Steel Hardness Determining
EP-calculation gives a mathematical model to determine the hardness of steel by knowing about the hardness or tensile strength of the material. At the same time receiving the necessary Wöhler curve for fatigue dimensioning and the EP-calculation option. The wear of bearing, bending of the bar, time running race can not according to formula E = m cc differ from 4d-world. Iron (steel) as the strength is not an end in itself, but rather the introduction of the EP-calculation in order to understand more of its formation. In order to ensure the model begins by examining the concept of the hardness of the known data.
Measurement Methods
- HB General Method of measurement of less than 400 HB hardness
- HRV Hardened and surface hardened steels
- HRB Method Rarely used
- HV Nitrided steels
- Shore Rubber
To surface hardness and a variety of surfaces can not set a common method of measurement, or an absolute value between them. Measuring the magnitude of the surface hardness is used jointly agreed measurement methods and systems, which are listed above. Each of these measurements only provide a method tied to the benchmark, which have limited comparing between the different methods.
Brinell test use hard balls, the load marking for example HB 10/3000/30. The ball is D = 10 mm, the force F = 3000 kps (30 kN), t = 30 sec. Normal test HB 10/3009/10 is usually marked by HB. At higher hardness than HB 400 the ball flattens, causing the result inaccuracies. HB hardness can also measure by Poldi method, which is used for example, to comparison of test-pieces.
Of the Rockwell hardness tests, the most common is HRC ( Cone) and the HRB (ball) methods, but the method is rarely used.
HRC hardness test is used to measure the hard pieces, if the surface layer is thick enough to press the cone into it. If the cone goes through the hard layer, is the result an incorrect value.
Vickers hardness test, the compressive force varies from 0.5 to 120 kgs (0.05 to 1.2 kN). HV hardness is measured in particular of thin surface layers.
The Poldi method has a comparative measurement with a known ( poldi ) material, setting a hardened test ball between the Poldi and test material. After hammer hitting a ball by comparing the pit area of the test material to Poldi material's pit. The test will thus correspond the Brinell test, but being less accurate .
Due to simplicity of the method it was used in previous wars to the destroyed enemy tanks. This to get to the targets a sufficient firepower. The writed seems plausible.
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