Research On Production Process Of Ultra-heavy Mould Steel Plate

Mould manufacturing is one of the main applications of the hot rolled heavy plate.In recent years,clad rolling method is used for the production of ultra-heavy plate.Two pieces of continuous casting slab are welded to a piece of extra thick slab,and the vacuum electron beam welding technology is used.Clad rolling method can not only solve the problems of high cost of ingot and long production cycle,but also to solve the thickness limits of continuous casting slab.The main research content of this paper is the production technology of clad rolling process for ultra-heavy mould manufacturing plate.The main contents and results are as follows;1)The cleaning and recombination of continuous casting slabs are studied.The dimension precision and surface cleaning method of slabs are determined.The welding parameters such as welding vacuum degree,welding flux,welding speed,are also be determined.The key of the final performance of the clad rolling products is to ensure the proper welding parameters of the qualified continuous casting slab,and the reasonable welding parameters.2)The heating process of the clad slab and the method of anti oxidation of the surface are studied.The temperature uniformity of the slab is ensured by two stage heating.Low-speed large-reduction mode to ensure the pass rate of deformation in the rough rolling stage,in favor of a composite metal atoms at the interface of diffusion bonding.In the fine stage,with a finishing mill for 3 to 5 passes,can effectively improve the accuracy of the thickness of the finished plate.3)Ultrasonic testing results shows that the internal quality of the plate to meet the requirements of GB/T 2970-2004 grade I.Penetration testing results shows that there is no surface crack,delamination and other defects.The inner quality of the ultra-heavy plate by clad rolling technology is good.4)Mechanical properties and microstructure show that the 1/2 position quality of steel plate is better than 1/4 position.The surface of the continuous casting slab is smaller than the inside.The 1/2 position of the continuous casting slab is changed into the 1/4 position of the steel plate by the composite rolling process,and at the same time the surface of continuous casting slabs is changed into the 1/2 position of the steel plate.During rolling process the deformation of the thickness of 1/4 position is larger than the thickness of 1/2 position.