CN105839015B

CN105839015B - A kind of production method of Mn-Cr series high-performances pinion steel

Info

Publication number: CN105839015B
Application number: CN201610328134.5A
Authority: CN
Inventors: 朱富强; 高宇波; 徐必靖; 王二庆; 冷永磊; 万文华
Original assignee: Zenith Steel Group Co Ltd
Current assignee: Changzhou Bangyi Iron and Steel Co., Ltd.; Zenith Steel Group Co Ltd
Priority date: 2016-05-17
Filing date: 2016-05-17
Publication date: 2018-06-29
Anticipated expiration: 2036-05-17
Also published as: CN105839015A

Abstract

The invention belongs to technical field of alloy steel, and in particular to a kind of manufacturing method of Mn Cr systems pinion steel.The composition range of pinion steel is C：0.17~0.22%, Si：0.15~0.25%, Mn：1.10~1.40%, Cr：1.00~1.30%, Mo≤0.08%, B≤0.0005%, Cu≤0.02%, Ni≤0.02%, Al：0.025~0.055%, P≤0.015%, S：0.020~0.035%, N≤130ppm, remaining is iron.The present invention is by optimizing refining process, slag system controls, and improves the cleanliness factor of molten steel；While carrying out nitrogen pick-up processing by feeding wire process so as to effectively refine the aluminium deoxidation gear crystalline grain of steel, the accurate control of quenching degree alloying element is realized, deoxidation is solved and protects sulphur contradiction, and ensures the good castability of molten steel and the excellent cutting ability of pinion steel.

Description

A kind of production method of Mn-Cr series high-performances pinion steel

Technical field

The invention belongs to technical field of alloy steel, and in particular to a kind of manufacturing method of Mn-Cr systems pinion steel.

Background technology

Actual working environment and requirement of the pinion steel based on its fabricated part, it usually needs have good obdurability and Wearability, in addition to this, High-performance gear also needs to absorb impact well with steel, is bent and contact stress, and can expire Foot deformation is small, and precision is high, and noise is low to wait requirement.

Due to the specific use of pinion steel, all kinds of stress that gear must be born at work are the weights for leading to its fatigue failure Want reason.Pinion steel fatigue crack major source is caused to be mingled with for oxide, and total inclusion content is mainly by the oxygen content in steel It determines.

Have a great impact whether the stabilization of end hardenability to the size of the deflection after gear heat treatment, gear shifting quadrant texturing The size of amount directly influences the noise level of gear-box；The austenite grain of fine uniform can stablize end hardenability, subtract Few heat-treatment distortion improves the anti-brittle failure ability of carburizing steel；On the other hand, fatigue crack rises at field trash after pinion steel carburizing It splits, is extended in carburized layer along crystal boundary, therefore crystal grain thinning is also remarkably improved fatigue behaviour；And the appearance of banded structure is past in steel Toward the unstability for easily causing gear wheel carburization tissue, make carburized layer deformation irregular, lead to gear workpieces deformation and fatigue behaviour Reduction, influence the precision and service life of gear；In addition, good cutting ability is to ensure Gear Processing precision and reduce to add The essential condition of work cost.Therefore, the quality level of High-performance gear steel mainly by cleanliness factor, end hardenability bandwidth and Dispersion, structural homogenity, grain size and cutting ability embody.

Invention content

The present invention provides a kind of manufacturing method of Mn-Cr systems pinion steel, using EAF-CONVERTER electricity converter smelting+ The process route of LF+VD+CCM,

The composition range of pinion steel is C：0.17~0.22%, Si：0.15~0.25%, Mn：1.10~1.40%, Cr： 1.00~1.30%, Mo≤0.08%, B≤0.0005%, Cu≤0.02%, Ni≤0.02%, Al：0.025~0.055%, P ≤ 0.015%, S：0.020~0.035%, N≤130ppm, remaining is iron.

