Stainless Steel Investment Casting vs. Welding

Somtimes, a stainless steel part could be produced in different ways, such as investment casting, welding, etc. CFS Foundry worked with a customer on a stainless steel investment cast mounting bracket, which was made by welding. Stainless steel investment casting of mounting Bracket can significantly reduce weight, simplify logistics, improve quality, cut costs, and support customers’requirements.

Stainless Steel Investment Casting vs. Welding

Compared to welding, stainless steel investment casting can potentially reduce labor costs, especially with complex components. Labor cost is expended with each increase in the number of joints, the difficulty of the weld, the assembly difficulty, and the number of pieces being joined. In addition to the cost component, stainless steel investment casting can be advantageous for improved part strength and uniformity, particularly with hard-to-weld alloys. Part appearance is also improved, since there will no longer be visible weld lines as welded and fastened parts can be cast as one piece. Stainless steel investment casting lends itself to parts that will be higher volume runs, since initial tooling cost may not be suitable for small runs.

Engineered stainless steel components often start as weldment. This is because welding a single prototype is a low cost solution as no tooling is required. The weldment is usually subsequently machined because machined tolerances are much more precise than those achievable with a plain weldment. The cost advantage of welding is mostly kept to prototyping phase or short runs.

As a part matures from prototype to short run to full production, part volumes start to rise. Rising volumes open the door to stainless steel casting. Specifically, with rising volumes, the cost of foundry tooling can be amortized over more and more.

Originally, two versions were offered for the Bracket. The original Trough Mounting Bracket was fabricated from mild carbon steel, machined and painted. The other was made in welded SAE 304 stainless steel stock, which is demanded by the food and pharmaceutical industries for safe food handling and health regulations, and subsequently machined as well.

The part demanded dimensional repeatability and consistency. The top surface had to be flat, and the angular flanges had to be at the correct angle. The hole locations and the key dimensions had to be exact, and if not, the unit would not operate properly. The welded parts could not produce the required dimensional repeatability and consistency. The rising prices for welding and subsquent machining compelled the customer’s purchasing department to seek alternate manufacturing methods to control costs by creating a near net shape earlier in the process. Investment casting is inherently a shaping or metal forming process, so a good casting design will minimize or eliminate the need for welding and machining the component.

Results when converting weldment to investment casting:

  • Reduced Part Count from 9 to 1
  • Reduced Weight by 32%
  • Reduced Costs by 26%
  • Nearly Eliminated Machining
  • Superior Surface Finish and elimination of process step – No painting operation needed / Produced a better looking part
  • Dimensional repeatability and consistency – tighter dimensional tolerances

If you want to make your stainless steel parts by investment casting process, pls feel free to contact our stainless steel foundry!

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