CN105543644A - Novel manufacturing technology of super-large size gear steel SCM822H for industrial speed reducer - Google Patents
Novel manufacturing technology of super-large size gear steel SCM822H for industrial speed reducer Download PDFInfo
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Abstract
The invention discloses a novel manufacturing technology of a super-large size gear steel SCM822H for industrial speed reducer, and aims to provide gear round steel blanks for super-large size gear (Phi 700-980 mm) to meet the internal quality requirements. A high purity steel smelting technology is adopted, and the internal control compositions are optimized. An upsetting and rolling technology and a large deformation forging technology are adopted, and the temperature of final forging is controlled below 930 DEG C. The annealing and normalizing are performed in several sections. The technology route comprises the following steps: steel making (electric furnace), external refining (LF and VD), ingot casting, forging (3150t quick forging press or 3500t quick forging press), heat treatment, and flaw detection. The technology has the advantages that by controlling the chemical components and smelting technology, the mechanical properties can be guaranteed, and hardenability and inclusion are stable and qualified; the aluminum is controlled in smelting, in forging, upsetting and rolling, the grain size is not less than six grades; the hydrogen is removed through smelting VD, vacuum degasifying, and a unique steel annealing technology; and the problems of purity, performance, hardenability, grain size, and white spot of large size gear steel are solved.
Description
Technical field
The invention belongs to metallic substance and manufacture field, relate to a kind of manufacture novel process of industrial step-down gear Pinion Steel, be mainly used in the production of Φ 700mm ~ Φ 980mm super large-scale SCM822H Pinion Steel.
Background technology
Along with the high speed development of industrial step-down gear, to reducer gear particularly specification have higher requirement compared with the use of master wheel.The relatively large gear in current home and abroad adopts round steel directly or indirectly to produce, and the such as outside diameter of gear at Φ 400mm ~ Φ 700mm, adopts the round steel bar producing dimension, direct machining gears blank after cross-sectional direction is cut off; For the outside diameter of gear at more than Φ 700mm, be then adopt the round steel bar first producing certain specification, sawing becomes material Duan Houzai upsetting to become the mode of cake part to produce, and the Big sized gear steel such as siemens all adopts above method to produce.Although the upsetting of material section becomes the mode of production of cake part to ensure, the flaw detection of steel internal soundness is qualified, too increases the production process that the heating of material section, material section upsetting cake, the annealing of material section etc. are more loaded down with trivial details simultaneously, and the cost of its great number brought.
Adopt the direct machining gears blank of SCM822H gear round steel of Φ 700mm ~ Φ 980mm super large-scale, compared with producing with employing cake part mode, not only can shorten the production cycle, and the production cost of great number can also be reduced.But on the one hand, large-size round steel forging material need adopt large steel ingot to produce, but alloying constituent segregation is comparatively seriously, mechanical property and Hardenability Technique index is more difficult reaches; Adopting conventional long-time soak technique to be then easy to produce coarse grains for thoroughly burning large ingot shape simultaneously, being difficult to meet grain fineness number technical indicator; On the other hand, SCM822H steel is chrome-molybdenum steel, belongs to the responsive steel of white point, and smelting process conventional VD Fruit storage deficiency of time can cause hydrogen richness in molten steel higher, makes steel ingot produce white point; Moreover, forging after annealing, because specification is comparatively large, conventional annealing deficiency of time or anneal insufficient, in steel hydrogen completely diffusion remove and also can produce white point.
The problems referred to above are the important technical obstacles in Big sized gear steel SCM822H production process, and the degassed dehydrogenation problem of the purity of molten steel, the stability of chemical composition and VD that how to ensure is one of core technology of steel-making; Reduce component segregation, thoroughly elimination white point on the other hand and prevent grain fineness number from being also one of gordian technique beyond target, have no the report that home and abroad document has relevant novel process research at present, the existing production technology in home and abroad is difficult to the requirement meeting Big sized gear steel.
