一、前言焊接技术的发展与国民经济各部门的发展都有密切的关系,如机械、冶金、造船、石油、化工、建筑以及国防工业等。厚板的焊接是近代工业大型化中的一项主要课题,引起了国内、外的重视,许多单位在这方面积极努力,进行了不少工作,取得了一定成绩。随着冶炼技术的提高,高炉向大容积方向发展,目前世界各国已拥有4000米~3以上的大型高炉二十余座,其中半数以上集中在日本,其次是苏联, I. Foreword The development of welding technology is closely related to the development of all sectors of the national economy, such as machinery, metallurgy, shipbuilding, petroleum, chemical, construction and defense industries. The welding of heavy plates is a major issue in the large-scale industrialization of modern China. It has drawn great attention both at home and abroad. Many units have made active efforts in this regard and have done a great deal of work and achieved some success. With the improvement of smelting technology, the blast furnace has been developed to a large volume. At present, more than 20 large-scale blast furnaces of 4,000 to 3 are in the world, of which over half are concentrated in Japan, followed by the Soviet Union,