塔式起重机吊臂是由数节臂节相互连接组成的格构式焊接件,臂节之间一般通过单接头和双接头用销轴连接在一起。目前塔机臂节接头一般分为两类,一类为锻打件,另一类为板式。锻打件接头通常采用16Mn或20Cr,一般要经过锻打、划线、机加工等多道工序,用料较多,制造成本较高,但其 Tower crane boom is composed of several sections connected to each other lattice welded parts, arm sections are generally connected by single-pin and double-pin with the pin. At present, tower crane boom joints are generally divided into two categories, one forged pieces, the other for the plate. Forged pieces of joints are usually 16Mn or 20Cr, generally go through forging, marking, machining and other processes, more materials, higher manufacturing costs, but its