不同線能量下低碳貝氏體鋼焊接接頭的組織及韌性

Microstructure and Toughness of Bainite Steel Welding Joint Presenting under Condition of Different Heat Input

摘要: 研究不同線能量下低碳貝氏體鋼焊接接頭的組織及沖擊性能。試驗(yàn)結(jié)果表明：低碳貝氏體鋼對接直縫焊接后，焊縫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，焊縫區(qū)和HAZ的晶粒都隨著焊接線能量的減小而減??；焊縫的斷裂形式多為韌性斷裂，沖擊性能均較好，當(dāng)焊接線能量從24.8 kJ/cm向28.2 kJ/cm增加，焊接接頭的焊縫區(qū)和HAZ的沖擊功呈先減小后增大的趨勢。

Abstract: Studied are the microstructure and impact resistance of the low carbon bainite steel welded joint presenting under the conditions of different heat inputs.Relevant testing results show that after being butt seam welded, the weld microstructure of the said steel is of both acicular ferrite and granular bainite, while the HAZ microstructure is of bainite-ferrite and granular bainite, and the grains of both the weld zone and the HAZ are reduced along with decrease of the heat input.The weld fracture type is in most cases a ductile one, and the weld impact resistance is rather good in any case.When the welding heat input is being increased from 24.8 kJ/cm to 28.2 kJ/cm, the impact energy of the weld zone and the HAZ present a trend of first decreasing, and then increasing.