CN105568178A - New manufacturing process of hot-rolled bar for carburized and quenched gear shaft of automobile transmission - Google Patents
New manufacturing process of hot-rolled bar for carburized and quenched gear shaft of automobile transmission Download PDFInfo
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Abstract
The invention discloses a new manufacturing process of a hot-rolled bar for the carburized and quenched gear shaft of an automobile transmission and solves the purity, grain size, hardenability and banded segregation problems of steel QS 4321 S0(20CrNiMoS6-4H) for a six-speed transmission. According to the technical scheme, the new manufacturing process includes: performing electric-furnace steel making, performing LF +VD external refining, allowing die casting ingot case to be 2.1t, using a 850 rolling machine for primary rolling and cogging, using 24 continuous mills for continuous rolling to form the hot-rolled bar, performing cooling/heat treatment, straightening, performing flaw detection, and polishing. The new manufacturing process has the advantages that molten steel purity is guaranteed by original material preparation and smelting process optimization; qualified steel hardenability is guaranteed by controlling chemical components, optimizing ingot case and controlling the casting process; a qualified steel band is guaranteed by using a high-temperature diffusion process; steel grain size is guaranteed by controlling rolling and cooling; steel oxygen content is kept below 20*10<-6>, the 5-level to 8-level steel carburization grain size requirements are satisfied, the qualified steel hardenability is guaranteed, and the banded structure requirement is satisfied.
Description
Technical field
The invention belongs to metallic substance and manufacture field, relate to a kind of manufacture method of automobile 6 gear gearbox vital part carburizing and quenching tooth axle-steel, be mainly used in the production of Φ 30mm ~ Φ 100mm carburizing tooth axial workpiece steel QS4321S0 (20CrNiMoS6-4H).
Background technology
Along with the high speed development of Domestic Automotive Industry, higher requirement be it is also proposed to the quality level such as purity, hardenability band, band shape of automobile steel.And determine that the key of automotive transmission quality and stability is the quality of tooth axial workpiece steel, therefore require that the quality index of carburizing tooth axial workpiece steel QS4321S0 (20CrNiMoS6-4H) is very high, low-gas content: hydrogen richness is not more than 2 × 10
-6, oxygen level is not more than 20 × 10
-6; High cleanliness: content of vanadium is not more than 0.02%, titanium content is not more than 0.02%, and arsenic content is not more than 0.05%, content of niobium is not more than 0.02%, Boron contents is not more than 0.0008%, and calcium contents is not more than 0.0020%, inclusion: B is carefully not more than 1.5 grades, B is slightly not more than 1.0 grades; The uniformity consistency of metallurgical quality: low power: center porosity is not more than 2.0 grades, General Loosen is not more than 2.0 grades, pattern segregation is not more than 2.0 grades, carburizing grain fineness number 5 grades ~ 8 grades, banded below 2.5 grades; Narrow hardening capacity (HRC): J5mm:43 ~ 48, J9mm:40 ~ 47, J15mm:35 ~ 44.At present, home and abroad uses the Cr-Ni-Mo system gear steel capital to there is composition and microstructure segregation problem, and cause part thermal treatment after strain large, engage bad between part, noise also has a strong impact on the work-ing life of part while increasing; Have no the report that home and abroad document has correlative study.
Summary of the invention
A kind of automotive transmission carburizing and quenching of disclosure of the invention tooth axle hot rolled rod manufactures novel process, solve 6 gear gearbox steel QS4321S0 (20CrNiMoS6-4H) purity, grain fineness number, hardening capacity and banded segregation problem.
For achieving the above object, the present invention adopts following technical scheme: by original ingredient and optimization smelting technology, ensure molten steel purity; By controlling chemical composition and ingot shape optimization, the control of pouring technology ensures that hardenability of steel is qualified; Steel band shape is qualified to adopt steel ingot high-temperature diffusion process to ensure; Ensure that by adopting controlled rolling and controlled cooling model steel grain fineness number is at 5 ~ 8 grades.
1. operational path: steel-making (electric furnace) → external refining (LF → VD) → die casting (ingot shape is 2.1t) → breaking down is opened 190 square billets (850 milling train) → tandem rolling and to be become a useful person (24 frame continuous mill) → cooling/thermal treatment → aligning → flaw detection → reconditioning.
