Nodular cast iron manhole cover casting method for preventing cold shut defects

A technology of nodular cast iron and nodular cast iron, applied in the field of nodular cast iron manhole cover casting, to achieve excellent quality, improve nodularization rate, and eliminate graphite distortion

Inactive Publication Date: 2019-01-04
安徽大来机械制造有限公司
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  • Summary
  • Abstract
  • Description
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AI Technical Summary

Problems solved by technology

Practice shows that cold insulation is the biggest defect in the production of ductile iron manhole covers

Method used

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Embodiment Construction

[0017] A method for casting a manhole cover of ductile cast iron for preventing cold shut defects, comprising the following specific steps:

[0018] (1) On the basis of pig iron, add appropriate amount of other components to make the components of ductile iron. Heat all the tools and molds at 200°C and take them out for later use. Ball milling for 3 hours to obtain composite iron powder; put the composite powder into the vacuum induction furnace, heat up to complete melting,

[0019] (2) Add the composite iron powder into the vacuum induction furnace, heat up and heat until the composite iron powder is melted, then add superfine silicon carbide powder with 1% of the composite iron powder mass, continue to heat up to 1500°C, keep the temperature for 10 minutes, and tap the iron. The molten iron flows into the ladle through the tap hole at the bottom of the furnace. At the same time, the molten iron is subjected to nodularization and inoculation treatment. The bottom of the ladl...

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PUM

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Abstract

The invention discloses a nodular cast iron manhole cover casting method for preventing cold shut defects. Molten iron component selection is controlled, microelements exceeding general standards arenot allowed, reasonable nodulizing agents and nucleating agents are added, lanthanum can eliminate graphite deterioration and graphite floatation, the tendency of blooming graphite aggregation is decreased, the number of graphite nodules can be increased, nodulizing rate is increased, shrinkage porosity tendency is decreased, high-quality nodular cast iron liquid is provided, and the cold shut defects of a formed cast iron manhole cover are decreased. By strictly controlling casting temperature and casting modes, the probability of casting defects such as sand burning, shrinkage and deformation is reduced, and each casting mould is uniformly filled with molten iron. The cold shut defects are prevented by the aid of component control, casting temperature and mode control and the like in thecasting process, the nodular cast iron manhole cover is excellent in quality and mechanical property and worthy of popularization, and the process is conveniently controlled.

Description

technical field [0001] The invention relates to the technical field of manhole cover manufacture, in particular to a casting method for a manhole cover of ball milled cast iron for preventing cold insulation defects. Background technique [0002] With the rapid development of modern science and technology and social economy, urban construction is gradually accelerating, and the scale of the city is constantly expanding. Various road facilities have gradually entered into standardized and standardized management. The market demand in construction is increasing. Since the manhole cover is a closure leading to the top of the entrance and exit of underground facilities, all urban roads, highways, tap water, drainage, telecommunications, electricity, fire hydrants, valves and other public facilities need to install manhole covers. Most of the materials used for manhole covers used to be reinforced concrete, but due to the defects of high brittleness, easy aging, and easy fractur...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C33/08C21C1/10C22C37/04C22C37/10
CPCC21C1/105C22C33/08C22C37/04C22C37/10
Inventor 何方杰
Owner 安徽大来机械制造有限公司
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