Of high-speed steel W18Cr4V forging
- source:GAENOR CNC Machining
7% ～ 0.
8% ≤ 0.
4% ≤ 0.
8% ～ 4.
5% ～ 19%1.
0% ～ 1.
4% composition characteristic is in steel, carbon is main with chromic, tungsten, molybdenum and vanadium (of carbide form an element) etc form carbide, in order to raise hardness, wearability and red rigid. Tungsten is the main element that raises red rigid, it forms carbide in steel. When heating, dissolve enters one part carbide austenite, after quenching, form contain the alloying element of many tungsten etc, martensite that has stability of very tall temper. When temper, one part tungsten the formal dispersion separate out with carbide, cause sclerosis 2 times. When heat, not the effect that the carbide of dissolve has to prevent austenite grain to be brought up. Vanadium can raise the red rigid of high-speed steel, hardness and wearability significantly. When the carbide that vanadium forms is heating, partial dissolve enters austenite, when temper with petty particle dispersion separate out, cause sclerosis 2 times and raise the red rigid of steel. Chromium basically is to increase its temper by dipping in water to appear a gender in high-speed steel, return what can raise steel to fight oxidation at the same time decarbonization and fight corrode ability. Cobalt also can raise the red rigid of steel and hardness significantly. The website of technology of cutting of constituent structure W18Cr4V(of W18Cr4V steel notes: The current name casting appearance organization for HS18-0-1) includes international those who submit skeletal form, carbide piece the Lai body that shape and martensite or troostite alternate with form, and black is organized (δ slants analyse) organize with white (martensite and leftover austenite) . The casting appearance organization of high-speed steel and chemical composition especially inhomogenous, and heat treatment is unalterable also, must undertake forming consequently, will bulky in all brilliant carbide is broken into pieces, make its distributing equably, next reoccupy reachs a mould with making all sorts of cutting tool. 2, forging when craft high-speed steel heats very incidental burn too, those who approach this temperature range forging to appear very easily disintegrate, should control its strictly to heat temperature. Forging temperature limits W18Cr4V belongs to tall alloy steel, its characteristic is to warm up rate is slow, forging temperature range is narrow. Only then forge temperature is 1100 ～ 1150 ℃ , eventually forge temperature is 900 ～ 950 ℃ . Heat the thermal conductivity of the affirmatory W18Cr4V steel of time is poor, need section to heat commonly. Microtherm paragraph heat temperature is 800 ～ 900 ℃ , heat time is calculated by 1min/mm commonly. Heat quickly when high temperature, heat time is pressed commonly 0.
5min/mm computation. When heating, to prevent overheat or burn too, want to control upper limit temperature strictly. In the meantime, the preform inside furnace should install furnace right amount, keep retroflexioning even, in order to make temperature of its inside and outside even. Forging forginging than steel ingot in the process, its forging than be in 8 above, forging to be in than choosing consequently 5 ～ 7 between can. Increase showing tremendous enthusiasm second decide W18Cr4V steel really increase showing tremendous enthusiasm second unplug by Dui the competence of energy of frequency, facilities and jockey person will decide. The production that comes for years according to us is carried out and ask to the technology of forging, before 3 fire are 3 Dui 3 unplug, or before 4 fire are 4 Dui 4 unplug, figuration of last fire nap. Fire second unfavorable and too much, below probable condition, should reduce fire as far as possible second, lest because forging,fight force,pass big and craze. 3, after the temperature that unit process of cargo bandling heats to ask to craft when preform, begin to forging namely. Before forginging, hammer anvil should warm-up arrives 200 ℃ of 100 ～ , at the same time even the size according to dimension of preform cross section, and ask to the technology of the spare parts, use most appropriate forging craft, namely axial relapses Dui is thick unplug long way, radial " crossed " forging law and 3 unplug to Dui forging law. Answer to be carried out strictly in unit process of cargo bandling " two weigh gently " forging method, should be in namely high temperature paragraph tip wants when 1150 ℃ of 1100 ～ , in order to prevent craze; Should forging temperature is when 1050 ℃ of 1000 ～ want a bang, can break carbide into pieces in order to assure; When forging stock temperature under tip wants when 1000 ℃ , in case inside crackle appears; Come when forging stock thermal drop forge stops when 950 ℃ of 900 ～ . Crackle appears when forginging to avoid, hammer of Dui thick phase is attacked not easy too heavy, when necessary but will carry a department first " riveting forge " hind again Dui is thick, unplug instantly after Dui is thick long. Unplug when growing, feed should be controlled 0 in forging height.
6 ～ 0.
Inside the limits of 8 times. Feed crosses small forge to be not appeared, too big meeting arises " crossed " crackle. Should avoid when Dui is thick bosseyed be out of shape or happen askew. Unplug when growing, retroflexion semifinished product wants even, unplug want to pour wine cup first when the circle, do not be in same place for many times hammer is attacked. When discovery preform appears when tiny flaw, after answering to try in time to eradicate again forge. 4, delay of the Yan Mai in white grey box or dry sandbox should be being put instantly after the refrigeration after forge and anneal forging forge is cold, cannot have appear part. Before forging embedded, white ash or do arenaceous temperature with 100 ～ 200 ℃ are advisable. After small forging forge, oven can be let after the heat preservation inside furnace cold give furnace air to 50 ℃ cold. Anneal should undertake instantly after the common anneal of high-speed steel and isothermal anneal forging are cooling, the purpose of anneal is to eliminate internal stress not only, reduce hardness to be machined at cutting with benefit, also be for at the same time the following quench the primitive microstructure with better preparation. The anneal craft of W18Cr4V has common anneal and isothermal anneal two kinds (see right graph) . 5, epilogue is analysed through the function to W18Cr4V steel, perfected further forging craft, this laid good foundation for the heat treatment of cutting tool not only, and the integrated and mechanical performance that improved W18Cr4 V steel, improved the service life of blade, mould. In recent years, high-speed steel forging of production, won the widespread recognition of the user. CNC Milling CNC Machining