Analysis of the cracking phenomenon in stainless steel head cold forming
Thread Content
Our factory recently sent a batch of S30408 end caps with a thickness of 5-6 and a diameter of 800 to an end cap manufacturing plant for processing, using whole-pressure cold forming. Cracking occurred in batches, and the end cap factory said it was not their fault. Later, we took samples for physical and chemical analysis. Could everyone please help analyze the cause? Thank you! Photos of the cracked items, showing cracks running longitudinally near the fold edges; results of spectral analysis; tests on mechanical properties
Check the material quality certificates to see if they meet the standards, especially regarding the heat treatment condition； Was no bending test conducted? Is it turning on the tablet?
In the picture, why are there so many pits on the lid?
Yes, so I’m not sure what the situation is either? It worked fine when it was stored at his place before, but this time it cracked in large numbers
Everyone is welcome to analyze and discuss! ! ! ! ! ! ! ! ! ! ! Is it a material issue or a problem with the clamping process?
It’s a matter of experience; you should be able to conduct physical and chemical experiments successfully, and the content of the materials should generally be fine as well. For the stainless steel material used to make pressure heads, there is no issue if you purchase it from Taiyuan Iron and Steel or Baosteel. If you purchase materials from other manufacturers, the likelihood of encountering this issue you mentioned is quite high. Generally, the stainless steel used in small factories tends to crack easily when used for pressing heads
What about chemical composition and metallographic analysis? Do them all first, and then analyze the reasons. Is the heat treatment condition of the flat plate meeting the requirements?
The spectroscopy has been done; there are data in the image above
The most likely reason is a flat plate; conduct a bending test to see
Yes, I see that it mentions the need to retest the mechanical properties of stainless steel flat sheets by batch number. But I have a question: is this retesting of mechanical properties done solely by our manufacturing plant to keep track of the material quality, or is it also carried out by inspection agencies for record-keeping purposes?