CN108085578A - A kind of automobile gear special steel and its production technology - Google Patents
A kind of automobile gear special steel and its production technology Download PDFInfo
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- CN108085578A CN108085578A CN201711406510.9A CN201711406510A CN108085578A CN 108085578 A CN108085578 A CN 108085578A CN 201711406510 A CN201711406510 A CN 201711406510A CN 108085578 A CN108085578 A CN 108085578A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/56—Manufacture of steel by other methods
- C21C5/567—Manufacture of steel by other methods operating in a continuous way
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
Abstract
The invention belongs to special steel technical field of smelting, and in particular to a kind of automobile gear special steel and its production technology.The production technology of gear special steel of the present invention includes pneumatic steelmaking → LF refining → RH vacuum outgas → billet continuous casting → slow cooling.The present invention is by further improving the degree of purity of automobile gear special steel to the optimization of the techniques such as LF refining deoxidation mode, RH vacuum outgas argon flow amount, soft blow time, billet continuous casting electromagnetic agitation mode and parameter, the degree of superheat and pulling rate and reducing its carbon segregation degree, stablize the narrow hardenability band of pinion steel, meet car transmissions material to high bearing capacity, high-precision, high reliability development trend, improve competitiveness of the domestic automobile with pinion steel in the international market.
Description
Technical field
The invention belongs to special steel technical field of smelting, and in particular to a kind of automobile gear special steel and its production work
Skill.
Background technology
China's automobile production in 2016, pin break through 28,000,000, and the continuous 8 years whole world first, huge automobile demand amount is to vapour
Automobile-used steel brings considerable market, at the same time with the development of science and technology domestic and international automobile positive and operates steadily, comfortably pacifies
Loopful is protected light-weighted direction and is developed, and automobile steel quality requirements are also continuously improved, and gear is the component of automobile important core,
Play a part of gearing, be subject to a variety of stress during the work time, therefore it is required that automobile gear possesses with special steel
High-strength tenacity, fatigue strength and good uniformity.Since gear needs to carry out quenching treatment in process, therefore it is required that
The high chemical composition of gear special steel uniformly, higher degree of purity and possess narrow hardenability band, how by optimizing vapour
The smelting process of skiving wheel special steel makes its chemical composition evenly, has higher degree of purity and possesses narrow hardenability band
It is special steel technical field of smelting urgent problem to be solved.
The content of the invention
To solve above-mentioned the deficiencies in the prior art, the present invention provides a kind of automobile gear special steel and its production works
Skill.
Technical solution of the present invention：
A kind of chemical composition percentage composition by weight of automobile gear special steel includes：C：0.12~0.18%, Si：
0.15~0.35%, Mn：0.55~0.90%, P≤0.030%, S≤0.025%, Cr：0.85~1.25%, Mo：0.10~
0.25%th, Ni≤0.25%, Cu≤0.30%, Al：0.020~0.040%, remaining is Fe and inevitable impurity.
A kind of production technology of automobile gear special steel includes pneumatic steelmaking → LF refining → RH vacuum outgas → square billet
Continuous casting → slow cooling, wherein：
In convertor steelmaking process：
Converter tapping steel ladle full argon bottom-blowing, strong mixing is changed to soft stirring afterwards for a period of time until molten steel enters LF refining
Position；When the weight percentage of carbon in molten steel and phosphorus reaches converter terminal requirement, start to tap at a certain temperature；Converter goes out
Steel to molten steel total weight half when, add in lime, lab-prepared refining slag, top slag modifier and aluminium cake；
During LF refining：
Under certain argon flow amount argon gas stream is heightened in line or after LF feed aluminum steel into the molten steel after converter tapping
Amount carries out alloying operation and recarburization practice successively；After the completion of alloying and recarburization practice, reduce argon flow amount and whole process is stringent
Control argon flow amount；The content of aluminium in sampling analysis molten steel, and by way of mending and feeding aluminum steel the aluminium in molten steel is made to reach certain
Weight percentage；The time that white slag refines is controlled to realize the purpose of deoxidation of molten steel by adding deoxidier into molten steel,
Deoxidier is aluminum shot before sampling, and deoxidier is ferrosilicon powder and carbon dust after sampling；
In RH Vacuum Degassing Process：
After feeding aluminum steel and silicon-calcium wire into the molten steel after LF refining, vacuum circular flow one is carried out under certain final vacuum
It fixes time, during which strictly controls argon flow amount；Argon flow amount is reduced after vacuum circular flow to start to molten steel soft blow certain time；
During billet continuous casting：
Molten steel whole process after soft blow is poured into a mould under protection of argon gas, to molten steel using M-EMS and end electricity
The mode that is combined of magnetic stirring is stirred, and controls certain continuous casting degree of superheat in casting process, crystallizer cooling water flow and
Pulling rate.
Further, the flow velocity of argon bottom-blowing strong mixing described in convertor steelmaking process and air pressure be 400~600L/min,
8.0~10.0bar, strong mixing time are 15min；The flow velocity of the weak stirring of argon bottom-blowing and air pressure be 50~250L/min,
1.0~4.0bar.
