不同保护Ar气含量下304不锈钢熔敷组织演变及夹杂物特征分析

Microstructure Evolution and Inclusion Characteristics of Cladding Tissue on 304 Stainless Steel Deposited under Different Protective Ar Gas Contents

为了提高304不锈钢熔敷组织的质量,选择Ar气对实心焊丝提供保护,并试验测试分析了不同保护Ar气含量对304不锈钢熔敷组织及夹杂物性能的影响。研究结果表明:当Ar在保护气内的含量降低后,熔敷层硬度减小,冲击韧性随温度升高呈现先上升后下降的趋势,屈强比先减小后增大。当保护气内存在80%的Ar后,获得了具备优异力学特性的熔敷层。熔敷层组织中存在较多的马氏体组织以及部分条状奥氏体组织,条状马氏体中形成了大量的位错结构。当Ar含量达到96%时,熔敷层生成了许多颗粒以及条形的碳化物,每个柱状晶中都形成了几乎呈平行排列状态的板条块结构。当Ar的含量降低后,夹杂物尺寸与数量都上升。当保护气内的Ar含量达到80%时,在熔敷层内形成了更多的有助于促进铁素体形核的杂质。所有熔敷层内形成的夹杂物都是由氧化物以及部分硫化物构成的夹杂物,靠近中心部位的Al与Ti含量更高。

In order to improve the quality of 304 stainless steel cladding tissue,Ar gas was selected to provide protection on solid welding wire,and the effects of different Ar gas contents on the cladding tissue and inclusion properties of 304 stainless steel were tested and analyzed experimentally.Results showed that when the content of Ar in the protective gas decreased,the hardness of the cladding layer decreased.The impact toughness increased first and then decreased with the increase of temperature,and the flexion strength ratio decreased first and then increased.When 80%Ar existed in the protective gas,the deposited layer with excellent mechanical properties was obtained.There were many martensitic structures and some striated austenite structures in the deposited layer,and a large number of dislocation structures formed in the striated martensite.When the Ar content reached 96%,the deposited layer produced a number of particles and strips of carbide,and each of which formed a slatted structure in an almost parallel arrangement.When the content of Ar decreased,the size and quantity of inclusions increased.When the content of Ar in the protective gas reached 80%,more impurities formed in the cladding layer to promote the formation core.All inclusions formed in the cladding layer were composed of oxides and some sulfides,and Al and Ti contents near the center were higher.