Method for overcoming defects of inner cavity of heat-resistant steel product

A technology of heat-resistant steel and inner cavity, which is applied in the direction of casting molding equipment, molds, cores, etc., can solve the problems of inability to produce small and small sand cores, high temperature resistance, etc., to meet the complex flow channel structure, solve erosion, high The effect of refractoriness

Active Publication Date: 2018-09-18
NANYANG FEILONG AUTOMOBILE PARTS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This invention solves the stratification at the water inlet of the mud core of the flow channel and avoids the problem of scabs inside the flow channel of the turbine shell. It is suitable for the manufacture of heavy turbine shells. This method cannot produce small sand cores and is not resistant to high temperatures.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] A method for solving inner cavity defects of heat-resistant steel products, comprising the following steps:

[0030] S1: Core making: Check that the core box is installed correctly and in place, set core making parameters: air source pressure 0.5-0.7MPa, oil pump pressure 2.5-5.0MPa, sand injection pressure 0.5-0.7MPa, curing temperature 200-230℃, sand injection time 4-6S, curing time 180S, exhaust time 5-9S, close the core box, turn on the heating for preheating, add high temperature resistant coated sand into the core box, the high temperature resistant coated sand cannot exceed the maximum scale line, can not When the temperature reaches the curing temperature, the mold is opened, the cavity is blown clean, the mold release agent is evenly attached to the surface of the inner cavity of the core box, and the core making cycle program is started to start the core making. The fast sand core is translated by a certain distance to take out the sand core without bumping th...

Embodiment 2

[0039]This embodiment provides a high temperature resistant coated sand, which is prepared from the following raw material components in parts by weight: 100 parts of raw sand, 1 part of resin binder, 10 parts of curing agent, 5 parts of lubricant, 0.1 part of additive, chrome 29 parts of iron ore.

[0040] The content of aluminum dioxide in the high temperature resistant coated sand is greater than or equal to 48%, and the content of silicon dioxide is greater than or equal to 48%.

[0041] The resin binder is a mixture of solid thermoplastic phenolic resin and liquid thermosetting phenolic resin, and the mass ratio of solid thermoplastic phenolic resin: liquid thermosetting phenolic resin is 1:3.

[0042] The curing agent is an aqueous solution of urotropine with a mass fraction of 40% to 50%.

[0043] The lubricant is a mixture of calcium stearate and ammonium stearate, and the mass ratio of calcium stearate: ammonium stearate is 1:2.5.

[0044] The additives are polyviny...

Embodiment 3

[0052] This embodiment provides a high temperature resistant coated sand, which is prepared from the following raw material components in parts by weight: 100 parts of raw sand, 2 parts of resin binder, 11 parts of curing agent, 5.5 parts of lubricant, 1 part of additive, chromium 29 parts of iron ore.

[0053] The content of aluminum dioxide in the high temperature resistant coated sand is greater than or equal to 48%, the content of silicon dioxide is greater than or equal to 48%, and the content of ferric oxide and silicon dioxide is less than or equal to 5%.

[0054] The resin binder is a mixture of solid thermoplastic phenolic resin and liquid thermosetting phenolic resin, and the mass ratio of solid thermoplastic phenolic resin: liquid thermosetting phenolic resin is 1:3.5.

[0055] The curing agent is an aqueous solution of urotropine with a mass fraction of 40% to 50%.

[0056] The lubricant is a mixture of calcium stearate and ammonium stearate, and the mass ratio of...

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Abstract

The invention discloses a method for overcoming defects of an inner cavity of a heat-resistant steel product, and belongs to the technical field of casting. The method comprises the following steps ofsand core making, drilling, hole plugging, sand core repairing, coating and baking. The invention further discloses a preparation method of high-temperature-resistant precoated sand. A sand core prepared from the high-temperature-resistant precoated sand which is prepared through the preparation method is stable in performance and has relatively-high refractoriness, and therefore the problem thata large amount of protrusions and pits are generated in the inner cavity of a casting due to the sand core is eroded by molten steel at a high temperature is fundamentally solved; gas is not separated out in the casting process, no gas defect exists in the casting, and therefore the technical requirement that the structure of a turbine casing runner is complex and high in precision requirement ismet, and the qualified rate of products is remarkably improved.

Description

technical field [0001] The invention belongs to the technical field of casting, and in particular relates to a method for solving inner cavity defects of heat-resistant steel products. Background technique [0002] In the production process of cast steel products, especially cast steel turbine casing products with narrow and complex inner cavities. Because the pouring temperature is relatively high, usually reaching 1600 ℃, the refractoriness requirements of the sand core are relatively high. However, the refractoriness of the company's existing coated sand is around the critical value, which cannot fundamentally prevent the erosion of the sand core by molten steel under high temperature, resulting in a large number of protrusions and pits in the inner cavity of the casting, and the yield is very low. [0003] The patent with the publication number CN105414488B discloses a core making method for the flow channel core of the turbine shell. The thick part of the flow channel ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22C9/10B22C9/18B22C9/12B22C1/02B22C1/22
CPCB22C1/02B22C1/2253B22C9/10B22C9/12B22C9/18
Inventor 谢会豪刘松奇齐晓波彭德楼高严柯张旭
Owner NANYANG FEILONG AUTOMOBILE PARTS CO LTD
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