Aim\ To study the way for improving properties of crankshaft made of 18Cr2Ni4WA steel. Methods\ The microstructures of various heat treated specimens made of 18Cr2Ni4WA steel are analysed with metallographical experiment. Results\ The microstructure of normal heat treated specimen is made up of granular bainnite(Bg) and granular structure (Gs). Granular structure is disappeared when specimen is cooled at higher rate. Conclusion\ Because strength and toughness of Gs are lower obviously than those of Bg
increasing the cooling rate in air quenching at the first stage can improve the properties of crankshaft.