Further, reach described in convertor steelmaking process the weight percentage of the carbon of converter terminal for 0.05~
0.07%, the weight percentage of phosphorus is less than 0.010%, and the tapping temperature is 1640~1660 DEG C；The lime addition
It measures as 6~7Kg/t, lab-prepared refining slag additive amount is 2Kg/t, and top slag modifier additive amount is 1Kg/t, and aluminium cake additive amount is 1.2-
1.5Kg/t。
Further, amount that is described online or feeding aluminum steel at LF is 300m during LF refining, described to feed aluminum steel mistake
Argon flow amount in journey is 120~200L/min；Argon flow amount during the alloying and carburetting is 360~600L/
Min, the alloying in controlling the weight percentage of each chemical composition control standard be Si：0.17~0.35%, Mn：0.65
~0.90%, P≤0.025%, S≤0.025%, Cr：0.90~1.25%, Mo：0.15~0.25%, Ni≤0.25%, Cu
≤ 0.20%；It is C that the weight percentage of carbon, which controls standard, during the carburetting controls：0.13~0.17%, the recarburization practice
Preceding guarantee liquid steel temperature is 1550 DEG C.
Further, during LF refining in the sampling analysis molten steel aluminium content, when the weight percentage of aluminium is
When less than 0.060%, the weight percentage for mending hello aluminum steel to aluminium reaches 0.070%；The whole stringent control argon flow amount
For argon flow amount is controlled by 120~200L/min to before sampling after the completion of alloying and recarburization practice, press 120 after sampling~
180L/min is controlled；The time of the white slag refining is 20~30min.
Further, it is to reach the weight percentage of aluminium in molten steel aluminum steel to be fed described in RH Vacuum Degassing Process
0.040%, the amount for feeding silicon-calcium wire is 2.5m/t.
Further, final vacuum described in RH Vacuum Degassing Process is 67Pa, the vacuum circular flow time for 18~
25min, wherein argon flow amount is 1800L/min in 0~12min, argon flow amount is 1200L/min after 12min, the soft blow
When argon flow amount be 50~90L/min, it is not exposed with molten steel, top of the slag fine motion be standard, the soft blow time be 20~30min.
Further, the M-EMS parameter is 500A/3.0Hz during billet continuous casting, and agitating mode is adopted
With alternative expression electromagnetic agitation；The end stirring parameter is 400A/8.0Hz, and agitating mode is stirred using Continuous Electromagnetic.
Further, the continuous casting degree of superheat is 20~35 DEG C during billet continuous casting, the crystallizer cooling water flow
For 2375~2425L/min；The pulling rate is in 0.75m/min under 25~40 DEG C of working condition for molten steel overheat.
Advantageous effect of the present invention：
First, the present invention is by the argon bottom-blowing in the adjustment of deoxidation mode, RH Vacuum Degassing Process during LF refining
The variation control and the adjustment of soft blow time of flow further reduce the field trash in molten steel, improve Molten Steel Cleanliness, into
And improve the fatigue life of automobile steel parts；
2nd, the present invention passes through to the adjustment of electromagnetic agitation mode, crystallizer cooling water flow, overheat in square billet casting process
The adjustment of the control range of degree and the technological parameter of pulling rate effectively increases the uniformity of chemical composition in steel billet, reduces finished product and rolls
Material carbon segregation index, and then stabilize the narrow hardenability band of automobile gear special steel；
3rd, the present invention stablizes pinion steel by promoting the degree of purity of automobile gear special steel and controlling its carbon segregation
Narrow hardenability band meets car transmissions material to high bearing capacity, high-precision, high reliability development trend, improves state
Produce the competitiveness of pinion steel for vehicles in the international market.
Description of the drawings
Fig. 1 is the cross-sectional fabric section intercept method schematic diagram of continuous casting square billet；
Fig. 2 is the sampling standard schematic diagram of the cross-sectional fabric section carbon segregation detection of continuous casting square billet；
Fig. 3 is the sampling standard schematic diagram of finished product bar cross section carbon segregation detection.
Specific embodiment
Technical scheme is described further with reference to embodiment, but is not limited thereto, it is every right
Technical solution of the present invention is modified or replaced equivalently, and without departing from the spirit and scope of technical solution of the present invention, should all be contained
It covers in protection scope of the present invention.
Embodiment 1
A kind of chemical composition percentage composition by weight of automobile gear special steel of the present embodiment includes：C：0.12~
0.18%th, Si：0.15~0.35%, Mn：0.55~0.90%, P≤0.030%, S≤0.025%, Cr：0.85~1.25%,
Mo：0.10~0.25%, Ni≤0.25%, Cu≤0.30%, Al：0.020~0.040%, remaining is Fe and inevitable miscellaneous
Matter.
