Hello,
We ordered a forging of AISI 1035 steel with a hydrogen content less than 1.7 ppm. The ladle analysis from the billet indicated 1.0 ppm. We then performed stress relief on the forgings in an electric arc furnace. Also, we cast a tin alloy with a steel temperature around 255C (500F) on the inner diameter of the forging with using any acids to avoid introducing hydrogen. Prior to shipping very fine hydrogen blistering of thin layers of the alloy were found and removed by machining only in the upper halves. No blistering was observed in the lower halves. After about a year, primarily in climate controlled storage, severe blistering in this layers of the alloy in the lower halves appeared.
Beyond control of hydrogen in the original billet, the use of an electric arc furnace, and avoiding contact with acids, what other suggestions might there be to avoid adding hydrogen during manufacturing of steel components? Is there a concern that a ladel analysis might provide an incomplete picture of the hydrogen distribution in the billet?
Thank you
------------------------------
Lyle Branagan
Engineering Manager
Pioneer Motor Bearing Company
Kings Mountain NC
------------------------------