3.2.2 Service Temperatures

Service temperatures do not generally affect the decision whether to choose forging over an alternate process. However, they are an important driver when deciding which forging alloy to choose. Service temperatures can not always be defined by a single number. For example:

  • A temperature may be steady state or cyclic. A familiar example is a forged aluminum piston in an internal combustion engine, which performs satisfactorily when exposed to cyclic flash temperatures that typically reach or exceed 1650°C (3000°F). In contrast, gas turbine engine components, operating at steady state temperatures of 870°C (1600°F), require nickel or cobalt superalloys.
  • Metal alloys can withstand occasional short-term temperature excursions, or "spikes", particularly those that occur when loads are at low levels.
  • When temperature gradients are present, unusually high temperature excursions may be tolerable if experienced in a localized low-stress area of the forging.

If mechanical properties are affected by low temperatures, such as those below the ductile-brittle transformation range, the forging should be tested at the anticipated low temperature. Ductile-brittle transformation can occur in some alloys at harsh environment test temperatures of -34°C (-30°F), and it is likely to occur in cryogenic applications.

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Service temperatures do not generally affect the decision whether to choose forging over an alternate process. However, they are an important driver when deciding which forging alloy to choose. Service temperatures can not always be defined by a single number. For example:

  • A temperature may be steady state or cyclic. A familiar example is a forged aluminum piston in an internal combustion engine, which performs satisfactorily when exposed to cyclic flash temperatures that typically reach or exceed 1650°C (3000°F). In contrast, gas turbine engine components, operating at steady state temperatures of 870°C (1600°F), require nickel or cobalt superalloys.
  • Metal alloys can withstand occasional short-term temperature excursions, or "spikes", particularly those that occur when loads are at low levels.
  • When temperature gradients are present, unusually high temperature excursions may be tolerable if experienced in a localized low-stress area of the forging.

If mechanical properties are affected by low temperatures, such as those below the ductile-brittle transformation range, the forging should be tested at the anticipated low temperature. Ductile-brittle transformation can occur in some alloys at harsh environment test temperatures of -34°C (-30°F), and it is likely to occur in cryogenic applications.

Return to Table of Contents
 

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Service temperatures do not generally affect the decision whether to choose forging over an alternate process. However, they are an important driver when deciding which forging alloy to choose. Service temperatures can not always be defined by a single number. For example:

  • A temperature may be steady state or cyclic. A familiar example is a forged aluminum piston in an internal combustion engine, which performs satisfactorily when exposed to cyclic flash temperatures that typically reach or exceed 1650°C (3000°F). In contrast, gas turbine engine components, operating at steady state temperatures of 870°C (1600°F), require nickel or cobalt superalloys.
  • Metal alloys can withstand occasional short-term temperature excursions, or "spikes", particularly those that occur when loads are at low levels.
  • When temperature gradients are present, unusually high temperature excursions may be tolerable if experienced in a localized low-stress area of the forging.

If mechanical properties are affected by low temperatures, such as those below the ductile-brittle transformation range, the forging should be tested at the anticipated low temperature. Ductile-brittle transformation can occur in some alloys at harsh environment test temperatures of -34°C (-30°F), and it is likely to occur in cryogenic applications.

Return to Table of Contents
 

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