超低碳貝氏體鋼埋弧焊焊縫金屬的組織與力學(xué)性能

超低碳貝氏體鋼埋弧焊焊縫金屬的組織與力學(xué)性能Microstructure and Mechanical Properties of Submerged Arc Welding Weld Metal for Ultra-low Carbon Bainitic Steel

針對超低碳貝氏體鋼HQ785DB的焊接特點, 在低碳鋼焊絲的基礎(chǔ)上設(shè)計了一種埋弧焊用焊絲, 將該焊絲匹配氟堿型SJ101焊劑對該鋼進(jìn)行焊接, 研究了焊縫金屬的顯微組織、力學(xué)性能及沖擊斷口形貌。結(jié)果表明: 焊縫金屬組織以針狀鐵素體和板條貝氏體為主, 另有少量彌散分布的粒狀貝氏體; 焊縫金屬的抗拉強度為806.25 MPa, 伸長率為16.78%, 20 ℃時的沖擊吸收功為183.25 J; 沖擊斷口上存在大量韌窩, 以微孔聚集型的韌性斷裂為主。

According to welding characteristics of ultra-low carbon bainitic steel HQ785DB, a submerged arc welding wire was developed on the basis of low carbon steel wire. Thus, the steel was welded with the welding wire and fluorine alkali SJ101 flux. The microstructure, mechanical properties and impact fracture morphology of weld metal were studied. The results show that the microstructure of the weld metal was mainly acicular ferrite and lath bainite mainly, and a small amount of granular bainite precipitated and dispersed in the weld metal. The tensile strength of weld metal was 806.25 MPa, the elongation was 16.78% and the impact toughness at 20 ℃ was 183.25 J. There were a large number of dimples in impact fracture surface, which mainly exhibited micro-void accumulation ductile fracture.

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