Formula of pattern material prepared from paraffin and stearic acid

Abstract

The invention belongs to the field of investment casting, and specifically relates to a formula of a pattern material prepared from paraffin and stearic acid. The mass ratio of 56# semi-refined paraffin wax to first-grade triple pressed stearic acid is 1:0.95-1.05; the mass ratio of a recycled paraffin which contains no saponifiable matter to first-grade triple pressed stearic acid is 1.2:0.75-0.85. A mixture of semi-refined paraffin wax and stearic acid is prepared according to the mass ratio, and is added into clear water; a heating temperature is controlled at 75 to 90 DEG C, and the temperature is strictly prohibited from exceeding 90 DEG C. According to the formula, volume contraction and linear contraction of a casting are controlled in a dimensional tolerance range of the casting that is permitted, demoulding efficiency and surface quality of the casting are increased, and production cost is reduced.

Description

technical field [0001] The present invention relates to investment casting, and in particular to the formulation of paraffin wax and stearic acid molding materials. Background technique [0002] Investment pattern manufacturing is an important link in the investment casting process. High-quality investment patterns are the prerequisite for obtaining high-quality castings. One of the important factors affecting the quality of investment patterns is the selection and ratio of mold materials. From the perspective of thermal stability, mold materials can be divided into: low temperature mold materials, medium temperature mold materials, and high temperature mold materials. There are many molding materials used and being developed in domestic and foreign production, and their components are different and have their own characteristics. Considering the trimming and welding of the model after molding, the dewaxing of the mold shell has the advantages of simplicity and speed, and...

AI Technical Summary

Problems solved by technology

The selection and ratio of traditional paraffin wax and stearic acid has been very immature, the production efficiency is low, and the wax mold produced has a low softening point and large shrinkage

The specific use of the two materials paraffin and stearic acid used in the mold material ratio is analyzed as follows: 1. The ratio under the condition of constant seasonal temperature: 1. If the mass fraction of paraffin wax is too high when the mold material is configured, stearin When the mass fraction of the acid is relatively reduced, the softening point of the produced wax pattern is low, resulting in longer demoulding time, lower production efficiency, and large shrinkage, resulting in a large change in the size of the wax pattern and an increase in the size of the casting compared to the actual size.

2. If the mass fraction of paraffin wax is low and the mass fraction of stearic acid is relatively increased when the mold material is configured, the needle penetration of the produced wax mold will be low, and the wax mold will be difficult to trim, resulting in a decrease in production efficiency; the shrinkage rate is small, resulting in wax molds. The size change becomes smaller, and the size of the produced casting is larger than the actual size deviation

2. If the influence of temperature is not considered in the ratio of mold materials: 1. When the temperature of the mold material with fixed ratio is high in summer, the demoulding time will be relatively prolonged, the production efficiency will be reduced, and the wax mold produced will have a large shrinkage rate. It has a great impact on the size of the casting; 2. When the temperature of the mold material with a fixed ratio is low in winter, the demoulding time will be relatively shortened, the wax mold produced will have low penetration, it will be difficult to trim the wax mold, and the production efficiency will be reduced. The shrinkage rate of the wax mold produced is large, which has a great influence on the size of the casting