Coated low-nitrogen sand and its prepn

A technology of coated sand and raw sand, which is applied in the direction of manufacturing tools, casting molding equipment, metal processing equipment, etc., can solve the problems of increased gas generation of coated sand, increased binder dosage, and increased porosity of castings. Achieve the effects of reducing usage, increasing hardening rate, and ensuring the surface quality of castings

Active Publication Date: 2007-12-19
SHANDONG SHENGQUAN NEW MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the casting of the shell (core), when a certain tensile strength at room temperature is met, it is more important to require the shell (core) to have good high-temperature tensile strength and long heat-resistant time. For this reason, it is often necessary to increase the viscosity. At the same time, the amount of hexamethylenetetramine added will increase, resulting in an increase in the gas generation of the coated sand, an increase in the porosity of the casting, and the quality of the casting will be affected

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The preparation of embodiment 1 thermosetting phenolic resin

[0021] First adjust the reaction device to a reflux state, put 500 grams of phenol and 560 grams of formaldehyde (37%) into the reactor together, and add 5 grams of calcium oxide. The temperature was raised to 90°C, and the reaction was carried out at this temperature for 2 hours. Then adjust the equipment to a vacuum distillation state, and measure the viscosity to 500cp / 25°C when discharging.

[0022] The detection index of thermosetting phenolic resin is shown in the table below:

[0023] project

Embodiment 2

[0025] 1) Raw sand is heated to 125°C;

[0026] 2) Add thermoplastic phenolic resin and mix for 40 seconds;

[0027] 3) Add thermosetting phenolic resin and mix for 20 seconds;

[0028] 4) Add hexamethylenetetramine aqueous solution and mix for 25 seconds;

[0029] 5) adding calcium stearate;

[0030] The above mixture is cooled, crushed and sieved to obtain the finished coated sand.

[0031] The raw sand is 5kg, the thermoplastic phenolic resin is 125g, the thermosetting phenolic resin is 20g, the hexamethylenetetramine (40%) solution is 6.25g, and the calcium stearate is 7.5g.

Embodiment 3

[0033] Except that thermosetting phenolic resin is changed into 38g, all the other are with embodiment 1.

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PUM

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Abstract

The present invention discloses one kind of coated low-nitrogen sand and its preparation process. The coated low-nitrogen sand consists of phenolic resin 1.5-4.0 wt% of the material, hexamethylene tetramine in 0-6 wt% of the phenolic resin, lubricant in 3-7 wt% of the phenolic resin, and raw sand for the rest. It has greatly lowered hexamethylene tetramine consumption, low nitrogen content and capacity of ensuring the surface quality of the casting. During its heated formation, the thermosetting phenolic resin can speed the curing, raise the hardening rate and raising the hot strength of the sand mold.

Description

technical field [0001] The invention relates to materials used in casting and a preparation method thereof, in particular to a low-nitrogen coated sand and a preparation method thereof. Background technique [0002] The foundry industry is the largest basic industry in the machinery manufacturing industry. The quality of casting directly affects the quality of mechanical products. With the development of industry and the progress of society, higher requirements are put forward for the quality of castings and the development of foundry industry. Coated sand is a molding material for shell-type precision casting. It has the characteristics of good preservation, high dimensional accuracy and smooth surface of the produced castings. It can be used in the production of cast steel, cast iron, alloy castings and non-ferrous metal castings. Coated sand is usually made of quartz sand as raw sand, supplemented with binder and curing agent. However, in the casting of the shell (core)...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22C1/00
Inventor 唐路林张宝印李枝芳邢介名
Owner SHANDONG SHENGQUAN NEW MATERIALS CO LTD
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