Hardness Test Method for Seamless Steel Pipe

The hardness test of stainless steel should take into account its mechanical properties, which is related to the performance and quality of deformation, stamping, cutting and other processing with stainless steel as raw material. Therefore, all seamless steel pipes must be tested for mechanical properties. Mechanical property test methods are mainly divided into two categories, one is tensile test and the other is hardness test.

The tensile test is to make a seamless steel pipe into a specimen, pull the specimen to break on a tensile testing machine, and then measure one or several mechanical properties, usually only tensile strength, yield strength, elongation after fracture and cross-sectional shrinkage.

Tensile test is the most basic mechanical property test method for metal materials. Almost all metal materials, as long as there are requirements for mechanical properties, have tensile tests specified. Especially for materials whose shapes are not convenient for hardness testing, tensile test becomes the only means of mechanical property testing.

The hardness test is to slowly press a hard indenter into the surface of the specimen under specified conditions, and then test the depth or size of the indentation to determine the hardness of the material.

Hardness test is the simplest, fastest and easiest method to implement in material mechanical property testing. Hardness test is non-destructive, and there is an approximate conversion relationship between material hardness value and tensile strength value. The hardness value of the material can be converted into tensile strength value, which has great practical significance.

Because tensile test is not convenient for testing, and it is very convenient to convert hardness to strength, people are increasingly testing material hardness and less testing its strength. In particular, due to the continuous progress and innovation of hardness tester manufacturing technology, some materials that could not be directly tested for hardness, such as seamless steel pipes, stainless steel plates and stainless steel strips, can now be directly tested for hardness. Therefore, there is a trend that hardness test gradually replaces tensile test.

In most national standards for stainless steel materials, tensile test and hardness test are stipulated at the same time. For those materials that are not convenient for hardness test, such as seamless steel pipes, only tensile test is stipulated. In stainless steel standards, three hardness test methods are generally stipulated: Burkhardness, Lowe's and Vickers' hardness test methods, which measure HB, HRB (or HRC) and HV hardness values, and only one of the three hardness values ​​is stipulated to be measured. In particular, the portable surface Rockwell hardness tester and pipe Rockwell hardness tester newly developed by our company can quickly and accurately test the hardness of stainless steel plates and stainless steel strips as thin as 0.05mm and seamless steel pipes as thin as 4.8mm, which solves the problems that were difficult to solve in the past.

Seamless steel pipe hardness testing tool

For annealed seamless steel pipes with an inner diameter of more than 6.0mm and a wall thickness of less than 13mm, the W-B type Webster hardness tester can be used. It is very fast and simple to test, and is suitable for fast and non-destructive qualified inspection of seamless steel pipes.

Seamless steel pipes with an inner diameter greater than 30mm and a wall thickness greater than 1.2mm use Rockwell hardness testers to test HRB and HRC hardness.

Seamless steel pipes with an inner diameter greater than 30mm and a wall thickness less than 1.2mm use surface Rockwell hardness testers to test HRT or HRN hardness.

Seamless steel pipes with an inner diameter less than 0mm and greater than 4.8mm use Rockwell hardness testers specifically for pipes to test HR15T hardness. When the inner diameter of the seamless steel pipe is greater than 26mm, the hardness of the inner wall of the pipe can also be tested with a Rockwell or surface Rockwell hardness tester.

Touch Screen Brinell Rockwell Vickers Multifunction Hardness Tester HBRVS-187.5

Main Parameters: