The preparation method of the black cast iron of bent axle
Technical field
The present invention relates to spheroidal graphite cast-iron field, and in particular to a kind of preparation method of the black cast iron of bent axle.
Background technology
Spheroidal graphite cast-iron is to obtain globular graphite by nodularization and inoculation, is effectively improved the mechanical performance of cast iron,
Plasticity and toughness are in particular improved, so as to obtain than carbon steel also high intensity.Spheroidal graphite cast-iron is from 20th century the fifties hair
A kind of high-strength cast iron material that exhibition is got up, its combination property is based on its excellent performance, successfully used close to steel
In casting, some stress are complicated, and intensity, toughness, wearability require higher part.Spheroidal graphite cast-iron has developed rapidly to be only second to
Gray cast iron, using quite varied cast iron materials.So-called " with iron for steel ", refers mainly to spheroidal graphite cast-iron.
Bent axle is one of critical component of engine, bent axle operationally bear big load and the moment of flexure that is continually changing and
Moment of torsion is acted on, and the strength and stiffness of bent axle have decisive influence to the reliability of engine.The common failure mode of bent axle has by force
Fatigue fracture and the low abrasion caused of hardness number caused by angle value is not enough.It is therefore desirable to bent axle material have higher rigidity and
Fatigue strength and good anti-wear performance.With the development of spheroidal graphite cast-iron technology, its performance is also being improved constantly, and high-quality is cheap
Spheroidal graphite cast-iron turn into one of important materials of manufacture bent axle.There are distinct issues and be not in existing ductile iron crankshaft
Can ensure high intensity while have high toughness concurrently, so the characteristic of the manufacture material of existing ductile iron crankshaft in itself into
For restriction high speed, high power, realize that energy-saving and emission-reduction develop the primary factor of purpose.The A of Chinese patent CN 103388112 are public
A kind of " component and its production method of ductile iron crankshaft " is opened, the spheroidal graphite cast-iron has good intensity and toughness, and
While the nodular cast iron of high-intensity high-tenacity is prepared, the problem of control production cost also turns into urgent need to resolve.
The content of the invention
The invention provides a kind of preparation method of nodular cast iron for crank shaft, the nodular cast iron for crank shaft has high-strength
Degree, high tenacity, while having higher rigidity and wearability.
To realize object above, the present invention is achieved by the following technical programs:
A kind of nodular cast iron for crank shaft, the mass percent of its each element composition is:C:3.6-3.8%, Si:1.9-
2.2%, Mn:0.4-0.6%, Cu:0.4-0.7%, Mg:0.03-0.035%, Sn:0.02-0.03%, Ni:0.04-
0.06%, Ge:0.005-0.015%, Sb:0.004-0.005%, P:≤ 0.03%, S:≤ 0.01%, surplus is Fe.
Preferably, the mass percent of each element composition is in the nodular cast iron for crank shaft:C:3.7%, Si:2.1%,
Mn:0.5%, Cu:0.55%, Mg:0.03%, Sn:0.025%, Ni:0.05%, Ge:0.01%, Sb:0.0045%, P:≤
0.03%, S:≤ 0.01%, surplus is Fe.
The preparation method of nodular cast iron for crank shaft, specifically includes following steps:
(1) raw material melting:The pig iron, high-quality carbon structure steel scrap are sequentially added in medium-frequency induction furnace and dissolved, is melted
It is 1450-1500 DEG C to ensure molten iron temperature during refining, then again adds the copper ingot got ready, nickel ingot in stove, in detection molten iron
The content of each element, and each element content is adjusted to recipe requirements are met, then carry out desulfurization process;
(2) spheroidising and inoculation:It is well mixed after magnesium-rare earth nodulizer and carburant are crushed, plus
Enter into nodularization bag, spheroidising is carried out using lid bag method, then carry out current-following inoculation, complete inoculation, cast;
(3) it is heat-treated:A, normalizing:The spheroidal graphite cast-iron of casting is gone out at 800-820 DEG C of temperature after shell to carry out automatic
Rotating spraying is cooled down;B, quenching:Casting after cooling is heated to after 900-940 DEG C, insulation 2-3h, with 18-22 DEG C/s speed
Degree is cooled to 400-450 DEG C, is incubated after 1-2h, is put into 250-300 DEG C of salt bath at 400-450 DEG C, is incubated 1-1.5h,
Room temperature is air-cooled to again, obtains the nodular cast iron for crank shaft.