A kind of automobile gear of the present embodiment is taken off with the production technology of special steel including pneumatic steelmaking → LF refining → RH vacuum
Gas → billet continuous casting → slow cooling, wherein：
In convertor steelmaking process：
Converter tapping steel ladle full argon bottom-blowing, strong mixing is changed to soft stirring afterwards for a period of time until molten steel enters LF refining
Position；When the weight percentage of carbon in molten steel and phosphorus reaches converter terminal requirement, start to tap at a certain temperature；Converter goes out
Steel to molten steel total weight half when, add in lime, lab-prepared refining slag, top slag modifier and aluminium cake；
During LF refining：
Under certain argon flow amount argon gas stream is heightened in line or after LF feed aluminum steel into the molten steel after converter tapping
Amount carries out alloying operation and recarburization practice successively；After the completion of alloying and recarburization practice, reduce argon flow amount and whole process is stringent
Control argon flow amount；The content of aluminium in sampling analysis molten steel, and by way of mending and feeding aluminum steel the aluminium in molten steel is made to reach certain
Weight percentage；The time that white slag refines is controlled to realize the purpose of deoxidation of molten steel by adding deoxidier into molten steel,
Deoxidier is aluminum shot before sampling, and deoxidier is ferrosilicon powder and carbon dust after sampling；
In RH Vacuum Degassing Process：
After feeding aluminum steel and silicon-calcium wire into the molten steel after LF refining, vacuum circular flow one is carried out under certain final vacuum
It fixes time, during which strictly controls argon flow amount；Argon flow amount is reduced after vacuum circular flow to start to molten steel soft blow certain time；
During billet continuous casting：
Molten steel whole process after soft blow is poured into a mould under protection of argon gas, to molten steel using M-EMS and end electricity
The mode that is combined of magnetic stirring is stirred, and controls certain continuous casting degree of superheat in casting process, crystallizer cooling water flow and
Pulling rate.
Embodiment 2
The chemical composition percentage composition by weight of High-quality automobile gear special steel provided in this embodiment includes：C：
0.12~0.18%, Si：0.15~0.35%, Mn：0.55~0.90%, P≤0.030%, S≤0.025%, Cr：0.85~
1.25%th, Mo：0.10~0.25%, Ni≤0.25%, Cu≤0.30%, Al：0.020~0.040%, remaining is Fe and can not
Avoid impurity.
The production technology of High-quality automobile gear special steel provided in this embodiment, it is characterised in that the production technology
Including pneumatic steelmaking → LF refining → RH vacuum outgas → billet continuous casting → slow cooling, wherein：
In convertor steelmaking process：
Converter smelting iron and steel stock uses molten iron and high-quality steel scrap of the total weight for 100t, converter tapping steel ladle full BOTTOM ARGON BLOWING
Gas uses argon flow amount as 400~600L/min, and air pressure carries out strong mixing for 8.0~10.0bar, is changed to after strong mixing 15min
50~250L/min of argon flow amount, 1.0~4.0bar carry out soft stirring until molten steel enters LF refining position；When the weight of carbon in molten steel
It is 0.05~0.07% to measure percentage composition, and the weight percentage of phosphorus reaches BOF Steelmaking Endpoint for less than 0.010%,
Start to tap at a temperature of 1640~1660 DEG C；By 6~7Kg/t of lime-crushed stone pile, lab-prepared refining slag additive amount during converter tapping 50t
2Kg/t, top slag modifier additive amount 1Kg/t, aluminium cake additive amount 1.2-1.5Kg/t added in into molten steel lime, lab-prepared refining slag,
Top slag modifier and aluminium cake make the substance of above-mentioned addition and mixing of molten steel uniform using the impact of molten steel when tapping；
During LF refining：
Aluminum steel 300m are fed online or at LF into the molten steel after converter tapping, argon flow amount is 120~200L/ at this time
Argon flow amount after completing the operation of feeding aluminum steel is heightened to 360~600L/min, carries out alloying operation and increasing successively by min
Carbon operates, alloying in control the weight percentage of each chemical composition control standard as Si：0.17~0.35%, Mn：0.65
~0.90%, P≤0.025%, S≤0.025%, Cr：0.90~1.25%, Mo：0.15~0.25%, Ni≤0.25%, Cu
≤ 0.20%, it is C that the weight percentage of carbon, which controls standard, during carburetting controls：0.13~0.17%, ensure steel before recarburization practice
Coolant-temperature gage is 1550 DEG C；After the completion of alloying and recarburization practice, argon flow amount is reduced to 120~200L/min；Sampling analysis steel
The content of aluminium in water, when the weight percentage of aluminium is less than 0.060%, the weight percentage for mending hello aluminum steel to aluminium reaches
0.070%；Argon flow amount is controlled by 120~180L/min after sampling, by adding deoxidier into molten steel white slag is controlled to refine
Time is 20~30min to realize the purpose of deoxidation of molten steel, and deoxidier is aluminum shot before sampling, after sampling deoxidier for ferrosilicon powder and
Carbon dust；
Argon flow amount is adjusted by observing the diameter of the exposed liquid level of molten steel in ladle during LF refining, in ladle
The diameter criteria of the exposed liquid level of molten steel is 100~200mm, and area is excessive, and appropriate reduction argon flow amount avoids molten steel from being connect with air
It touches and excessively generates new field trash, area is too small, properly increases argon flow amount and ensures argon gas mixing effect；
In RH Vacuum Degassing Process：
Aluminum steel is fed into the molten steel after LF refining makes the weight percentage of aluminium in molten steel reach 0.040%, feeds silicon
The amount of calcium line is 2.5m/t；After the completion of the operation for feeding aluminum steel and silicon-calcium wire, vacuum circular flow is carried out under 67Pa final vacuums
18~25min, wherein argon flow amount is 1800L/min in 0~12min, argon flow amount is 1200L/min after 12min；Vacuum
Argon flow amount is down to 50~90L/min after circulation to start to carry out soft blow to molten steel, not exposed with molten steel, top of the slag fine motion is
Standard, soft blow time are 20~30min；
During billet continuous casting：
Molten steel whole process is poured into a mould under protection of argon gas after soft blow, to molten steel using M-EMS and end electromagnetism
It stirs the mode being combined to be stirred, M-EMS parameter is 500A/3.0Hz, and agitating mode is using alternative expression electricity
Magnetic stirs, and end stirring parameter is 400A/8.0Hz, and agitating mode is stirred using Continuous Electromagnetic；It is controlled in casting process
The continuous casting degree of superheat is 20~35 DEG C, and crystallizer cooling water flow is 2375~2425L/min；Pulling rate is in 25 for molten steel overheat
0.75m/min under~40 DEG C of working condition.
