【摘要】：對低碳貝氏體鋼進行雙面埋弧焊焊接,并用光學顯微鏡和PSW750型示波沖擊試驗機對焊接接頭進行表征,研究了鋼的顯微組織和低溫韌性。結(jié)果表明:低碳貝氏體鋼雙面埋弧焊后,焊縫區(qū)的組織為針狀鐵素體和粒狀貝氏體;HAZ的組織為貝氏體鐵素體和粒狀貝氏體;HAZ熔合線附近的硬度最高,遠離熔合線硬度降低并逐漸接近母材金屬的硬度;隨著溫度的降低焊接過程中的凝固偏析、高度集中的位錯源來不及松弛應(yīng)力集中以及分布在晶界上的Ti、Mo等微合金元素形成的碳氮化物,導致焊接接頭焊縫區(qū)和HAZ韌性降低并在-20℃和-60℃發(fā)生韌脆轉(zhuǎn)變。
[Abstract]:The low carbon bainitic steel was welded by submerged arc welding on both sides. The microstructure and low temperature toughness of the steel were studied by means of optical microscope and PSW750 oscillographic impact testing machine. The results show that the microstructure of the weld zone is acicular ferrite and granular bainite HAZ, and the hardness near the fusion line of bainite ferrite and granular bainite is the highest after double-sided submerged arc welding of low carbon bainite steel. The hardness decreases away from the fusion line and gradually approaches the hardness of the base metal; as the temperature decreases, the solidification segregation occurs during the welding process. The highly concentrated dislocation causes too late relaxation of stress concentration and the formation of carbides formed by microalloyed elements such as Tipo Mo on grain boundaries, which results in the decrease of weld zone and HAZ toughness of welded joints and ductile brittle transition at -20 鈩，

本文編號：2193281