采用微机控制的平板刚性拘束裂纹(PRRC)试验装置,测定了不同拘束度下灰铸铁同质焊缝的拘束应力和焊缝冷却温度,对灰铸铁焊缝的裂纹产生温度、裂纹产生时间及焊缝断裂时的应力进行了定量评定,并研究了它们与拘束度之间的关系.对灰铸铁同质焊缝裂纹性质进行了探讨,对实际铸件补焊提供了理论指导. The constrained stress and weld cooling temperature of the homogeneous weld of gray cast iron with different restraint degree were measured by computer controlled rigid restraining crack (PRRC) test device. The temperature, time and the crack initiation time of the weld of the gray cast iron were measured. The stress of fracture is quantitatively evaluated, and the relationship between them and restraint degree is studied.The crack characters of homogeneous weld of gray cast iron are discussed, which provides the theoretical guidance for the actual casting repairing.