◎ Temperature of solution annealing shall be agreed for simulated heat-treated test-pieces.
① Solution annealing may be omitted if the conditions for hot working and subsequent cooling are such that the requirements for the mechanical properties of the product and the resistance to intergranular corrosion as defined in EN ISO 3651-2 are obtained.
② If heat treatment is carried out in a continuous furnace, the upper part of the range specified is usually preferred, or even exceeded.
③ Lower end of the range specified for solution annealing should be aimed at the heat treatment as part of further processing,because otherwise the mechanical properties might be affected. If the temperature of hot forming does not drop below the lower temperature for solution annealing, a temperature of 980℃ is adequate as a lower limit for Mo-free steels, a temperature of 1000℃ for steels with Mocontents up to 3 % and a temperature of 1020°C for steels with Mo contents exceeding 3 %.
④ Cooling sufficiently rapidly in order to avoid the occurrence of intergranular corrosion as defined in EN ISO 3651-2. |
