FORGING METHOD FOR ULTRA-HIGH TEMPERATURE SOFT CORE OF STEEL INGOT

摘要

Provided is a forging method for ultra-high temperature soft core of a steel ingot, comprising firstly subjecting a cast steel ingot with a liquid core to ultra-high temperature demoulding; then placing same in a temperature-holding car to a uniform temperature and conveying to a forging press, subjecting the steel ingot with the liquid core to high-temperature and pressure-maintaining forging to fully crush dendrites at the solidification end, which forms a large amount of equiaxial crystal structures, eliminates the shrinkage porosity and looseness, and alleviates the dendritic crystal segregation; finally, performing a conventional forging to fully refine the crystalline grains and structures. The above-mentioned method breaks through conventional methods for forging mould cast steel ingots only after full solidification. The ultra-high temperature demoulding of a steel ingot with a liquid core, creates semi-solid state structure with excellent fluidity in the core of the steel ingot and a large temperature difference between the surface and the core, and after combination with a subsequent heavy pressurization and pressure-maintaining method, a forced feeding and pressure solidification can be achieved, which not only solves problems of shrinkage porosities, looseness, segregation etc., in the centre of the steel ingot to improve the metallurgical quality, but also reduces the riser weight and the heating number for forging, and prolongs the mould service life.