A smooth and steady molding method of spherical graphite iron castings

Abstract

The invention discloses a smooth filling method of a nodular graphite casting, which comprises sand discharging and molding, and casting through a pouring channel. At casting, the invention adopts a slow speed casting, for a casting lower than 100 kilogram, the casting time is 15 to 30 seconds; for a casting of 100-1,000 kilogram, the casting time is 30 to 60 seconds; for a casting of 1,000 to 4,000 kilogram, the casting time is 60 to 180 seconds; for a casting more than 4,000 kilogram, the casting time is 180 to 480 seconds. The invention can realize smooth filling and guarantee good quality in nodular graphite castings.

Description

Technical field: [0001] The invention relates to a mold filling method for ductile iron castings. Background technique: [0002] With the development of the global economy and industrial technology requirements, more industrial equipment is developing towards large-scale, and the requirements for castings are increasing. Electricity has always occupied a basic position in my country's national economy. With the lack of coal, natural gas, oil and other mineral resources and the impending depletion, the development of traditional electric power using coal, natural gas, oil, water conservancy and nuclear materials as raw materials or resources Cause a lot of environmental burdens, such as environmental pollution, acid rain, climate anomalies, radioactive waste disposal, oil spills, etc. In this case, it is imperative for wind power to become an important follow-up energy source for the world, especially China. Wind energy resources are endless, and it is a renewable energy sour...

AI Technical Summary

Problems solved by technology

[0008] Therefore, in order to prevent defects such as sand flushing and sand inclusions caused by slow pouring on resin sand castings, foundries design the pouring system according to the pouring time recommended in the above table. There are contradictions in the smooth filling of parts. Rapid pouring is easy to form turbulent flow, while ductile iron has a large tendency to generate secondary oxidation slag, so internal defects of castings are difficult to avoid. If non-destructive testing is not done, internal defects cannot be seen at all. For general Castings may be available, but for castings with high requirements such as wind power products, each casting must pass 100% visual inspection, magnetic particle inspection and ultrasonic inspection to detect internal secondary oxidation slag and sand inclusions and other internal defects

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