CN102513400B - Method for forging alloy seamless steel pipe by die cast hollow ingot - Google Patents
Method for forging alloy seamless steel pipe by die cast hollow ingot Download PDFInfo
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- CN102513400B CN102513400B CN201110416940.5A CN201110416940A CN102513400B CN 102513400 B CN102513400 B CN 102513400B CN 201110416940 A CN201110416940 A CN 201110416940A CN 102513400 B CN102513400 B CN 102513400B
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Abstract
The invention provides a method for forging an alloy seamless steel pipe by a die cast hollow ingot. The method comprises the following steps: casting the smelted and finely smelted alloy molten steel into the hollow ingot; heating the hollow ingot to a deformation temperature, forging the hollow ingot for 2-3 times; setting a core rod in the hollow ingot during the forging process; rounding the forged hollow ingot by a round anvil, and then processing into a desired steel pipe. The method for forging the alloy seamless steel pipe by the die cast hollow ingot of the invention is featured with high metal yield, short production period and low production cost. The specification and length of the product are unlimited, so that the seamless steel pipe with desired outer diameter and wall thickness can be forged.
Description
Technical field
The present invention relates to seamless steel pipe manufacturing technology, particularly relate to a kind of die casting hollow steel ingot forging heavy caliber and the method for the alloy seamless steel pipe of heavy wall.
Background technology
Seamless steel pipe adopts pilger mill, tandem rolling tube machine, extruder to be rolled production usually, general carbon steel, low-alloy steel and structural alloy steel adopt the direct tube rolling of pipe mill to produce, but the chrome molybdenum high-alloy seamless steel pipe of high-pressure boiler as P91, P92 because alloy content is high, milling train perforation load is high, and infolding defect easily appears in steel pipe internal-surface.Production is rolled again after usual employing forging stock, strip plate or electroslag ingot bore hole, to reduce punch load, improve steel pipe internal-surface quality, and adopt this technique, recovery rate of iron is low, production cycle is long, and by the impact of Tube Rolling Train ability, pipe specification and compression ratio, steel pipe specification can be very limited.
At present, there is the method adopting Radial Forging Technology to produce Large diameter steel alloy seamless pipe, the method is: be centrifuged through the molten steel of refining and be cast as Large diameter hollow bloom, the surfaces externally and internally of Large diameter hollow bloom carries out machined, the thickness of cutting of inner surface is no less than 5 millimeters, and outer surface thickness of cutting is no less than 2 millimeters; And at the affixed carbon steel in the one or both ends of hollow bloom " chuck material ", the length of " chuck material " is 300 ~ 800 millimeters; The Large diameter hollow bloom machined heats through two kinds of mode of heatings; In hollow bloom, insert plug, then import in radial forging and carry out forging shaping, the obtained satisfactory pipe fitting of wall thickness, diameter and length.There is following defect in the method: Large diameter hollow bloom is centrifugal casting, need to carry out surfaces externally and internally machined, at pipe two ends welding " chuck material ", pipe production cost is high, recovery rate of iron is low, and by the restriction of centrifugal casting machine and footpath forging capabilities, the external diameter of pipe, weight and length all will be restricted, and the Large diameter tube outer diameter therefore produced and wall thickness all can be very limited.
Adopt the mode of open die forging also can produce large-sized heavy-wall tube, but because steel pipe is compared with long and internal diameter is little, therefore diameter of bore is difficult to forge, and is only forged into solid bar, then machined endoporus, for production large-sized heavy-wall tube, causes great waste of material.In addition, the requisite large allowance of open die forging also exacerbates the waste of material, simultaneously greatly increase machined cost, what is more important has to because stock utilization is extremely low use large steel ingot and large tonnage pressing machine, makes like this to produce difficulty and properties of product are difficult to ensure.
