High-strength core-preparing precoated sand and preparation process thereof

A preparation process and coated sand technology, which is applied in the direction of manufacturing tools, cores, casting molding equipment, etc., can solve the problems of reducing resin, affecting the strength of coated sand, and not having both fish and bear's paws, so as to improve heat resistance Sexuality, beneficial to heat transfer, prolonging the effect of retention time

Active Publication Date: 2012-09-26
西峡县众德汽车部件有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As an essential binder and curing agent in the mixture, reducing the amount of resin

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] This example is the coated sand used for the sand core of the high-nickel austenitic nodular cast iron automobile supercharger shell, which is prepared by mixed rolling with a planetary rotor sand mixer.

[0028] The raw materials prepared before preparing the coated sand are: 1. 200 kg of basic raw sand; 2. 3.6 kg of mixed resin; 3. 1.3 kg of urotropine solution; 4. 150 g of aqueous solution of coupling agent; 5. Stearic acid Calcium 0.2kg.

[0029] Preparation of basic raw sand: Take 170kg of paddock sand of 70-140 mesh, iron sand (ferric oxide): 30 kg, and mix them evenly to form 200 kg of basic raw sand.

[0030] Preparation of mixed resin: use high-strength and low-gas-forming phenolic resin as the skeleton resin, use high-softening point phenolic resin as the auxiliary resin, and use heat-resistant phenolic resin as the ingredient resin. The weight ratio of these three resins is 1 : 1:1 for mixing to form a mixed resin. Specifically, 1.2 kg of 9910-type phenolic...

Embodiment 2

[0036]In this example, the sand mixer and raw materials are used in Example 1 to mix and grind the finished sand. The total amount of basic raw sand in the raw material remains unchanged, and the ratio of silica sand to iron sand is adjusted: take 190kg of 70-140 mesh paddock sand , Iron sand (ferric oxide): 10 kg, mixed evenly to form 200 kg of basic raw sand. All the other raw materials are the same as in Example 1. The main components of the prepared coated sand are: by weight percentage, iron sand 4.8%, mixed resin 1.75%, urotropine 0.21%, calcium stearate 0.097%, coupling agent 0.024%, water 0.047%, and the rest for silica sand.

Embodiment 3

[0038] In this example, the sand mixer and raw materials are used in Example 1 to mix and grind the finished sand. The total amount of basic raw sand in the raw material remains unchanged, and the ratio of silica sand to iron sand is adjusted: take 180kg of 70-140 mesh paddock sand , Iron sand (ferric oxide): 20 kg, mixed evenly to form 200 kg of basic raw sand. All the other raw materials are the same as in Example 1. The main components of the prepared coated sand are: by weight percentage, iron sand 10%, mixed resin 1.75%, urotropine 0.21%, calcium stearate 0.097%, coupling agent 0.024%, water 0.047%, and the rest for silica sand.

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PUM

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Abstract

The invention discloses high-strength core-preparing precoated sand comprising the following components by weight percent: 4.8%-14.7% of iron sand, 1.65%-1.76% of mixed resin, 0.18%-0.24% of methenamine, 0.07%-0.11% of calcium stearate, 0.34%-0.54% of water and the balance of silica sand. The preparation process comprises the following steps of: adding basic roughing sand to a sand mixing machine after the basic roughing sand is heated to be 125-135 DEG C; adding the mixed resin accounting for 1.7%-1.8% of the weight of the basic roughing sand to the sand mixing machine for mixing and grinding; when the sand temperature in the sand mixing machine is reduced to be 102-108 DEG C, adding a methenamine solution for continuously mixing and grinding; and when the sand temperature in the sand mixing machine is reduced to be 70-75 DEG C, adding the calcium stearate, and screening and cooling after mixing and grinding so as to obtain finished sand. With the adoption of the preparation process, formation of N2 is effectively controlled, restraint to defects of subcutaneous blowholes is up to more than 96%, the barrier in the prior art is broken through, and the formation of nitrogen holes is truly prevented.

Description

technical field [0001] The invention relates to a coated sand and a preparation process thereof, in particular to a coated sand for core making and a preparation process thereof. Background technique [0002] The chemical reaction between the high temperature molten metal poured into the mold and the casting material, cold iron, slag, etc. leads 2 、H 2 The gas dissolves and diffuses in the metal liquid, and when the metal solidifies, it precipitates to form bubbles, thereby forming tiny subcutaneous pores. Nitrogen is the main factor that causes subcutaneous pores. It is a pity that casting products are often scrapped because of a nitrogen hole. It is true that the purpose of increasing the exhaust channel is to allow the gas to be smoothly discharged out of the mold along the channel set by the process, but in the actual production process, a considerable part of the gas generated by the sand core cannot be discharged along the set channel. [0003] The gas generation of...

Claims

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Application Information

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IPC IPC(8): B22C1/00B22C1/02B22C1/22
Inventor 田中青
Owner 西峡县众德汽车部件有限公司
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