1. Raw material selection of JIS G3444 STK400 steel pipe
In order to save cost, some JIS G3444 STK400 steel pipe manufacturers will select round steel produced by small steel plants for processing, but the JIS G3444 STK400 steel pipe produced by these small steel plants will contain many impurities, bubbles, interlayer, pores and so on. After the later processing, it is easy to cause cracking problems.
2. JIS G3444 STK400 steel pipe heat treatment temperature control is not in place
Small manufacturers do not have professional production experience and technology, workshop workers can not guarantee whether the steel pipe heat treatment is in place by relying on the heating temperature and time, and heat treatment will change the mechanical properties of JIS G3444 STK400 steel pipe. But the general manufacturers for different steel grades, wall thickness, mechanical properties, do not have clear indicators, nor testing equipment to determine whether the pipe has reached the performance indicators required by customers.
Each batch of JIS G3444 STK400 steel pipe produced by us has clear temperature and speed index for normalizing, annealing and tempering, and will carry out tensile test to determine whether JIS G3444 STK400 steel pipe reaches the performance required by customers. With these data and parameters as the basis of production, the quality stability of JIS G3444 STK400 steel pipe, as well as the end use.
