Accurate Test Methods for Rockwell Hardness of SA-213M T22 Steel Thin Wall Pipe

The Rockwell hardness test results of a batch of SA-213M T22 steel thin wall pipe was relatively low. Through the room temperature tensile test and five methods of Rockwell hardness test, combined with the results of the room temperature tensile test, the different Rockwell hardness test methods were compared and analyzed. The results show that if the surface Rockwell hardness test or Rockwell hardness test was carried out directly on the surface of the steel thin wall pipe, the insufficient support of the pipe wall would cause the deformation of the sample and resulted in the low test result; if the steel thin wall pipe was supported by a cylinder in the middle, the axis of the indenter and the loading direction could not be ensured to be perpendicular to the surface of the steel pipe, and the outer surface of the steel pipe had a gap with the cylindrical support There was a gap between the surface and the supporting surface of the cylinder, which would also result in low test results. By using the method of converting the measured Vickers hardness to Rockwell hardness after sampling, inlaying and polishing the steel pipe, or the method of removing the oxide skin and decarburized layer on the steel pipe surface, machining the test plane on the outer surface and inlaying, converting the measured surface Rockwell hardness to Rockwell hardness, the Rockwell hardness test result was more accurate.