3.4.2.6 Powder Metallurgy Processes

Conventional powder metallurgy (P/M), metal injection molding (MIM) and powder forging (P/F) are the three most commonly specified powder metallurgy processes. The processes are used for essentially the same alloys groups as forging. MIM is currently limited to very small components, up to approximately 100 gm (3.5 oz) of complex configuration. It is rarely an alternative to forging. Conventional P/M and powder forging may be alternatives in some applications.

Conventional P/M produces very close dimensional precision, but the process is characterized by porosity, which reduces mechanical properties. Tensile and yield strengths are reduced approximately in proportion to the level of porosity, while ductility and dynamic properties, such as impact toughness, fracture toughness and fatigue strength, are usually much lower than for forgings. Process options such as infiltration and special sintering procedures can improve properties. However, dynamic properties are not equivalent to forgings made from similar alloys.

Dynamic properties in P/M approach those of forgings only when the porosity is reduced to 0.5% or less, and this level is generally achieved only by powder forging. Powder forging is an alternative to impression die forging for small and medium sized components with a high degree of symmetry and high production volumes, such as automotive gears and connecting rods.

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Conventional powder metallurgy (P/M), metal injection molding (MIM) and powder forging (P/F) are the three most commonly specified powder metallurgy processes. The processes are used for essentially the same alloys groups as forging. MIM is currently limited to very small components, up to approximately 100 gm (3.5 oz) of complex configuration. It is rarely an alternative to forging. Conventional P/M and powder forging may be alternatives in some applications.

Conventional P/M produces very close dimensional precision, but the process is characterized by porosity, which reduces mechanical properties. Tensile and yield strengths are reduced approximately in proportion to the level of porosity, while ductility and dynamic properties, such as impact toughness, fracture toughness and fatigue strength, are usually much lower than for forgings. Process options such as infiltration and special sintering procedures can improve properties. However, dynamic properties are not equivalent to forgings made from similar alloys.

Dynamic properties in P/M approach those of forgings only when the porosity is reduced to 0.5% or less, and this level is generally achieved only by powder forging. Powder forging is an alternative to impression die forging for small and medium sized components with a high degree of symmetry and high production volumes, such as automotive gears and connecting rods.

Return to Table of Contents

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Conventional powder metallurgy (P/M), metal injection molding (MIM) and powder forging (P/F) are the three most commonly specified powder metallurgy processes. The processes are used for essentially the same alloys groups as forging. MIM is currently limited to very small components, up to approximately 100 gm (3.5 oz) of complex configuration. It is rarely an alternative to forging. Conventional P/M and powder forging may be alternatives in some applications.

Conventional P/M produces very close dimensional precision, but the process is characterized by porosity, which reduces mechanical properties. Tensile and yield strengths are reduced approximately in proportion to the level of porosity, while ductility and dynamic properties, such as impact toughness, fracture toughness and fatigue strength, are usually much lower than for forgings. Process options such as infiltration and special sintering procedures can improve properties. However, dynamic properties are not equivalent to forgings made from similar alloys.

Dynamic properties in P/M approach those of forgings only when the porosity is reduced to 0.5% or less, and this level is generally achieved only by powder forging. Powder forging is an alternative to impression die forging for small and medium sized components with a high degree of symmetry and high production volumes, such as automotive gears and connecting rods.

Return to Table of Contents

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