2. concrete technology system:
(1) chemical composition
Automotive transmission tooth axle steel QS4321S0 (20CrNiMoS6-4H) chemical composition should meet table 1 and specify;
Table 120CrNiMoS6-4H chemical composition
Table 1(continues)
(2) process for making
1. eaf process
Total batch 65t ~ 68t, batching selects high-quality steel scrap, the pig iron, and the high duty pig iron amount of allocating into is greater than 40%; Electric furnace steel tapping adds slag charge and adopts high-quality lime (calcium oxide is not less than 90%, and raw burn rate is not more than 10%) 700kg ~ 900kg, and before tapping, oxygen intensity is used in 3min ~ 5min reduction, and increase spray carbon dust consumption, every stove is about 200kg ~ 300kg; Tapping does not allow lower oxidation sludge; Tapping process adds aluminium by 1.0kg/t; Tapping temperature is not less than 1630 DEG C, and tapping phosphorus is not more than 0.010%;
2. LF stove refinery practice
Omnidistance employing carbon dust and the diffusive deoxidation of aluminum shot mixture, first batch of reductor all uses aluminum shot, and add-on 30kg ~ 60kg(suitably can adjust add-on according to slag condition).Slag samples in vain, after taking sample 1, adopts aluminum shot and toner mixture deoxidation to keep white slag; According to the full aluminium result of sample 1 (considering in stove), feed aluminium by 0.08%, suitably can adjust according to slag condition and feed aluminum amount, the white slag hold-time is not less than 30min; Omnidistance medium tenacity argon gas stirs, and when adding alloy material, large argon gas stirs; Tapping temperature: 1670 DEG C ~ 1690 DEG C;
3. VD technique
Carry out before VD enters tank skimming processing controls thickness of slag layer at 40mm ~ 80mm, consider in stove by 0.06% feeding aluminum steel (suitably can adjust feed quantity according in stove); VD vacuum tightness is not more than 100Pa, hold-time 10min ~ 20min, and under must keeping vacuum, large discharge argon gas stirs; Sample after uncapping, adjust sulphur according to finished product sample, adjust aluminium, after feeding, the soft blow time is not less than 15min; VD tapping temperature 1580 DEG C ~ 1600 DEG C;
4. pouring technology
Cast 2.1t ingot shape, ingot mould temperature: 30 DEG C ~ 80 DEG C, carry out thermal pretreatment lower than this temperature; Argon for protecting pouring is adopted in casting process; When molten steel rises to cap mouth line 2/3 place, add heat-generating agent.
(3) rolling technology
1. breaking down cogging technics
Table temperature to show temperature 1250 DEG C ± 10 DEG C insulation 8h ~ 10h, is then cooled to 1230 DEG C by steel ingot in process furnace, and ingot temperature is that 1210 DEG C ± 10 DEG C insulation 1h come out of the stove. be rolled into 190 square billets; Roll rear steel billet and enter to cheat slow cooling 55h;
2. tandem rolling heating process
Steel billet adopts walking beam furnace to carry out heating, and (process furnace divides preheating section → heating I section → heating II section → soaking zone, count 4 sections), 120min is greater than to time requirement of coming out of the stove from entering stove, total time 75min is greater than to coming out of the stove from heating I section (intensification section), first stove steel billet arrives after fire door (namely at soaking zone) needs insulation 30min ~ 40min and to come out of the stove rolling, and steel billet is soaking zone Heating temperature 1150 DEG C ± 30 DEG C.
(4) thermal treatment process
Steel are paid with hot rolling or as-annealed condition, and annealing process is 670 DEG C ± 10 DEG C insulation 9h ~ 12h, air cooling of coming out of the stove; As rolled delivery material rolls rear cooling in heap.
(5) detect a flaw
Steel 100% carry out UT (Ultrasonic Testing) detection according to GB/T4162, A level qualified (by φ 2mm flat-bottom hole standard).
