异型焊接接头局部焊后热处理

Local postweld heat treatment of heterogeneous welded joint

为研究和描述非对称传热焊接接头局部焊后热处理温度场特征,提出了异型焊接接头的概念,并根据热传导方向的不同,将异型焊接接头分为横向单向导热、横向双向导热、横向和纵向导热3种类型。与对称传热焊接接头温度场比较,异型焊接接头局部焊后热处理时,加热区域最高温度偏移加热装置的中心,均温范围变小,第三类异型接头还存在纵向温度梯度、局部区域温差剧烈等特征。为了改善异型焊接接头温度分布,提出并开发了温度补偿法和功率补偿法两种焊后热处理工艺,并从加热装置的设置、温度测点的布置和工艺参数的选择等方面概括了两种工艺的要点,以实例说明了两种工艺在工程上的应用。

A concept of heterogeneous welded joint was proposed for researching and describing the characteristics of local postweld heat treatment（ PWHT） temperature field for asymmetric thermal conductivity welded joint. Three types welded joints were classified according to thermal conductivity direction around the weld,separately,welded joint with transverse unidirection thermal conductivity,transverse bidirection thermal conductivity,transverse and longitudinal thermal conductivity. Compared with temperature field of symmetric thermal conductivity welded joint,heating zone maximum temperature of heterogeneous welded joint deviates from the heating device center,and uniform temperature zone shrinks. In addition,longitudinal temperature gradient and severe temperature difference of local zone have arisen in the third heterogeneous welded joint. In order to improve the temperature distribution,two PWHT methods i. e temperature compensation method and power compensation method are put forward and developed. Their main points including the arrangement of heating device,the setting of temperature measuring point and the selection of PWHT parameters are summarized. Several practical applications of two process in engineering are illustrated as examples.