Technology for producing ductile iron flange

Abstract

The invention discloses a technology for producing a ductile iron flange. The technology comprises the following steps: (1) mould preparing, wherein a special shape molding box is used for molding; (2) smelting, wherein the target chemical components are 3.6-38% of C, 2.5-3.2% of Si, 0.3-0.5% of Mn, 0.05-0.07% of P, less than 0.03% of S and the balance of Fe, and an appropriate amount of rare earth alloy purification iron liquid is added, the molten iron discharge temperature is not less than 1450 DEG C, an inoculator adopts 0.8% FeSi75, a nodularizer adopts rare earth magnesium alloy, spheroidizing is carried out at 1380-1450 DEG C, and the residual amount of rare earth magnesium is controlled between 0.02-0.04%; (3) pouring, wherein the pouring temperature is between 1400-1430 DEG C, and the pouring velocity is connected to be 20 kilograms / second; and (4) thermal treatment, wherein a casting is austenitized in an electric furnace, is then oil-quenched and is tempered. The technology has the beneficial effects the nodularizer is adopted, so that the tissue of the ductile iron flange is small, uniform and dense, the corrosion resistance is improved, and the mechanical strength is also obviously improved; and reasonable pouring dimensions and dead heads are adopted, so that the defects of subsurface porosity, slag inclusion, shrinkage porosity and the like of the product are reduced.

Description

technical field [0001] The invention relates to a production process of a metal casting, in particular to a production process of a nodular iron flange, belonging to the technical field of casting. Background technique [0002] Due to its excellent performance, ductile iron can sometimes replace expensive cast steel and forged steel in use, and is widely used in the machinery manufacturing industry. The low cost of ductile iron makes this material more popular, casting more efficient, and less machining cost of ductile iron. Since the stress concentration caused by ductile iron is small and the splitting effect on the matrix is ​​also small, the tensile strength, plasticity and toughness of ductile iron are higher than those of other cast irons, but ductile iron is not perfect. In addition to general casting In addition to defects, some unique defects will also occur, such as shrinkage porosity, slag inclusions, subcutaneous pores, poor spheroidization and recession. These...

AI Technical Summary

Problems solved by technology

Since the stress concentration caused by ductile iron is small and the splitting effect on the matrix is ​​also small, the tensile strength, plasticity and toughness of ductile iron are higher than those of other cast irons, but ductile iron is not perfect. In addition to general casting In addition to defects, some unique defects will also occur, such as shrinkage porosity, slag inclusions, subcutaneous pores, poor spheroidization and recession, etc.

These defects affect the performance of castings and increase the casting rejection rate