Continuous casting square billet transverse cross-sectional size obtained be 250mm × 280mm, after continuous casting billet is entered to burial pit slow cooling in time, delay
Cool time is 48h.
Embodiment 3
The chemical composition percentage composition by weight of High-quality automobile gear special steel provided in this embodiment includes：C：
0.12~0.18%, Si：0.15~0.35%, Mn：0.55~0.90%, P≤0.030%, S≤0.025%, Cr：0.85~
1.25%th, Mo：0.10~0.25%, Ni≤0.25%, Cu≤0.30%, Al：0.020~0.040%, remaining is Fe and can not
Avoid impurity.
The production technology of High-quality automobile gear special steel provided in this embodiment, it is characterised in that the production technology
Including pneumatic steelmaking → LF refining → RH vacuum outgas → billet continuous casting → slow cooling, wherein：
In convertor steelmaking process：
Converter smelting iron and steel stock uses molten iron and high-quality steel scrap of the total weight for 100t, converter tapping steel ladle full BOTTOM ARGON BLOWING
Gas uses argon flow amount as 500L/min, and air pressure carries out strong mixing for 9.0bar, and argon flow amount is changed to after strong mixing 15min
200L/min, 3.0bar carry out soft stirring until molten steel enters LF refining position；When the weight percentage of carbon in molten steel is
0.06%, the weight percentage of phosphorus reaches BOF Steelmaking Endpoint for less than 0.010%, starts at a temperature of 1650 DEG C
Steel；Lime-crushed stone pile 7Kg/t, lab-prepared refining slag additive amount 2Kg/t, top slag modifier additive amount 1Kg/ are pressed during converter tapping 50t
T, aluminium cake additive amount 1.3Kg/t add in lime, lab-prepared refining slag, top slag modifier and aluminium cake into molten steel；
During LF refining：
Aluminum steel 300m are fed online or at LF into the molten steel after converter tapping, argon flow amount is 150L/min at this time,
Argon flow amount is heightened to 450L/min after completing the operation of feeding aluminum steel, alloying operation and recarburization practice is carried out successively, closes
Aurification in controlling the weight percentage of each chemical composition control standard be Si：0.17~0.35%, Mn：0.65~0.90%, P
≤ 0.025%, S≤0.025%, Cr：0.90~1.25%, Mo：0.15~0.25%, Ni≤0.25%, Cu≤0.20% increase
It is C that the weight percentage of carbon, which controls standard, during carbon controls：0.13~0.17%, it is 1550 to ensure liquid steel temperature before recarburization practice
℃；After the completion of alloying and recarburization practice, argon flow amount is reduced to 180L/min；The content of aluminium, works as aluminium in sampling analysis molten steel
Weight percentage be less than 0.060% when, mend feed aluminum steel to aluminium weight percentage reach 0.070%；It is pressed after sampling
160L/min controls argon flow amount, is 25min to realize molten steel by adding deoxidier into molten steel control white slag refining time
The purpose of deoxidation, deoxidier is aluminum shot before sampling, and deoxidier is ferrosilicon powder and carbon dust after sampling；
Argon flow amount is adjusted by observing the diameter of the exposed liquid level of molten steel in ladle during LF refining, in ladle
The diameter criteria of the exposed liquid level of molten steel is 100~200mm, the excessive then appropriate reduction argon flow amount of area, and area is too small then appropriate
Improve argon flow amount；
In RH Vacuum Degassing Process：
Aluminum steel is fed into the molten steel after LF refining makes the weight percentage of aluminium in molten steel reach 0.040%, feeds silicon
The amount of calcium line is 2.5m/t；After the completion of the operation for feeding aluminum steel and silicon-calcium wire, vacuum circular flow is carried out under 67Pa final vacuums
20min, wherein argon flow amount is 1800L/min in 0~12min, argon flow amount is 1200L/min after 12min；Vacuum circular flow
After by argon flow amount be down to 70L/min start to molten steel carry out soft blow, it is not exposed with molten steel, top of the slag fine motion be standard, it is soft
The time is blown for 25min；
During billet continuous casting：
Molten steel whole process is poured into a mould under protection of argon gas after soft blow, to molten steel using M-EMS and end electromagnetism
It stirs the mode being combined to be stirred, M-EMS parameter is 500A/3.0Hz, and agitating mode is using alternative expression electricity
Magnetic stirs, and end stirring parameter is 400A/8.0Hz, and agitating mode is stirred using Continuous Electromagnetic；It is controlled in casting process
The continuous casting degree of superheat is 30 DEG C, and crystallizer cooling water flow is 2400L/min；Pulling rate is in 30 DEG C of work shape for molten steel overheat
0.75m/min under state.
