Abstract: Based on the Ingot Weight-compatible ( IWC) design, three ingot designs [ embedded insulation board (C) , assemble ferrule (T) and assemble gasket ( D) ] are designed, and the solidification pattern of the 10~15t,20~ 27 t,29 ~35 t,39 ~45 t and 50 ~60t 42CrMo4 steel ingots is predicted by finite element software. It can be seen that with 10 ~ 60 t ingot the liquid core more and more deep into ingot body especially in D design with die increase of compatible volume. When the compatible volume is less than 10% of the original ingot weight, the solidification time of the three designs is similar,and the difference of the center porosity length is below 69 mm. When the compatible volume is greater than 10% , the solidification time of D ingot decreases compared with two other mode ( C and T ingot) ,and the center porosity length extends 107 ~232 mm. However, when the compatible volume exceeds 20% ,the length of the center porosity of ingot will of ingot increase more than two times,and the quality of the ingot will worsen obviously. Therefore,when the compatible volume is less than 10% ,T and D mode should be selected. T and C mode are taken into consideration when the compatible volume is between 10% and 20% . The in-situ commercial application for 42CrMo4 steel 20 ~27 t IWC ingot shows that, the ultrasonic detection results of ingots have reached Ⅱ grade requirement.