Enhancing the mechanical and magnetic properties for low magnetic stainless-steel plates by non-recrystallization hot rolling and solution treatment

Developing low magnetic stainless-steel plates with high yield strength while ensuring good plasticity, corrosion resistance, and paramagnetism is a tough technical challenge, especially under conditions of limited rolling mill capacity and total reduction. In this study, a low magnetic stainless-steel plate with excellent yield strength (620 MPa), ultimate tensile strength (891 MPa), and ductility (42.7%) was prepared by rolling in the non-recrystallization region (below the recrystallization temperature Tnr) and subsequent solution treatment. The effects of different thermomechanical processing techniques on the recrystallization behavior, grain size, dislocation density, grain boundary characteristics, micro-texture, mechanical and magnetic properties of low magnetic stainless steel were studied. Compared with conventional high-temperature hot rolling, rolling in the non-recrystallization region and subsequent solid solution treatment can effectively refine the grain size and form Brass {001} < 211 > texture in the plate, with texture intensity increasing with greater deformation in this region. The main strengthening contribution mechanisms of high yield strength are N-element solid solution strengthening and fine grain strengthening. Due to the high austenite stability and appropriate rolling temperature, the paramagnetism of low magnetic stainless steel was not disrupted after rolling in the non-recrystallization region, and the relative permeability of all samples was less than 1.01. From the perspectives of production efficiency, process difficulty, and economy, the HR3-S process route in this study makes it easier to achieve large-scale industrialization, providing theoretical and process references for developing low magnetic stainless-steel plates toward high yield strength and high paramagnetic stability.