【摘要】 通过药皮过渡添加B,研究了微量B对440MPa级焊条熔敷金属低温冲击韧性的影响。试验发现,冲击韧性对B含量的变化较敏感,同时当焊缝中Ti含量不同时,B含量的影响也不同。当Ti含量为0.01%~0.04%(w)时,B含量在30×10-6(w)左右时韧性最好;当Ti含量为0.04%~0.07%时,B含量在(40~90)×10-6范围内韧性最好。B含量适中时熔敷金属组织几乎全是均匀细小的针状铁素体,B含量过低组织中出现大量的先共析铁素体,B含量过高则会生成沿原奥氏体晶界分布的粒状贝氏体和上贝氏体。更多还原

【Abstract】 Effect of trace boron on the impact toughness of 440MPa deposited metal has been investigated.It was found that the best impact toughness was obtained by maintaining boron contents within 30ppm when Ti content is 0.01%～0.04% and 40ppm～90ppm when Ti content is 0.04%～0.07% respectively.With the boron contents in these ranges,the microstructure of the deposited metal is almost fine acicular ferrite.Otherwise there will be large volume fraction of pro-eutectoid ferrite or upper bainite and granular bainite along the prior austenite grain boundary which will deteriorate the impact toughness.更多还原