High-strength thin-wall gray iron casting and preparation method thereof

Abstract

The invention relates to the technical field of metal processing, in particular to a high-strength thin-wall gray iron casting and a preparation method thereof. The gray iron casting is composed of the following chemical components of, by weight, 2.25%-3.3% of C, 2%-2.5% of Si, 0.2%-0.4% of Mn, 0.35%-0.45% of Cu, 0.2%-0.4% of Sr, 0.1%-0.2% of Zr, 0.2%-0.3% of Cr, 0.08%-0.1% of Sn, 0.06%-0.08% of Re, 0.02%-0.04% of P, 0.06%-0.08% of S and the balance Fe and inevitable impurities. A two-time inoculation pouring method is adopted, the SiC-Sr-Fe alloy serves as an inoculant for the first time of inoculation, Si73Sr1.0 or Si75Sr1.5 serves as an inoculant for the second time of inoculation, the prepared gray iron casting has the performance of being thin in wall, high in tensile strength and high in hardness, meanwhile, the phenomena of air holes, shrinkage sinking and the like are not prone to being generated in the pouring process, and therefore the rejection rate of products is greatly reduced by%.

Description

technical field [0001] The invention relates to the field of metal processing technology, in particular to a high-strength thin-walled gray iron casting and a preparation method thereof. Background technique [0002] C, Si, Mn, P, and S are the basic elements of gray cast iron. C and Si elements can strongly promote graphitization. If the content of carbon and silicon is too high, it will lead to coarsening of graphite, increase of ferrite volume fraction, pearlescent As the volume fraction decreases, the strength and hardness of cast iron decrease. In the current production of high-grade gray cast iron, in order to ensure the performance requirements of high-strength castings, it is necessary to select an appropriate carbon equivalent. Generally, the carbon equivalent of the original iron liquid is controlled at 3.8% to 3.9%, which can improve the casting performance of cast iron and reduce White mouth, shrinkage cavity, shrinkage porosity and leakage defects can reduce th...

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Problems solved by technology

[0003] However, a lower carbon equivalent will inevitably lead to a decrease in casting performance, and castings are prone to produce waste products such as pores, cold shut, shrinkage porosity, and shrinkage.

The addition of copper, chromium or higher-priced molybdenum, tin and other alloys will significantly increase the production cost of castings.

The use of low-sulfur and low-nitrogen graphitization recarburizer can avoid nitrogen pores in castings from the source and reduce the difficulty of smelting process control, but it loses the alloying effect of low-cost nitrogen, and low-sulfur and low-nitrogen graphitization carburization The agent treatment process is complicated and the cost is relatively high

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