Effect of Solution Temperature on Cold Rolling Properties of Lean Duplex Stainless Steel

The effect of solution temperature on cold rolling properties of lean duplex stainless steel (LDSS) was studied. The cold-rolling test was used to observe the crack of the material after solution at different temperatures; the work hardening curve of the solution treated material was obtained by compression test at room temperature, and the austenite element in LDSS was calculated by Thermo-Calc software. The different element contents obviously affect the stacking fault energy (SFE) of the materials, which leads to the change of the difficulty of transformation induced martensite in austenite. The phase transformation induced plasticity (TRIP) effect in LDSS was analyzed by optical microscopy (OM), transmission electron microscopy (TEM), and electron backscatter diffraction (EBSD). It is found that different solution temperature can significantly affect the grain size of austenite, and then affect the difficulty of strain-induced martensitic transformation (SIMT) of austenite grain in LDSS. When solution treated at 900-1100 degrees C, with the increase of temperature, the content of quenched martensite decreases, the amount of austenite which can induce transformation induced plasticity increases, and the rolling performance improve. However, when the temperature is higher than 1200 degrees C, Cr2N phase precipitates in ferrite, which reduces the plasticity of the material.