Choose less distortion of materials, with the correct heat treatment
In order to prevent and reduce distortion, cracking, the need for linear cutting parts, deal with the material selection, heat treatment, heat treatment process each link until the finished should fully concern and attention.
(1) the strict control of material chemical composition, microstructure and inspected, avoid the unqualified raw material and coarse grain steel and harmful impurity content exceed the standard steel mixed.
(2) to the selection of vacuum smelting, refining outside the furnace and electroslag remelting steel, should choose the hardenability is poor, easy distortion to avoid carbon tool steel.
(3) shall comply with reasonable blank forging, upsetting, pull long, appropriate forging ratio forging specification.
(4) the improvement of heat treatment process, the vacuum heating, protective atmosphere heating and fully deoxygenated salt bath furnace heating and quenching, isothermal quenching, cooling rate and cooling medium and ideal choice.
(5) should be timely quenching and tempering steel, try to eliminate quenching stress, reduce the brittleness; longer tempering, improve the fracture toughness of mould; multiple tempering the retained austenite transformation and elimination of fully new stress on die steel, high temperature tempering second temper brittleness after rapid cooling (water or oil cooled).
(6) by diffusion annealing, spheroidization, modulation processing before the heat treatment of die steel chemistry, fully refined primitive organization.