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Technical Information about Stainless Steel - Effects of Temperature Stainless steels find application over a wide range of temperatures - more than any other metal. Low Temperature - Cyrogenic Applications As the temperature of most steels is lowered, it is found that although the tenile strength does not suffer, the toughness of the steel decreases. This means that the steels are likely to suffer brittle fracture under impact loading. Amongst the few alloy groups where this decrease in toughness with temperature is not a problem, is the austenitic stainless steels. The duplex steels also suffer a drop in toughness commencing at around 0°C and are not normally used below around -60°C. It is because of this retention of mechanical properties at low temperatures that the austenitic stainless steels are used in refrigeration plants, the processing, storage, and transportaion of liquified gases and structural applications designed to operate at very low temperatures. Elevated Temperature Applications Metals designed for elevated temperature applications must survive corrosion arising from the high temperature environment and the effect of the high temperature will have on the strength of the metal. Oxidation or Scaling Stainless steels are particularly resistant to oxidation effects. The chromium that provides the pasive corrosion resistant film at room temperature also helps to resist oxidation at elevated temperatures.
High Temperature Strength - Creep The strength of a metal at room temperature does not accurately reflect the strength at high temperatures. At elevated temperatures time and temperature both affect the strength of the metal. The effect of timeintroduces creep. The creep strength of a metal can be expressed in two ways:
Although not classified as creep resisting materials, stainless steels all have relatively high creep strengths, particularly the 'H' or higher carbon grades, and are often used at intermediate temperatures because of this.
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