What will happen to the stainless steel pipe after pickling

with the wide application of stainless steel pipes, people's requirements for them are becoming higher and higher, and the processing technology has become diversified. pickling is one of the processing techniques. do you know why hydrogen embrittlement occurs in stainless steel pipes after pickling?

this is because when stainless steel pipes are pickled, hydrogen has a peeling effect on the iron oxide scale, and also diffuses into the interior of the steel blank matrix, and then gathers at impurities or pores, which will lead to an increase in internal stress and the plasticity of the steel. when the temperature decreases, the brittleness of the steel increases. this effect is called hydrogen embrittlement. hydrogen embrittlement is mainly affected by the diffusion speed of hydrogen atoms.

1. the diffusion speed of hydrogen in sulfuric acid solution is much faster than the diffusion speed of hydrogen in hydrochloric acid solution.
2. if the pickling temperature is increased, the diffusion rate of hydrogen will increase sharply, but if the pickling concentration is increased, the diffusion rate of hydrogen will not increase much, so try not to pickle at low concentration and high temperature.
3. during the pickling process of stainless steel pipes, if there are inclusions such as hydrogen sulfide, carbon dioxide, and arsenic, the diffusion rate of hydrogen atoms will increase, which will increase the possibility of hydrogen embrittlement.