EAF-CONVERTER electricity converters：

The electric total charge weight control of converter is at 100 tons or so, and hot metal ratio 90%, cold material control is 10%, wherein 3% makes a living Iron, remaining is high-quality steel scrap (steel scrap chooses the non-steel alloy containing Mo, B, W, Cu, Ni, Ti).Electric converter utilizes molten iron tipple Using online molten iron loading pattern, with reference to foam slag operation technique, stablize reaction between carbon and oxygen atmosphere in stove, reach the mesh of de- P temperature controls 's；Though this steel grade is mild steel, tapping carbon is too low, and when particularly C content is less than 0.08%, oxygen content in steel will drastically increase Long, the increase of corresponding deoxidation products will be unfavorable for improving the cleanliness factor of molten steel, therefore, tight using this steel grade during electric converter just refining Prohibit tapping Molten Steel over-oxidation, tapping carbon need to be strict controlled in the range of 0.08%~0.12%, while require tapping P≤ 0.010%；Using eccentric bottom tapping, tapping temperature T >=1640 DEG C, it is ensured that rapid slugging；Tap is controlled at 85 ± 2 tons, with Ensureing Steel ladle clearance height, it is ensured that vacuum suction is smooth, meanwhile, more remaining steel amount is also beneficial to prevent the hair of tapping slag It is raw；Tapping process adds in appropriate Al blocks and calcium carbide deoxidation, using low titanium ferro-silicon (Ti≤0.02%), low-carbon low titanium ferrochromium (Ti≤ 0.02%), low-carbon ferromanganese and part high carbon ferromanganese alloying, and add in lime and low titanium synthesis slag charge (TiO₂≤ 0.05%) into Row slag making；Tapping latter stage strictly controls remaining steel amount in stove, forbids slag of tapping, and effectively avoids electroslag (special to molten steel component P, Si, Ti) influence and refining condition deterioration effect.High-cleanness, high ladle is selected in tapping, especially pays attention to not can be used Just completed the turnover ladle of the alloy steel smelting containing Ti, B, and select new packet or in repair ladle have to pass through have enough to meet the need twice with On.

LF refining and VD vacuum processings：

LF refining early period carries out deoxidation using Al and a small amount of SiC, and middle and later periods small lot repeatedly uniformly drifts carbon-free deoxidation Slag is protected in agent SiFe powder to top of the slag deoxidation, is kept the reducing atmosphere of well-refined and is prevented the fluctuation of carbon content；First sample ingredient goes out High duty alloy adjusting component is added after coming, LF refining adjustment argon pressure early period to 0.4~0.6MPa (is adjusted depending on clinker situation It is whole), middle and later periods argon pressure is 0.2~0.35MPa, micro-positive pressure in holding furnace；LF refining process makes high basicity slag (dual alkalinity R：3.5~5.0), it is ensured that deoxidation and absorption Al₂O₃While ability, good mobility and slag separation property are taken into account；LF refining Reach the finished product target component of each element in addition to Mn, Cr, N, S before bull ladle, 10 minutes C, Si contents wherein before LF refining bull ladle Heating requirement need to be completed when reaching desired value simultaneously, high current energization is no longer carried out later and the top of the slag adds in largely no longer into stove Slag deoxidier is protected, increases silicon to prevent carburetting, and Mn, Cr reach the lower limit of target component range before LF bull ladles, are follow-up nitrogen pick-up It feeds silk and stays certain accurate adjustment surplus, while consider follow-up vacuum aluminum damage, Al is controlled by the control range most upper limit, in addition specific remaining member Element need to meet Mo≤0.005%, B≤0.0003%, V≤0.01%, Cu≤0.01%, Ni≤0.01%, W≤0.005%, Ti ≤ 0.0015% content requirement；Refining time reaches 40~70 minutes, and molten steel temperature meets the requirements, slag condition is reasonable, i.e. bull ladle Vacuum processing is carried out into VD stations.VD processing procedures are evacuated to high vacuum (≤67Pa) pressurize 15 minutes afterwards, are required under high vacuum Clearly visible molten steel is exposed to seethe.

Feed silk and soft blow：

The MnN silks of appropriate weight and ratio are fed according to N content practical in steel and Mn, Cr content, adjustment after VD processing And CrN, nitrogen pick-up and the accurate adjustment of Mn, Cr content are completed, when necessary, is aided with the fine tuning that C content is completed in carbon filament feeding, to realize stove The fluctuation of C is ± 0.01% between stove, the range of the undulated control of main alloy element (Cr, Mn) 0.03%, and N in steel Content control ensures that Al/N is 3~5 in steel in 70~100ppm, and crystal grain thinning while is conducive to eliminate remaining quenching degree quick Feel element particularly influence of the residual boron to hardenability of steel,

Since even if there are the micro molten boron of acid in steel, the negative shadow of highly significant can also be generated to the quenching degree of steel It rings, and excessive part nitrogen can combine acid-soluble boron and form boron nitride, so as to eliminate residual boron to hardenability of steel It influences；