Preferably, the weight ratio of the pig iron and high-quality carbon structure steel scrap is 1-3 in the step (1):10-12.
Preferably, the addition of the nodulizer is the 1.1-1.2% of molten iron gross weight.
Preferably, the mass percent of each element composition is in the inovulant:Si:40-48%, Ca:2-3%, Ba:
0.2-0.4%, Mn:4-5%, Sn:0.4-0.6%, surplus is iron.
Beneficial effects of the present invention are:Carburant is placed in sealing nodularization bag by the present invention, and nodulizer meets high temperature iron aquatic products
Pressure moment rises in raw a large amount of magnesium vapors, bag, forms malleation anaerobic state, can anti-oxidation it is excessive and carburetting effect occur not
The obvious and inadequate situation of casting carbon content, drastically reduce the area pig iron consumption.And use lid bag method to carry out spheroidising, prevent
The oxidization burning loss of magnesium, spheroidizing quality is stably and controllable, while reducing nodulizer consumption.Germanium and nickel are added in formula, can be increased
Rigidity, intensity and the toughness of spheroidal graphite cast-iron.Tin is formulated into inovulant, the alloying action of tin has not only been given full play to, again
Pregnant effect is enhanced, while changing the microstructure segregation state of copper, makes distribution of the element in material matrix more uniform.This
Invention first obtains the main spheroidal graphite casting containing pearlite using normalizing, then makes after special hardening the intensity, tough of spheroidal graphite casting
Property and wearability have further raising compared with traditional handicraft.The present invention passes through reasonable disposition each element composition, obtained ball
Black cast iron has high intensity, a high tenacity, and with higher rigidity and wearability, improves the bearing capacity of bent axle and reliable
Property, service life extension, while reducing production cost by optimizing preparation method, improves production efficiency.
Embodiment
The technical solution of the present invention is further illustrated with reference to specific embodiment, embodiment is not to be construed as pair
The limitation of technical solution.
Embodiment 1:
A kind of nodular cast iron for crank shaft, the mass percent of its each element composition is:C:3.7%, Si:2.1%, Mn:
0.5%, Cu:0.55%, Mg:0.03%, Sn:0.025%, Ni:0.05%, Ge:0.01%, Sb:0.0045%, P:≤
0.03%, S:≤ 0.01%, surplus is Fe.
The preparation method of nodular cast iron for crank shaft, specifically includes following steps:
(1) raw material melting:The pig iron, high-quality carbon structure steel scrap are sequentially added in medium-frequency induction furnace and dissolved, is melted
It is 1500 DEG C to ensure molten iron temperature during refining, then again adds the copper ingot got ready, nickel ingot in stove, each element in detection molten iron
Content, and adjust each element content to recipe requirements are met, then carry out desulfurization process;
(2) spheroidising and inoculation:The magnesium-rare earth nodulizer and carburant of molten iron gross weight 1.1% are carried out
It is well mixed, is added in nodularization bag after crushing, spheroidising is carried out using lid bag method, then carry out current-following inoculation, completes pregnant
Processing is educated, is poured into a mould;
(3) it is heat-treated:A, normalizing:The spheroidal graphite cast-iron of casting is gone out at 820 DEG C of temperature after shell to carry out automatic rotary turn
Misting cooling;B, quenching:Casting after cooling is heated to after 900 DEG C, insulation 3h, 400 DEG C are cooled to 22 DEG C/s speed,
It is incubated at 400 DEG C after 1h, in the salt bath for being put into 300 DEG C, is incubated 1h, then be air-cooled to room temperature, is obtained the bent axle and cast with spheroidal graphite
Iron.
The weight ratio of the pig iron and high-quality carbon structure steel scrap is 1 in the step (1):12.
