Views: 5 Author: Site Editor Publish Time: 2024-10-12 Origin: Site
Stretching austenitic stainless steel sheets sometimes cracks, and each phenomenon is different.
Some crack after stretching deformation; some crack immediately when withdrawing from the die; some crack when they are hit or vibrated after stretching deformation; some crack suddenly after being stored for some time or during use after stretching deformation.
The main reason for cracking is that the ductility of austenitic stainless steel sheets is relatively low, the elastic modulus E is a bit large, the hardening index is relatively high, and the plastic deformation stage from yield to cracking is relatively short.
The cold work hardening index of austenitic stainless steel is relatively high, and it is a metastable stainless steel. When deformed, phase transformation will occur to form a martensitic structure. The martensitic phase is relatively brittle, so it is easy to crack. During plastic deformation, as the deformation of the austenite phase increases, the induced martensitic phase content will also increase with the increase in deformation, and the residual stress will be higher. Thus forming a vicious circle, the austenitic stainless steel sheet is more likely to crack during the stretching process.
The following preventive measures can be taken during the stretching process of austenitic stainless steel plates:
(1) Lubricant can be applied between the concave and convex dies to produce a film with a certain toughness and ductility, which has a significant effect on the stretching of austenitic stainless steel plates.
(2) White cast iron can be used as a blank holder mold, and a conical blank holder can also be used because white cast iron has better oil storage performance and is very easy to produce a lubricating oil film.
(3) The edges of the austenitic stainless steel plates should be processed smoother, without microcracks or notches, which can effectively avoid cracking.