P91与10CrMo910异种钢焊接接头特性分析

Analysis of the P91/10CrMo910 dissimilar steel welded joints

关键词:  异种钢  焊接接头  冲击韧度  显微硬度

Key words:  dissimilar steel  welded joint  impact toughness  microhardness

摘要:

通过冲击韧度和显微硬度测试及金相组织观察,研究了采用2.25Cr-1Mo型和5Cr-0.5Mo型两类国产焊接材料,按实际焊接要求制备的P91钢与10CrMo910钢异质焊接接头,在二次回火前后的特性。结果发现,焊接接头的韧性受所用焊接材料和焊后热处理条件影响,用2.25Cr-1Mo型焊接材料所焊接头韧性较高,而用5Cr-0.5Mo型焊接材料所焊接头韧性较差,焊后二次回火处理在一定程度上能改善接头组织,提高接头韧性。由于组织变化和碳迁移的原因,在接头异质界面熔合线两侧产生了较大的硬度差,二次回火使接头硬度整体下降,但几乎不影响其分布规律。在靠近P91钢侧的焊缝中存在未混合区。

Abstract:

The welded joints of P91/10CrMo910 dissimilar steel using two types filler materials 2.25Cr-1Mo and 5Cr-0.5Mo were made according to the real condition and their properties were investigated by measuring the impact toughness, microhardness distribution and observing the microstructure. The effects of the second tempering on the joint properties were discussed. The results showed that the toughness of the joint using 2.25Cr-1Mo was higher and that of the one using 5Cr-0.5Mo was lower; By double tempering the microstructures of the joints were improved and the toughness of the joints increased in some way; There were obvious difference of microhardness on both sides of the fusion line and there was an unmixed zone in the weld adjacent to P91 due to the microstructure changing and carbon diffusion across the fusion line. Microhardness of the joints after double tempering was lower than that of the joints without heating treatment and their microhardness distributing curve were similar.