不锈钢喷丸管热处理的可行性分析

Feasibility Analysis of Heat Treatment of Stainless Steel Shot Peening Tube

为最大限度保证喷丸层在后续服役过程中的抗氧化作用,不锈钢喷丸管在锅炉制造单位一般不参与受热面管屏焊接后的重新再加热处理.通过Super304H-SB不锈钢喷丸管模拟管屏热处理的工艺性试验及电厂实炉取样检测Super304H-SB不锈钢喷丸管,发现喷丸层的氧化与碎化晶层有着密不可分的关系.碎化晶层的形貌、大小、厚度、再结晶速度等几乎不受热处理循环过程的影响,即提供给铬元素向内表面扩散的短路通道数量没有实质上的减少.结果表明:(745±15)℃消应力热处理及锅炉长期高温运行不会使喷丸层的组织产生明显退化,喷丸层依然可以保持较强的抗氧化性能.不锈钢喷丸管可以参与锅炉制造过程中的管屏焊后整体消应力热处理.

In order to maximize the anti-oxidation effect of shot blasting layer in the subsequent service and operation process,the stainless steel shot peened tube is generally not involved in reheat treatment after welding of the heating surface tube panel by the boiler manufacturer.Through the process test of simulating the heat treatment of the tube panel with Super304H-SB stainless steel shot tube and testing Super304H-SB stainless steel shot peening tube by sampling in power plant,it is found that the oxidation of the shot peened layer is closely related to the broken crystal layer.The morphology,size,thickness and recrystallization rate of the broken crystal layer are hardly affected by the heat treatment cycle,that is,there is no substantial reduction in short-circuit channel data provided for Cr element diffusion to the inner surface.The results show that(745±15)℃stress relief heat treatment and boiler operation at high temperature for a long time will not cause obvious degradation of the structure of shot blasting layer.The shot peened layer can still maintain strong oxidation resistance.The stainless steel shot peened tube can participate in the overall stress relief heat treatment after welding of the tube panel in the manufacturing process of the boiler.