3. physicochemical property inspection
(1) banded structure
From rod iron surface to 1/2 radius sampling, sample, through 950 DEG C ± 10 DEG C heating and thermal insulation rapid cooling, after 600 DEG C ± 10 DEG C isothermal 1h air coolings, is graded according to annex under 100X, should without obvious band shape, and banded structure must not be worse than Fig. 4 (Abb.4);
(2) the qualified rank of non-metallic inclusion should meet table 2 and specifies;
The qualified rank of table 2 non-metallic inclusion
(3) grain fineness number adopts cementing process, and 5 grades ~ 8 grades qualified;
(4) hardenability of steel should meet table 3 and specifies;
The requirement of table 3 hardenability of steel
(5) the unannealed delivery hardness (HBW) of hot rolling is not more than 269; Hot-roll annealing delivery hardness (HBW)
Be not more than 255;
(6) macrostructure assay should meet table 4 and specifies;
The qualified rank of table 4 macrostructure
(7) finished product hydrogen richness is not more than 2 × 10
-6, oxygen level is not more than 20 × 10
-6.
Innovative point of the present invention is:
(1) process for making:
For improving QS4321S0 (20CrNiMoS6-4H) Molten Steel Cleanliness, control following five key links of process for making:
1. material: adopt high-quality steel scrap, (phosphorus is not more than 0.15% to high duty pig iron, sulphur is not more than
0.10%), ensure that every stove is allocated high duty pig iron into and is not less than 30t, stove tapping adds slag charge and refining must use pure white ash, and require that lime meets the above specification of quality calcium oxide of one-level and is not less than 90%, raw burn rate is not more than 10% simultaneously);
2. strictly control electric furnace steel tapping amount (electric furnace stays steel amount to be not less than 5t) and melt down speed, ensureing not
Lower oxidation sludge, ensures that VD ladle freeboard is not less than 800mm;
3. the LF white slag time is not less than 30min, and the omnidistance medium tenacity argon gas of LF stirs, and when adding alloy material, large argon gas stirs, to ensure that inclusion fully floats;
4. VD adjusts aluminium before entering tank, and adjust aluminium after VD uncaps, after adding aluminium, soft blow is not less than again
15min, the inclusion formed in molten steel to add al dissolution after ensureing can effectively float, and soft blow is as the criterion with molten steel no leakage face, prevents air inlet;
5. pour into a mould the stage, adopt argon for protecting pouring during cast, prevent molten steel secondary oxidation and gas from entering
Enter in molten steel;
(2) ensure hardening capacity technique
1. by computed in software and with reference to similar steel grade, make and reasonably smelt control composition; Cast 2.1t ingot shape is selected, to reduce pattern segregation according to production specification;
(3) control grain fineness number technique
1. aluminium content is controlled 0.025% ~ 0.04%, to ensure grain fineness number;
2. rolling adopts cooling controlling and rolling controlling process, requires that steel finishing temperature is not more than 930 DEG C;
(4) control banded technique
1. steel ingot carries out High temperature diffusion to show temperature 1250 ± 10 DEG C insulation 8h ~ 10h in process furnace;
2. steel billet is greater than 120min from entering stove to time requirement of coming out of the stove, and total time is greater than 75min from heating I section (intensification section) to coming out of the stove, and the first stove steel billet arrives after fire door (namely at soaking zone) needs insulation 30min ~ 40min and to come out of the stove rolling.
Of the present invention benefiting is: ensure that the hardening capacity of steel is qualified by accurately controlling chemical composition; Steel oxygen level is 20 × 10 to adopt vacuum degassing process to ensure
-6below; Banded structure requirement is met by carrying out high-temperature diffusion process to steel ingot; Cooling controlling and rolling controlling process is adopted to meet 5 grades ~ 8 grades requirements of steel carburizing grain fineness number; Solve wheel box tooth axle steel part band shape, purity, grain fineness number and hardening capacity problem.
Accompanying drawing explanation
Fig. 1 is the banded standard diagram Abb.1 of round steel;
Fig. 2 is the banded standard diagram Abb.2 of round steel;
Fig. 3 is the banded standard diagram Abb.3 of round steel;
Fig. 4 is the banded standard diagram Abb.4 of round steel;
Fig. 5 is QS4321S0 (20CrNiMoS6-4H) the round steel strip-chart of heat (batch) number 15203011768;
Fig. 6 is QS4321S0 (20CrNiMoS6-4H) the round steel strip-chart of heat (batch) number 15203011777;
Fig. 7 is QS4321S0 (20CrNiMoS6-4H) the round steel strip-chart of heat (batch) number 15203021585.
