一、前言随着工业技术的进步,所用的钢结构不断向大型化方向发展,由此对如海上采油平台,石油贮罐,水电站高压叉管和压力容器等高强度级别厚板的需求日益增加。这样,金属材料的焊接质量便成为影响构件寿命的主要矛盾。为了防止金属构件焊接裂纹的形成,往往需要焊前预热,因此使工艺复杂化而导致施工困难和劳动条件恶化。由于施工现场处于野外环境,即使采用焊前严格预热也难以避免焊缝冷裂纹的形成。CF 钢是一种具有高的强度和韧性的新材料。特别是其脆性转变温度和裂纹敏感性都很低。这类钢 I. INTRODUCTION With the advancement of industrial technology, the steel structure used has been increasingly developed in large scale. Therefore, there is an increasing demand for high-strength heavy plate such as offshore oil platform, oil storage tank, high-pressure fork pipe and pressure vessel of hydropower station . In this way, the welding quality of metal materials has become the main contradiction affect the life of the components. In order to prevent the formation of welding cracks in metal components, it is often necessary to preheat before welding, thereby complicating the process and causing construction difficulties and deteriorating working conditions. As the construction site in the wild environment, even with the strict preheating before welding is difficult to avoid the formation of cold cracks in the weld. CF steel is a new material with high strength and toughness. In particular, its brittle transition temperature and crack sensitivity are very low. This type of steel