Spiral welded pipe equipment steel or sample in the stretch, when the stress exceeds the elastic limit, even if the stress is no longer added, and steel or samples continue to attack the significant plastic deformation, Hebei spiral welded pipe equipment company said the scene for the submission, and The minimum stress value when the succumbing to the scene is the point of submission.
      Flexion strength. Some of the metal material yield point is very significant, in the measurement of a difficult, so in order to measure the material yield characteristics, the rules of persistent residual plastic deformation is equal to the value of the stress, known as the conditional subordinate strength or the yield strength σ0 .2 .
      Flexor ratio. The ratio of the yield point of the steel to the tensile strength is called the yield ratio. The higher the strength ratio, the higher the reliability of the structural parts, the carbon steel yield ratio is 0.6-0.65, the low alloy structural steel is 0.65-0.75 alloy structural steel is 0.84-0.86.
tensile strength. Data in the drawing process, from the beginning to the onset of cracking to reach the maximum stress value. It shows that steel can resist the crack. And tensile strength corresponding to the compressive strength, bending strength and so on.
       Elongation. Data in the pull off, the length of its plastic elongation and the original sample length as the percentage of elongation or elongation.
Hardness. Hardness indicates the ability of the material to resist hard objects into its appearance. It is one of the main performance indicators of metal data. Usually the higher the hardness, the better the wear resistance. Commonly used hardness indicators are Brinell hardness, Rockwell hardness and Vickers hardness. Brinell hardness: with a certain load to the size of the hardened steel ball into the data appearance, to maintain a period of time, after loading, the load and its indentation area ratio, that is, Brinell hardness value, the unit of force / mm2 The Rockwell hardness: When HB> 450 or the sample is too small, can not use Brinell hardness test and use Rockwell hardness measurement. It is a vertex angle of 120 ° with a diamond cone or diameter of 1.59,3.18mm ball, under a certain load into the measured data appearance, the depth of indentation from the hardness of the data. According to the hardness of the experimental data is not the same, divided into three different scales to show:
HRA: is the choice of 60kg load and diamond cone press the hardness obtained for high hardness of the information.
HRB: is the choice of 100kg load and 1.58mm diameter hardened steel ball, the hardness obtained for the lower hardness of the information.
HRC: is the choice of 150kg load and diamond cone press the hardness obtained for high hardness of the information.
Vickers hardness: within 120kg load and the top angle of 136 ° diamond square cone press into the material appearance, with the information indentation of the appearance of the pits to the load value, that is, Vickers hardness value.