301L不锈钢药芯焊丝MAG焊接头高周疲劳性能研究
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摘要
采用药芯焊丝对301L不锈钢进行熔化极活性气体保护焊(MAG焊),研究了接头的高周疲劳性能,重点分析了给定疲劳寿命下接头的疲劳强度和断口形态。研究结果表明:在应力小于300 MPa下,疲劳试样均达到极限寿命;采用升降法计算得接头的疲劳强度为312.86 MPa。因药芯中氧化物的存在且焊接过程中其不能熔化,裂纹源易在其上萌生。301L不锈钢扩展区有疲劳辉纹,不同扩展阶段疲劳辉纹的大小、间距不同,显示不同的裂纹扩展速率。疲劳寿命次数较少时,瞬断区呈现大量韧窝;随疲劳寿命的增加,瞬断区表现为脆性断裂。
The metal active gas(MAG) shielded welding of 301 L stainless steel was carried out by using flux cored wire,and the high cycle fatigue performance of the joint was studied and the fatigue strength and fracture morphology were mainly discussed under given fatigue life. The experimental results show that the fatigue life of specimens reaches limit life when the stress is lower than 300 MPa, and the fatigue strength of the joint calculated by up and down method is 312.86 MPa. Because of the presence of oxides in the fulx core and it cannot be melted during welding, the crack easily initiates from oxides.Fatigue striations exist in crack propagation region, the size and spacing of fatigue striations in different propagation stages are different, which shows different crack growth rates. A large number of dimples appear in the transient fracture zone when the number of fatigue life is less, and the transient fracture zone shows brittle fracture with the increase of fatigue life.
The metal active gas(MAG) shielded welding of 301 L stainless steel was carried out by using flux cored wire,and the high cycle fatigue performance of the joint was studied and the fatigue strength and fracture morphology were mainly discussed under given fatigue life. The experimental results show that the fatigue life of specimens reaches limit life when the stress is lower than 300 MPa, and the fatigue strength of the joint calculated by up and down method is 312.86 MPa. Because of the presence of oxides in the fulx core and it cannot be melted during welding, the crack easily initiates from oxides.Fatigue striations exist in crack propagation region, the size and spacing of fatigue striations in different propagation stages are different, which shows different crack growth rates. A large number of dimples appear in the transient fracture zone when the number of fatigue life is less, and the transient fracture zone shows brittle fracture with the increase of fatigue life.
引文
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[7]余圣甫,李志远,石仲堃,等.低合金高强度钢药芯焊丝焊缝中夹杂物诱导针状铁素体形核的作用[J].机械工程学报,2001,37(7):65-70.
[2]张文钺,许玉环,丁萍,等.不锈钢CO2气保护药芯焊丝飞溅产生机理及影响因素的研究[J].焊接技术,1999(1):2-4.
[3]李伟,栗桌新,李国栋,等.双相不锈钢药芯焊丝GDQA2205的研制[J].焊接学报,2009,30(1):63-67
[4]丁光柱,郭建峰,李世会.不锈钢管道药芯焊丝钨极氩弧焊焊接工艺[J].现代焊接,2016(1):53-55.
[5]董红刚,杨丽群,翟南,等.药芯焊丝焊接铝合金/不锈钢接头组织及性能分析[J].焊接学报,2011,32(10):1-4
[6]王斌,栗卓新,李红,等.不锈钢药芯焊丝立焊性的分析与评价[J].焊接学报.2011,32(4):55-58
[7]余圣甫,李志远,石仲堃,等.低合金高强度钢药芯焊丝焊缝中夹杂物诱导针状铁素体形核的作用[J].机械工程学报,2001,37(7):65-70.