The mass percent of each element composition is in the inovulant:Si:40%, Ca:3%, Ba:0.4%, Mn:4%,
Sn:0.6%, surplus is iron.
Embodiment 2:
A kind of nodular cast iron for crank shaft, the mass percent of its each element composition is:C:3.8%, Si:1.9%, Mn:
0.6%, Cu:0.4%, Mg:0.035%, Sn:0.02%, Ni:0.06%, Ge:0.005%, Sb:0.005%, P:≤
0.03%, S:≤ 0.01%, surplus is Fe.
The preparation method of nodular cast iron for crank shaft, specifically includes following steps:
(1) raw material melting:The pig iron, high-quality carbon structure steel scrap are sequentially added in medium-frequency induction furnace and dissolved, is melted
It is 1450 DEG C to ensure molten iron temperature during refining, then again adds the copper ingot got ready, nickel ingot in stove, each element in detection molten iron
Content, and adjust each element content to recipe requirements are met, then carry out desulfurization process;
(2) spheroidising and inoculation:The magnesium-rare earth nodulizer and carburant of molten iron gross weight 1.2% are carried out
It is well mixed, is added in nodularization bag after crushing, spheroidising is carried out using lid bag method, then carry out current-following inoculation, completes pregnant
Processing is educated, is poured into a mould;
(3) it is heat-treated:A, normalizing:The spheroidal graphite cast-iron of casting is gone out at 800 DEG C of temperature after shell to carry out automatic rotary turn
Misting cooling;B, quenching:Casting after cooling is heated to after 940 DEG C, insulation 2h, 450 DEG C are cooled to 18 DEG C/s speed,
It is incubated at 450 DEG C after 2h, in the salt bath for being put into 250 DEG C, is incubated 1.5h, then be air-cooled to room temperature, obtains the bent axle spheroidal graphite
Cast iron.
The weight ratio of the pig iron and high-quality carbon structure steel scrap is 3 in the step (1):10.
The mass percent of each element composition is in the inovulant:Si:48%, Ca:2%, Ba:0.2%%, Mn:
5%, Sn:0.4%, surplus is iron.
Embodiment 3:
A kind of nodular cast iron for crank shaft, the mass percent of its each element composition is:C:3.6%, Si:2.2%, Mn:
0.4%, Cu:0.7%, Mg:0.03%, Sn:0.03%, Ni:0.04%, Ge:0.015%, Sb:0.004%, P:≤
0.03%, S:≤ 0.01%, surplus is Fe.
The preparation method of nodular cast iron for crank shaft, specifically includes following steps:
(1) raw material melting:The pig iron, high-quality carbon structure steel scrap are sequentially added in medium-frequency induction furnace and dissolved, is melted
It is 1480 DEG C to ensure molten iron temperature during refining, then again adds the copper ingot got ready, nickel ingot in stove, each element in detection molten iron
Content, and adjust each element content to recipe requirements are met, then carry out desulfurization process;
(2) spheroidising and inoculation:The magnesium-rare earth nodulizer and carburant of molten iron gross weight 1.15% are entered
Row is well mixed after crushing, and is added in nodularization bag, is carried out spheroidising using lid bag method, is then carried out current-following inoculation, is completed
Inoculation, cast;
(3) A, normalizing:Going out after shell to carry out automatic rotary at 800 DEG C of temperature by the spheroidal graphite cast-iron of casting, to turn spraying cold
But;B, quenching:Casting after cooling is heated to after 920 DEG C, insulation 3h, 420 DEG C are cooled to 20 DEG C/s speed, then at
It is incubated at 420 DEG C after 1.5h, in the salt bath for being put into 280 DEG C, is incubated 1h, then be air-cooled to room temperature, obtains the nodular cast iron for crank shaft.
The weight ratio of the pig iron and high-quality carbon structure steel scrap is 1 in the step (1):11.
The mass percent of each element composition is in the inovulant:Si:45%, Ca:2.5%, Ba:0.3%, Mn:
4%, Sn:0.6%, surplus is iron.
