A medium and high pressure pump body material of alloy gray cast iron

Abstract

The invention discloses an alloy grey cast iron material for medium and high-pressure pump bodies, and manufacturing of pump body castings. The pump body material comprises the following chemical components in mass percent: 3.3-3.8% of C, 1.4-2.5% of Si, 0.4-0.8% of Mn, at most 0.01% of S, at most 0.06% of P, 0.1-0.5% of Sb, 0.3-0.5% of Mo, 0.08-0.12% of Ti, 0.40-0.60% of Cu, 0.01-0.03% of Al, 0.01-0.023% of Re and the balance of Fe. A medium-frequency induction furnace is used for smelting, rare earth ferrosilicon and silicon barium inoculant is used for inoculation, precoated sand shooting is used for molding the pump body casting and forming shell and core; the as-cast alloy grey cast iron material has tensile strength sigma b of at least 400Mpa and ductility delta of 1.5-2%, has the technical features of low stress, good structure density, excellent heat conduction and heat dissipation performance, steady casting technology and high yield, and replaces nodular cast iron to produce the medium and high-pressure pump bodies belonging with the pressure level of 18Mpa-30Mpa; moreover, the medium and high-pressure pump bodies are used in engineering machineries, such as a loading machine and a mini-excavator, are not liable to cause the defects, such as leakage and expansion, and have long service life.

Description

technical field [0001] The invention relates to the casting field, in particular to medium and high pressure pump body castings for loaders and small excavators. Background technique [0002] In recent years, the domestic construction machinery industry, especially loaders and excavators, has developed by leaps and bounds. At present, the stock has exceeded several million units. The manufacturing technology of the oil pump body is one of its key technologies. The working pressure of oil pumps for loaders and small excavators is generally between 18MPa-30MPa, which belongs to the medium and high pressure range, and the maximum temperature of hydraulic oil reaches about 90°C, which requires that the castings of the pump body have sufficient strength, compact structure, and stable dimensions , to prevent swelling and leakage failures, and at the same time, the pump body material is required to have good heat conduction and heat dissipation properties. At present, the pump bod...

AI Technical Summary

Problems solved by technology

At present, the pump bodies for loaders and small excavators generally use ductile iron materials. Although ductile iron materials have high strength, their casting performance is not as good as that of gray cast iron. The cast iron pump body is prone to defects such as leakage and swelling during use, and its service life is short

Traditional high-grade gray cast iron, in order to achieve high strength performance, adopts low carbon equivalent, which has a large whitening tendency and large internal stress of the casting, which requires heat treatment to eliminate the internal stress of the casting, and it is difficult to meet the strength performance requirements of the medium and high pressure pump body