碳和氮元素对高强度奥氏体焊缝组织和性能的影响

Effect of carbon and nitrogen on microstructure and properties of austenite weld metal

关键词:  奥氏体焊条  抗拉强度  韧性  碳化物

Key words:  austenitic electrode  tensile strength  toughness  carbide

摘要:

采用扫描电镜(SEM)和透射电镜(TEM)等分析研究了碳、氮元素对奥氏体焊条熔敷金属组织和性能的影响。结果表明,随着碳含量的增加,熔敷金属晶界上M₂₃C₆碳化物析出物逐渐增多,析出颗粒增大,虽然熔敷金属的抗拉强度有所提高,但韧性明显降低,碳含量增加到一定程度后,对强度的影响趋于平缓,但对晶界碳化物的数量和尺寸仍然有强烈的促进作用,韧性持续降低,耐晶间腐蚀性能大大降低。随着氮含量的增加,抗拉强度呈持续上升趋势,同时韧性仍能保持在较高水平,晶界上析出碳化物少,抗晶间腐蚀性能良好。

Abstract:

Effect of carbon and nitrogen on microstructure and properties of austenite weld metal were studied by scanning electron microscope, transmission electron microscope and other methods. With increasing C content, the quantity of M₂₃C₆ carbide particles at austenite grain boundaries increased and the size of M₂₃C₆ enlarged. The tensile strength of deposited metal increased, however, the toughness decreased markly. When the content of C increases to a high level, the solution strengthening effect doesn't express anymore, but the quantity and size of carbide particles formed at austenite grain boundartes is still increasing. The toughness and intergranular corrosion resistance decreased continuously. With increasing N content, tensile strength increased, at the same time, the toughness kept at high level. Owing to small quantity of carbide particles formed at austenite grain boundaries, intergranular corrosion resistance displayed good performance.