Different batches of multidiameter shafts used for rail truck, produced by 0Cr16Ni5Mo in a factory, were tested, analyzed and researched by many testing techniques. They were chemical composition analysis, mechanics performance testing, ultrasonic flaw detection, microstructure observation, areascan of elements and energy dispersive spectrometer analysis. The results showed that the products smelted in a dualprocess and forged in different stage could meet technical requirement. The smelting process was smelting in vacuum induction furnace and electroslag remelting. Diameter of the electrode bar was 330 mm and diameter of the steel ingot smelted was 610 mm. Some conclusions were drawn in this paper. One was that the accurate control on chemical component of the electrode bar could be achieved by setting correct parameters on the frequentness of whisking and temperature in refining period. The other was that the gaseous oxygen content also reduced from 66×10-6 to 30×10-6. Besides, detailed optimized parameters of Multidiameter shaft produced by 0Cr16Ni5Mo in the process were determined. The smelting frequency was 150 Hz. The whisking rate of flow with gaseous Ar was 70～80 L/min and the whisking frequency 65 Hz. The temperature of the homogenized diffusion process was 1 150 ℃ for 3 h and 1 050 ℃ for 5 h. The tonnage in the stage of upsetting and molding were 3 500 and 2 000 respectively.