In LF refining and VD processing procedures, sulfur content constantly reduces, VD with the lasting progress of molten steel deep deoxidation in steel Sulfur content after processing in molten steel is far below content requirement range, for sulphur is made to reach slave mode, using " sulfuration process again ".And It needs to complete Calcium treatment by feeding appropriate calcium silk into molten steel before " again vulcanizing " process is carried out, this aspect is because in steel Al is difficult to realize when sulphur is high₂O₃Complete denaturation, therefore select to carry out Calcium treatment when molten steel sulfur content is relatively low before " sulfuration process again " And the soft blow interval of 10 minutes or more is kept, with a large amount of generations for avoiding CaS as possible and by Al₂O₃Fully denaturation, improving molten steel can The property poured, on the other hand, the mCaOnAl that Calcium treatment generates₂O₃Cladding core will be provided for the sulfide being subsequently generated, avoid giving birth to Into the single-phase sulfide largely with strong ductility, and it is formed with to improve the spindle-type oxygen sulphur duplex impurity of cutting ability Object.

CCM continuous castings：

The continuous casting degree of superheat is strict controlled in 15~25 DEG C, this steel grade strict implement slow rhythm perseverance casting speed control, two cold uses Weak cold；Casting process uses alkaline covering agent, and magnesia barricade is installed in middle packet, and black top of the slag operation is wrapped in holding, strengthens big Bao Shui Argon gas between mouth and long nozzle is protected, and increases big packet collector nozzle and long nozzle seam crossing external argon ring, keeps micro-positive pressure (0.7~0.9pa) reduces the secondary oxidation of casting process to the greatest extent；Using the four hole mouths of a river and electromagnetic agitation is opened, is promoted in molten steel Inclusion floating improves center segregation of casting blank while reducing shrinkage cavity probability；In addition to this, using sulfur bearing steel mould flux, To prevent casting process from the situation of covering slag failure occur, and the field trash in molten steel is effectively adsorbed, further improve molten steel Castability.

The beneficial effects of the present invention are：By selecting specific high-quality steel scrap, alloy raw material, optimization refining process, slag system Control improves the cleanliness factor of molten steel, greatly reduce the oxide for influencing gear fatigue life, titanium nitride level of inclusions and Harmful residual constituent content, while also advantage is created for follow-up Prepared by Low Superheat Pouring；

While carrying out nitrogen pick-up processing by feeding wire process so as to effectively refine the aluminium deoxidation gear crystalline grain of steel, realize The accurate control of quenching degree alloying element, and the reduction molten boron of associated residual element, particularly residual acid significantly is to the shadow of quenching degree It rings, obtaining stable narrowband through hardening characteristic for the High-performance gear steel has established important foundation, although therefore of the invention existing Nitrogen content is increased on the basis of technology, but does not occur in traditional technology " toughness and the plasticity reduction of steel；Nitrogen and titanium in steel etc. Element forms the brittle inclusion with corner angle, reduces the cold and hot deformation processing of steel；The macrostructure of steel is loose or even forms skin Bubble；The negative issues such as the cracked defect of strand "；

By feeding " the vulcanizing again " of wire process and the stringent control of Ca processing, solve deoxidation and protect sulphur contradiction, and ensure molten steel While good castability, oxide morphology and distribution in steel are optimized, the excellent cutting ability of the pinion steel has been effectively ensured； By strengthening the low overheat perseverance casting speed control of casting process and the synergistic effect of secondary cooling system, the four hole mouths of a river and electromagnetic agitation, The segregation of element is reduced, improves the uniformity of steel.

Specific embodiment

Embodiment 1：

Using the process route of EAF-CONVERTER electricity converter smelting → LF stoves refining → VD vacuum processings → CCM continuous castings Produce Mn-Cr series high-performance pinion steels.

Smelt the control of finished product composition：C：0.17~0.22%, Si：0.15~0.25%, Mn：1.10~1.40%, Cr： 1.00~1.30%, Mo≤0.08%, B≤0.0005%, Cu≤0.02%, Ni≤0.02%, Al：0.025~0.055%, P：≤ 0.015%, S：0.020~0.035%, N：≤130ppm.

At 102.2 tons, hot metal ratio 90%, pig iron addition is 3.6 tons for the electric total charge weight control of converter, remaining is high-quality useless Steel.Tap terminal ingredient C：0.10%th, P：0.008%th, tapping temperature T：1645 DEG C, 86.3 tons of tap；Tapping process adds in 100kg Al blocks and 50kg calcium carbide deoxidations, add in 780kg low-carbon ferromanganeses, 220kg low titanium ferro-silicons, 1550kg low-carbons low titanium ferrochromium and 375kg high carbon ferromanganeses carry out alloying after stove, and add in 700kg lime and 400kg low titaniums synthesis slag charge carries out slag making, and tapping adopts With eccentric bottom tapping, ensure remaining steel amount in stove, forbid slag of tapping.

