加热温度对奥氏体不锈钢管内壁喷丸处理效果的影响

INFLUENCE OF HEATING TEMPERATURE UPON SHOT-BLASTING TREAMENT ON INTERNAL SURFACE OF AUSTENITIC STAINLESS STEEL TUBES

在不同温度下对进口Super304H和国产S30432喷丸管进行的保温2h的热处理对比试验结果表明:当加热温度超过750℃时喷丸形变层的微观组织会发生退化,且碎化晶层组织退化速度高于多滑移层组织,导致Cr元素向表面扩散迁移的能力降低;喷丸处理质量会显著影响喷丸形变层的抗高温软化能力;进口Super 304H喷丸管因形变组织硬度更高且分布均匀而使其短时间抗高温软化能力比国产S30432喷丸管高出100℃以上。为了充分利用喷丸处理的表面加工硬化能力,需确保喷丸处理的质量以及弯管加工或者焊后热处理时的温度不超过730℃。

The compared results in heat treatment testing under different temperature after two hours show that the deformed microstructure of the shot - blasted layer may be degraded as the heating temperature being higher than 750 ℃ ,and the degradation speed of microstructure at broken grain layer is faster than that at multi- slide layer,the microstructure degradation of deformed layer will further result in the reduction of Cr diffusion capability from base metal to the surface. The shot - blasted quality can remarkably affect the resistant capability to high - temperature softening of the deformed layer.. The short - biased Super 304 tube is 100 ℃ higher than that on domestic shot - blasted S30432 steel tube due to higher hardness and better uniformity of said hardness of the former. In order to fully utilize the hardening ability of surface treatment on shot - blasted tubes, the shot - blasted quality should be ensured, and the heating temperature during post bending and post welding has to be less than 730 ℃.