Stainless steel tube tensile strength and yield strength

One said that the tensile strength of the stainless steel tube seems to have a sense of understanding. At least in theory, it seems to be better than the hardness. It is better to stretch the rod of the same diameter with an external force and compare the force at the time of the fracture. The term "tensile strength" as used in science refers to the value of a specified sample measured on a specified test machine according to the specified test method.

The stainless steel tube tensile specimens have 16 fixed shapes and sizes from 1 to 14. The use of these specimens depends on the type of material being tested, such as bars, plates, wires, etc. These standards are specified in JIS. In addition to the tensile strength, the yield strength, the specified residual elongation stress, the elongation after break, the reduction in area, and the like can be detected, and the method of detection is also specified in JIS.

In the JIS standard for stainless steel pipes, the values ​​of these items are specified according to their specifications (uses). The wire only specifies the tensile strength, and the structural steel not only specifies the yield strength, but also defines the residual elongation stress, elongation after fracture, and reduction in area. The tensile test of the stainless steel tube is to clamp the two ends of the standard sample and slowly stretch until it breaks. There is no guarantee that the sample and the object will be the same, but as long as it is produced in a large enterprise and has sufficient quality management, there should be no major differences. Especially in the case of heat treatment, there is no fear that the actual object is inconsistent with the sample.

Finally, introduce the meaning of the term:

Tensile strength: The quotient of the tensile force divided by the initial cross-sectional area of ​​the parallel part of the sample, in units of kgf/mm 2 , generally omitted by f and square mm expressed in kg. A 41 in SS41 indicates that his tensile strength is 41 kg. (The tensile strength unit and writing method are different from those in China. For example, the Japanese tensile strength is 41kg; the national system is adopted in China, and its corresponding writing method is 410MPa or 410N/mm2.

Elongation after break: The percentage (%) of the elongation after breaking of the sample from the initial length.

Yield strength: During the tensile test, there is a sudden drop in stress, and the sample is still at a stress point where the stress is not large. This stress point is called the yield strength, and is expressed in kgf/mm 2 . Generally, the f and square mm are omitted. For metallic materials, no greater force should be applied to it.

Prescribed residual elongation: In addition to mild steel, the yield point of other objects is not obvious. It can be expressed by the specified residual elongation stress. That is, in the tensile test, although the tensile force was eliminated, the sample could not be restored to its original state and maintained at an elongation of 0.2%. Expressed in kgf/mm 2 . This material is no longer available due to a plastic deformation of 0.2%, so this is the limit.

Section Shrinkage: The maximum reduction in cross-sectional area after the sample is broken (the difference between the initial cross-section and the smallest cross-section) and the original cross-sectional area of ​​the specimen.