Effect of residual stress on the continuous cooling transformation of high‐strength low‐alloy hot‐rolled strip

The external stress will change the transformation process and microstructure of the material, and the residual stress generated during the processing of the material will also affect the transformation. In this paper, the effect of residual stress was simulated by applying uniaxial elastic loads during the continuous cooling of high‐strength low‐alloy hot‐rolled strip. The transformation process and microstructure of the samples under different stress conditions were investigated. The results show that residual stress could accelerate the transformation process, and the tensile stress was greater than the compressive stress. The degree of lattice mismatch in stressed samples was larger than that in unstressed samples, leading to dislocation proliferation. It was found that there was a phenomenon of residual stress induced grain growth according to the statistics of grain size of different samples. Due to the higher dislocation density and smaller curvature of the parent phase interface under compressive stress, the compressive stress samples had a higher nucleation rate, resulting in smaller grain size than the tensile stress samples. In addition, the transformation texture also changed under residual stress.

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