X80管线钢埋弧焊用烧结焊剂的研制  

Agglomerated alkali flux for submerged arc welding of high strength-toughness steel X80

作　　者：张敏[1] 姚成武[1] 李继红[1] 刘斌[1] 

机构地区：[1]西安理工大学材料科学与工程学院,西安710048

出　　处：《焊接学报》2006年第10期29-32,共4页Transactions of The China Welding Institution

基　　金：陕西省教育厅自然科学基金资助项目(05JK277)

摘　　要：从高强度低合金钢(HSLA)焊缝熔敷金属中的针状铁素体形核机理出发,确定以CaF2-MgO-Al2O3-MnO-TiO2-B2O3氟碱性渣系进行高强韧性埋弧焊烧结焊剂设计。结果表明,焊剂中添加MnO有利于焊缝中Mn元素的过渡,降低γ→α温度,从而抑制高温铁素体的生成而对焊缝中针状铁素体的形成有利。由于焊缝金属裂纹敏感指数(Pcm)较高,焊后空冷奥氏体晶粒较细,过量添加MnO,将会导致焊缝中Mn元素过高而细化奥氏体晶粒,使得奥氏体晶界增加。进一步冷却,贝氏体形核质点增加,因而对晶内形核的针状铁素体不利。稀土元素对提高焊缝金属中针状铁素体含量有一定的促进作用。Through analyzing acicular ferrite nucleating mechanism in the weld metal of the high strength low-alloy structural steel(HSLA), a submerged arc welding agglomerated flux with the CaF_2-MgO-Al_2O_3-MnO-TiO_2-B_2O_3 fluorine was developed by using alkali flux system. The results indicate that the existence of MnO in the flux benefits the transition of Mn to weld metal, and brings down the γ→α transformation temperature, thus high temperature ferrite production is held down, but the acicular ferrite increases in the weld metal. Because the Pcm of weld metal is higher, the austenite grain is thinner as-welded in air cooling condition. However, a excessive content of MnO in the flux will lead to the excessive Mn in the weld metal and a too low γ→α transform temperature. Thereby, the austenite grain boundaries cannot be decorated by allotriomorphic ferrite, thus the austenite grain boundary increases, which make more bainite nucleation site being produced. It is disadvantageous to the intragranularly nucleated acicular ferrite. In addition, the rare-earth element has some contributions to enhance the acicular ferrite content in the weld metal.

关 键 词：烧结焊剂 强韧性 针状铁素体 晶内形核 相变温度 

分 类 号：TG113[金属学及工艺—物理冶金]