Embodiment 4:
A kind of nodular cast iron for crank shaft, the mass percent of its each element composition is:C:3.6%, Si:1.9%, Mn:
0.6%, Cu:0.6%, Mg:0.035%, Sn:0.03%, Ni:0.04%, Ge:0.01%, Sb:0.004%, P:≤
0.03%, S:≤ 0.01%, surplus is Fe.
The preparation method of nodular cast iron for crank shaft, specifically includes following steps:
(1) raw material melting:The pig iron, high-quality carbon structure steel scrap are sequentially added in medium-frequency induction furnace and dissolved, is melted
It is 1450 DEG C to ensure molten iron temperature during refining, then again adds the copper ingot got ready, nickel ingot in stove, each element in detection molten iron
Content, and adjust each element content to recipe requirements are met, then carry out desulfurization process;
(2) spheroidising and inoculation:The magnesium-rare earth nodulizer and carburant of molten iron gross weight 1.15% are entered
Row is well mixed after crushing, and is added in nodularization bag, is carried out spheroidising using lid bag method, is then carried out current-following inoculation, is completed
Inoculation, cast;
(3) A, normalizing:Going out after shell to carry out automatic rotary at 820 DEG C of temperature by the spheroidal graphite cast-iron of casting, to turn spraying cold
But;B, quenching:Casting after cooling is heated to after 900 DEG C, insulation 2.5h, 400 DEG C are cooled to 18 DEG C/s speed, then at
It is incubated at 400 DEG C after 1-2h, in the salt bath for being put into 250 DEG C, is incubated 1.5h, then be air-cooled to room temperature, is obtained the bent axle and cast with spheroidal graphite
Iron.
The weight ratio of the pig iron and high-quality carbon structure steel scrap is 2 in the step (1):12.
The mass percent of each element composition is in the inovulant:Si:48%, Ca:3%, Ba:0.2%, Mn:4%,
Sn:0.6%, surplus is iron.
Embodiment 5:
A kind of nodular cast iron for crank shaft, the mass percent of its each element composition is:C:3.8%, Si:2.2%, Mn:
0.5%, Cu:0.6%, Mg:0.035%, Sn:0.02%, Ni:0.06%, Ge:0.015%, Sb:0.0045%, P:≤
0.03%, S:≤ 0.01%, surplus is Fe.
The preparation method of nodular cast iron for crank shaft, specifically includes following steps:
(1) raw material melting:The pig iron, high-quality carbon structure steel scrap are sequentially added in medium-frequency induction furnace and dissolved, is melted
It is 1460 DEG C to ensure molten iron temperature during refining, then again adds the copper ingot got ready, nickel ingot in stove, each element in detection molten iron
Content, and adjust each element content to recipe requirements are met, then carry out desulfurization process;
(2) spheroidising and inoculation:The magnesium-rare earth nodulizer and carburant of molten iron gross weight 1.1% are carried out
It is well mixed, is added in nodularization bag after crushing, spheroidising is carried out using lid bag method, then carry out current-following inoculation, completes pregnant
Processing is educated, is poured into a mould;
(3) A, normalizing:Going out after shell to carry out automatic rotary at 810 DEG C of temperature by the spheroidal graphite cast-iron of casting, to turn spraying cold
But;B, quenching:Casting after cooling is heated to after 940 DEG C, insulation 3h, 450 DEG C are cooled to 22 DEG C/s speed, then at
It is incubated at 450 DEG C after 1h, in the salt bath for being put into 300 DEG C, is incubated 1.5h, then be air-cooled to room temperature, obtains the nodular cast iron for crank shaft.
The weight ratio of the pig iron and high-quality carbon structure steel scrap is 1 in the step (1):10.
The mass percent of each element composition is in the inovulant:Si:40%, Ca:2%th, Ba:0.34%, Mn:5%,
Sn:0.5%, surplus is iron.
Performance test:To carrying out performance test, after testing, this hair as the nodular cast iron for crank shaft obtained by embodiment 1-5
The tensile strength of bright nodular cast iron for crank shaft is 920-940MPa, and yield strength is 615-625MPa, and elongation percentage is 5-7%, tough
Property is 39-42J/cm2, nodulizing grade is 1-2 grades.