High-strength alloy gray cast iron valve body manufacturing technology

Abstract

The invention discloses a high-strength alloy gray cast iron valve body manufacturing technology, and relates to the technical field of valve body manufacturing. The high-strength alloy gray cast ironvalve body manufacturing technology comprises the following steps that a casting is manufactured by adopting a wet dry core molding technology, the thickness wall of the casting is 12 mm, and the thickness of reinforcing ribs is 12 mm; a rare earth alloy is crushed, fully preheated and then put at the bottom of a ladle, and the chemical components of the rare earth alloy comprise, by mass, 10% ofCe, 5% of Mo, 43% of Si and the balance Fe; the casting is molten into molten iron and then put into the ladle, and pouring starts to be conducted when the molten iron temperature is 1,290-1,340 DEGC; and subsequent technologies are conducted after pouring is completed, and the product can be obtained. According to the high-strength alloy gray cast iron valve body manufacturing technology, the rare earth alloy is added into the molten iron to refine crystalline grains, and the crack problem of the gray cast iron valve body reinforcing ribs is solved.

Description

technical field [0001] The invention relates to the technical field of valve body manufacturing, in particular to a manufacturing process of a high-strength alloy gray cast iron valve body. Background technique [0002] Gray cast iron refers to cast iron with flake graphite, because the fracture is dark gray when broken, so it is called gray cast iron. The main components are iron, carbon, silicon, manganese, sulfur, and phosphorus. It is the most widely used cast iron, and its output accounts for more than 80% of the total output of cast iron. Gray cast iron is divided into ferrite matrix gray cast iron, pearlite-ferrite matrix gray cast iron, and pearlite matrix gray cast iron. Different gray cast irons can be used according to the use direction of castings to meet the requirements of use. They are generally used in hydraulic parts. Gray cast iron with a pearlitic matrix is ​​required. [0003] The sampling part of the hydraulic parts is close to the middle of the solid ...

AI Technical Summary

Problems solved by technology

Since the mold process has been determined and cannot be changed on a large scale, the above problems can only be solved through production process control

Generally, the production of gray cast iron by electric furnace adopts the smelting method of pig iron + returned material + a small amount of scrap steel. The proportion of returned material is relatively large, and the price of high-quality pig iron is relatively high. However, the shape of gray iron flake graphite produced is not stable, and the core strength of thick and large pieces is very low. Difficult to meet

[0004] During the casting process of the gray cast iron valve body, cracks often appear in the reinforcing ribs of large-diameter valves. Due to the appearance of cracks, the quality of the valve is affected, and the valve becomes a waste product, causing great losses.

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