What is the performance of stainless steel pipe at low temperature?_Shandong Baixinxin Metal Material Co., Ltd.

What is the performance of stainless steel pipe at low temperature?

Published:

2021-08-20

　　Regarding the low temperature state, ferritic stainless steel pipes have low temperature brittleness like carbon steels, but austenitic steels do not. Therefore, ferritic or martensitic stainless steels exhibit low-temperature embrittlement while austenitic stainless steels or nickel-based alloys do not exhibit low-temperature embrittlement. Ferritic stainless steel pipes such as SUS410 (13Cr) and SUS430 (18Cr) show a sharp drop in impact value at low temperatures. Therefore, it is necessary to pay special attention when using it in a low temperature state. As a method for improving the impact toughness of ferritic stainless steel, a high purification process can be considered.
　　1. Low temperature embrittlement of stainless steel tube --- In low temperature environment, the deformation energy is small. In a low temperature environment, the phenomenon of reduced elongation and area reduction is called low temperature embrittlement. Most of them are produced on the body-centered cubic structure of the ferrite series.
　　2. Low temperature processing of stainless steel tubes --- Quenching the martensitic series stainless steel from the austenitizing temperature and then cooling it to a very low temperature to promote the quenching method of producing martensite. Suitable for stainless steels that are easy to produce retained austenite.
　　At low temperature, the resistance, linear expansion coefficient, thermal conductivity, mass thermal melting and magnetic properties of stainless steel pipes will change greatly. Electrical resistance and coefficient of linear expansion decrease at low temperature; thermal conductivity and mass heat capacity decrease sharply at low temperature; Young's modulus (longitudinal elastic modulus) increases at the same time as temperature decreases. Because the austenitic series stainless steel pipe has a low temperature (Subzreo temperature) Ms point (martensite transformation start temperature or martensite formation temperature), when it is kept below the Ms point, martensite can be formed. The formation of martensite at low temperature makes SUS304 (18Cr-8Ni), the representative steel of austenitic series stainless steel, non-magnetic at room temperature, but becomes magnetic at low temperature.
　　Etc. are applied to the shell of refrigeration appliances. Because ferritic stainless steel has a body-centered cubic structure, when the material properties become weak, sharp cracks will rapidly expand and cause brittle failure. Austenitic stainless steels do not suffer from brittle failure because of their face-centered cubic structure. Arcane input stainless steel SUS304L (18Cr-9Ni-LC) and SUS316L (18Cr-12Ni-2Mo-LC) etc. show excellent impact characteristics at low temperature. However, attention should be paid to the precipitation of ferrite or the precipitation of martensite due to processing, as well as the tendency to embrittlement due to the precipitation of carbides or σ-phase heterogeneous phases due to sensitization.

Keyword:

How to prevent the decarburization of thick-walled steel pipes?

What is the use of anti-corrosion steel pipe

How to prevent the decarburization of thick-walled steel pipes?

What is the use of anti-corrosion steel pipe