Extend gear life with clean steels
It's a tough world out there for gears, which are routinely exposed to heavy loads, bending stresses, and frictional forces. To increase both the performance and the fatigue limit of components, researchers at the Timken Co. are continuously working on methods to produce cleaner steels and to better control steel composition. Why? The amount of non-metallic inclusions in steel has been correlated with lower gear life. Timken's newest offering is a modified 4615 alloy, which is produced by an air melting process in an electric air furnace, extensive refining, and a strand cast process. And the alloy is exhibiting extremely good performance. "In given applications, we've improved gear life significantly" says Craig Darragh, product technologist.The Timken Co
Near-net shapes invar extrusions
For designers seeking to minimize thermal expansion mismatch, Invar-36(R), a specialized nickel alloy, is an attractive option. And Plymouth Tube Co. is now offering near-net shape invar extrusions. Invar's low coefficient of thermal expansion (0.72 in/in/ degrees F x 10-6 at 200 degrees F to 4.22in/in/ degrees F x 10-6 at 700 degrees F makes it particularly ideal for tooling components used in the production of composite structures. "By using Invar-36 tools, warpage can be minimized," says Dennis Gudgel, marketing manager for Plymouth Extruded Shapes. "And with near-net extruded shapes," he adds, "designers can eliminate a lot of costly machining and waste." Parts must have a maximum cross-section design that fits within a six-inch-diameter circle. Average maximum length of a finished part is 30 feet.
Plymouth Tube Co
New alloy toughs it out
Tool breakage is a frustration for any machine shop. But a new alloy developed by Carpenter Specialty Alloys specifically for tools is preventing the problem and getting kudos from the field. Called AerMet(R)-For-Tooling, the iron-cobalt-nickel alloy possess high hardness and strength, combined with exceptional durability and toughness. According to Carpenter, the alloy is designed for components that require a combination of HRC 53/55 hardness with the highest toughness available. AerMet(R)-For-Tooling is an air-hardenable alloy virtually free of distortion when properly heat treated. minimal distortion is a definite advantage when making parts with critical tolerances or complex shapes.
Carpenter Specialty Alloys
New apps for Be-Al alloys targeted
The idea of partnering beryllium with aluminum in a single alloy with high specific strength and stiffness has long been an attractive one. In a joint development effort in the early 1990s, the partnership of Nuclear Metals and Lockheed Martin Electronics & Missiles made a breakthrough in learning how to investment-cast beryllium-aluminum alloys. Called Beralcast, these alloys consist of beryllium, aluminum, cobalt, and either silicon or germanium. Historically, they been used primarily in aerospace applications, such as the F-22 jet fighter. Now the company is targeting commercial markets where a high-strength-to-weight ratio is desirable, says Frank Venbaco, such as sporting goods equipment and medical prostheses. The company, which has recently changed its name to Starmet Corp, will market the alloys under its new Starmet Comcast subsidiary.
Castable graphite cuts machining time
A new castable graphite, called Hyper-Cast, is now available for producing net shape parts. In developing the material, Frank Gojny had to overcome one major obstacle: Traditional resin systems used to bind very fine-grain graphite particles have a low decomposition temperature. "The challenge was to develop a material with a higher ash content, giving it an essentially unlimited temperature range," says Gojny. Castable graphite has a number of advantages over monolithic graphic. The net shape parts produced require less machining. And, claims the inventor, Hyper-Cast graphite shows superior strength and abrasion resistance. The higher strength is attributed to the carbonaceous bonds of the chemical cross-linking. A trial size (1 gallon castable liquid, which equals 231 cubic inches of cured material) of the material is available for $175.00.
Molten metal sensor has extended range
Haraeus Electro-Nite, the company which pioneered the concept of disposal sensors for the metals industry, continues to push the envelope. The company has recently introduced the Model DT-260 portable digital temperature measurement system for molten metal. According to Electro-Nite's Bob Kuball, the new system is compatible with a wider range of materials, including brass, aluminum, and bronze. A new design for the leadwire offers longer pole life and requires less maintenance. As with its long-lasting predecessor, the DT-250, Kuball expects the DT-260 to meet the needs of customers for the next decade.
Carbide-tipped bandsaw is tough
Titanium alloys, stainless steel, and other materials with a high degree of hardness are notoriously difficult to machine. But a new carbide-tipped bandsaw blade just introduced by Sandvik Saws & Tools Co. can improve cutting productivity in tough-to-machine materials by as much as 3X. In one comparison, involving a type 17-4 stainless steel, the new Series 3868 blade improved cutting rates by a factor of 3.25. The secret is a tool design that produces equal chip thickness, resulting in a smooth cutting operation. Unlike other carbide-tipped blades, the teeth are not subject to premature chipping. And finishes are equal to that of bimetal blades.
Sandvik Saws & Tools Co
Salt bath nitriding improves properties
An alternative to conventional heat treating methods, ferritic nitrocarburizing enhances the properties of ferrous metals. According to the Kolene company, its SBN(TM) processing method increases wear resistance and improves fatigue strength by as much as 100%. A low coefficient of friction and a tough surface layer allow excellent sliding and running properties, reducing seizing and galling.