Abstract:

Based on testing comparison, the paper makes a systematic analysis of the differences between the homemade shot-blasted S30432 tubes and the imported shot-blasted Super304H tubes in terms of surface appearance, microstructure features and hardening effect of the deformed metal layer. The study results indicate that the hardening effect of shot blasting mainly depends on the eveloping extent of the broken-grain sub-layer and the multiple-slipped-grain sub-layer in the deformed metal layers, especially the broken-grain sub-layer. The homemade SB tubes are inferior to the imported SB ones not only in the thickness and homogeneity of the broken-grain sub-layer and multiple-slipped-grain sub-layer, but also in the depth，hardness and homogeneity of the effective hardening layers. Therefore, the domestic manufacturers still lag behind the foreign counterparts in shot blasting techniques, and needs further modification and improvement.