| Summary: | 碩士 === 中華技術學院 === 機電光工程研究所碩士班 === 97 === The slurry erosion characteristics of hot-rolled SUS 403 stainless steel was studied in a function of reduction ratios and temperatures. The experimental material was hot rolled with reduction ratios of 15, 30 and 50%. Then, the sample of 50% reduction ratio was tempered at 200-500℃ to investigate the influence of tempering temperatures on the erosion. Both 15% and 30% reduction ratio samples were tempered at 500℃ to compare the effect of rolling reduction ratio on the erosion with those of 50% reduction ratio sample. In this study, the erosion mode, rolling reduction, tempering temperature, grain size and mechanical properties repeat to erosion rate at different impact angle were discussed partially.
The results show that a fine grained structure was obtained after hot rolling and the grain size decreased with increasing in reduction. The dominated mechanism for material removal at oblique impact angle (15° and 30°) is cutting. At higher impact angle (90°), the mechanism is based on extrusion crater. However, at medium impact angle (45° and 60°), the wear is dominated by transition of mechanism mixed with cutting and crater. For all reduction ration samples, when the samples were tempered at 500℃, the maximum erosion rate occurred at impact angle of 30°, while the minimum erosion rate occurred at normal impact angle. When the 50% reduction samples were tempered at 200-500℃, apart the 200℃ tempering sample, the maximum erosion rate occurred at impact angle of 45°, the others were at impact angle of 30°. Generally, the maximum erosion rate decreased with increasing in reduction ratios. Because the tensile strength, hardness, ductility and toughness were increased with decreasing in grain size, and then the erosion resistance was improved.
The XRD analysis also show that the strain-induced transformed ε-martensite increased with increasing in impact angle.
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