LF refining early period strengthens deoxidation using 30kg aluminum shots and 130kg silicon carbide, argon bottom-blowing pressure adjust to 0.45MPa, electrified regulation realize white slag after 8 minutes；46kg ferrosilicon, 450kg low-carbons are added after taking the same measuring components of LF Low titanium ferrochromium, 150kg low-carbon ferromanganeses, refining middle and later periods small lot repeatedly uniformly drift SiFe powder to top of the slag deoxidation protect slag, altogether 12kg, argon bottom-blowing pressure are adjusted to 0.25MPa；Mn, Cr reach target component range in 15 minutes molten steel before LF refining bull ladle Lower limit, stay certain surplus subsequently to feed silk nitrogen pick-up, 10 minutes C, Si contents reach desired value and meet before LF refining bull ladle Bull ladle temperature requirement no longer carries out high current energization later, to prevent electrode carburetting, while considers follow-up vacuum aluminum damage, LF bull ladles Feeding aluminium wire adjusts Al content to 0.052% within first 5 minutes, and slag viscosity adequate liquidity is preferable, i.e., VD stoves on bull ladle, bull ladle temperature 1635 DEG C of degree, LF refining duration 62 minutes.VD processing when under condition of high vacuum degree (≤67Pa) pressurize 16 minutes, immediately break sky, VD Vacuum processing total time-consuming 27 minutes breaks 1583 DEG C of air temperature degree.

VD breaks empty sampling immediately and carries out composition detection, and MnN and CrN 50m are fed respectively according to Mn, Cr, N content in steel And 65m, and do not occur big fluctuation before C, Si content and vacuum, therefore be not adjusted, it is fed after 5 minutes uniform molten steel of soft blow Calcium silk 100m behind 10 minutes soft blow intervals, then carries out " vulcanizing again " by feeding sulphur iron wire 160m and handles, to reach elementary sulfur Content requirement range feeds and homogenizes continuous casting revolving platform on soft blow 15 minutes i.e. bull ladle, upper 1563 DEG C of steel temperature after the completion of wire process.

27 DEG C of the continuous casting degree of superheat, the constant 0.85m/min of pulling rate；Open M-EMS (200A/3Hz) and end electricity Magnetic stirs (80A/6Hz), it is ensured that molten steel uniformity；Casting process uses alkaline covering agent, installs magnesia barricade in middle packet, keeps The middle black top of the slag operation of packet, strengthens the argon gas protection between big water-coating port and long nozzle, increases big packet collector nozzle and long nozzle seam Locate external argon ring, keep micro-positive pressure 0.8Pa, reduce secondary oxidation to the greatest extent；Using the high-quality four hole mouth of a river of built-in type and sulfur-bearing Steel mould flux, casting cycle Mold face are steadily controllable.

As the above method smelt Mn-Cr systems pinion steel through rolling obtained by round steel main component and gas content：C： 0.19%, Si：0.23%, Mn：1.28%, Cr：1.15%, Mo：0.003%, B：0.0001%, Cu：0.005%th, Ni： 0.005%th, Al：0.028%, P：0.011%, S：0.029%, W：0.001%, Ti：0.0009%, N：73.6ppm O： 11.2ppm；Low power Indexs measure result display centre is loose, General Loosen, center segregation are 0.5 grade；Metallographic high power detects Show 1.0 grades of A (thin) type impurity, 1.0 grades of A (thick) type impurity, C classes non-metallic inclusion is 0 grade, and B, D class are not more than Cross 0.5 grade；1.5 grades of banded structure, 7 grades of grain size；Quenching for same heat (batch) number difference stocking sample is made using above-mentioned smelting process Permeability detected value deviation range is J1.5：43 ± 0.5HRC, J9：37.5 ± 0.5HRC, J15：31.5±1.0HRC.

Embodiment 2：

At 103.4 tons, hot metal ratio 91%, pig iron addition is 3.1 tons for the electric total charge weight control of converter, remaining is high-quality useless Steel.Tap terminal ingredient C：0.12%th, P：0.0010%th, tapping temperature T：1641 DEG C, 86.8 tons of tap；Tapping process adds in 100kg Al blocks and 50kg calcium carbide deoxidations, add in 800kg low-carbon ferromanganeses, 210kg low titanium ferro-silicons, 1750kg low-carbons low titanium ferrochromium and 350kg high carbon ferromanganeses carry out alloying after stove, and add in 680kg lime and 420kg low titaniums synthesis slag charge carries out slag making, and tapping adopts With eccentric bottom tapping, ensure remaining steel amount in stove, forbid slag of tapping.

