论文部分内容阅读
利用焊接热模拟实验机,采用3种t8/5对Q550钢焊接热影响区进行热模拟实验,观察试样的金相组织,研究其拉伸和冲击性能。结果表明,粗晶区(CGHAZ)组织为粗大的贝氏体,随着t8/5增加,原奥氏体晶界逐渐消失,铁素体板条的宽度增加,长度变小,强度逐渐下降,断面收缩率则呈线性缓慢增加。细晶区(FGHAZ)组织为铁素体+珠光体,随着t8/5增加,组织粗化,强度呈线性下降,断面收缩率逐渐提高。临界区(ICHAZ)为不均匀的铁素体+珠光体,随着t8/5增加,铁素体晶粒变小,珠光体含量增加,组织不均匀性增加,强度缓慢下降,断面收缩率缓慢增加。
The thermal simulation experiment was carried out by using the welding thermal simulation machine. Three kinds of t8 / 5 were used to simulate the heat-affected zone of Q550 steel. The microstructure of the sample was observed and its tensile and impact properties were studied. The results show that coarse CGHAZ is coarse bainite. With the increase of t8 / 5, the original austenite grain boundaries gradually disappear, the width of ferrite slab increases, its length decreases and its strength decreases gradually. The cross-sectional shrinkage increased linearly and slowly. Fine grained region (FGHAZ) was ferrite + pearlite. With the increase of t8 / 5, the structure became coarse, the strength decreased linearly, and the reduction of area decreased gradually. The critical zone (ICHAZ) is a non-uniform ferrite + pearlite. With the increase of t8 / 5, the ferrite grains become smaller, the pearlite content increases, the organization heterogeneity increases, the strength decreases slowly, and the reduction of area decreases slowly increase.