Smooth and steady molding method of spheroidal graphite cast iron

Abstract

The invention relates to a ductile cast iron piece steady flow method, which comprises a sand blowing mounding and precede casting by a pouring path. While casting, the invention adopts slow casting speed, to the casting piece which is smaller than 100 kilogram, the casting time is 15 to 30 seconds, to the casting between 100 to 1000 kilogram, the casting time is 30 to 60 seconds, to the casting between 1000 to 4000 kilogram, the casting time is 60 to 180 seconds, to the casting piece larger than 4000 kilogram, the casting time is 180 to 480 seconds. The invention can realize stable flow, which makes the ductile cast iron have good quality.

Description

Technical field: [0001] The invention relates to a filling method of ductile iron parts. Background technique: [0002] With the development of global economy and industrial technology requirements, more industrial equipment is developing towards large-scale, and the requirements for castings are increasing. Electricity has always occupies a basic position in my country's national economy. With coal, natural gas, oil and other mineral resources being depleted and about to be exhausted, traditional power development using coal, natural gas, oil, water conservancy and nuclear materials as raw materials or resources Causes a lot of environmental burdens, such as environmental pollution, acid rain, abnormal weather, radioactive waste disposal, oil spills, etc. In this case, wind power becomes an important follow-up energy source for the world, especially China. Wind energy resources are endless and are renewable energy sources. Electric power development using wind energy as a resour...

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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