Continuous casting billet is entered to burial pit slow cooling, temperature retention time 48h in time after completing billet continuous casting.
Embodiment 4
The chemical composition percentage composition by weight of High-quality automobile gear special steel provided in this embodiment includes：C：
0.12~0.18%, Si：0.15~0.35%, Mn：0.55~0.90%, P≤0.030%, S≤0.025%, Cr：0.85~
1.25%th, Mo：0.10~0.25%, Ni≤0.25%, Cu≤0.30%, Al：0.020~0.040%, remaining is Fe and can not
Avoid impurity.
The production technology of High-quality automobile gear special steel provided in this embodiment, it is characterised in that the production technology
Including pneumatic steelmaking → LF refining → RH vacuum outgas → billet continuous casting → slow cooling, wherein：
In convertor steelmaking process：
Converter smelting iron and steel stock uses molten iron and high-quality steel scrap of the total weight for 100t, converter tapping steel ladle full BOTTOM ARGON BLOWING
Gas uses argon flow amount as 550L/min, and air pressure carries out strong mixing for 9.0bar, and argon flow amount is changed to after strong mixing 15min
150L/min, 3.0bar carry out soft stirring until molten steel enters LF refining position；When the weight percentage of carbon in molten steel is
0.05%, the weight percentage of phosphorus reaches BOF Steelmaking Endpoint for less than 0.010%, starts at a temperature of 1660 DEG C
Steel；Lime-crushed stone pile 6Kg/t, lab-prepared refining slag additive amount 2Kg/t, top slag modifier additive amount 1Kg/ are pressed during converter tapping 50t
T, aluminium cake additive amount 1.3Kg/t add in lime, lab-prepared refining slag, top slag modifier and aluminium cake into molten steel；
During LF refining：
Aluminum steel 300m are fed online or at LF into the molten steel after converter tapping, argon flow amount is 160L/min at this time,
Argon flow amount is heightened to 480L/min after completing the operation of feeding aluminum steel, alloying operation and recarburization practice is carried out successively, closes
Aurification in controlling the weight percentage of each chemical composition control standard be Si：0.17~0.35%, Mn：0.65~0.90%, P
≤ 0.025%, S≤0.025%, Cr：0.90~1.25%, Mo：0.15~0.25%, Ni≤0.25%, Cu≤0.20% increase
It is C that the weight percentage of carbon, which controls standard, during carbon controls：0.13~0.17%, it is 1550 to ensure liquid steel temperature before recarburization practice
℃；After the completion of alloying and recarburization practice, argon flow amount is reduced to 160L/min；The content of aluminium, works as aluminium in sampling analysis molten steel
Weight percentage be less than 0.060% when, mend feed aluminum steel to aluminium weight percentage reach 0.070%；It is pressed after sampling
140L/min controls argon flow amount, is 20min to realize molten steel by adding deoxidier into molten steel control white slag refining time
The purpose of deoxidation, deoxidier is aluminum shot before sampling, and deoxidier is ferrosilicon powder and carbon dust after sampling；
Argon flow amount is adjusted by observing the diameter of the exposed liquid level of molten steel in ladle during LF refining, in ladle
The diameter criteria of the exposed liquid level of molten steel is 100~200mm, the excessive then appropriate reduction argon flow amount of area, and area is too small then appropriate
Improve argon flow amount；
In RH Vacuum Degassing Process：
Aluminum steel is fed into the molten steel after LF refining makes the weight percentage of aluminium in molten steel reach 0.040%, feeds silicon
The amount of calcium line is 2.5m/t；After the completion of the operation for feeding aluminum steel and silicon-calcium wire, vacuum circular flow is carried out under 67Pa final vacuums
18min, wherein argon flow amount is 1800L/min in 0~12min, argon flow amount is 1200L/min after 12min；Vacuum circular flow
After by argon flow amount be down to 80L/min start to molten steel carry out soft blow, it is not exposed with molten steel, top of the slag fine motion be standard, it is soft
The time is blown for 20min；
During billet continuous casting：
Molten steel whole process is poured into a mould under protection of argon gas after soft blow, to molten steel using M-EMS and end electromagnetism
It stirs the mode being combined to be stirred, M-EMS parameter is 500A/3.0Hz, and agitating mode is using alternative expression electricity
Magnetic stirs, and end stirring parameter is 400A/8.0Hz, and agitating mode is stirred using Continuous Electromagnetic；It is controlled in casting process
The continuous casting degree of superheat is 32 DEG C, and crystallizer cooling water flow is 2400L/min；Pulling rate is in 32 DEG C of work shape for molten steel overheat
0.75m/min under state.
