Taking the gas turbine guide blade as the research object

the hot crack of blade produced by the investment casting process was analyzed

and the macro and micro morphology was investigated. DSC and THERMO-CALC were used to analyze the characteristics of the solidification interval of Mar-M247 alloy. Meanwhile

the temperature field and stress field of the blade solidification process were calculated combined with the numerical simulation software ProCAST

and the physical field characteristics and formation mechanism of thermal crack were described. The results indicate that the characteristics of the alloy solidification interval is the prerequisites for the formation of hot cracks

and the constraint conditions and tensile stress around the dendrite boundaries are the essential conditions. Thereinto

the R corner of the blade is the most sensitive area of thermal crack with slower solidification rate and larger temperature gradient

and the basin position with the faster solidification rate and the larger tensile stress is the thermal crack insensitive area.