LF refining early period strengthens deoxidation using 25kg aluminum shots and 120kg silicon carbide, argon bottom-blowing pressure adjust to 0.45MPa, electrified regulation realize white slag after 8 minutes；25kg ferrosilicon, 200kg low-carbons are added after taking the same measuring components of LF Low titanium ferrochromium, 100kg low-carbon ferromanganeses, refining middle and later periods small lot repeatedly uniformly drift SiFe powder to top of the slag deoxidation protect slag, altogether 17kg, argon bottom-blowing pressure are adjusted to 0.25MPa；Mn, Cr reach target component range in 15 minutes molten steel before LF refining bull ladle Lower limit, stay certain surplus subsequently to feed silk nitrogen pick-up, 10 minutes C, Si contents reach desired value and meet before LF refining bull ladle Bull ladle temperature requirement no longer carries out high current energization later, to prevent electrode carburetting, while considers follow-up vacuum aluminum damage, LF bull ladles Feeding aluminium wire adjusts Al content to 0.045% within first 5 minutes, and slag viscosity adequate liquidity is preferable, i.e., VD stoves on bull ladle, bull ladle temperature 1629 DEG C of degree, LF refining duration 65 minutes.VD processing when under condition of high vacuum degree (≤67Pa) pressurize 15 minutes, immediately break sky, VD Vacuum processing total time-consuming 29 minutes breaks 1578 DEG C of air temperature degree.

VD breaks empty sampling immediately and carries out composition detection, and MnN and CrN 60m are fed respectively according to Mn, Cr, N content in steel And 45m, and do not occur big fluctuation before C, Si content and vacuum, therefore be not adjusted, it is fed after 5 minutes uniform molten steel of soft blow Calcium silk 100m behind 10 minutes soft blow intervals, then carries out " vulcanizing again " by feeding sulphur iron wire 180m and handles, to reach elementary sulfur Content requirement range feeds and homogenizes continuous casting revolving platform on soft blow 15 minutes i.e. bull ladle, upper 1558 DEG C of steel temperature after the completion of wire process.

21 DEG C of the continuous casting degree of superheat, the constant 0.85m/min of pulling rate；Open M-EMS (180A/3Hz) and end electricity Magnetic stirs (50A/6Hz), it is ensured that molten steel uniformity；Casting process uses alkaline covering agent, installs magnesia barricade in middle packet, keeps The middle black top of the slag operation of packet, strengthens the argon gas protection between big water-coating port and long nozzle, increases big packet collector nozzle and long nozzle seam Locate external argon ring, keep micro-positive pressure 0.9Pa, reduce secondary oxidation to the greatest extent；Using the high-quality four hole mouth of a river of built-in type and sulfur-bearing Steel mould flux, casting cycle Mold face are steadily controllable.

As the above method smelt Mn-Cr systems pinion steel through rolling obtained by round steel main component and gas content：C： 0.19%, Si：0.22%, Mn：1.29%, Cr：1.15%, Mo：0.004%, B：0.0003%, Cu：0.002%th, Ni： 0.003%th, Al：0.036%, P：0.011%, S：0.027%, W：0.001%, Ti：0.0009%, N：81.8ppm O： 9.2ppm；Loose 1.0 grades of low power Indexs measure result display centre, General Loosen, center segregation are 0.5 grade；Metallographic high power Detection shows 1.0 grades of A (thin) type impurity, 0.5 grade of A (thick) type impurity, and C classes non-metallic inclusion is 0 grade, B, D class highest No more than 0.5 grade；1.0 grades of banded structure, 8 grades of grain size；Same heat (batch) number difference stocking sample is made using above-mentioned smelting process Quenching degree detected value deviation range be J1.5：43.0 ± 0.5HRC, J9：37.0 ± 0.5HRC, J15：31.5±0.5HRC.

Embodiment 3：

At 105.9 tons, hot metal ratio 88%, pig iron addition is 5.6 tons for the electric total charge weight control of converter, remaining is high-quality useless Steel.Tap terminal ingredient C：0.08%th, P：0.006%th, tapping temperature T：1650 DEG C, 85.6 tons of tap；Tapping process adds in 120kg Al blocks and 50kg calcium carbide deoxidations, add in 700kg low-carbon ferromanganeses, 250kg low titanium ferro-silicons, 1800kg low-carbons low titanium ferrochromium and 500kg high carbon ferromanganeses carry out alloying after stove, and add in 750kg lime and 350kg low titaniums synthesis slag charge carries out slag making, and tapping adopts With eccentric bottom tapping, ensure remaining steel amount in stove, forbid slag of tapping.

