What is the Difference Between Investment Casting and Hot Rolling?

Manufacturing metal parts, like doing research for your metal fabrication partners, requires careful consideration of the end use of the product. If you're in the research phase of a large part project, you might be comparing molding processes. Hot rolling and investment casting are two popular forming methods for making steel components for equipment, transportation and construction projects. So what is the difference between hot rolling and investment casting?

1. Forming methods of hot rolling and investment casting

In investment casting, metal is heated above its melting point and then poured into (uninjected) molds to solidify. Modern investment casting technology guarantees wear parts and precision for complex geometries. Investment casting is a popular choice for parts used in the transportation industry as well as the gun industry, medical equipment, construction and machine tools, and more. Net shape/near net shape of investment castings can provide significant savings in material, machining and labor costs.

The hot rolling process takes place at temperatures above 1000 degrees Fahrenheit. Hot rolled steel reconfigures itself as it cools, allowing the finished product to have looser tolerances than the original material. These looser tolerances make hot-rolled steel ideal for making structural components, such as I-beams for supporting trusses or simple cross-sections for railroad tracks.

2. The application of hot rolling and investment casting

Both hot rolling and investment casting produce tough, strong parts of reliable quality for use in transportation applications, industrial equipment, tools and construction. One of the main advantages of investment casting is that it is more suitable for wear parts that require smooth surfaces and low tolerances. For complex-shaped parts that require dimensional accuracy, investment casting delivers strong products at competitive prices at below-average tooling costs. Hot rolled steel is used in applications where precise shapes and tolerances are not required; the end product is often used as a solution for rods, structural profiles and rails.

3. Metal specifications and grades for hot rolling and investment casting

Hot rolled steel will reconfigure itself during cooling, which allows the finished product to have looser tolerances than the virgin material (compared to investment casting). There is less control over the final shape of hot rolled steel because it cools after processing, which makes it less suitable for precision applications. It is often used for transportation and construction projects where very specific dimensions are not critical. Most hot rolling processes involve steel, but aluminum hot rolling is popular in electrical and automation equipment. Investment casting is far more precise than hot rolling, making it a popular choice for projects that require high precision, integrity, and multiple production iterations.