About 97% of the material that enters the powder metallurgy process leaves as part of the final product, which translates to extremely minimal waste and scraps. Powder metallurgy thereby is beneficial both environmentally and financially because it eliminates the need for subtractive processes in manufacturing, lowering material loses and the cost of the final product. ISO 5755:2022: Sintered Metal Material – Specifications provides requirements for sintered metal materials that are manufactured from the powder metallurgy process.
The ISO 5755:2022 Standard for Sintered Metal Material
ISO 5755:2022 specifies the requirements of sintered metal materials used for bearings and structural parts. Sintered metal is a solid product made via the process of powder metallurgy called sintering, a form of heat treatment. The standard focuses on the following requirements of sintered metal materials:
- Chemical composition
- Mechanical and physical properties
How Is Sintered Metal Made?
The elements for manufacturing a powder metal material are metallic powder (the raw material of a powder component) and tooling (the mechanism that compacts powder into its final shape). The metallic powder can be a pure metal (copper, iron) or an alloyed powders (brass, steel, bronze). The powders are different in nature (sponge, irregular, spherical, laminar), which gives particular properties to the component. With these elements of metallic powder and tooling, the operations of powder mixing, compacting, and sintering produce a sintered metal part.
- Powder Mixing: mixes different types of metal powders homogenously in one mixing chamber to allow for successful sintering of these metals. The base metallic powder is mixed with different alloying elements and an organic solid lubricant that is necessary to compact the powder. The material chemical composition while powder mixing is ensured in ISO 5755:2022 through strict dosing and control processes to achieve the mechanical, physical, or chemical characteristics of the material.
- Compacting: pressing or compacting of metal powders is divided in two areas, hot pressing (compaction at elevated temperatures, usually also done while sintering) and cold pressing (applying pressure upon a column of loose metal powders within a closed die to create a green part/compact). Pressing of metal powders depends on their characteristics and properties like particle size, shape, composition, and size distribution.
- Sintering: applies heat just below the materials melting point to hold the metal particles into its new shape. This precise sintering temperature [usually between 1382°F (750°C) and 2372°CF (1,300°C)] allows the metals to retain their properties while getting fused tightly together.
The result of these three operations is a sintered metallic part with a certain micro-porosity and high dimensional precision that is properly functional when the obtained characteristics meet the component specifications in ISO 5755:2022.
Sintered Metal Products
Sintered metal products are used across a variety of industries and application. Here is a list of some metal parts that metal sintering is used to create:
- Bearing retainers
- Custom bearings
- Electrical contacts
- Lock rings
- Valve seats
ISO 5755:2022: Sintered Metal Material – Specifications is available on the ANSI Webstore.