Continuous casting billet is entered to burial pit slow cooling, temperature retention time 48h in time after completing billet continuous casting.
Comparative example 1
This comparative example is differed only in embodiment 2, and comparative example 1 is in RH Vacuum Degassing Process, before vacuum outgas not
Aluminum steel is fed, only feeds the silicon-calcium wire of 1.5m/t, the argon gas in progress vacuum circular flow 18min, wherein 18min under 67Pa final vacuums
Flow remains 1800L/min, and the soft blow time is 18min；
Comparative example 1 is during billet continuous casting, and M-EMS parameter is 400/3.0Hz, and agitating mode is using friendship
For formula electromagnetic agitation, end stirring parameter is 320A/8.0Hz, and agitating mode Continuous Electromagnetic stirs；Crystallizer cooling water
Flow is 2275~2325L/min, and pulling rate is the 0.68m/min under 25~40 DEG C of working conditions.
Comparative example 2
This comparative example is differed only in embodiment 2, and comparative example 2 is whole during LF refining to use aluminum shot as de-
Aluminum steel and silicon-calcium wire are not fed in oxygen agent before RH vacuum outgas, vacuum circular flow 15min is carried out under 67Pa final vacuums, wherein
Argon flow amount remains 1200L/min in 15min, and the soft blow time is 15min；
Comparative example 2 is during billet continuous casting, and M-EMS parameter is 280/3.0Hz, and agitating mode is using friendship
For formula electromagnetic agitation, end stirring parameter is 220A/8.0Hz, and agitating mode Continuous Electromagnetic stirs；Crystallizer cooling water
Flow is 2275L~2325/min, and pulling rate is the 0.65m/min under 20~45 DEG C of working conditions.
Test experience one, the detection of continuous casting square billet carbon segregation
Embodiment 2, comparative example 1, the continuous casting square billet that transverse cross-sectional size made from comparative example 2 is 250mm × 280mm press Fig. 1
Shown method cuts the cross-sectional fabric section that thickness is 30mm, and what the cross-sectional fabric section carbon segregation of continuous casting square billet detected as shown in Figure 2 takes
Cross section is divided into 5 rows × 6 and arranges totally 30 detection sample points by sample standard, with the drill bit of a diameter of 6mm on each detection sample point
Steel cuttings is drilled through, the steel cuttings drilled through using brill foam chemical analysis to each detection sample point carries out carbon segregation detection.
The carbon segregation scope that continuous casting square billet made from embodiment 2 measures is 0.125~0.166%, and deviation range is
0.04% (± 0.02%), it is as shown in table 1 that continuous casting square billet made from embodiment 2 specifically respectively detects sample point carbon segregation numerical value：
Table 1
The carbon segregation numerical value that embodiment 2, comparative example 1, continuous casting square billet made from comparative example 2 measure is as shown in table 2：
Table 2
| Test item | Embodiment 2 | Comparative example 1 | Comparative example 2 |
| Carbon segregation scope (%) | 0.125~0.166 | 0.118~0.172 | 0.113~0.190 |
| Deviation range (%) | 0.04(±0.02) | 0.06(±0.03) | 0.08(±0.04) |
Test experience two, the detection of finished product bar carbon segregation
Continuous casting square billet made from embodiment 1, comparative example 2 and comparative example 3 is rolled into bar, finished product stick as shown in Figure 3
The sampling standard of material cross section carbon segregation detection, in bar circle centre position, at the half of the center of circle and apart from the center of circle four/
One sets three test sample points, steel cuttings is drilled through on each detection sample point with the drill bit of a diameter of 6mm, using brill foam chemistry point
The steel cuttings that analysis method drills through each detection sample point carries out carbon segregation detection.
