For SSAW steel pipe, although the results of tensile test specimens are basically independent of the direction of sampling, the test results of v-Sharpy impact specimens are closely related to the direction of sampling. When the CVN is maximized along the rolling direction, the vertical CVN of the rolling sample is the smallest.


The difference between SSAW and LSAW steel tubes in rupture is that the latter is the consistent initiation or expansion of the maximum driving direction of the minimum resistance (axial), so it must be initiated and expanded along uranium. On the contrary, the maximum driving direction (for oil) and the minimum resistance path (rolling direction) of spiral initiation or expansion are not the same, so there are two possible directions for crack initiation and propagation: one axial vent and two along rolling direction (i.e. spiral welding direction).


This ratio is usually considered to be the maximum and minimum CVN. When three or more changes can be considered, the diversion will be determined according to the rolling direction.


In some cases, although the initiation of spiral fracture is in the rolling direction and large cracks extend along the axial direction of the shell, the rolling direction should still be considered in the calculation of the crack initiation criterion.