厚钢板焊接接头CTOD断裂韧度的温度影响

Influence of Temperature on Fracture Toughness CTOD in Welded Joints of Thick Steel Plate

大型厚壁钢结构建造中,研究温度对焊接接头断裂韧度的影响十分重要.笔者对65 mm厚S355ML钢板,编制自动埋弧焊(WPS017)工艺和手工电弧焊(WPS016,WPS016A)工艺,对其焊接接头进行常温(15℃)和低温(-20℃)裂纹尖端张开位移(CTOD)评定.发现自动埋弧焊(WPS017)接头焊缝低温CTOD最小值比常温低13.9%,焊缝低温CTOD均值比常温低8.0%;热影响区CTOD断裂韧度值高于焊缝和母材,且对温度变化不敏感.手工电弧焊接头焊缝低温CTOD最小值只有常温的34.5%,焊缝低温CTOD均值只有常温的25.9%;热影响区低温CTOD断裂韧度也很低.在常温(15℃)下,自动埋弧焊焊缝CTOD值比手工电弧焊焊缝CTOD值大得多;在低温(-20℃)下,自动埋弧焊的焊缝和热影响区的CTOD值,都远远大于手工电弧焊CTOD值.

It is very important to explore the influence of temperature on fracture toughness CTOD in welded joints of thick steel plate in the process of fabrication of modem huge steel structure. The submerged arc welding （SAW） craft （WPS017） and shielded metal arc welding （SMAW） craft （WPS016 and WPS016A） were designed for $355ML steel with thickness of 65 ram. At 15oC and -20℃, the Crack Tip Opening Displacement （CTOD） tests were performed for the welded joints in WPS017, WPS016 and WPS016A. The results are following：For the weld position（WP） of SAW craft , the minimum CTOD value at -20℃ is lower than the minimum CTOD value at 15℃ about 13.9%, and the average CTOD value at -20℃ is also lower than the average CTOD value at 15℃ about 8.0%. But the CTOD values of heat affected zone （HAZ） are higher than the CTOD values of WP and basic metal（BS）. What is more, the CTOD values of HAZ are almost insensitive to the changes of temperature. For the SMAW craft, the minimum CTOD value of WP at - 20 ℃ is about 34.5% of the minimum CTOD value of WP at 15℃, and the average CTOD value of WP at - 20 ℃ is about 25.9% of the average CTOD value of WP at 15℃. The CTOD values of HAZ at -20℃ are also very lower. Under the room temperature （ 15℃ ）, the WP of SAW （WPS017） posses higher CTOD values than the WP of SMAW （WPS016）. In low temperature （ -20℃ ）, the WP and HAZ of SAW （WPS017） have higher CTOD values than SMAW （WPS316）.