CN106048404A - Antifatigue wear-resisting nodular iron casting for car crankshaft and preparation method of antifatigue wear-resisting nodular iron casting - Google Patents

Abstract

The invention discloses an antifatigue wear-resisting nodular iron casting for a car crankshaft and a preparation method of the antifatigue wear-resisting nodular iron casting. The nodular iron casting is prepared from, by weight percent, 3.7%-3.9% of C, 2.1%-2.4% of Si, 0.3%-0.6% of Mn, 0.2%-0.4% of Cr, 0.15%-0.3% of Zr, 0.1%-0.2% of Hf, 0.06%-0.09% of Ce, 0.04%-0.07% of Dy, 0.03%-0.05% of Lu, not larger than 0.04% of P, not larger than 0.03% of S and the balance Fe. Cr, Zr, Hf and other metal elements are added into an alloy, so that the wear resistance of the nodular iron casting is more excellent; and Ce, Dy, Lu and other rare earth elements are added, and therefore the fatigue strength of the nodular iron casting can be remarkably improved to resist fatigue damage. The nodular iron casting for the car crankshaft is high in mechanical strength, excellent in wear resistance and fatigue resistance and long in service life.

Description

A kind of automobile crane resisting fatigue wearable ductile iron part and preparation method thereof

Technical field

The present invention relates to a kind of automobile crane resisting fatigue wearable ductile iron part and preparation method thereof, belong to spheroidal graphite cast-iron Technical field.

Background technology

The birth of automobile has had the history of a century, quickly grows, has the most become the most topmost vehicles With the important driving force spurred economic growth, also it is that people live indispensable important component part.Foundry goods is automobile product One of important composition of parts, cast product application on auto parts and components occupies critical role.The master of automotive castings Want feature be complex-shaped, wall thickness is relatively thin, dimensional accuracy is high, production lot is big, require that reliability is the most high.Automobile will to the greatest extent may be used Low can alleviate own wt, it is desirable to foundry goods should be light, also to have the highest intensity.The material of past many auto parts and components It is casting pig, the most mostly changes nodular iron casting into.

Bent axle is one of critical component of automobile engine, and its performance quality directly affects the life-span of automobile.Bent axle works Time subject big load and the moment of flexure that is continually changing and moment of torsion effect, common failure mode is crooked fatigue fracture and axle journal mill Damaging, therefore, this just requires that bent axle material has the anti-wear performance of higher fatigue strength and excellence.

Summary of the invention

It is an object of the invention to provide a kind of automobile crane resisting fatigue wearable ductile iron part and preparation method thereof.

For achieving the above object, the present invention adopts the following technical scheme that

A kind of automobile crane resisting fatigue wearable ductile iron part, the percentage by weight of its each chemical constituent is: C 3.7-3.9%, Si 2.1-2.4%、Mn 0.3-0.6%、Cr0.2-0.4%、Zr 0.15-0.3%、Hf 0.1-0.2%、Ce0.06-0.09%、Dy 0.04-0.07%, Lu0.03-0.05%, P≤0.04%, S≤0.03%, surplus is Fe.

The preparation method of a kind of car bent axle resisting fatigue wearable ductile iron part, comprises the following steps:

(1) weigh the furnace charges such as the pig iron, steel scrap, molybdenum-iron, ferrochrome, foundry returns to join medium-frequency induction furnace carries out melting, melting Temperature is 1465-1495 DEG C, and after furnace charge all melts, sample analysis also adjusts ferrum liquid composition, is warming up to after reaching requirement 1480-1510 DEG C, be 200-400W at power, and rotating speed is magnetic agitation 14-18min under conditions of 1200-1400r/min, quiet Put 25-40min, come out of the stove；

