Volume 3 | Issue 3 | Year 2000

To many people, the word “metallurgy” evokes images of medieval blacksmiths pounding hot iron into shape upon an anvil. Although the word itself may seem locked in lost centuries, the real science behind the word is very much alive. In fact, at SSI-Sintered Specialties, it’s downright cutting-edge.

Take, for example, the recent award-winning automotive flanges produced by Sintered Specialties, a division of SSI Technologies Inc. Used in the Ford Contour and the Mercury Mystique, as well as the Ford Mondeo in Europe, Sintered Specialties’ powder metal flanges dramatically reduce exhaust leakage at the manifold-exhaust system junction, leading to improved emissions control.

“The stainless steel used for the automotive exhaust control application has superior tensile properties compared to wrought stainless steel at elevated operating temperatures, as well as improved corrosion and oxidation properties,” says Gary E. Regan, manager of market development. “Because Sintered Specialties’ flange products offer an improved solution to exhaust leakage problems, these designs have opened a new and growing market opportunity.”

That’s just one example of one product from one division of SSI Technologies Inc., a company unrivaled in its pursuit of metallurgical excellence on behalf of customers ranging from U.S. automotive manufacturers and major systems suppliers to the global automotive industry — as well as to industrial markets.

Heavy Metallurgy

Headquartered in Janesville, Wis., SSI Technologies Inc. produces custom-ordered components such as sensors, solenoids and powder metal components for automotive and industrial markets. SSI boasts approximately 235,000 square feet of manufacturing space and more than 1,000 employees. The two operating business units of SSI Technologies are Speed Sensors and Sintered Specialties. Its Advanced Engineering Group develops new sensing and other technologies for future applications in the automotive and other industries.

The powder metallurgy (P/M) process offers benefits not frequently found in products of other metalworking processes. The advantages of Sintered Specialties’ structural P/M components include good dimensional reproducibility, the elimination or minimization of machining, excellent surface finishes, long-term performance and reliability in critical applications. The P/M process offers a cost-effective alternative to forging, die casting, gravity casting, investment casting, fine blanking and stamping.

P/M processes are particularly well suited for components that require fine finishes and bearing properties, and features requiring close production tolerances, irregular shapes, long holes and blind holes. P/M processing lends itself to a variety or applications, including automotive components, aerospace and aviation, small and large appliances, agricultural equipment and machinery, food and beverage processing, and lawn and garden equipment.

“At Sintered Specialties, quality means surpassing our customers’ expectations for performance, delivery, reliability and service,” says Regan. “We provide our customers with world-class, custom powdered metal parts produced by team members in a growth-oriented environment using a unique variety of manufacturing processes.”

Structural Products

“Structural products are the lifeblood of most powder metal manufacturers. At Sintered Specialties we have taken structural components to the next level,” states Regan. “Structural components are normally sintered at temperatures in the range of 2,050ºF to 2,100ºF in controlled atmospheres. At Sintered Specialties our temperatures range from 2,350ºF to 2,550ºF, and a 100 percent hydrogen atmosphere is usually used. For this reason Sintered Specialties is known as the innovator and leader in the powder metal, stainless steel market,” says Regan. “Sintered Specialties processing technology, along with being the largest consumer of stainless steel powder in the United States has given us the competitive edge. This has allowed Sintered Specialties to produce millions of components such as mirror mounts, exhaust flanges and sensor bosses, anti-lock brake sensor rings and a wide variety of other structural products,” stated Regan.

Full Density

“We are a leader in full-density applications and custom-controlled porosity (primarily stainless steel), an innovator in metal injection molding components and a high-volume producer in structural applications, especially stainless steel parts requiring soft magnetic properties,” says Regan. Full-density P/M tool steels and stainless steel parts are produced at Sintered Specialties using patented processing methods. Examples of specific full-density components include cam rings, pump liners, pump blades, cut-off inserts, knurling blanks, stamping dies, insert chasers and milling cutters. Non-interconnected porosity and corrosion resistance, the feature properties of Sintered Specialties’ high-density stainless steel, are useful for such applications as food processing equipment where interconnected porosity can trap food, allowing for bacterial growth, and in highly corrosive environments where normal P/M 316 stainless steel is not adequate.

“Using high-temperature vacuum furnaces and controlled atmosphere furnaces, Sintered Specialties can deliver P/M components suitable for the most demanding applications,” says Regan. “Such high-temperature sintering creates components with superior mechanical and magnetic properties.”

Controlled Porosity

For nearly 25 years, Sintered Specialties has made a wide variety of controlled-porosity powder metal components. Controlled-porosity components are characterized by interconnected porosity, the volume of void space within the part that can be controlled from 10 percent to 70 percent of the total part volume.

According to Regan, controlled-porosity components are ideal for a variety of applications, including writing instruments, arming delays, and communications equipment because they attenuate sound, control vacuum or pneumatic signals, arrest flame, restrict flow, filter and act as breathers. “These components are used as time delays where the part’s resistance, coupled with the system’s volume, provides the equivalent of an electronic resistance-capacitance circuit,” says Regan.

MIM’s the Word

Metal injection molding (MIM) combines two manufacturing technologies: thermoplastic injection molding and conventional powder metallurgy. Fine metal powders are blended with thermoplastics to form a moldable paste. After molding a shape in a standard injection-molding machine, the thermoplastic binder is removed and the powder is sintered to high density.

“Over the years, more and more industries have found uses for the unique capabilities of the metal injection molding process,” says Regan. “In some cases, plastic injection molded parts and zinc die castings have been replaced by metal injection molded parts for improved performance.” Some industries and applications that have been serviced by SSI’s MIM process include automotive (locks, actuators), firearms (sights, safeties, triggers), medical (surgical tools), hardware (locks), computers (hard disk drives), dental (orthodontic braces) and electrical (connectors, switches).

In closing, Regan stated, “To our knowledge, Sintered Specialties is the only powder metal company, anywhere, that offers four specific powder metal technologies under the same roof. This, along with our high temperature and vacuum sintering technologies, allows Sintered Specialties the benefit of producing powder metal components that offer superior mechanical properties, weldability and corrosion resistance. These properties have greatly increased the number and variety of applications that can now utilize powder metal products.”

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