LF refining early period strengthens deoxidation using 25kg aluminum shots and 150kg silicon carbide, argon bottom-blowing pressure adjust to 0.45MPa, electrified regulation realize white slag after 8 minutes；Take add after the same measuring components of LF 120kg low-carbons low titanium ferrochromium, 130kg low-carbon ferromanganeses, refining middle and later periods small lot repeatedly uniformly drift SiFe powder to top of the slag deoxidation and protect slag, altogether 13kg, bottom blowing Argon pressure is adjusted to 0.25MPa；Mn, Cr reach the lower limit of target component range in 15 minutes molten steel before LF refining bull ladle, Certain surplus is stayed subsequently to feed silk nitrogen pick-up, and reach desired value and meet bull ladle temperature will for 10 minutes C, Si contents before LF refining bull ladle It asks, no longer carries out high current energization later, to prevent electrode carburetting, while consider follow-up vacuum aluminum damage, fed within 5 minutes before LF bull ladles Aluminium wire adjusts Al content to 0.048%, and slag viscosity adequate liquidity is preferable, i.e., VD stoves on bull ladle, 1625 DEG C of bull ladle temperature, LF Refine duration 59 minutes.(≤67Pa) pressurize 18 minutes, immediately broken sky, VD vacuum processings always consume under condition of high vacuum degree during VD processing When 29 minutes, break 1576 DEG C of air temperature degree.

VD breaks empty sampling immediately and carries out composition detection, and MnN and CrN 65m are fed respectively according to Mn, Cr, N content in steel And 50m, and C 15m are fed, it is to feed calcium silk 120m after 5 minutes uniform molten steel of soft blow, behind 10 minutes soft blow intervals, then passes through It feeds sulphur iron wire 180m and carries out " vulcanizing again " processing, it is uniform after the completion of hello wire process to reach the content requirement range of elementary sulfur Change continuous casting revolving platform on soft blow 18 minutes i.e. bull ladle, upper 1553 DEG C of steel temperature.

19 DEG C of the continuous casting degree of superheat, the constant 0.88m/min of pulling rate；Open M-EMS (200A/3Hz), it is ensured that steel Liquid uniformity；Casting process uses alkaline covering agent, and magnesia barricade is installed in middle packet, and black top of the slag operation is wrapped in holding, is strengthened big Argon gas protection between water-coating port and long nozzle, increases big packet collector nozzle and long nozzle seam crossing external argon ring, and holding is micro- just 0.7Pa is pressed, reduces secondary oxidation to the greatest extent；Using the high-quality four hole mouth of a river of built-in type and sulfur bearing steel mould flux, casting cycle Mold face is steadily controllable, this group even pours 6 stoves.

As the above method smelt Mn-Cr systems pinion steel through rolling obtained by round steel main component and gas content：C： 0.20%, Si：0.25%, Mn：1.30%, Cr：1.14%, Mo：0.005%, B：0.0002%, Cu：0.008%th, Ni： 0.006%th, Al：0.031%, P：0.013%, S：0.033%, W：0.001%, Ti：0.0015%, N：81.9ppm O： 8.6ppm；Low power Indexs measure result display centre is loose, General Loosen, center segregation are 0.5 grade；Metallographic high power detects table Bright 1.5 grades of A (thin) type impurity, 1.0 grades of A (thick) type impurity, C classes non-metallic inclusion are 0 grade, B classes not more than 1.0 Grade, not more than 0.5 grade of D classes；1.5 grades of banded structure, 8 grades of grain size；Same heat (batch) number is made not using above-mentioned smelting process Quenching degree detected value deviation range with stocking sample is J1.5：43.5 ± 0.5HRC, J9：37.5 ± 1.0HRC, J15：31.5 ±1.0HRC。

Comparative example 1

With embodiment 2, difference is only for remaining operation, parameter：VD breaks feeding MnN and CrN not into steel after sky, and Be by Mn, Cr content are adjusted before LF bull ladles enter VD processes so that it is guaranteed that in product steel both elements content It is constant,

