The Sky’s the Limit for Stainless Steel Investment Casting
Technological milestones have helped foundries achieve next-level productivity, quality, and precision in metal pouring. These capital investments in hardware and software not only benefit the foundry in terms of lead times and customer satisfaction, but they help drive innovation at the part level. The more a foundry can expand its capabilities, the more an original equipment manufacturer (OEM) can push the envelope with part design.
This is especially true with stainless steel investment casting. Stainless steel is a superior material in manufacturing when you consider versatility, availability, and practicality. Its durability, hygienic properties, corrosion resistance and high heat tolerance make it ideal for harsh environments including nuclear, oil and gas, NAVSEA, and food and beverage. Stainless steel also possesses the ability to weld, bend, and cut; is infinitely recyclable with no loss of quality; and requires minimal maintenance – making it a popular choice for components across many manufacturing sectors.
For nearly 80 years, Stainless Foundry & Engineering (SF&E) has played a major role in pouring precise, high-quality stainless steel investment castings to meet the most demanding needs of the defense, food and dairy processing, paper and pulp, power generation, oil and gas, and petrochemical industries. Today, still on our original Milwaukee, WI footprint, stainless steel castings make up about 70 percent of the more than 250 alloys we cast.
A combination of technology and experience have allowed SF&E to remain adaptable and competitive, which leads to history-making pours, according to Terry Groth, Foundry Engineer for SF&E.
“Customers approach SF&E with a variety of needs – some require a specific alloy recipe, some request custom attributes such as increased strength, and others are looking for the most cost-effective process for a desired shape,” Groth said. “We leverage our technical capabilities to determine the approach, and then modify from there until we have achieved the customer goal while still adhering to quality standards and specifications.”
Complexity and Size
The most common customer stainless steel requests are for tighter tolerances, intricate designs, and durability, according to Anthony Geiger, Senior Foundry Engineer for SF&E. That’s where investment casting comes in.
“Our increasing focus on stainless steel investment casting is in response to customers requiring near net shape with a tight tolerance and a naturally smooth finish,” Geiger said. “Investment casting is a cost-effective way to produce multiple high-quality and complex castings that are more structurally sound than welded machined parts.”
SF&E can cast walls as thin as 0.125 inches and parts as light as 0.2 pounds. Our stainless steel investment castings now weigh up to 170 pounds, a range much larger than they were capable of in the past, according to Groth.
Leveraging 3D modeling, scanning, and printing has significantly reduced the margin for error in our processes. Whether the models are provided by the customer or developed in-house, this technology has proven to be a game-changer, leading to fewer trials and errors and, ultimately, higher customer satisfaction.
MAGMASOFT® software helps the SF&E engineering team simulate the casting process by creating a 3D model. We can analyze the pour and identify where shrinkage, porosity, and inclusions may occur. The software also provides recommended pouring temperatures and pour time for a perfect pour designed for manufacturability.
“With 3D modeling, everyone can agree on what the part should look like,” said Jacob Fell, Jr. Foundry Engineer for SF&E. “We can take that model, work with our trusted supplier tool makers, and make the tool precisely to accommodate those dimensions. Now we have a high probability of getting it right the first time, which is a KPI for us.”
Metallurgy
We work closely with our customers to truly understand the benefits of different alloys for their application. This firsthand knowledge has proven time and again to increase the quality and efficiency in manufacturing a part and identify techniques to improve the life of a part.
Adding or refocusing on an alloy is challenging for any foundry. SF&E accomplishes this several times per year for key customers. The following are examples of stainless steel alloys introduced within the past five years.
Antimicrobial Stainless Steel– In 2021, SF&E worked with Advancing Medical Innovations (AMI) and Performance Compounds Inside (PCI) to manufacture the first antimicrobial stainless steel. It was created using 3PRE Technology, a proprietary process of activating microbial properties. 3PRE Technology can be added to stainless steel during the foundry process to render it capable of destroying and inhibiting bacteria and other disease-causing microorganisms.
Precipitation Hardening Stainless Steel – CB7Cu-1/17-4 is an alloy that provides ruggedness and reliability. Its corrosion resistance holds up against the elements, including sea water. Precipitation hardening stainless steel is a high-strength, weight-bearing stainless steel that is more than two times stronger than a typical stainless steel alloy.
Martensitic Stainless Steel – CA-15/CA-40/CA6NM is a medium-strength, corrosion-resistant stainless steel that is durable enough to protect elevator mechanicals on an aircraft carrier from the impact of a weight-bearing collision.
Austenitic Stainless Steel – CF8M/CF3M is strong and highly corrosion resistant. It can stand up to abrasive media in severe applications, such as impellers that rotate at high speeds, for example. At the same time, it can still be heavily machined down to a thin dimension.
As technology evolves rapidly, SF&E is well-prepared to meet future challenges. Our strategy involves leveraging the technical training of our younger employees and the seasoned experience of veteran leaders to uncover innovative approaches alongside our client teams.
If you are interested in learning how SF&E can help you advance your stainless steel investment castings, contact us today.