter and the depth of the indentation.
The instrument uses the world's first patented non-destructive testing method for concrete. 1950 – J. Kaiser introduces acoustic emission as an NDT method. (Basic source for above: Hellier, 2001) Note the number of advancements made during the WWII era, a time when industrial quality control was growing in importance.
Janka hardness test, for wood; Meyer hardness test; Rockwell hardness test (HR), principally used in the USA; Shore durometer hardness, used for polymers; Barcol hardness test, for composite materials; Tensile testing, used to obtain the stress-strain curve for a material, and from there, properties such as Young modulus, yield (or proof ...
A scleroscope is a device used to measure rebound hardness.It consists of a steel ball dropped from a fixed height. The device was invented in 1907. As an improvement on this rough method, the Leeb Rebound Hardness Test, invented in the 1970s, uses the ratio of impact and rebound velocities (as measured by a magnetic inducer) to determine hardness.
A variety of hardness-testing methods are available, including the Vickers, Brinell, Rockwell, Meyer and Leeb tests. Although it is impossible in many cases to give an exact conversion, it is possible to give an approximate material-specific comparison table for steels .
The Leeb Rebound Hardness Test (LRHT) invented by Swiss company Proceq SA is one of the four most used methods for testing metal hardness. This portable method is mainly used for testing sufficiently large workpieces (mainly above 1 kg). [citation needed] It measures the coefficient of restitution. It is a form of nondestructive testing.
Hard science fiction is a category of science fiction characterized by concern for scientific accuracy and logic. [ 1 ] [ 2 ] [ 3 ] The term was first used in print in 1957 by P. Schuyler Miller in a review of John W. Campbell 's Islands of Space in the November issue of Astounding Science Fiction .