(2), before ferrum liquid is come out of the stove, first add in the base wells on bag dam, nodularization bag side and be equivalent to ferrum liquid quality 1.3-1.7% Rare earth Mg-Si nodularizer, covers the silico-calcium inovulant being equivalent to ferrum liquid quality 0.4-0.7%, then at inovulant on nodulizer Surface uniformly spreads that last layer is clean, be dried, rustless magnesium iron is considered to be worth doing and consolidated, when ferrum liquid is come out of the stove, by ferrum liquid by lid bag aperture stream Carrying out nodularization and inoculation in entering nodularization bag, temperature controls at 1460-1480 DEG C, after treating spheroidizing reacion, immediately at ferrum Collection swelling perlite powder is spread on liquid surface, is 300-500W at power, and frequency is ultrasonic vibration 25-under conditions of 20-40kHz 45mim, and scratch clean the scum silica frost on ferrum liquid surface, stand 15-25min, then chill block analysis is produced in sampling, and detection nodularization is qualified After can pour into a mould；

(3) before cast, nodularization bag and bag being baked to 830-870 DEG C, pouring temperature controls at 1440-1460 DEG C, cast speed Degree controls at 0.7-0.8kg/s；

(4) foundry goods to moulding by casting carries out heat treatment: first with the ramp of 70-90 DEG C/h to 900-950 DEG C, be incubated 2- 3h, then it is cooled to 450-500 DEG C with the speed of 30-50 DEG C/h, it is incubated 4-5h；Then Cooling Quenching in 20-40 DEG C of warm oil is put into, Cooling 30-50s；Last microwave heating 5-7h under conditions of power is 200-300W, then be the condition of 500-600W at power Lower microwave heating 2-3h, then microwave heating 1-2h under conditions of power is 900-1000W, air cooling of coming out of the stove.

Beneficial effects of the present invention:

The present invention is by adding the metallic elements such as Cr, Zr, Hf in the alloy so that the wearability of nodular iron casting is more excellent, Add the rare earth elements such as Ce, Dy, Lu, the fatigue strength of nodular iron casting can be obviously enhanced, damage with resisting fatigue.The present invention Automobile crane is high by nodular iron casting mechanical strength, and wearability and fatigue resistance are excellent, and service life is long.

Detailed description of the invention

A kind of automobile crane resisting fatigue wearable ductile iron part, the percentage by weight of its each chemical constituent is: C 3.7- 3.9%、Si 2.1-2.4%、Mn 0.3-0.6%、Cr0.2-0.4%、Zr 0.15-0.3%、Hf 0.1-0.2%、Ce0.06- 0.09%, Dy 0.04-0.07%, Lu0.03-0.05%, P≤0.04%, S≤0.03%, surplus is Fe.

The preparation method of a kind of car bent axle resisting fatigue wearable ductile iron part, comprises the following steps:

(1) weigh the furnace charges such as the pig iron, steel scrap, molybdenum-iron, ferrochrome, foundry returns to join medium-frequency induction furnace carries out melting, melting Temperature is 1485 DEG C, and after furnace charge all melts, sample analysis also adjusts ferrum liquid composition, is warming up to 1505 DEG C after reaching requirement, Being 300W at power, rotating speed is magnetic agitation 15min under conditions of 1300r/min, stands 30min, comes out of the stove；

(2), before ferrum liquid is come out of the stove, in the base wells on bag dam, nodularization bag side, the rare earth being equivalent to ferrum liquid quality 1.5% is first added Mg-Si nodularizer, covers the silico-calcium inovulant being equivalent to ferrum liquid quality 0.6% on nodulizer, then uniform on inovulant surface Spread that last layer is clean, be dried, rustless magnesium iron consider and consolidated, when ferrum liquid is come out of the stove, by ferrum liquid by lid bag aperture inflow nodularization bag Inside carrying out nodularization and inoculation, temperature controls at 1470 DEG C, after treating spheroidizing reacion, spreads collection immediately on ferrum liquid surface and expands Crushed crude pearlite, is 400W at power, and frequency is ultrasonic vibration 35mim under conditions of 30kHz, and scratches clean the scum silica frost on ferrum liquid surface, Standing 20min, then chill block analysis is produced in sampling, can pour into a mould after detection nodularization is qualified；