Summary of the invention
The present invention discloses a kind of industrial step-down gear super large-scale Pinion Steel SCM822H and manufactures novel process,
Object is for Φ 700mm ~ Φ 980mm super large-scale gear provides gear round steel blank, and reaches internal soundness requirement.
For achieving the above object, the present invention adopts following technical scheme:
1. ensure molten steel purity and stable mechanical property, hardening capacity by high purity steel smelting technology and internal control composition optimization design; Secondly adopt upsetting pull technique, gross distortion forging and control final forging temperature and is not more than 930 DEG C, ensure materials microstructure even compact, meet the requirement of flaw detection, mechanical property and grain fineness number; Dehydrogenation object is reached additionally by employing annealing and the process of normalizing multistage;
Operational path: steel-making (electric furnace) → external refining (LF, VD) → ingot casting → forging (3150t quick forging machine or 3500t quick forging machine) → thermal treatment → flaw detection.
2. concrete technology system:
(1) process for making
1. chemical composition
Large gear steel SCM822H chemical composition inner quality standard, in table 1.
Table 1SCM822H steel chemical composition inner quality standard
2. eaf process
Batching must not add briquetting, and the pig iron is allocated into and is no less than 20 tons, and electric furnace steel tapping amount controls at 60t ~ 65t; Before charging, every stove adds lime 800kg ~ 1500kg, and latter stage is striven early making foamed slag in fusing, improves thermo-efficiency; Get fine melt sample temperature and be not less than 1540 DEG C, before tapping, spray carbon dust is no less than 200kg; Electric furnace steel tapping temperature is not less than 1630 DEG C.
3. LF stove refinery practice
Put in place and do not consider to feed aluminum steel by 0.08% in stove, silicon carbide or aluminum shot is used to carry out diffusive deoxidation and keep atmosphere, first batch of add-on 40kg ~ 60kg, when slag bleaches, temperature (T) can sample 1 when being not less than 1540 DEG C, and silicon carbide or aluminum shot can add in batches, keeps white slag effect, the white slag time is not less than 30min, and tapping requires that sulphur is not more than 0.010%.
4. VD technique
Carry out process of skimming before entering tank, control thickness of slag layer at 60mm ~ 80mm, freeboard is not less than 800mm, and vacuum outgas is less than 100Pa, keeps 15min(20min in rainy season); After uncapping, hydrogen is determined in sampling; Keep a close eye on the top of the slag fluctuation situation during soft blow, with top of the slag fine motion, molten steel face is not exposed to be as the criterion, and the soft blow time is no less than 20min; Liquidus line+70 DEG C ~+90 DEG C tappings are pressed in VD tapping.
5. pouring technology
Ingot mould temperature: 20 DEG C ~ 80 DEG C, carry out thermal pretreatment lower than this temperature; To ingot mould applying argon gas before cast; Heat-generating agent is added when molten steel rises to cap mouth line 2/3 place; Argon for protecting pouring is adopted in casting process.
(2) forging process
Protect 7h ~ 10h for 1200 DEG C ~ 1220 DEG C can to come out of the stove jumping-up; Forging ratio requires to be not less than 5.Specification is less than Φ 600mm forging process and adopts a upsetting one to pull out technique, and specification is not less than Φ 600mm forging process and adopts two upsettings two to pull out technique, and pulling process will have and is no less than the above weight of two passage 150mm; Final forging temperature is not more than 930 DEG C.
(3) thermal treatment process
Air cooling to 500 DEG C ~ 550 DEG C of shove charges after forging, rise to after 870 DEG C ± 10 DEG C insulation 15h ~ 20h air coolings to 300 DEG C carry out insulation for some time after 650 DEG C ± 10 DEG C insulation 20h, 650 DEG C of soaking time at least 15h/100mm are warming up to again to be not more than 80 DEG C/h, stove is chilled to 400 DEG C afterwards, then is cooled to 200 DEG C of air coolings of coming out of the stove (see Fig. 1) to be not more than 15 DEG C/h speed.
