Stress Relaxation Performance and Prediction Models for Bolt Material of 1Cr10NiMoW2VNbN

Stress relaxation tests of the newly developed bolt alloy 1Cr10NiMoW2VNbN were carried out in order to investigate and predict its long-term relaxation performance.Effects of the environment tem-perature and primary stress on the relaxation performance were discussed.Based on the experimental results,the applicability of Hook-Norton model,generalized Maxwell relaxation model,logistic model and polyno-mial model for the extrapolation of residual stress was reexamined.Results indicate that temperature is the dominating contributor for the relaxation performance of bolt material.According to the experimental results in this paper,stress relaxation limit of the newly developed bolt alloy 1Cr10NiMoW2VNbN is still unavail-able.Compared to the experimental data,the developed polynomial relaxation model can lead to an appro-priate extrapolation of the remaining stress.