(3) before cast, nodularization bag and bag being baked to 850 DEG C, pouring temperature controls at 1450 DEG C, and poring rate controls 0.7kg/s；

(4) foundry goods to moulding by casting carries out heat treatment: first with the ramp of 80 DEG C/h to 920 DEG C, be incubated 3h, then with 40 DEG C/speed of h is cooled to 480 DEG C, is incubated 4h；Then put into Cooling Quenching in 30 DEG C of warm oil, cool down 40s；At power it is finally Microwave heating 6h under conditions of 250W, then microwave heating 2.5h under conditions of power is 550W, then be the bar of 900W at power Microwave heating 1.5h under part, air cooling of coming out of the stove.

Through inspection, its mechanical property is: tensile strength 846Mpa, yield strength 704Mpa, percentage elongation 11.9%, tired strong Degree 443Mpa.

Claims (2)

1. an automobile crane resisting fatigue wearable ductile iron part, it is characterised in that the percentage by weight of its each chemical constituent For: C 3.7-3.9%, Si 2.1-2.4%, Mn 0.3-0.6%, Cr0.2-0.4%, Zr 0.15-0.3%, Hf 0.1-0.2%, Ce0.06-0.09%, Dy 0.04-0.07%, Lu0.03-0.05%, P≤0.04%, S≤0.03%, surplus is Fe.

2. a preparation method for automobile crane resisting fatigue wearable ductile iron part as claimed in claim 1, its feature exists In comprising the following steps:

Weigh the furnace charges such as the pig iron, steel scrap, molybdenum-iron, ferrochrome, foundry returns to join medium-frequency induction furnace carries out melting, smelting temperature For 1465-1495 DEG C, after furnace charge all melts, sample analysis also adjusts ferrum liquid composition, is warming up to 1480-after reaching requirement 1510 DEG C, be 200-400W at power, and rotating speed is magnetic agitation 14-18min under conditions of 1200-1400r/min, stands 25- 40min, comes out of the stove；

Before ferrum liquid is come out of the stove, in the base wells on bag dam, nodularization bag side, first add the rare earth being equivalent to ferrum liquid quality 1.3-1.7% Mg-Si nodularizer, covers the silico-calcium inovulant being equivalent to ferrum liquid quality 0.4-0.7%, then on inovulant surface on nodulizer Uniformly spread that last layer is clean, be dried, rustless magnesium iron consider and consolidated, when ferrum liquid is come out of the stove, by ferrum liquid by lid bag aperture inflow ball Carrying out nodularization and inoculation in changing bag, temperature controls at 1460-1480 DEG C, after treating spheroidizing reacion, immediately at ferrum liquid table Collection swelling perlite powder is spread in face, is 300-500W at power, and frequency is ultrasonic vibration 25-45mim under conditions of 20-40kHz, and Scratching clean the scum silica frost on ferrum liquid surface, stand 15-25min, then chill block analysis is produced in sampling, can enter after detection nodularization is qualified Row cast；

Before cast, nodularization bag and bag being baked to 830-870 DEG C, pouring temperature controls at 1440-1460 DEG C, poring rate control System is at 0.7-0.8kg/s；

(4) foundry goods to moulding by casting carries out heat treatment: first with the ramp of 70-90 DEG C/h to 900-950 DEG C, be incubated 2- 3h, then it is cooled to 450-500 DEG C with the speed of 30-50 DEG C/h, it is incubated 4-5h；Then Cooling Quenching in 20-40 DEG C of warm oil is put into, Cooling 30-50s；Last microwave heating 5-7h under conditions of power is 200-300W, then be the condition of 500-600W at power Lower microwave heating 2-3h, then microwave heating 1-2h under conditions of power is 900-1000W, air cooling of coming out of the stove.