3. physicochemical property
(1) the qualified rank of non-metallic inclusion should meet table 2 and specifies.
The qualified rank of table 2 non-metallic inclusion
(2) grain fineness number adopts cementing process, and assay should be not less than 6 grades.
(3) mechanical property should meet table 3 and specifies.
The qualified rank of table 3 mechanical property
(4) hardness of delivering goods (HBW) 160 ~ 210.
(5) the qualified rank of macrostructure should meet table 4 and specifies.
The qualified rank of table 4 macrostructure
(6) H should meet table 5 and specifies.
Table 5 H (7) UT (Ultrasonic Testing) UT is qualified.
| From quenched end distance mm | 1.5 | 3 | 5 | 7 | 9 | 11 | 13 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 |
| Higher limit | 50 | 50 | 50 | 49 | 48 | 46 | 43 | 41 | 39 | 38 | 37 | 36 | 36 | 36 | 36 |
| Lower value | 43 | 42 | 41 | 39 | 36 | 32 | 33 | 27 | 24 | 24 | 23 | 22 | 22 | 21 | 21 |
Innovative point of the present invention is:
(1) control the key link of process for making
For improving Molten Steel Cleanliness, control following five key links of process for making:
1. starting material: adopt high-quality steel scrap, the pig iron, batching must not add briquetting, and the pig iron is allocated into and is no less than 20 tons;
2. strictly control electric furnace steel tapping amount, do not ensure oxidation sludge;
3. the LF white slag time is no less than 30min, and LF whole process uses silicon carbide or aluminum shot carry out diffusive deoxidation and keep atmosphere, and when adding alloy material, large argon gas stirs, to ensure that inclusion fully floats;
4. carry out before VD enters tank skimming processing controls thickness of slag layer at 60mm ~ 80mm, freeboard is not less than 800mm, and vacuum outgas is less than 100Pa, keeps 15min(20min in rainy season); The soft blow time is no less than 20min, and to ensure that the inclusion in molten steel can fully, effectively float, soft blow is as the criterion with molten steel no leakage face, prevents air inlet;
5. pour into a mould the stage, covering slag toasts, and when molten steel rises to cap mouth line 2/3 place, adds heat-generating agent in time; Adopt argon for protecting pouring during cast, prevent molten steel secondary oxidation and enter gas in molten steel;
(2) conservative control chemical composition
Formulate internal control composition, ensure that smelting component is in span of control, stablize to make mechanical property and hardening capacity.
(3) control grain fineness number technique
1. steel aluminium content is in 0.015% ~ 0.035% scope, to control grain fineness number;
2. forging adopts upsetting pull technique, controls final forging temperature, with large processing than (processing is than being not less than 5) Broken Crystal, obtains small grains;
3. heat treatment normalizing process is adopted, effective crystal grain thinning.
(4) anti-white point technique
1. control hydrogen richness in steel and be not more than 1.7 × 10
-6;
2. air cooling to 500 DEG C after steel forging ~ 550 DEG C carries out redly sending annealing, prevents low temperature hydrogen from separating out, formation white-spot defects.
3. adopt unique annealing process, prevent hydrogen to be dissolved in a large number in residual austenite, during cooling, concentrate release; Annealing and the process of normalizing multistage will contribute to hydrogen slow releasing, to reach dehydrogenation object.
Of the present invention benefiting is: it is qualified to be stablized by control chemical composition and the guarantee of Clean Steel smelting technology mechanical property, hardening capacity and inclusion; Adopt to smelt and control aluminium technique, forging upsetting pull technique reaches large-size round steel grain fineness number and is not less than 6 grades of requirements; Dehydrogenation object is reached by the steel annealing technique of smelting VD vacuum outgas and uniqueness; Solve the purity of large gear steel, performance, hardening capacity, grain fineness number and white point problem.
