A kind of powder metallurgy planetary gear and preparation method thereof
Technical field
The present invention relates to field of powder metallurgy, be specifically related to a kind of powder metallurgy planetary gear and preparation method thereof.
Background technology
PM technique can reduce the cutting cost significantly with the parts of the shape production requirement high dimensional accuracy extremely close with article shape, complicated shape.Therefore, sintered metal product is as the parts of various machineries, device and utilize in many-side.
Generally speaking, alloy such as mixing graphite powder is with lubricant powders such as powder and stearic acid, paraffin and after forming the iron-based powder mixed powder in the iron-based powder, this iron-based powder mixed powder is filled into metal die, press molding and make powder metallurgical with iron-based powder formed body (press-powder body).Wherein, iron-based powder can be divided into iron powder (straight iron powder etc.), powdered alloy steel etc. according to composition.And iron-based powder also can be divided into atomized iron powder, reduced iron powder etc. according to manufacture method.The density of iron-based powder formed body is generally 6.6-7.1 mg/m3.Further implement sintering processes and form sintered body for these iron-based powder formed bodies, and implement finishing, machining as required and form sintered metal product.When needing to improve hot strength, fatigue strength, also implement carburizing heat treatment, brightness heat treatment behind the sintering.But existing powdered metal parts is because the proportion difference of various raw materials in the prescription, be difficult to guarantee during mixing to mix, cause the density unevenness of the green compact that are pressed into even, by heat treatment, the global density of the part of gained is inhomogeneous, causes every mechanical property bad.
Summary of the invention
The invention provides a kind of powder metallurgy planetary gear and preparation method thereof, with special raw material proportioning and the technology of science, produce the powder metallurgy planetary gear to have wearability good, intensity height, hardness height, machinability are good, corrosion-resistant, be not prone to fracture, the characteristics of long service life.
The technical solution used in the present invention is as follows:
A kind of powder metallurgy planetary gear, it is characterized in that, powder stock compacting by following weight portion forms: iron powder 100, copper powder 1.8-2.0, titanium valve 0.5-0.8, vanadium powder 0.1-0.3, bismuth meal 0.8-1.2, graphite powder 0.5-0.8, modification trees ashes 0.1-0.3, rare earth ferrosilicon alloy 0.2-0.6, paraffin 0.1-0.3, ethylene bis stearic acid amide 0.1-0.2, molybdenum bisuphide 0.1-0.3, alundum (Al 0.2-0.4, boron nitride 0.2-0.4, LiF 0.4-0.5, described rare earth ferrosilicon alloy the trade mark be FeSiRE23, granularity 5-20 mm.
The planetary preparation method of described powder metallurgy is characterized in that, may further comprise the steps:
(1) at first the base-material iron powder of 40-50% is packed in the high-speed mixer, to the silane resin acceptor kh-550 that wherein adds base-material iron powder quality 0.3-0.6%, high-speed stirred 5-6 minute, then with copper powder, titanium valve, vanadium powder, bismuth meal, graphite powder, modification trees ashes powder, paraffin, ethylene bis stearic acid amide and remaining iron powder add wherein successively, the heating of high-speed mixing limit, limit, when temperature is raised to 125-130 ℃, all the other components in will filling a prescription all add wherein, continue again to mix 8-10 minute, allow its cooling then, obtain the uniform iron base powder mixture of density end;
(2) pack in the mould in the iron base powder mixture end that step (1) is obtained, press forming under 550-580Mpa pressure;
(3) green compact of press forming are placed in the sintering furnace, in the protective atmosphere of hydrogen and nitrogen mixture body, it is 1000~1050 ℃ in temperature at first, sintering time is 10-20 minute, then with 10-20 ℃/minute speed rising temperature to 1150-1180 ℃, under this temperature, knot 10-15 minute reburns, room temperature is down in cooling then, is carrying out fine finishining;
(4) carry out Quenching Treatment after the heat treatment fine finishining again, hardening heat is 805~815 ℃, cool time 2-3 hour; Under 500-520 ℃, carry out high tempering then and handle, be incubated 1.5-2 hour; Carry out lonneal at 155~165 ℃ then, 2-3 hour;
(5) the 700 ℃ of carbo-nitridings 50 minutes in atmosphere controlled heat treatment furnace of gas carburizing nitrogen, the powder metallurgy planetary gear after the lonneal are cooled to 120 ℃, are incubated 5-8 hour, then cool to room temperature;
(6) the powder metallurgy planetary gear behind the steam treatment carburizing nitrogen nitrogen carries out steam treatment, and vapor (steam) temperature 600-700 ℃, processing time 3-4 hour, be incubated 2-3 hour down at 200-250 ℃ then, naturally cool to room temperature at last, get final product.
Described powder metallurgy planetary gear is characterized in that, the particle diameter of various metal dusts is in 200-400 order scope in the described raw material.