Embodiment
Below in conjunction with the drawings and the specific embodiments, the present invention is elaborated.
Implement 1 ~ 3 and jointly perform following technique:
1. eaf process: batching selects high-quality steel scrap, the pig iron, and the high duty pig iron amount of allocating into is greater than 40%; Tapping phosphorus is 0.010%; Tapping process adds aluminium by 1.0kg/t;
2. LF stove refinery practice: omnidistance employing carbon dust+aluminum shot mixture diffusive deoxidation, first batch of reductor all uses aluminum shot, add-on 30kg; Omnidistance intermediate flow argon gas stirs, and when adding alloy material, large discharge argon gas stirs;
3. carry out process of skimming before VD technique: VD enters tank, consider in stove by 0.06% feeding aluminum steel adjustment aluminium content; Sample after uncapping, carry out tune sulphur according to finished product sample, adjust aluminium;
4. pouring technology: ingot mould temperature 35 DEG C ~ 40 DEG C, cast 2.1t ingot shape, when molten steel rises to cap mouth line 2/3 place, adds heat-generating agent; Argon for protecting pouring is adopted in casting process;
5. breaking down cogging technics: steel ingot is to show temperature 1250 DEG C ± 10 DEG C insulation 8h ~ 10h in stove, and ingot temperature is that 1210 DEG C ± 10 DEG C insulation 1h come out of the stove rolling, rolls rear steel billet and enters to cheat slow cooling 55h;
6. tandem rolling heating process: steel billet is greater than 120min from entering stove to time requirement of coming out of the stove, namely heat up I section from heating I section and be greater than 75min to total time of coming out of the stove, first stove steel billet arrives after fire door (namely at soaking zone) needs insulation 30min ~ 40min and to come out of the stove rolling, soaking zone Heating temperature 1150 DEG C ± 30 DEG C.
7. process for cooling: steel roll rear cooling in heap.
Embodiment 1
Heat (batch) number: 15203011768, round steel trimmed size Φ 80mm;
1. production technique
(1) process for making
1. finished product (molten inspection) chemical composition is in table 5;
Table 5 finished product (molten inspection) chemical composition
Table 5(continues)
2. eaf process
Total batch 66t, wherein the pig iron allocates 35 tons into, accounting 53%; Electric furnace steel tapping adds slag charge high-quality lime 800kg; Before tapping, 5min sprays into carbon dust 200kg in stove; Electric furnace steel tapping temperature 1659 DEG C;
3. LF stove refinery practice
Feeding aluminum steel 30m, white slag time 40min after sample 1; Tapping temperature 1683 DEG C;
4. VD technique
Control thickness of slag layer of skimming is about 60mm; VD vacuum tightness 60Pa, hold-time 15min, large discharge argon gas stirs; Soft blow 25min, VD tapping temperature 1591 DEG C;
5. breaking down cogging technics
Heating Steel Ingots 8.5h;
6. tandem rolling heating process
Steel billet is 80min from heating I section to total time of coming out of the stove, and be incubated 50min when first steel billet arrives fire door, steel billet is in soaking zone Heating temperature: 1140 DEG C ~ 1165 DEG C;
2. production testing result
(1) the examination of nonmetallic inclusion the results are shown in Table 6;
Table 6 examination of nonmetallic inclusion result
(2) grain fineness number adopts cementing process, and assay is 8 grades ~ 6 grades;
(3) hardening capacity assay is in table 7;
Table 7 hardening capacity assay
(4) hardness of delivering goods (HBW): 245,248,251;
(5) macrostructure assay is in table 8;
Table 8 macrostructure assay
(6) finished product hydrogen richness: 1 × 10
-6, oxygen level: 10 × 10
-6, nitrogen content 122 × 10
-6;
(7) banded structure meets Abb.2 (see Fig. 5).