Concrete technology is：

LF refining early period strengthens deoxidation using 25kg aluminum shots and 120kg silicon carbide, argon bottom-blowing pressure adjust to 0.45MPa, electrified regulation realize white slag after 8 minutes；25kg ferrosilicon, 200kg low-carbons are added after taking the same measuring components of LF Low titanium ferrochromium, 100kg low-carbon ferromanganeses, refining middle and later periods small lot repeatedly uniformly drift SiFe powder to top of the slag deoxidation protect slag, altogether 17kg, argon bottom-blowing pressure are adjusted to 0.25MPa；According to the content of Mn, Cr in final products, control within 15 minutes before LF refining bull ladle Mn, Cr reach the middle limit of target component range in molten steel processed；10 minutes C, Si contents reach desired value and expire before LF refining bull ladle Sufficient bull ladle temperature requirement no longer carries out high current energization later, to prevent electrode carburetting, while considers follow-up vacuum aluminum damage, LF is hung 5 minutes feeding aluminium wires adjust Al content to 0.045% before packet, and slag viscosity adequate liquidity is preferable, i.e., VD stoves, bull ladle on bull ladle 1629 DEG C of temperature, LF refining duration 65 minutes.VD processing when under condition of high vacuum degree (≤67Pa) pressurize 15 minutes, immediately break sky, VD vacuum processings total time-consuming 29 minutes breaks 1578 DEG C of air temperature degree.

VD breaks empty sampling immediately and carries out composition detection, does not occur big fluctuation before C, Si content and vacuum, therefore is not adjusted It is whole, i.e. feeding calcium silk 100m after 5 minutes uniform molten steel of soft blow, behind 10 minutes soft blow intervals, then by feed sulphur iron wire 180m into Row " vulcanizing again " processing, to reach the content requirement range of elementary sulfur, feeding wire process, homogenization soft blow is hung for 15 minutes after the completion Wrap continuous casting revolving platform, upper 1558 DEG C of steel temperature.

As the above method smelt Mn-Cr systems pinion steel through rolling obtained by round steel main component and gas content：C： 0.19%, Si：0.23%, Mn：1.29%, Cr：1.15%, Mo：0.006%, B：0.0005%, Cu：0.003%th, Ni： 0.005%th, Al：0.032%, P：0.014%, S：0.031%, W：0.001%, Ti：0.0014%, N：42.7ppm O： 9.3ppm；Low power Indexs measure result is shown：1.0 grades of center porosity, General Loosen, center segregation are 0.5 grade；Metallographic high power Detection shows 1.5 grades of A (thin) type impurity, 1.0 grades of A (thick) type impurity, and C classes non-metallic inclusion is 0 grade, and B classes highest is not More than 1.0 grades, not more than 0.5 grade of D classes；2.0 grades of banded structure, 7 grades of grain size；It is made same using above-mentioned smelting process The quenching degree detected value deviation range of heat (batch) number difference stocking sample is J1.5：43.0 ± 1.0HRC, J9：38.5 ± 3.0HRC, J15：33.5±3.0HRC.

Comparative example 2

After vacuum breaker soft blow, using the technique of " first feed sulphur, feed calcium again ", remaining operation, parameter with embodiment 2 not Become, concrete technology is：

VD breaks empty sampling immediately and carries out composition detection, and MnN and CrN 60m are fed respectively according to Mn, Cr, N content in steel And 45m, and do not occur big fluctuation before C, Si content and vacuum, therefore be not adjusted, it is fed after 5 minutes uniform molten steel of soft blow Sulphur iron wire 180m carries out " vulcanizing again " and handles, and behind 10 minutes soft blow intervals, then feeds calcium silk 100m, uniform after the completion of hello wire process Change continuous casting revolving platform on soft blow 15 minutes i.e. bull ladle, upper 1558 DEG C of steel temperature.

As the above method smelt Mn-Cr systems pinion steel through rolling obtained by the low power Indexs measure result of round steel show： Center porosity, General Loosen, center segregation are 0.5 grade；The detection of metallographic high power shows 3.5 grades of A (thin) type impurity, A (thick) 1.0 grades of type impurity, C classes non-metallic inclusion are 0 grade, not more than 1.5 grades of B classes, not more than 1.5 grades of D classes；It is band-like 2.0 grades of tissue, 8 grades of grain size；The quenching degree detected value that same heat (batch) number difference stocking sample is made using above-mentioned smelting process is inclined Difference ranging from J1.5：42.5 ± 0.5HRC, J9：37.0 ± 1.0HRC, J15：31.5±1.5HRC.