Accompanying drawing explanation
Fig. 1 is large gear steel SCM822H heat treatment cycle curve figure;
Fig. 2 is heat (batch) number 15203021124 Big sized gear steel SCM822H round steel grain fineness number figure;
Fig. 3 is heat (batch) number 15203021088 Big sized gear steel SCM822H round steel grain fineness number figure;
Fig. 4 is heat (batch) number 15203021087 Big sized gear steel SCM822H round steel grain fineness number figure.
Embodiment
Below in conjunction with the drawings and the specific embodiments, the present invention is elaborated.
Embodiment 1, embodiment 2, embodiment 3 adopt same technical process: electric furnace → LF → VD → ingot casting → forging (3500 tons of quick forging machines) → thermal treatment → flaw detection.
Embodiment 1
Heat (batch) number: 15203021124, round steel trimmed size Φ 780mm, forging ratio: 5.83
1. production technique
(1) process for making
1. chemical composition assay is in table 6.
Table 6 chemical composition assay
2. eaf process
The pig iron allocates 30 tons into, steel scrap 33.45 tons, returns steel 5.6 tons, electric furnace steel tapping amount 65t; Lime 882kg is added before charging; Get fine melt sample temperature 1557 DEG C, spray carbon dust 400kg before tapping, electric furnace steel tapping temperature 1659 DEG C.
3. LF stove refinery practice
Put in place in stove and feed aluminum steel 240m, omnidistance silicon carbide and the aluminum shot of using carries out diffusive deoxidation and keeps atmosphere, first batch of add-on silicon carbide 60kg, aluminum shot 30kg, slag bleaches, 1 is sampled during temperature 1540 DEG C, follow-uply add three batches of silicon carbide and aluminum shot altogether, altogether 90kg, keep white slag effect, white slag time 55min, tapping S:0.005%.
4. VD technique
Carry out process of skimming before VD enters tank, control thickness of slag layer and be about 60mm, freeboard 800mm,
VD final vacuum 60Pa, hold-time 20min, large discharge argon gas stirs; Fixed [H] 1.3 × 10 of sampling after uncapping
-6; Top of the slag fine motion, molten steel does not have exposed, soft blow time 30min, VD tapping temperature 1594 DEG C.
5. pouring technology
Ingot mould temperature 35 DEG C ~ 40 DEG C; To ingot mould applying argon gas before cast; When molten steel rises to cap mouth line 2/3 place, add heat-generating agent; Argon for protecting pouring is adopted in casting process.
(1) forging process
Protect 8h for 1220 DEG C to come out of the stove jumping-up, forging ratio 5.83; Adopt two upsettings two to pull out explained hereafter, pulling process has the weight of two passages, and heavy draught reaches 160mm ~ 180mm, final forging temperature 870 DEG C.
(2) thermal treatment process
Air cooling to 521 DEG C shove charge after forging, rise to after 870 DEG C of insulation 15h air coolings to 300 DEG C carry out insulation 10h after 650 DEG C of insulation 20h, be warming up to 650 DEG C of insulation 105h to be not more than 80 DEG C/h again, stove is chilled to 400 DEG C, then is cooled to 200 DEG C of air coolings of coming out of the stove to be not more than 15 DEG C/h speed.
2. production testing result
(1) the examination of nonmetallic inclusion the results are shown in Table 7.
Table 7 examination of nonmetallic inclusion result
(2) grain fineness number adopts cementing process, and assay is 7 grades ~ 6 grades (see figure 2)s.
(3) mechanical properties test the results are shown in Table 8.
Table 8 mechanical properties test result
(4) hardness of delivering goods (HBW) 189,191.
(5) macroscopic examination the results are shown in Table 9.
Table 9 macrostructure assay
(6) H assay is in table 10.
