Stainless steel forging blank heating process basic method

Before the stainless steel forging heating furnace are available, and can also use flame furnace. In the production of multi-purpose furnace flame, because of its low cost. Furnace gas should be neutral or slightly oxidizing atmosphere. For austenitic stainless steel, not by reducing atmosphere, lest produce carbon or poor chromium, bring down the intergranular corrosion resistance; For martensitic stainless steel, because of the high carbon content, cannot use excessive oxidation atmosphere, lest cause serious decarburization. Flame furnace heating, should also pay attention to the gas should be keep basically not containing hydrogen sulfide and other sulfur-containing pollutants, especially for high nickel steel, more can't use sulphur content of fuel, as sulfur infiltration in steel to form the NiS with nickel ( Melting point 797 ℃) Or Ni + Ni3S2 eutectic ( Melting point 645 ℃) , it mainly distributed on the grain boundary, the process of stainless steel plastic drop, and forging forming crack. Under 700 ~ 800 ℃, the coefficient of thermal conductivity of stainless steel than ordinary small coefficient of thermal conductivity of alloy steel. However, the coefficient of thermal conductivity of stainless steel is increased with the increase of temperature increase, in the range of 700 ~ 800 ℃ and the coefficient of thermal conductivity of ordinary alloy steel consistent. The blank, as a result, 100 mm in diameter are two heating system should be adopted: in the preheat phase, keep temperature of 800 ~ 850 ℃ with slow heating speed; In heating and soaking phase, high temperature ( Initial forging temperature limit) In order to be able to quickly heated to forging temperature. Higher requirements for surface quality of precision forging, or allowance for smaller important forgings, such as compressor blade, before heating often on a rough surface with a layer of protective coatings ( Glass lubricant) And then within the ordinary furnace heating. Glass can protect metals from oxidation protective coating and pollution, at the same time, it was forging processing lubricant. Stainless steel heating time can press 0. 3 to 0. 5 min/mm calculation.