高强度钢板焊接接头疲劳性能研究

Study on fatigue properties of welded joints in high-strength steel plate

为探索转向架构架轻量化之路,文章采用典型焊接接头疲劳试验方法,对WYS700、Q460ME、16MnDR三种不同强度等级的钢板进行了对接焊接接头疲劳性能测试,根据测试数据绘制了这三种钢板对接焊接接头的S-N曲线,并与IIW标准中规定的对接接头的疲劳极限进行了对比。结果表明:WYS700、Q460ME、16MnDR三种焊接接头在极限疲劳寿命(循环次数N=10^(7))下,疲劳极限分别为203.75 MPa、198.88 MPa、203.33 MPa,三者相差不大,WYS700、Q460ME的S-N曲线斜率相近,16MnDR的S-N曲线斜率比前两者小,曲线显得更加平缓,说明在现有的焊接工艺下,通过提升母材强度不能提升焊接接头疲劳强度;与IIW标准中规定的对接接头在N=10^(7)下的疲劳极限41.5 MPa,N=2×10^(6)下的疲劳极限71 MPa相比,三种材质的焊接接头试验值远大于该标准要求值。

To explore the way of lightweight bogie frame,this paper adopts the typical welded joint fatigue test method to test the fatigue properties of butt welded joints of WYS700,Q460ME and 16MnDR steel plates with different strength grades.According to the test data,the S-N curves of butt welded joints of these three steel plates are drawn and compared with the fatigue limits of butt welded joints specified in IIW standard.The results show that under the ultimate fatigue life N=10^(7) cycles,the fatigue limits of WYS700,Q460ME and 16MnDR welded joints are 203.75 MPa,198.88 MPa and 203.33 MPa respectively,with little difference among them;the slopes of S-N curves of WYS700 and Q460ME are similar,while that of 16MnDR is smaller than the first two and the curve is more gentle.The above indicates that the fatigue limits of welded joints cannot be improved by improving base metal strength under the existing welding process.Compared with the fatigue limit of 41.5 MPa under N=10^(7) cycles and 71 MPa under N=2×10^(6) cycles specified in IIW standard,the test values of welded joints made of three materials are far greater than those required by IIW standard.