Embodiment 2
Heat (batch) number: 15203011777, round steel trimmed size Φ 90mm;
1. production technique
(1) process for making
1. finished product (molten inspection) chemical composition is in table 9;
Table 9 finished product (molten inspection) chemical composition
Table 9(continues)
2. eaf process
Total batch 66t, wherein the pig iron allocates 30 tons into, accounting 45%; Electric furnace steel tapping adds slag charge high-quality lime 800kg, and before tapping, 5min sprays into carbon dust 200kg in stove; Electric furnace steel tapping temperature 1664 DEG C;
3. LF stove refinery practice
Feeding aluminum steel 30m after sample 1, white slag time 45min, tapping temperature 1688 DEG C;
4. VD technique
Control thickness of slag layer of skimming is about 60mm, considers in stove by 0.06% feeding, 160 meters of aluminum steels adjustment Al content; VD vacuum tightness 70Pa, hold-time 20min, large discharge argon gas stirs; Soft blow 20min, VD tapping temperature 1590 DEG C;
5. cogging technics is rolled
Heating Steel Ingots 9h;
6. tandem rolling heating process
Steel billet is 75min from heating I section to total time of coming out of the stove, and be incubated 50min when first steel billet arrives fire door, steel billet is in soaking zone Heating temperature: 1145 DEG C ~ 1168 DEG C;
2. production testing result
(1) the examination of nonmetallic inclusion the results are shown in Table 10;
Table 10 examination of nonmetallic inclusion result
(2) granularity adopts cementing process, and assay is 8 grades ~ 6 grades;
(3) hardening capacity assay is in table 11;
Table 11 hardening capacity assay
(4) hardness of delivering goods (HBW): 248,247,250;
(5) macrostructure assay is in table 12;
Table 12 macrostructure assay
(6) finished product hydrogen richness: 1.0 × 10
-6, oxygen level: 10 × 10
-6, nitrogen content 125 × 10
-6;
(7) shape tissue meets Abb.2 (see Fig. 6).
Embodiment 3
Heat (batch) number: 15203021585, round steel trimmed size Φ 30mm;
1. production technique
(1) process for making
1. finished product (molten inspection) chemical composition is in table 13;
Table 13 finished product (molten inspection) chemical composition
Table 13(continues)
2. eaf process
Total batch 68t, wherein the pig iron allocates 33 tons into, accounting 48.5%; Electric furnace steel tapping adds slag charge high-quality lime 900kg, and before tapping, 5min sprays into carbon dust 300kg in stove; Electric furnace steel tapping temperature 1666 DEG C;
3. LF stove refinery practice
Feeding aluminum steel 70m after sample 1, white slag time 50min, tapping temperature 1690 DEG C;
4. VD technique
Control thickness of slag layer of skimming is about 70mm, considers in stove by 0.06% feeding, 180 meters of aluminum steels adjustment Al content; VD vacuum tightness 70Pa, hold-time 15min, large discharge argon gas stirs; Soft blow 22min, VD tapping temperature 1590 DEG C;
5. cogging technics is rolled
Heating Steel Ingots 9h;
6. tandem rolling heating process
Steel billet is 75min from heating I section to total time of coming out of the stove, and be incubated 50min when first steel billet arrives fire door, steel billet is in soaking zone Heating temperature: 1140 DEG C ~ 1165 DEG C;
2. production testing result
(1) the examination of nonmetallic inclusion the results are shown in Table 14;
Table 14 examination of nonmetallic inclusion result
(2) granularity adopts cementing process, and assay is 8 grades ~ 6 grades;
(3) hardening capacity assay is in table 15;
Table 15 hardening capacity assay
(4) hardness of delivering goods (HBW): 249,250,253;
(5) macrostructure assay is in table 16;
Table 16 macrostructure assay
(6) finished product hydrogen richness: 1.0 × 10
-6, oxygen level 11 × 10
-6, nitrogen content 120 × 10
-6;
(7) shape assay meets Abb.3 figure (see figure 7).