Claims

1. a kind of smelting process of Mn-Cr series high-performances pinion steel, it is characterised in that：The composition range of the pinion steel is,

C：0.19%, Si：0.23%, Mn：1.28%, Cr：1.15%, Mo：0.003%, B：0.0001%, Cu：0.005%、Ni： 0.005%、Al：0.028%, P：0.011%, S：0.029%, W：0.001%, Ti：0.0009%, N：73.6ppm O：11.2ppm Yu Weitie,

Or

C：0.19%, Si：0.22%, Mn：1.29%, Cr：1.15%, Mo：0.004%, B：0.0003%, Cu：0.002%、Ni： 0.003%、Al：0.036%, P：0.011%, S：0.027%, W：0.001%, Ti：0.0009%, N：81.8ppm O：9.2ppm, Yu Weitie,

Or

C：0.20%, Si：0.25%, Mn：1.30%, Cr：1.14%, Mo：0.005%, B：0.0002%, Cu：0.008%、Ni： 0.006%、Al：0.031%, P：0.013%, S：0.033%, W：0.001%, Ti：0.0015%, N：81.9ppm O：8.6ppm, Yu Weitie；

The method is that electric converter smelting, VD vacuum processings, feeds silk and soft blow, CCM continuous castings at LF refining,

During feeding silk, according to N content practical in steel and Mn, Cr content, adjustment feeding MnN and CrN, N content in steel Control Al/N in 70 ~ 100ppm, guarantee steel is 3 ~ 5.

2. the smelting process of Mn-Cr series high-performances pinion steel as described in claim 1, it is characterised in that：During electric converter smelting, Using molten iron tipple using online molten iron loading pattern, with reference to foam slag operation technique, the control of tapping carbon 0.08% ~ In the range of 0.12%, while P≤0.010% of tapping；Using eccentric bottom tapping, tapping temperature T >=1640 DEG C, tap is controlled 85 ± 2 tons,

Al blocks and calcium carbide deoxidation are added in tapping process, using low titanium ferro-silicon, low-carbon low titanium ferrochromium, low-carbon ferromanganese and high carbon ferromanganese Alloying, and add in lime and low titanium synthesis slag charge progress slag making；Forbid slag of tapping.

3. the smelting process of Mn-Cr series high-performances pinion steel as described in claim 1, it is characterised in that：When LF refining refines Between for 40 ~ 70 minutes, early period repeatedly uniformly drifts no C deoxidiser using Al and SiC progress deoxidations, middle and later periods small lot Slag, holding reducing atmosphere and the fluctuation for preventing carbon content are protected in SiFe powder to top of the slag deoxidation, and first sample ingredient is added high-quality after coming out Alloy adjusting component,

Argon pressure is adjusted LF refining early period to 0.4~0.6MPa, middle and later periods argon pressure is 0.2~0.35MPa, in holding furnace Micro-positive pressure；LF refining process makes high basicity slag；

Reach the finished product target component of each element in addition to Mn, Cr, N, S before LF refining bull ladle, wherein 10 points before LF refining bull ladle Clock C, Si content completes heating requirement simultaneously when reaching desired value, and Mn, Cr reach target component range before LF bull ladles Lower limit, Al by the control range most upper limit control, in addition specific residual elements meet Mo≤0.005%, B≤0.0003%, V≤ 0.01%th, the content requirement of Cu≤0.01%, Ni≤0.01%, W≤0.005%, Ti≤0.0015%.

4. the smelting process of Mn-Cr series high-performances pinion steel as described in claim 1, it is characterised in that：VD vacuum processings Cheng Zhong, be evacuated to≤high vacuum of 67Pa after pressurize 15 minutes, require molten steel is exposed to seethe under high vacuum.

5. the smelting process of Mn-Cr series high-performances pinion steel as described in claim 1, it is characterised in that：During feeding silk, root According to N content practical in steel and Mn, Cr content, adjustment feeding MnN and CrN, N content control is in 70 ~ 100ppm, guarantor in steel It is 3 ~ 5 to demonstrate,prove Al/N in steel；It is fed again into molten steel after calcium silk completes Calcium treatment and carries out " sulfuration process again " again.

6. the smelting process of Mn-Cr series high-performances pinion steel as described in claim 1, it is characterised in that：CCM casting process In, the continuous casting degree of superheat is controlled at 15~25 DEG C, performs slow rhythm perseverance casting speed control, and two is cold using weak cold；Casting process uses alkali Property coverture, the magnesia barricade of installation in middle packet wraps black top of the slag operation, strengthens the argon gas between big water-coating port and long nozzle in holding Protection keeps the micro-positive pressure of 0.7 ~ 0.9pa；Using the four hole mouths of a river and open electromagnetic agitation；In addition to this, it is special using sulfur bearing steel Covering slag.