In addition, require that steel pipe length is greater than 5 meters for the heavy caliber of overcritical power station unit, heavy wall chrome molybdenum high alloy (such as P91, P92) high-pressure boiler tube, external diameter is greater than Φ 450mm, and wall thickness is greater than 60mm, and compression ratio is greater than 3.And the high-alloy steel deformation temperature range of such as P91, P92 is narrow, plasticity is poor, resistance of deformation is large, cause processing difficulties, production cost is high and production process is long, and be the difficult problem that high-alloy steel pipe is produced, especially large-sized heavy-wall tube relies on import for a long time always.Because chrome molybdenum high-alloy steel perforation load is large, by the restriction of mill capacity, directly to bore a hole tube rolling with steel ingot, there will be and wear motionless or steel pipe internal-surface and produce infolding defect, and by the impact of steel ingot weight, after tube rolling, compression ratio does not reach regulation requirement.
Summary of the invention
In order to solve the above-mentioned one or more problem existed in prior art, the invention provides a kind of method of forging alloy seamless steel pipe by die cast hollow ingot, described method comprises the steps: the alloy molten steel through smelting and refining to be molded into hollow steel ingot; Hollow steel ingot is heated to its deformation temperature range, through the forging and stamping of 2-3 passage, forging is carried out to hollow steel ingot; When forging and pressing, in hollow steel ingot, be provided with plug; With circular anvil mould, the hollow steel ingot after forging is peeped circle to be shaped, be reprocessed into the steel pipe of expectation.
Can be 1150 DEG C-1250 DEG C by the deformation temperature range of the hollow steel ingot of chrome molybdenum high alloy molten steel die casting.
When carrying out every time forging and stamping, stopping forging and stamping when hollow steel ingot temperature reaches 870 ± 20 DEG C, and again hollow steel ingot being heated to its deformation temperature range, until each passage has forged and pressed.
The diameter of plug can 10mm to 25mm less of the endoporus of hollow steel ingot, and plug can water flowing cooling.
The drafts of the first passage can be 40mm to 60mm, and the drafts of the second passage can be 25mm to 35mm, and the drafts of the 3rd passage can be 5mm to 20mm.
The method of employing hollow steel ingot forging steel pipe of the present invention is not by the restriction of Ingot Type, and outer diameter of steel pipes and length can not be subject to strict restriction, and thickness of steel pipe is thicker, and the recovery rate of metal is higher, and cost is lower.Therefore, the method of employing hollow steel ingot wrought alloy seamless steel pipe of the present invention has the advantages such as recovery rate of iron is high, with short production cycle, production cost is low, and malleablely make external diameter at more than Φ 450mm, wall thickness at the seamless steel pipe of more than 60mm, be particularly suitable for high-alloy steel heavy caliber thick wall seamless steel tube and produce.
Detailed description of the invention
Comprise the steps: the alloy molten steel (such as, chrome molybdenum high alloy molten steel) through smelting and refining to be molded into hollow steel ingot according to the method for wrought alloys seamless steel pipe of the present invention; Hollow steel ingot is heated to its deformation temperature range, through the forging and stamping of 2-3 passage, forging is carried out to hollow steel ingot; When forging and pressing, in hollow steel ingot, be provided with plug; With circular anvil mould, the hollow steel ingot after forging is peeped circle to be shaped, be reprocessed into the steel pipe of expectation.
Can be 1150 DEG C-1250 DEG C by the deformation temperature range of the hollow steel ingot of chrome molybdenum high alloy molten steel die casting.
When carrying out every time forging and stamping, stopping forging and stamping when hollow steel ingot temperature reaches 870 ± 20 DEG C, and again hollow steel ingot being heated to its deformation temperature range, until each passage has forged and pressed.
The diameter of plug can 10mm to 25mm less of the endoporus of hollow steel ingot, and plug can water flowing cooling.
The drafts of the first passage can be 40mm to 60mm, and the drafts of the second passage can be 25mm to 35mm, and the drafts of the 3rd passage can be 5mm to 20mm.