Claims (4)
1. an automotive transmission carburizing and quenching tooth axle hot rolled rod manufactures novel process, it is characterized in that: described novel process comprises process for making, rolling technology, thermal treatment process, described process for making comprises eaf process, LF stove refinery practice, VD technique, pouring technology; Described rolling technology comprises breaking down cogging technics, tandem rolling becomes a useful person technique;
Described eaf process:
Total batch 65t ~ 68t, batching selects high-quality steel scrap, the pig iron, and the amount of allocating into is not less than 40%; Electric furnace steel tapping adds slag charge and adopts high-quality lime, and calcium oxide is not less than 90%, and raw burn rate is not more than 10%, 700kg ~ 900kg, and before tapping, oxygen intensity is used in 3min ~ 5min reduction, and increase spray carbon dust consumption, every stove is about 200kg ~ 300kg; Tapping does not allow lower oxidation sludge; Tapping process adds aluminium by 1.0kg/t; Tapping temperature is not less than 1630 DEG C, and tapping phosphorus is not more than 0.010%;
Described LF stove refinery practice:
Omnidistance employing carbon dust and the diffusive deoxidation of aluminum shot mixture, first batch of reductor all uses aluminum shot, add-on 30kg ~ 60kg, suitably can adjust add-on according to slag condition; Slag samples in vain, after taking sample 1, adopts aluminum shot and toner mixture deoxidation to keep white slag; According to the full aluminium result of sample 1, feed aluminium by 0.08%, suitably can adjust according to slag condition and feed aluminum amount, the white slag hold-time is not less than 30min; Omnidistance medium tenacity argon gas stirs, and when adding alloy material, large argon gas stirs; Tapping temperature: 1670 DEG C ~ 1690 DEG C;
Described VD technique:
Carry out before VD enters tank skimming processing controls thickness of slag layer at 40mm ~ 80mm, consider to feed aluminum steel by 0.06% in stove, suitably can adjust feed quantity according in stove; VD vacuum tightness is not more than 100Pa, hold-time 10min ~ 20min, and under must keeping vacuum, large discharge argon gas stirs; Sample after uncapping, adjust sulphur according to finished product sample, adjust aluminium, after feeding, the soft blow time is not less than 15min; VD tapping temperature 1580 DEG C ~ 1600 DEG C;
Described pouring technology:
Cast is not more than 2.1t ingot shape, ingot mould temperature: 30 DEG C ~ 80 DEG C, carry out thermal pretreatment lower than this temperature; Argon for protecting pouring is adopted in casting process; When molten steel rises to cap mouth line 2/3 place, add heat-generating agent;
Described rolling technology:
Breaking down cogging technics:
Table temperature to show temperature 1250 DEG C ± 10 DEG C insulation 8h ~ 10h, is then cooled to 1230 DEG C by steel ingot in process furnace, and ingot temperature is that 1210 DEG C ± 10 DEG C insulation 1h come out of the stove. be rolled into 190 square billets; Roll rear steel billet and enter to cheat slow cooling 55h;
Tandem rolling heating process:
Steel billet adopts walking beam furnace to heat, process furnace divides preheating section → heating I section → heating II section → soaking zone, count 4 sections, 120min is greater than to time requirement of coming out of the stove from entering stove, from the heating I section i.e. section of intensification, to coming out of the stove, total time is greater than 75min, and the first stove steel billet arrives fire door and is namely in after soaking zone needs insulation 30min ~ 40min and comes out of the stove rolling, and steel billet is soaking zone Heating temperature 1150 DEG C ± 30 DEG C;
Described thermal treatment process
Steel are paid with hot rolling or as-annealed condition, and annealing process is 670 DEG C ± 10 DEG C, insulation 9h ~ 12h, air cooling of coming out of the stove; As rolled delivery material rolls rear cooling in heap.
2. automotive transmission carburizing and quenching tooth axle hot rolled rod manufactures novel process according to claim 1, it is characterized in that:
Described eaf process: total batch 66t, wherein the pig iron allocates 35 tons into, accounting 53%; Electric furnace steel tapping adds slag charge high-quality lime 800kg; Before tapping, 5min sprays into carbon dust 200kg in stove; Electric furnace steel tapping temperature 1659 DEG C;
Described LF stove refinery practice: first batch of reductor all uses aluminum shot, add-on 30kg; Feeding aluminum steel 30m, white slag time 40min after sample 1; Tapping temperature 1683 DEG C;
Described VD technique: control thickness of slag layer of skimming is about 60mm; VD vacuum tightness 60Pa, hold-time 15min, large discharge argon gas stirs; Soft blow 25min, VD tapping temperature 1591 DEG C;
Described pouring technology: ingot mould temperature 35 DEG C ~ 40 DEG C, cast 2.1t ingot shape;
Described rolling technology, breaking down cogging technics: Heating Steel Ingots 8.5h, temperature 1250 DEG C; To come out of the stove when ingot temperature 1220 DEG C rolling;
Tandem rolling heating process: steel billet is 2h from shove charge to the time of coming out of the stove, steel billet is 80min from heating I section to total time of coming out of the stove, and be incubated 50min when first steel billet arrives fire door, steel billet is in soaking zone Heating temperature: 1140 DEG C ~ 1165 DEG C.
