Effects of Surface Peening on Residual Stress and Microstructure of Nickel-base Alloy 182 and 52 M Welds
Effects of Surface Peening on Residual Stress and Microstructure of Nickel-base Alloy 182 and 52 M Welds
Baosheng Bai(Pusan National University); Sungyu Kim(Pusan National University); Joonho Moon(Pusan National University); Wongeun Yi(Pusan National University); Eunsub Yun(Pusan National University); Chi Bum Bahn(Pusan National University)
31권 5호, 1352~1368쪽
초록
The effects of surface peening techniques on morphology, residual stress, hardness, and microstructure were studied usingAlloy 182 and 52 M specimens treated with water jet peening (WJP), air laser peening (ALP), underwater laser peening(ULP), and ultrasonic nanocrystal surface modification (UNSM). To simulate actual plant conditions, the surfaces of specimenswere pre-treated with heavy grinding. Specimens processed a single time and multiple times (× 2, × 4, and × 8) wereprepared to evaluate the impact of repeated treatments. The results indicated that all techniques achieved a compressiveresidual stress field of at least 1 mm depth, as intended. UNSM generated the highest compressive residual stress on the surface,followed by ULP, WJP, and ALP. UNSM also introduced the deepest layer of plastic deformation and grain refinement. ULP initially showed dislocations after a single treatment, while grain refinement occurred after two treatments. WJP andALP introduced the thinnest layers of plastic deformation, but the smallest grains were observed near the surface. Increasingtreatment number deepened plastic deformation but had limited effect on increasing surface residual stress, with only ALPshowing a continuous increase. In addition, the mechanism for the differences in the effects of each peening technique onsurface characteristics was discussed.
Abstract
The effects of surface peening techniques on morphology, residual stress, hardness, and microstructure were studied usingAlloy 182 and 52 M specimens treated with water jet peening (WJP), air laser peening (ALP), underwater laser peening(ULP), and ultrasonic nanocrystal surface modification (UNSM). To simulate actual plant conditions, the surfaces of specimenswere pre-treated with heavy grinding. Specimens processed a single time and multiple times (× 2, × 4, and × 8) wereprepared to evaluate the impact of repeated treatments. The results indicated that all techniques achieved a compressiveresidual stress field of at least 1 mm depth, as intended. UNSM generated the highest compressive residual stress on the surface,followed by ULP, WJP, and ALP. UNSM also introduced the deepest layer of plastic deformation and grain refinement. ULP initially showed dislocations after a single treatment, while grain refinement occurred after two treatments. WJP andALP introduced the thinnest layers of plastic deformation, but the smallest grains were observed near the surface. Increasingtreatment number deepened plastic deformation but had limited effect on increasing surface residual stress, with only ALPshowing a continuous increase. In addition, the mechanism for the differences in the effects of each peening technique onsurface characteristics was discussed.
- 발행기관:
- 대한금속·재료학회
- 분류:
- 재료공학