稀土氧化物对碱性焊条焊缝组织与低温韧性的影响
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摘要
在典型碱性结构钢焊条药粉成分基础上,以镧、铈及钇的混合氧化物作为焊条药粉添加剂,设计了六组含稀土氧化物碱性焊条,观察了焊缝显微组织和冲击断口形貌特征,测定了焊缝低温冲击韧性。结果表明,在焊条药皮中适量添加稀土氧化物可细化焊缝金属晶粒,而且有利于形成强韧性较好的针状铁素体组织;适量添加稀土可提高焊缝低温冲击韧性,当焊条药粉中的稀土氧化物添加量为2.0%时,低温冲击韧性相对最好,冲击吸收功为56.66 J,其冲击断口韧窝较密集,韧性断裂特征明显。
On the basis of the powder composition of typical basic structural steel electrode, the mixed oxides of lanthannum, cerium and yttrium were used as electrode powder additives, six sets of basic electrode with rare earth oxides were designed. The microstructure and impact fracture morphology of the welds were observed and the low temperature impact toughness of the welds was measured. The result shows that, the appropriate addition of rare earth oxides in the electrode coating can refine the weld metal's grains and it is beneficial for the formation of acicular ferrite structure with good strength and toughness. Moderate addition of the rare earth oxides can improve the low temperature impact toughness of the welds. When the amount of the rare earth oxides in the electrode power is 2.0%, the impact toughness at low temperature is the best, the impact absorbing energy is 55.66 J, the impact fracture dimple is compact and the ductile fracture characteristics are obvious.
On the basis of the powder composition of typical basic structural steel electrode, the mixed oxides of lanthannum, cerium and yttrium were used as electrode powder additives, six sets of basic electrode with rare earth oxides were designed. The microstructure and impact fracture morphology of the welds were observed and the low temperature impact toughness of the welds was measured. The result shows that, the appropriate addition of rare earth oxides in the electrode coating can refine the weld metal's grains and it is beneficial for the formation of acicular ferrite structure with good strength and toughness. Moderate addition of the rare earth oxides can improve the low temperature impact toughness of the welds. When the amount of the rare earth oxides in the electrode power is 2.0%, the impact toughness at low temperature is the best, the impact absorbing energy is 55.66 J, the impact fracture dimple is compact and the ductile fracture characteristics are obvious.
引文
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