Investment Casting Defects Analysis and Remedies

2021-11-23

Investment casting Defects Analysis and Remedies

The defects of investment castings are not only related to the process, but also related to a series of factors such as the characteristics of the alloy, the melting of the alloy, and the product structure. Today, Stone Industrial analyze some of the main causes of casting defects for you, conduct a comprehensive analysis according to the characteristics, locations, and processes of the defects, and then takes corresponding technical measures to prevent and eliminate defects.

1. Gas Porosity

Q: How Gas Porosity occurs?

A: As the solid form of the metal cannot hold as much gas as the liquid form, when the casting cools and solidifies, the bubbles will form and appear on casting as circular cavities or holes.

Q: How to Prevent Gas Porosity?

A: Make sure that the tooling is fully dry when use and stored under dry conditions, and control well the pouring temperature.

2. Shrinkage

Q: How Shrinkage occurs?

A: Shrinkage occurs because metals are less dense as a liquid than a solid. Shrinkage cavity is the surface rough hole in the casting surface or internal, slight shrinkage cavity is many scattered small shrinkage cavity, namely shrinkage. It is a depression in a casting that occurs during the solidification process.

Q: How to Prevent Shrinkage Defect? 

A: Design a running gate system with risers, choose a suitable pouring position. And if possible, improve the part structure to have a good continuous flow of molten metal.

3. Tooling Defects

Q: How Tooling Defects occur?

A: Caused by tooling material defects or tooling design problem.

Q: How to Prevent Tooling Defects?

A: Let the tooling receive enough ramming and let the molten metal continuously flow is an effective way to cut down on all these problems.

4. Pouring Casting Defects

Q: How Casting Defects occur?

A: The defects maybe are caused by pouring the metal when it is not hot enough. However, even with suitable temperature, defects can be caused by poor gating systems that let the metal to cool off too fast before it gets into the mold or to reach the thin positions.

Q: How to Prevent Casting Defects?

A: This can generally be done by ensuring that the molten metal has a sufficient temperature to fully conform to the mold interior. This can generally be done by ensuring that the molten metal has a sufficient temperature to fully conform to the mold interior. 

As a standard operation, we will make a trial order and confirm all details with our customers. After the trial order is passed, and ensure our parts are met customers’ requirements, then we start the mass production. Our Investment casting quality control aim is to meet customers’ requirements.