Table 10 H assay
| From quenched end distance mm | 1.5 | 3 | 5 | 7 | 9 | 11 | 13 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 |
| HRC | 47.0 | 46.0 | 45.0 | 45.0 | 46.0 | 45.5 | 43.0 | 41.0 | 39.0 | 37.0 | 36.0 | 36.0 | 34.0 | 31.5 | 31.0 |
(7) UT (Ultrasonic Testing) UT is qualified.
Embodiment 2
Heat (batch) number: 15203021088, round steel trimmed size Φ 820mm, forging ratio: 5.47
1. production technique
(1) process for making
1. chemical composition assay is in table 11.
Table 11 chemical composition assay
2. eaf process
The pig iron allocates 30 tons into, steel scrap 32.9 tons, returns steel 5.95 tons, electric furnace steel tapping amount 65t; Lime 995kg is added before charging; Get fine melt sample temperature 1572 DEG C, spray carbon dust 300kg before tapping, electric furnace steel tapping temperature 1671 DEG C.
3. LF stove refinery practice
Put in place in stove and feed aluminum steel 240m, omnidistance silicon carbide and the aluminum shot of using carries out diffusive deoxidation and keeps atmosphere, first batch of add-on silicon carbide 50kg, aluminum shot 30kg, slag bleaches, 1 is sampled during temperature 1568 DEG C, follow-uply add three batches of silicon carbide and aluminum shot altogether, altogether 80kg, keep white slag effect, white slag time 65min, tapping S:0.007%.
4. VD technique
Carry out process of skimming before VD enters tank, control thickness of slag layer and be about 70mm, freeboard 800mm,
VD final vacuum 60Pa, hold-time 20min, large discharge argon gas stirs; Fixed [H] 1.1 × 10 of sampling after uncapping
-6; Top of the slag fine motion, molten steel does not have exposed, soft blow time 38min, VD tapping temperature 1590 DEG C.
5. pouring technology
Ingot mould temperature 35 DEG C ~ 42 DEG C; To ingot mould applying argon gas before cast; When molten steel rises to cap mouth line 2/3 place, add heat-generating agent; Argon for protecting pouring is adopted in casting process.
(2) forging process
Protect 9h for 1220 DEG C to come out of the stove jumping-up.Forging ratio 5.47; Adopt two upsettings two to pull out explained hereafter, pulling process has the weight of two passages, and heavy draught reaches 160mm ~ 180mm, final forging temperature 870 DEG C.
(3) thermal treatment process
Air cooling to 527 DEG C shove charge after forging, rise to after 880 DEG C of insulation 15h air coolings to 300 DEG C carry out insulation 15h after 650 DEG C of insulation 20h, be warming up to 650 DEG C of insulation 155h to be not more than 80 DEG C/h again, stove is chilled to 400 DEG C, then is cooled to 200 DEG C of air coolings of coming out of the stove to be not more than 15 DEG C/h speed.
2. production testing result
(1) the examination of nonmetallic inclusion is in table 12.
Table 12 examination of nonmetallic inclusion result
(2) grain fineness number adopts cementing process, and assay is 7 grades ~ 8 grades (see figure 3)s.
(3) mechanical properties test the results are shown in Table 13.
Table 13 mechanical properties test result
(4) hardness of delivering goods (HBW) 192,187.
(5) macroscopic examination the results are shown in Table 14.
Table 14 macroscopic examination result
(6) H assay is in table 15.
Table 15 H assay
| From quenched end distance mm | 1.5 | 3 | 5 | 7 | 9 | 11 | 13 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 |
| HRC | 46.0 | 45.0 | 45.5 | 45.0 | 43.0 | 41.5 | 41.0 | 38.5 | 37.5 | 35.5 | 32.0 | 31.0 | 31.0 | 30.58 | 29.0 |
(7) UT (Ultrasonic Testing) UT is qualified.
