Low-temperature mechanical properties of stainless steel 316L: Tests and constitutive models

To investigate mechanical behaviours of structural stainless steel (SS) 316L at cold-region cooling environment, this paper firstly performed tension tests on SS 316L at varying low temperatures. Thirty-two standard samples in different thickness, cut from different square/circular SS tubes, were tested under combined uniaxial tension and varying low temperatures (T) of -80, -60, -30, and 20 degrees C. These tests showed that the low-temperature stress-strain (sigma-epsilon) curves behave differently from those ambient-temperature ones, which exhibits S-shaped strain hardening stages with a much larger sloped second strain hardening stage than that of the first strain hardening stage. Decreasing T from 20 to -80 degrees C increased the elastic modulus (E), yield (sigma 0.2) and ultimate (sigma u) strength of SS 316L, but reduced its ultimate (epsilon u) and fracture (epsilon F) strains as well as the ductility. However, all the SS 316L samples failed in ductile mode even though their ductility was compromised. Empirical models were also developed to estimate the enhancing factors for E, sigma 0.2, sigma u, and epsilon u due to low temperatures using the best subset regression analysis method. In addition, modified true sigma-epsilon constitutive models at low temperatures were also developed for SS 316L. The validations proved that the developed constative models described well the sigma-epsilon behaviour of SS 316L at a low temperature range of -80 ~ 20 degrees C.

Automated summary

This paper investigates the mechanical behaviors of SS 316L at different low temperatures through tension tests. The results show that the stress-strain curves at low temperatures behave differently, and the material's ductility is reduced. Empirical models were developed to estimate the strength and hardness of SS 316L at low temperatures, and their validity was validated.