The carbon segregation scope for the bar that the continuous casting square billet as made from embodiment 2 rolls is 0.13~0.15%, batch production
The carbon segregation scope of this finished product bar is 0.02% (± 0.01%), the carbon for the bar that continuous casting square billet made from embodiment 2 rolls
It is as shown in table 3 to be segregated scope：
Table 3
Embodiment 2, comparative example 1, the carbon segregation numerical value of the bar of continuous casting square billet rolling is as shown in table 4 made from comparative example 2：
Table 4
| Test item | Embodiment 2 | Comparative example 1 | Comparative example 2 |
| Carbon segregation scope (%) | 0.13~0.15 | 0.13~0.17 | 0.12~0.18 |
| Deviation range (%) | 0.02(±0.01) | 0.04(±0.02) | 0.06(±0.03) |
Detection experiment three, the examination of nonmetallic inclusion
It is sampled on the bar being rolled into continuous casting square billet made from embodiment 2, comparative example 1 and comparative example 2, by ASTME45A
Just now the middle examination of nonmetallic inclusion, testing result were as shown in table 5 for method evaluation progress：
Table 5
By the smelting of embodiment 2 it can be seen from the testing result of detection experiment one, detection experiment two and detection experiment three
Continuous casting square billet and the carbon segregation scope of finished product bar prepared by process is minimum, and non-metallic inclusion rate range is minimum, explanation
High-quality automobile gear special steel provided by the invention production technology production special composition of steel uniformly, high purity, matter
Amount is stablized.
Reason is that the embodiment of the present invention 2 feeds silicon-calcium wire 2.5m/t before RH vacuum outgas, and comparative example 1 only feeds silicon-calcium wire
1.5m/t, and no hello the silicon-calcium wire of comparative example 3, the purpose for feeding silicon-calcium wire is the inclusion modification made in steel, particularly aluminium deoxidation
Steel, there are a large amount of Al in molten steel2O3Solid phase field trash may block middle water containing opening in casting process, and molten steel is through Calcium treatment
Afterwards, Al2O3Solid phase field trash can be converted into low melting point CaAlO3Liquid phase is mingled with, and can assemble and exclude quickly, reach better steel
Water purifying effect.
Argon bottom-blowing flow and soft blow time of the embodiment of the present invention 2 in RH Vacuum Degassing Process are above comparative example 1
With comparative example 2, what this illustrated that the present invention sets calm the anger flow and the soft blow time can be more fully driven on the field trash in molten steel
It is floating；And if the phenomenon that using easy slag, air-breathing can be caused than 2 higher argon flow amount of the embodiment of the present invention and soft blow time,
The field trash of molten steel surface is made to be involved in again in molten steel, soft blow overlong time will also result in the exposed part of molten steel and be connect with air
It touches and increases, easily aoxidized, regenerate field trash, therefore when argon flow amount of the present invention in RH Vacuum Degassing Process and soft blow
Between can preferably play reduce molten steel in field trash, promoted Molten Steel Cleanliness effect；
Comparative example 2 is whole during LF refining to use aluminum shot as deoxidier, not using ferrosilicon powder and carbon dust as
Deoxidier is unable to reach the embodiment of the present invention 2 and aluminum shot is used to use ferrosilicon powder and carbon dust after sampling as deoxidier before sampling
Fast into white slag as the rapid deoxidation of deoxidier, deoxidation effectiveness is high, the later stage keeps atmosphere, reduces steel grade Al2O3Field trash and molten steel
The effect of high purity.
The embodiment of the present invention 2 is during billet continuous casting, and M-EMS parameter and end stirring parameter are all
Higher than comparative example 1 and comparative example 2, since stronger electromagnetic force field generates the non-metallic particle field trash being scattered in molten steel
The effect of the power of bigger, makes non-metallic particle be separated by repulsion and from molten steel, while can also improve casting blank solidification prevention, subtracts
The light internal flaws such as center segregation and center porosity；But higher mixing parametric can make molten steel be involved in bent moon due to vortex action
The field trash in face is directly solidified shell capture, it is difficult to exclude.Therefore the crystallizer electricity that the present invention is set during billet continuous casting
The metallurgical effect of magnetic mixing parametric and end stirring parameter is optimal.
The embodiment of the present invention 2 is made whole by the Proper Match of crystallizer cooling water flow, the degree of superheat and pulling rate technological parameter
Tank molten steel solidifies ground more uniformly fully during billet continuous casting, so as to preferably reducing continuous casting square billet on longitudinal ingredient
Carbon segregation scope, and then stabilize the narrow hardenability band of automobile gear special steel；And if pulling rate is too fast, it can cause to cast
Center porosity, shrinkage cavity and the segregation defects of base, therefore the smelting of crystallizer cooling water flow, the degree of superheat and the pulling rate of the invention set
Refine best results.
Claims (10)
- A kind of 1. automobile gear special steel, it is characterised in that the chemical composition percentage composition by weight of the gear special steel Including：C：0.12~0.18%, Si：0.15~0.35%, Mn：0.55~0.90%, P≤0.030%, S≤0.025%, Cr： 0.85~1.25%, Mo：0.10~0.25%, Ni≤0.25%, Cu≤0.30%, Al：0.020~0.040%, remaining is Fe And inevitable impurity.
