Characteristics of precision casting shell manufacturing process

Update:11 Jan 2020
Summary:

Features of Precision Casting Shell Making Process: 1. […]

Features of Precision Casting Shell Making Process:

1. Water glass shell. This process has a production history of nearly 50 years in China. After unremitting efforts, the application and research of water glass shell technology has reached a high level. Over the years, due to the improvement of the back-layer shell refractory and the promotion and application of new hardeners, the strength of water glass shells has doubled. Low cost, shortest production cycle, excellent shelling performance and high air permeability are still the advantages of any other shell technology.

2. Composite shell. Compared with the water glass shell, the surface quality of its casting has been greatly improved, the surface roughness is reduced, the surface defects are reduced, and the repair rate is reduced. Can be applied to high alloy steels such as stainless steel and heat-resistant steel. The production cycle is much shorter than the low temperature wax-silica sol shell, which is similar to the water glass shell.

3. Silica sol (low temperature wax) shell. This process is in line with national conditions, and has greater adaptability and superiority when casting more than 1kg, especially medium and large pieces. The quality is more stable than that of the composite shell, especially the dimensional accuracy of the casting is high. Because it does not have water glass, the shell has good high-temperature performance. After baking at 1000-1200 ℃, the shell has high permeability and strong creep resistance. Thin-walled parts, small and medium-sized parts with complex structure, and can produce extra large parts weighing 50-100kg, such as water pumps, impellers, guide shells, pump bodies, ball valve bodies, valve plates, etc. For thin-walled small or large pieces, a fork shell or lifting shell can be directly cast in front of the furnace, and a high yield can be obtained.

4. Silica sol (medium temperature wax) shell. This is an internationally used precision casting production process. It has the highest quality of precision castings and the lowest rework rate. It is especially suitable for small and medium-sized and extra-small parts (2-1000g) with high surface roughness requirements and high dimensional accuracy. However, due to equipment and cost constraints, it is rarely used in medium and large pieces (5-100kg).