Location:HOME > NEWS > Defects of seamless steel pipe pickling

Defects of seamless steel pipe pickling

2018-09-06 09:37:22   COMMENT:0 HITS:
  In addition to stripping iron oxide scale, hydrogen diffuses into the billet matrix and aggregates at impurities or pores during pickling of seamless steel pipe, resulting in increased internal stress, reduced plasticity and increased brittleness of the steel. This effect is called hydrogen embrittlement. Hydrogen embrittlement is mainly affected by the diffusion rate of hydrogen atoms. The diffusion rate of hydrogen is related to the following factors:

  1) the diffusion rate of hydrogen in sulfuric acid solution is higher than that in hydrochloric acid solution.

  2) With the increase of pickling temperature, the diffusion rate of hydrogen increases sharply, but with the increase of acid concentration, the diffusion rate of hydrogen does not increase much. Therefore, DIN2448 st52 Carbon Steel Seamless Steel Pipe is best not to pickle at low temperature and high temperature.

  3) Seamless steel pipe inclusions in pickling, such as As, Sb, H2S and SO2, increase the diffusion rate of hydrogen atoms, that is, increase the possibility of hydrogen embrittlement.

  4) the chemical composition of seamless steel pipe also affects the diffusion of hydrogen atoms. The measures to prevent hydrogen embrittlement are to operate according to the prescribed acid concentration and temperature, to shorten the pickling time as far as possible, and to add corrosion inhibitors on time and in quantity.

previous_pageCorrosion behavior of welded steel pipes
next_pageThe performance of oil pipe