Sintered Steel Parts

Sintered Steel Parts

Sintered steel parts are solid metal components created through the controlled heating of powdered steel materials, also known as the process of powder metallurgy. Aerospace, electrical, automotive, transit, medical, machine building, computer and security firms all utilize sintered steel parts in an assortment of applications. The most common of all metal alloys, steel is composed with a majority of iron and lesser amounts of carbon and provides a high strength and durable fabrication material. Other metals may be added to enhance the qualities already provided by iron and carbon. The addition of carbon and other elements to iron lower the melting point, making steel well suited to sintering and lowering costs of that process. While the lower melting point aids the sintering, the high tensile strength and rugged durability of steel allow its use for a variety of industrial applications. Some common uses for metal powder parts include cams, bearings, counterweights, armatures, bushings, magnetic parts and powdered metal gears. As sintering maintains the purity of materials due to the simplicity of the process, the desirable characteristics of the alloys are preserved, making sintering or the larger process of powder metallurgy a preferred method of production in most industries. Other benefits of using sintering over stamping, forging or molding include higher purity of raw materials, product stability and uniform density.

There are three basic steps in the production of sintered metal parts. The first, powdering which consists of turning solid steel bars or parts into fine powder. This can be done through a number of processes including grinding, atomization, chemical deconstruction and centrifugal disintegration. The next stage of producing sintered steel parts involves forcing the powdered metal into a press or die mold. The particles of powder conform to the interior of the mold cavity and under great pressure compact into the shape of the component. The last stage involves heating the powdered metal so that the particles fuse together. The metal is heated to just below the melting point, and can be used to affect the porosity of the finished product. For steel, the melting point is 2400 degrees Fahrenheit, sintering occurs at about 2/3 of this temperature or 1600 degrees Fahrenheit. In this manner sintering changes the mechanical bonds to metallurgical bonds thus fusing the particles into a solid mass. Secondary finishing operations such as sizing, coining, infiltration, heat treating, machining, plating, drilling, grinding, reaming or resin impregnation may be used to further finish the product and ensure its reliability in its final application.