3. automotive transmission carburizing and quenching tooth axle hot rolled rod manufactures novel process according to claim 1, it is characterized in that:
Described eaf process: total batch 66t, wherein the pig iron allocates 30 tons into, accounting 45%; Electric furnace steel tapping adds slag charge high-quality lime 800kg, and before tapping, 5min sprays into carbon dust 200kg in stove; Electric furnace steel tapping temperature 1664 DEG C;
Described LF stove refinery practice: first batch of reductor all uses aluminum shot, add-on 30kg, feeding aluminum steel 30m after sample 1, white slag time 45min, tapping temperature 1688 DEG C;
Described VD technique: control thickness of slag layer of skimming is about 60mm, considers in stove by 0.06% feeding, 160 meters of aluminum steels adjustment Al content; VD vacuum tightness 70Pa, hold-time 20min, large discharge argon gas stirs; Soft blow 20min, VD tapping temperature 1590 DEG C;
Described pouring technology: ingot mould temperature 35 DEG C ~ 40 DEG C, cast 2.1t ingot shape;
Described rolling technology, breaking down cogging technics: Heating Steel Ingots 9h, temperature 1250 DEG C; To come out of the stove when ingot temperature 1220 DEG C rolling;
Tandem rolling heating process: steel billet is 2h from shove charge to the time of coming out of the stove, steel billet is 75min from heating I section to total time of coming out of the stove, and be incubated 50min when first steel billet arrives fire door, steel billet is in soaking zone Heating temperature: 1145 DEG C ~ 1168 DEG C.
4. automotive transmission carburizing and quenching tooth axle hot rolled rod manufactures novel process according to claim 1, it is characterized in that:
Described eaf process: total batch 68t, wherein the pig iron allocates 33 tons into, accounting 48.5%; Electric furnace steel tapping adds slag charge high-quality lime 900kg, and before tapping, 5min sprays into carbon dust 300kg in stove; Electric furnace steel tapping temperature 1666 DEG C;
Described LF stove refinery practice: first batch of reductor all uses aluminum shot, add-on 30kg, feeding aluminum steel 70m after sample 1, white slag time 50min, tapping temperature 1690 DEG C;
Described VD technique: control thickness of slag layer of skimming is about 70mm, considers in stove by 0.06% feeding, 180 meters of aluminum steels adjustment Al content; VD vacuum tightness 70Pa, hold-time 15min, large discharge argon gas stirs; Soft blow 22min, VD tapping temperature 1590 DEG C;
Described pouring technology: ingot mould temperature 35 DEG C ~ 40 DEG C, cast 2.1t ingot shape;
Described rolling technology, breaking down cogging technics: Heating Steel Ingots 9h, temperature 1250 DEG C; To come out of the stove when ingot temperature 1220 DEG C rolling;
Tandem rolling heating process: steel billet is 2h from shove charge to the time of coming out of the stove, steel billet is 75min from heating I section to total time of coming out of the stove, and be incubated 50min when first steel billet arrives fire door, steel billet is in soaking zone Heating temperature: 1140 DEG C ~ 1165 DEG C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510872137.0A CN105568178A (en) | 2015-12-03 | 2015-12-03 | New manufacturing process of hot-rolled bar for carburized and quenched gear shaft of automobile transmission |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510872137.0A CN105568178A (en) | 2015-12-03 | 2015-12-03 | New manufacturing process of hot-rolled bar for carburized and quenched gear shaft of automobile transmission |
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| CN105568178A true CN105568178A (en) | 2016-05-11 |
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| CN201510872137.0A Pending CN105568178A (en) | 2015-12-03 | 2015-12-03 | New manufacturing process of hot-rolled bar for carburized and quenched gear shaft of automobile transmission |
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| CN105925908A (en) * | 2016-06-16 | 2016-09-07 | 安庆市吉安汽车零件锻轧有限公司 | Automobile axle material |
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| CN110306009A (en) * | 2019-07-25 | 2019-10-08 | 山东钢铁股份有限公司 | A kind of control method for cutting down low-carbon toothed wheel steel band structure |
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