Investment Casting Material Options
Investment casting is such a versatile manufacturing solution in part because the material options are nearly endless.
There are many factors to consider when choosing the best alloy for the job. To narrow it down, here are some frequently asked questions about investment casting materials and options, answered below:
Which alloys are best for plating or painting?
Any material can be painted. The easiest alloys to paint are usually those that do not oxidize heavily. For example, stainless steel can be difficult to paint without some secondary heat treatment, but plain carbon low alloy steel is easy to paint. Another factor that affects painting and plating is the surface finish of each unique part. If the parts are too smooth, the paint won't stick either. Generally, low alloy steel works best with paint and plating.
Can you use the same tool to make the same part in different alloys, or do you need a tool for each alloy of the same part?
Because each alloy has a different coefficient of thermal expansion, a tool that accommodates the shrinkage of one alloy may not be able to accommodate the shrinkage of another. Although the dimensions of the wax pattern are the same regardless of the alloy, the part shrinks differently during and after solidification of different metals.
Are some alloys better at reducing porosity than others?
Some alloys are better suited to minimize porosity without secondary operations, but minimal porosity can always be achieved with an additional heating process. For example, aluminum alloys can be difficult to manufacture without a secondary shrinkage operation. Due to its high hydrogen solubility, bubbles can form as the part cures, necessitating additional processing steps to prevent impacting the properties and porosity of the final product. Generally speaking, stainless steel is good for minimizing porosity during initial production.
What alloys are best for thin walls?
Because we spend a lot of time designing each casting, we can achieve very thin walls with most materials. Aluminium is suitable for thin-walled parts as well as desulfurized steel
