Near-threshold fatigue crack growth behavior of the weld metal and heat-affected zone in an ex-service CrMoV steel joint. (November 2022)

• Record Type: Journal Article
• Authors: Sun, Qixing; Liu, Qu; Li, Xiaogang; Cai, Zhipeng; Huo, Xin; Fan, Manjie; He, Yi; Yao, Xinzhe; Pan, Jiluan; Li, Kejian
• Is Part Of: International journal of fatigue. Volume 164(2022)
• Publication Date: 2022-11
• Subjects: Fatigue crack growth -- Threshold value -- Weld metal -- Heat-affected zone -- Temperature; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2022.107175
• Languages: English
• ISSNs: 0142-1123

Abstract

Highlights: Effects of temperature on the Δ K th of CrMoV steel WM and HAZ were studied. The Δ K th at high-temperature were high due to oxide-induced crack closure (OICC). The Δ K th at high-temperature in HAZ was higher than in WM due to its higher OICC. The higher OICC in HAZ was due to its lower Cr and Si content, and finer grains. Both thermal oxidation and fretting oxidation occurred during high-temperature tests. Abstract: Threshold value ( Δ K th ) and fatigue crack growth behavior at different temperatures and stress ratios were investigated in weld metal (WM) and heat-affected zone (HAZ) of an ex-service CrMoV steel joint. Compared with the Δ K th at 25 ℃, the Δ K th at 500 ℃ and 540 ℃ were still high, because significant oxide-induced crack closure (OICC) occurred in WM and HAZ during high-temperature tests. The high-temperature Δ K th of HAZ were higher than those of WM, due to their more severe oxidation and more significant OICC. This was owing to the lower Si and Cr content and smaller grain size in HAZ.