Embodiment 3
Heat (batch) number: 15203021087, round steel trimmed size Φ 980mm, forging ratio: 5.13
1. production technique
(1) process for making
1. chemical composition assay is shown in 16.
Table 16 chemical composition assay
2. eaf process
The pig iron allocates 30 tons into, steel scrap 31.95 tons, returns steel 7.05 tons, electric furnace steel tapping amount 60.6t; Lime 994kg is added before charging; Get fine melt sample temperature 1570 DEG C, spray carbon dust 300kg before tapping, electric furnace steel tapping temperature 1670 DEG C.
3. LF stove refinery practice
Put in place in stove and feed aluminum steel 240m, omnidistance silicon carbide and the aluminum shot of using carries out diffusive deoxidation and keeps atmosphere, first batch of add-on silicon carbide 50kg, aluminum shot 30kg, slag bleaches, 1 is sampled during temperature 1576 DEG C, follow-uply add three batches of silicon carbide and aluminum shot altogether, altogether 80kg, keep white slag effect, white slag time 60min, tapping S:0.006%.
4. VD technique
Carry out process of skimming before VD enters tank, control thickness of slag layer and be about 70mm, freeboard 800mm,
VD final vacuum 60Pa, hold-time 20min, large discharge argon gas stirs; Fixed [H] 1.1ppm after uncapping.Top of the slag fine motion, molten steel does not have exposed, 39 minutes soft blow time.VD tapping temperature 1590 DEG C.
5. pouring technology
Ingot mould temperature 38 DEG C ~ 45 DEG C; To ingot mould applying argon gas before cast; When molten steel rises to cap mouth line 2/3 place, add heat-generating agent; Argon for protecting pouring is adopted in casting process.
(1) forging process
Protect 9h for 1220 DEG C to come out of the stove jumping-up.Forging ratio 5.13; Adopt two upsettings two to pull out explained hereafter, pulling process has the weight of two passages, and heavy draught reaches 150mm ~ 180mm, final forging temperature 870 DEG C.
(3) thermal treatment process
Air cooling to 530 DEG C shove charge after forging, rise to after 880 DEG C of insulation 15h air coolings to 300 DEG C carry out insulation 15h after 650 DEG C of insulation 20h, be warming up to 650 DEG C of insulation 155h to be not more than 80 DEG C/h again, stove is chilled to 400 DEG C, then is cooled to 200 DEG C of air coolings of coming out of the stove to be not more than 15 DEG C/h speed.
2. production testing result
(1) the examination of nonmetallic inclusion is in table 17.
Table 17 examination of nonmetallic inclusion result
(2) grain fineness number adopts cementing process, and assay is 7 grades ~ 8 grades (see figure 4)s.
(3) mechanical properties test the results are shown in Table 18.
Table 18 mechanical properties test result
(4) hardness of delivering goods (HBW) 190,199.
(5) macroscopic examination the results are shown in Table 19.
Table 19 macroscopic examination
(6) H assay is in table 20.
Table 20 H assay
| From quenched end distance mm | 1.5 | 3 | 5 | 7 | 9 | 11 | 13 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 |
| HRC | 47.0 | 46.0 | 46.5 | 44.0 | 42.0 | 39.5 | 40.0 | 41.0 | 32.5 | 32.5 | 30.5 | 30.5 | 30.5 | 27.5 | 29.5 |
(7) UT (Ultrasonic Testing) UT is qualified.
Claims (5)
1. industrial step-down gear super large-scale Pinion Steel SCM822H manufactures a novel process, it is characterized in that: described new procedure optimization internal control composition design, employing high purity steel smelting technology; Adopt upsetting pull technique, gross distortion forging and control final forging temperature and be not more than 930 DEG C; Adopt annealing and normalizing multistage treatment process; Operational path: steel-making (electric furnace) → external refining (LF, VD) → ingot casting → forging (3150t quick forging machine or 3500t quick forging machine) → thermal treatment → flaw detection.
