Cold pressing head deformation quantity predicating method based on deformation-induced martensite phase transformation

Abstract

The invention relates to quality detection techniques used for heads molded through cold pressing and aims to provide a cold pressing head deformation quantity predicating method based on deformation-induced martensite phase transformation. The deformation quantity predicating method includes specific steps of conducting a head cold pressing molding test, performing finite element simulation in a cold pressing process and creating a relation curve of the deformation quantities and the martensite phase transformation quantities of the cold pressing head; using a ferrite measuring instrument for measuring martensite phase transformation quantities of areas of the cold pressing head requiring predication respectively; and substituting the measured martensite phase transformation quantities of the different areas of the cold pressing head into the obtained relation curve of the deformation quantities and the martensite phase transformation quantities of the corresponding areas respectively, so that the deformation quantities of the areas of the cold pressing head are obtained. By adopting the deformation quantity predicating method provided by the invention, curves of the deformation quantities of transition segments, straight sections and shell parts of different austenitic stainless steel heads can be determined and the plastic deformation quantities of the heads can be obtained conveniently, quickly and accurately by using the ferrite measuring instrument. The deformation quantity predicating method is very suitable for applying to the field of engineering.

Description

technical field [0001] The invention relates to a quality detection process of a cold stamping head, in particular to a deformation amount prediction method for a cold stamping head based on deformation-induced martensitic transformation. Background technique [0002] With the rapid development of the national economy, low-temperature liquefied gases, including liquid nitrogen, liquid oxygen, liquid hydrogen, and liquefied natural gas (LNG), are widely used. Austenitic stainless steel cryogenic container is one of the main storage and transportation equipment for liquefied gas, and its demand is also increasing. The cold stamping forming head has the advantages of good surface quality, regular shape, precise forming size, especially the fast forming of the head, and easy mass production, so it is widely used in the manufacture of small and medium-sized cryogenic containers. However, the plastic deformation of the head formed by cold stamping is relatively large, especially ...

AI Technical Summary

Problems solved by technology

First of all, the results calculated by different formulas are quite different. This is because the deformations examined by different formulas are different. Some examine the average deformation of the head in the meridian direction, while others examine the maximum compressive deformation in the circumferential direction. For heads subjected to multiaxial stress during the stamping process, the formula is difficult to reflect the real deformation of the head; in addition, the formula is applicable to the calculation of the deformation of all austenitic stainless steel stamped heads, and different materials due to their material properties Even under the same deformation, the performance of the head will be quite different

[0004] At present, there is no simple and accurate method for predicting the deformation of austenitic stainless steel cold stamping heads at home and abroad.

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