A three-dimensional mathematical model for consumable-electrode vacuum melting process of 14Cr-13Co- 5Mo-2Ni gear steei (/% ： 0.014C

0.26Si

0.17Mn

13.79Cr

12.69Co

4.66Mo

2.00Ni

0.53Al) diameter 290 mm

9 t ingot has been established to study the effect of cooling water pressure

electric current and smelting rate on distribution of solidified structure and grain size of consumable-electrode vacuum melting ingot. Research results show that as the cooling water pressure increases from 6000 MPa to 8000 MPa

the current and smelting rate respectively decrease from 6.2500 kA and 1.250 kg/s to 6.228 6 kA and 1.125 kg/s

the equiaxed zone in melted ingot increases nearly by one fold

amount of grain increases by 45.17%

average grain size decreases by 17% and max spacing between secondary dendritic arms decreases by 4.88%

basically to achieve the object of grain fining and uniform distribution of alloying elements in steel.