2. industrial step-down gear super large-scale Pinion Steel SCM822H manufactures novel process according to claim 1, it is characterized in that: described optimization internal control composition design, chemical composition inner quality standard are chemical composition (massfraction/%): carbon 0.21 ~ 0.23, manganese 0.65 ~ 0.75, silicon 0.20 ~ 0.30, chromium 1.00 ~ 1.10, molybdenum 0.37 ~ 0.40, sulphur is not more than 0.010, and phosphorus is not more than 0.015, aluminium 0.015 ~ 0.035, copper is not more than 0.30, and titanium is not more than 0.03, and nickel is not more than 0.25.
3. industrial step-down gear super large-scale Pinion Steel SCM822H manufactures novel process according to claim 1, it is characterized in that: described smelting technology:
Eaf process: must not prepare burden and add briquetting, the pig iron is allocated into and is no less than 20 tons, and electric furnace steel tapping amount controls at 60t ~ 65t; Before charging, every stove adds lime 800kg ~ 1500kg, and latter stage is striven early making foamed slag in fusing, improves thermo-efficiency; Get fine melt sample temperature and be not less than 1540 DEG C, before tapping, spray carbon dust is no less than 200kg; Electric furnace steel tapping temperature is not less than 1630 DEG C;
LF stove refinery practice: put in place and do not consider to feed aluminum steel by 0.08% in stove, silicon carbide or aluminum shot is used to carry out diffusive deoxidation and keep atmosphere, first batch of add-on 40kg ~ 60kg, when slag bleaches, temperature (T) can sample 1 when being not less than 1540 DEG C, and silicon carbide or aluminum shot can add in batches, keeps white slag effect, the white slag time is not less than 30min, and tapping requires that sulphur is not more than 0.010%;
VD technique: carry out process of skimming before entering tank, control thickness of slag layer at 60mm ~ 80mm, freeboard is not less than 800mm, and vacuum outgas is less than 100Pa, keeps 15min(20min in rainy season); After uncapping, hydrogen is determined in sampling; Keep a close eye on the top of the slag fluctuation situation during soft blow, with top of the slag fine motion, molten steel face is not exposed to be as the criterion, and the soft blow time is no less than 20min; Liquidus line+70 DEG C ~+90 DEG C tappings are pressed in VD tapping;
Pouring technology: ingot mould temperature 20 DEG C ~ 80 DEG C, carries out thermal pretreatment lower than this temperature; To ingot mould applying argon gas before cast; Heat-generating agent is added when molten steel rises to cap mouth line 2/3 place; Argon for protecting pouring is adopted in casting process.
4. industrial step-down gear super large-scale Pinion Steel SCM822H manufactures novel process according to claim 1, it is characterized in that: described upsetting pull technique: jumping-up of can coming out of the stove after protecting 7h ~ 10h at 1200 DEG C ~ 1220 DEG C; Forging ratio requires to be not less than 5; Specification is less than Φ 600mm forging process and adopts a upsetting one to pull out technique, and specification is not less than Φ 600mm forging process and adopts two upsettings two to pull out technique, and pulling process will have and is no less than the above weight of two passage 150mm; Final forging temperature is not more than 930 DEG C.
5. industrial step-down gear super large-scale Pinion Steel SCM822H manufactures novel process according to claim 1, it is characterized in that: described employing annealing and normalizing multistage treatment process, air cooling to 500 DEG C ~ 550 DEG C of shove charges after forging, rise to after 870 DEG C ± 10 DEG C insulation 15h ~ 20h air coolings to 300 DEG C carry out insulation for some time after 650 DEG C ± 10 DEG C insulation 20h, 650 DEG C of soaking time at least 15h/100mm are warming up to again to be not more than 80 DEG C/h, stove is chilled to 400 DEG C afterwards, then is cooled to 200 DEG C of air coolings of coming out of the stove to be not more than 15 DEG C/h speed.
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