摘要:
在Gleeble-1500模拟装置上,模拟WT-62CF(CF-60)钢热影响区的焊接热循环,在两种冷却温度范围内施加不同的热应变(e=4%,6%,8%,11%),采用三点弯曲却贝边缺口试样,测定了粗晶区的断裂韧性(Jm)。在800~500℃冷却温度范围,Jm值分别为18.62N/mm(e=0),106.2N/mm(e=4%),114.1N/mm(e=6%),107.4N/mm(e=8%)。在400~200℃内,Jm值分别为18.62N/mm(e=0),111.2N/mm(e=4%),109.1N/mm(e=6%),99.9N/mm(e=8%),93.2N/mm(e=11%)。断裂区M-A%随应变量的变化与断裂韧性随应变量的变化有相同的规律性。其原因是模拟热影响区显微组织粒状贝氏体中M-A组元的影响,M-A组元弥散相对粒状贝氏体的断裂韧性是有利的。
Abstract:
Using charpy-size three-point bending specimens with side-grooves, the authors evaluated the fracture toughness of HAZ of WT-62CF steel subjected to different thermal prestrains (e=4%, 6%, 8%, 11%) in two cooling temperature ranges on Gleeble-l500. In the 800~500℃ cooling temperature range, the values of Jm were respectively 10.84kg/mm(e=4%),11.65kg/mm(e=6%) and 10.96kg/mm(e=8%). In the 400~200℃ range, the values of Jm decreased continuously from 11.53kg/mm to 11.1, 102, 9.51kg/mm with the increasing of e from 4% to 6, 8, 11%. This was due to the effect of M-A constituent in the granular Bainite, which was the microstructure of simulated HAZ. The area fraction of M-A changed also with the thermal prestrains in a similar regularity to the fracture toughness. The disperse phase M-A is of benifit to the fracture toughness of Bainite.
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