摘要
采用自行研制的固定式排水罩,使用大、小2种典型热输入参数对EH 36钢进行水下局部干法焊接试验,对焊后工件按AWS D3.6 M-2010标准进行接头性能测试。结果表明,所有试样除硬度外各项性能指标都能满足该标准规定的A级焊缝要求。在大热输入条件下,焊缝组织为先共析铁素体、侧板条铁素体和针状铁素体;在小热输入条件下,焊缝组织含有较多的针状铁素体。在小热输入条件下,热影响区粗晶区组织以粒状贝氏体和上贝氏体为主,并含有少量板条状马氏体;在大热输入条件下,热影响区原奥氏体晶粒尺寸变大,贝氏体组织增多。
With a specially designed drainage cover, the EH36 steel is welded respectivelyby local dry underwater welding method under low and high heat input values. The mechani-cal properties and microstructure of welds are checked according to AWS I）3. 6 M--2010standard. The results indicate that most mechanical properties can meet the requirement ofClass A welds in the AWS D3.6 M--2010. The weld metal contains proeutectoid ferrite, fer-rite side plate and acicular ferrite in the case of high heat input, whereas the weld metal con-tains more acieular ferrite with low heat input. For the heat treatment zone （HAZ）, it mainlycontains granular bainite and upper bainite, as well as a small amount of lath martensile withlow heat input. The austenite grain size and the bainite ratio increases obviously if high heatinput is adopted.
