What happens to the stainless steel pipe after pickling

With the wide application of stainless steel pipes, people's requirements are getting higher and higher, and the processing technology has become diversified. Pickling is one of the processing techniques. Do you know why the stainless steel pipe undergoes a hydrogen embrittlement reaction after pickling?

The reason is that hydrogen has the effect of peeling off the iron oxide scale during the pickling of the stainless steel tube, and it also diffuses into the steel embryo matrix and then accumulates at the impurities or pores, which will lead to an increase in internal stress and the plasticity of the steel. Decrease, the brittleness of steel increases, this effect is called hydrogen embrittlement. The hydrogen embrittlement is mainly affected by the diffusion rate 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 hydrogen diffusion rate will increase sharply, and if the pickling concentration is increased, the hydrogen diffusion rate will not increase much, so try not to pickle at low concentration and high temperature.

3. In the pickling process of stainless steel pipe, if there are inclusions such as hydrogen sulfide, carbon dioxide, and arsenic, it will increase the diffusion rate of hydrogen atoms, which will increase the possibility of hydrogen embrittlement.