- A kind of 2. production technology of automobile gear special steel as described in claim 1, it is characterised in that the production technology bag Pneumatic steelmaking → LF refining → RH vacuum outgas → billet continuous casting → slow cooling is included, wherein：In convertor steelmaking process：Converter tapping steel ladle full argon bottom-blowing, strong mixing is changed to soft stirring afterwards for a period of time until molten steel enters LF refining position； When the weight percentage of carbon in molten steel and phosphorus reaches converter terminal requirement, start to tap at a certain temperature；Converter tapping To molten steel total weight half when, add in lime, lab-prepared refining slag, top slag modifier and aluminium cake；During LF refining：Under certain argon flow amount into the molten steel after converter tapping line or LF feed aluminum steel after, heighten argon flow amount according to Secondary progress alloying operation and recarburization practice；After the completion of alloying and recarburization practice, argon flow amount and whole stringent control are reduced Argon flow amount；The content of aluminium in sampling analysis molten steel, and by way of mending and feeding aluminum steel the aluminium in molten steel is made to reach certain weight Measure percentage composition；The time that white slag refines is controlled to realize the purpose of deoxidation of molten steel by adding deoxidier into molten steel, is sampled Preceding deoxidier is aluminum shot, and deoxidier is ferrosilicon powder and carbon dust after sampling；In RH Vacuum Degassing Process：After feeding aluminum steel and silicon-calcium wire into the molten steel after LF refining, one timing of vacuum circular flow is carried out under certain final vacuum Between, during which strictly control argon flow amount；Argon flow amount is reduced after vacuum circular flow to start to molten steel soft blow certain time；During billet continuous casting：Molten steel whole process after soft blow is poured into a mould under protection of argon gas, and molten steel is stirred using M-EMS with end electromagnetism It mixes the mode being combined to be stirred, certain continuous casting degree of superheat, crystallizer cooling water flow and pulling rate is controlled in casting process.
- A kind of 3. production technology of automobile gear special steel according to claim 2, it is characterised in that convertor steelmaking process Described in argon bottom-blowing strong mixing flow velocity and air pressure be 400~600L/min, 8.0~10.0bar, the strong mixing time is 15min；The flow velocity of the weak stirring of argon bottom-blowing and air pressure are 50~250L/min, 1.0~4.0bar.
- A kind of 4. production technology of automobile gear special steel according to Claims 2 or 3, it is characterised in that pneumatic steelmaking The weight percentage for reaching the carbon of converter terminal described in journey is 0.05~0.07%, and the weight percentage of phosphorus is Less than 0.010%, the tapping temperature is 1640~1660 DEG C；The lime-crushed stone pile is 6~7Kg/t, and lab-prepared refining slag adds Dosage is 2Kg/t, and top slag modifier additive amount is 1Kg/t, and aluminium cake additive amount is 1.2-1.5Kg/t.
- 5. a kind of production technology of automobile gear special steel according to claim 4, it is characterised in that during LF refining Amount that is described online or feeding aluminum steel at LF is 300m, and the argon flow amount during hello the aluminum steel is 120~200L/min； Argon flow amount during the alloying and carburetting is 360~600L/min, each chemical composition in the alloying control It is Si that weight percentage, which controls standard,：0.17~0.35%, Mn：0.65~0.90%, P≤0.025%, S≤0.025%, Cr：0.90~1.25%, Mo：0.15~0.25%, Ni≤0.25%, Cu≤0.20%；The weight of carbon in the carburetting control It is C that percentage composition, which controls standard,：0.13~0.17%, it is 1550 DEG C to ensure liquid steel temperature before the recarburization practice.
- 6. a kind of production technology of automobile gear special steel according to claim 5, it is characterised in that during LF refining The content of aluminium in the sampling analysis molten steel when the weight percentage of aluminium is less than 0.060%, mends and feeds aluminum steel to the weight of aluminium Amount percentage composition reaches 0.070%；The whole process strictly controls argon flow amount as extremely sampling after the completion of alloying and recarburization practice Preceding argon flow amount is controlled by 120~200L/min, is controlled after sampling by 120~180L/min；The time of white slag refining is 20~30min.
- A kind of 7. production technology of automobile gear special steel according to claim 6, it is characterised in that RH vacuum outgas It is that the weight percentage of aluminium in molten steel is made to reach 0.040% that aluminum steel is fed described in journey, and the amount for feeding silicon-calcium wire is 2.5m/t.
- A kind of 8. production technology of automobile gear special steel according to claim 7, it is characterised in that RH vacuum outgas Final vacuum described in journey is 67Pa, and the vacuum circular flow time is 18~25min, wherein argon flow amount is in 0~12min Argon flow amount is 1200L/min after 1800L/min, 12min, and argon flow amount is 50~90L/min during the soft blow, with molten steel Not exposed, top of the slag fine motion is standard, and the soft blow time is 20~30min.
- A kind of 9. production technology of automobile gear special steel according to claim 8, it is characterised in that billet continuous casting process Described in M-EMS parameter be 500A/3.0Hz, agitating mode use alternative expression electromagnetic agitation；The end electromagnetism Mixing parametric is 400A/8.0Hz, and agitating mode is stirred using Continuous Electromagnetic.
- A kind of 10. production technology of automobile gear special steel according to claim 9, it is characterised in that billet continuous casting process Described in the continuous casting degree of superheat be 20~35 DEG C, the crystallizer cooling water flow be 2375~2425L/min；The pulling rate is steel The water degree of superheat is in 0.75m/min under 25~40 DEG C of working condition.
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