Effect of annealing on corrosion and wear properties of 310S stainless steel

310S stainless steel shows different corrosion and wear properties when treated with different annealing times, which is mainly related to the shape and quantity of precipitates and the corrosion mechanism of stainless steel in pure water and acidic environments. It can be seen that there are many furrows on the scratched surface, indicating that the wear mechanism of stainless steel in deionized water is furrow wear. The hard precipitates at the grain boundaries of the sample are beneficial to improving the strength of the machine body and have a blocking effect on furrow cutting.

As the annealing time increases, the precipitates gradually increase and coarsen, and their blocking effect on furrow cutting also gradually increases, resulting in a gradual reduction in the number and width of scratches and improving its wear resistance. As the annealing time increases, the furrows gradually become shallower, and obvious corrosion marks and spalling pits gradually appear on the scratched surface. This is because the precipitation of Cr-rich precipitates at the grain boundaries leads to Cr depletion near the grain boundaries, thereby reducing its corrosion resistance. The mechanical strength is reduced under the corrosion of acidic solutions, resulting in fatigue under the action of periodic shear forces. fall off. This shows that the wear mechanism of stainless steel in acidic environment is the combination of furrow wear and corrosion fatigue wear. As the annealing time increases, the number of precipitates in the stainless steel increases and becomes coarser, and the corrosion resistance of the stainless steel becomes worse and worse. The dominant role in the wear mechanism of stainless steel gradually changes from furrow wear to corrosion fatigue wear.

Through various test methods, it can be concluded that the proportion of static corrosion of stainless steel in acidic solutions is very small and can be ignored. Although stainless steel has extremely strong corrosion resistance, due to the promotion of corrosion by wear during the corrosion and wear process, the proportion of corrosion and wear interaction in the entire corrosion and wear still reaches 13.74%-5894%. As the annealing time increases, the proportion of pure wear gradually decreases, while the proportion of corrosion-wear interaction increases. It is worth noting that when the annealing time is 5-20 hours, the proportion of corrosion loss interaction increases slowly. "When the annealing time continues to extend, the proportion of corrosion loss interaction increases rapidly. At this time, the corrosion resistance of stainless steel is A small loss on the material can reduce the overall corrosion loss material loss due to the improvement of wear resistance.

(1) The precipitates of AISI310S stainless steel increase as the annealing time increases, and at the same time, the precipitates gradually coarsen, changing from needle-like or point-like to bone mesh-like.

(2) The wear mechanism of stainless steel in deionized water is mainly furrow wear. The corrosion wear mechanism in acidic environments is determined by both furrow wear and corrosion fatigue wear. When the corrosion performance of stainless steel is slightly reduced, furrow wear plays a leading role. When the number of precipitates increases and coarsens, causing a significant reduction in corrosion performance, corrosion fatigue plays a leading role.

(3) After pure grinding in a deionized water environment, as the annealing time increases, its wear resistance increases. In an acidic environment, when the annealing time is 50 hours, the material has the best corrosion and wear resistance.