excessive yield drop after pipe forming
excessive yield drop after pipe forming
(OP)
We are having considerable drop in yield strength once we have steel coil formed into pipe. We are seeing average drop of 15-18 ksi, where normally only 2-5 ksi is expected. Without having seen steel mill test data, what could be causing such drop in yield???





RE: excessive yield drop after pipe forming
Or better yet, was the yield where it was to start with because of residual stress from cold work?
When you form it you are redistributing the stresses.
We used to do this with wire all of the time, deform it in order to lower the yield. But it only works on materials with high residual stress levels to start with.
The steel may have been too soft, so they cold rolled it in order to get it to pass.
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Plymouth Tube
RE: excessive yield drop after pipe forming
RE: excessive yield drop after pipe forming
RE: excessive yield drop after pipe forming
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Plymouth Tube
RE: excessive yield drop after pipe forming
RE: excessive yield drop after pipe forming
RE: excessive yield drop after pipe forming
RE: excessive yield drop after pipe forming
Therefore any difference in stress levels, strain rates, and a dozen other things can change the apparent yield strength without having any impact on the UTS and elongation at fracture.
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Plymouth Tube