Q235B/304双金属热轧复合卷板结合强度测试分析

Test Analysis of Bonding Strength of Q235B/304 Hot Rolled Composite Steel Coils

为了分析Q235B/304热轧复合钢卷板的结合强度,采用OM、SEM、EDS和剪切试验研究了Q235B/304双金属复合钢卷板中部和尾部界面区微观组织结构和合金元素分布,并测试了界面剪切强度。结果表明,同一复合钢卷板,中部位置界面剪切强度值较高,平均值达350 MPa,尾部位置界面剪切强度较低,平均值仅为194 MPa。中部位置复合界面主要合金元素Cr、Ni扩散距离约为尾部位置的2~3倍,两部位结合界面处均存在Fe的高温氧化物,且尾部位置复合界面处大量存在尺寸约为1~2μm的空隙,对界面剪切强度有一定影响。

For the development of Q235 B/304 bimetal composite pipe for corrosive medium transportation,the microstructure,alloy element distribution and shear strength in the interfacial position of the middle and tail of the Q235 B/304 bimetallic composite steel coil were analyzed by OM,SEM,EDS and shear test. Experimental results show that in the given composite coil,the highest shear strength appears at middle position of the coil and the average value is 350 MPa,the lowest shear strength appears at tail of the coil and the average value is 194 MPa. The diffusion distances of the main alloying elements Cr and Ni in the composite interface at the middle position are about 2~3 times higher than those at the tail. The high-temperature oxides of Fe are present at the joint interface of the two sites,and the tail joints have a large number of interspace about 1~2 μm at the composite interface. The interspace has a certain influence on the shear strength of the interface.