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本文研究了Mn(0.75～1.33％),Si(0.44～0.82％)含量对10CrCuSiV耐海水飞溅带腐蚀的低合金高强钢埋弧焊缝在焊态下的金相组织、抗裂性及低温韧性的影响.焊缝中Mn、Si含量的变化是用相同的焊剂,由改变焊丝成分来达到的。 试验结果表明,Si含量的提高将使晶粒长大和晶界先共析铁素体量增加,Si提高到0.7％以上后晶界形成粗大网状先共析铁素体,此时抗裂性和低温韧性均恶化。当焊缝Si为0.4～0.7％,Mn为0.9～1.1％时焊缝合氧量<400PPm,晶粒度较细,金相组织为粒状贝氏体+针状铁素体,晶界有不连续的细小先共析铁素体,其面积占3～10％,这时焊缝具有良好的抗裂性和低温韧性,可保证-20℃时a_k(指V缺口的却贝冲击值,下同)≥4.3公斤·米/厘米~2。Mn<0.9％时,先共析铁素体量增加,抗裂性下降。Mn>1.1％后,因晶粒长大而在晶界出现粗大网状先共析铁素体,此时焊缝虽仍有良好的抗裂性,但低温韧性将下降。
In this paper, the microstructure, crack resistance and low temperature toughness of low alloy high strength steel submerged arc welded steel with corrosion resistance of 10CrCuSiV in seawater splash zone with Mn (0.75-1.33%) and Si (0.44-0.82%) were studied. Of the impact of changes in the weld Mn, Si content is the same flux, by changing the wire composition to achieve. The results show that the increase of Si content will increase the grain size and the amount of proeutectoid ferrite in the grain boundary. When Si is increased to above 0.7%, the coarse network pro-eutectoid ferrite will be formed in the grain boundary, and the crack resistance And low temperature toughness are deteriorated. When the weld Si is 0.4 ~ 0.7%, Mn is 0.9 ~ 1.1% when the weld oxygen <400PPm, fine grain size, the microstructure of granular bainite + acicular ferrite, grain boundaries are not Continuous small proeutectoid ferrite, the area of 3 to 10%, then the weld has good resistance to cracking and low temperature toughness, -20 ℃ can guarantee a_k (V notch Charpy impact value, under Same) ≥ 4.3 kg · m / cm ~ 2. When Mn <0.9%, the amount of pro-eutectoid ferrite increases and the crack resistance decreases. When Mn> 1.1%, coarse network pro-eutectoid ferrite appears in the grain boundaries due to the grain growth. At this time, though the weld seam still has good crack resistance, the low-temperature toughness will decrease.