The planetary preparation method of described powder metallurgy, it is characterized in that, described modification trees ashes powder is prepared from by the following method: with the trees ashes earlier with 25% salt acid soak 30-40 minute, neutralize with alkali lye then, use the deionized water rinsing impurity elimination again, mix again and with small amount of ethanol dissolved dilution NDZ-311 titanate coupling agent, the consumption of NDZ-311 titanate coupling agent is the 1-2% of trees ashes weight, add in the high speed mixer with Sprayable, discharging behind the stirring 15-20min, oven dry grinds to form 300-400 order powder, obtains modification trees ashes powder.
Advantage of the present invention and beneficial effect:
1. powder metallurgy planetary gear of the present invention, adopt substep to mix, guaranteed the density uniformity of finished parts, improved planetary comprehensive mechanical performance, add man-hour, in the operation of mixed-powder material, at first wetting to the part iron powder with coupling agent, and then alloyed powder and lubricant added in the wetting iron powder in proportion mix, adding wherein through remaining iron powder at last, fully mix, the mixed-powder of gained is repressed, sintering, heat treatment, surface treatment obtains final product at last, the powder metallurgy processing technology of employing, significantly reduce manufacturing cost, improved stock utilization and productivity ratio.
2. powder metallurgy planetary gear of the present invention adds the metal dust of different proportion in composition of raw materials, make the planetary gear of preparing reach high strength, the performance of high rigidity and high abrasion; In prescription, add an amount of kollag, increased the self-lubricating property of product; Add an amount of vanadium powder, modification trees ashes powder, improved intensity and anti-wear performance and the self-lubricating property of product.
The specific embodiment
Below by embodiment, the present invention is described in further detail, but the present invention not only is confined to following examples.
Embodiment takes by weighing following raw material (kg) iron powder 100, copper powder 1.9, titanium valve 0.6, vanadium powder 0.2, bismuth meal 1.0, graphite powder 0.7, modification trees ashes 0.2, rare earth ferrosilicon alloy 0.5, paraffin 0.2, ethylene bis stearic acid amide 0.15, molybdenum bisuphide 0.2, alundum (Al 0.3, boron nitride 0.3, LiF 0.45, described rare earth ferrosilicon alloy the trade mark be FeSiRE23, granularity 5-20 mm
The preparation method may further comprise the steps:
(1) at first the base-material iron powder of 40-50% is packed in the high-speed mixer, to the silane resin acceptor kh-550 that wherein adds base-material iron powder quality 0.3-0.6%, high-speed stirred 5-6 minute, then with copper powder, titanium valve, vanadium powder, bismuth meal, graphite powder, modification trees ashes powder, paraffin, ethylene bis stearic acid amide and remaining iron powder add wherein successively, the heating of high-speed mixing limit, limit, when temperature is raised to 125-130 ℃, all the other components in will filling a prescription all add wherein, continue again to mix 8-10 minute, allow its cooling then, obtain the uniform iron base powder mixture of density end;
(2) pack in the mould in the iron base powder mixture end that step (1) is obtained, press forming under 550-580Mpa pressure;
(3) green compact of press forming are placed in the sintering furnace, in the protective atmosphere of hydrogen and nitrogen mixture body, it is 1000~1050 ℃ in temperature at first, sintering time is 10-20 minute, then with 5-8 ℃/minute speed rising temperature to 1150-1180 ℃, under this temperature, knot 10-15 minute reburns, room temperature is down in cooling then, is carrying out fine finishining;
(4) carry out Quenching Treatment after the heat treatment fine finishining again, hardening heat is 805~815 ℃, cool time 2-3 hour; Under 500-520 ℃, carry out high tempering then and handle, be incubated 1.5-2 hour; Carry out lonneal at 155~165 ℃ then, 2-3 hour;
(5) the 700 ℃ of carbo-nitridings 50 minutes in atmosphere controlled heat treatment furnace of gas carburizing nitrogen, the powder metallurgy planetary gear after the lonneal are cooled to 120 ℃, during insulation 5-8, and cool to room temperature then;
(6) the powder metallurgy planetary gear behind the steam treatment carburizing nitrogen nitrogen carries out steam treatment, and vapor (steam) temperature 600-700 ℃, processing time 3-4 hour, be incubated 2-3 hour down at 200-250 ℃ then, naturally cool to room temperature at last, get final product.
The particle diameter of various metal dusts is in 300-400 order scope in the raw material.
Modification trees ashes powder is prepared from by the following method: with the trees ashes earlier with 25% salt acid soak 30-40 minute, neutralize with alkali lye then, use the deionized water rinsing impurity elimination again, mix again and with small amount of ethanol dissolved dilution NDZ-311 titanate coupling agent, the consumption of NDZ-311 titanate coupling agent is the 1-2% of trees ashes weight, adds in the high speed mixer discharging behind the stirring 15-20min with Sprayable, oven dry grinds to form the 300-350 powder, obtains modification trees ashes powder.
The Performance Detection of the powder metallurgical gear that present embodiment makes is as follows:
Tensile strength sigma b (MPa): 785
Yield strength σ s (MPa): 568
Percentage elongation δ 5 (%): 17.1
Contraction percentage of area ψ (%): 36.