Be described in detail below in conjunction with the method for specific embodiment to wrought alloys seamless steel pipe of the present invention.
embodiment 1
In embodiment 1, P91 steel is adopted to carry out alloying seamless steel pipe.First, carry out electric arc furnace smelting to first steel-making water, tap when carbon≤0.03%, phosphorus≤0.004%, temperature >=1650 ~ 1680 DEG C in molten steel, tapping process carries out liquid steel pre-deoxidizing and alloying.Then, make molten steel through LF external refining, carry out deoxidation, desulfurization, removal of inclusions, adjustment alloying component at LF stove.Hang out LF stove when liquid steel temperature reaches 1680 DEG C ~ 1700 DEG C and chemical composition meets standard-required, the molten steel of using LF stove carries out VD application of vacuum, removes gas and field trash.Subsequently, the molten steel after electric furnace smelting and external refining, application of vacuum is molded into the hollow steel ingot of internal diameter Φ 330mm, external diameter Φ 930mm.
The hollow steel ingot be cast into is delivered to gas-fired heater heat, and hollow steel ingot is heated to deformation temperature range, for chrome molybdenum high alloy steel ingot, deformation temperature range is 1150 DEG C ~ 1250 DEG C.Then the hollow steel ingot heated is placed on the anvil of forging press, feeder clamps the endoporus of the plug insertion hollow steel ingot of external diameter Φ 310mm, water flowing cooling in plug simultaneously, forging machine carries out the pulling of the first passage to hollow steel ingot by the drafts of 60mm, stop forging and stamping when hollow ingot temperature reaches 870 ± 20 DEG C.Then, hollow blank is sent back to heating furnace and carry out second time heating, and make hollow blank reach deformation temperature range, such as 1150 DEG C ~ 1250 DEG C, subsequently the steel ingot heated is hung out and carry out the second passage forging and stamping, by the drafts of 35mm, hollow steel ingot is carried out to the pulling of the second passage, stop forging and stamping when hollow ingot temperature reaches 870 ± 20 DEG C.Through after different drafts carries out the forging of several time, the hollow bloom that formation external diameter is 545mm, internal diameter is 320mm and wall thickness 112.5mm.
Finally, with the circular anvil mould of endoporus 530 ~ 540mm, the hollow bloom of formation can be peeped circle and be shaped, reduce the processing capacity of steel tube surface, improve recovery rate of iron, reduce production cost.Then, send heating furnace to anneal the steel pipe of forging, steel pipe two end-grain cutting after annealing is put down, and machining surface is processed into the steel pipe of 510mm (external diameter) × 85mm (thickness), becomes qualified tubing after Overheating Treatment.
embodiment 2
In example 2, P92 steel is adopted to carry out alloying seamless steel pipe.Carry out electric arc furnace smelting to first steel-making water, tap when carbon≤0.03%, phosphorus≤0.003%, temperature >=1650 ~ 1680 DEG C in molten steel, tapping process carries out liquid steel pre-deoxidizing and alloying.Then, make molten steel through LF external refining, carry out deoxidation, desulfurization, removal of inclusions, adjustment alloying component at LF stove.Hang out LF stove when liquid steel temperature reaches 1680 DEG C ~ 1700 DEG C and chemical composition meets standard-required, the molten steel of using LF stove carries out VD application of vacuum, removes gas and field trash.Subsequently, the molten steel after electric arc furnace smelting and external refining, application of vacuum is molded into the hollow steel ingot of internal diameter Φ 320mm and external diameter Φ 1080mm.
The hollow steel ingot be cast into is delivered to gas-fired heater heat, and hollow steel ingot is heated to deformation temperature range, for chrome molybdenum high alloy steel ingot, deformation temperature range is 1150 DEG C ~ 1250 DEG C.Then the hollow steel ingot heated is placed on the anvil of forging press, feeder clamps the endoporus of the plug insertion hollow steel ingot of external diameter Φ 310mm, water flowing cooling in plug simultaneously, forging machine carries out the pulling of the first passage to hollow steel ingot by the drafts of 40mm, stop forging and stamping when hollow ingot temperature reaches 870 ± 20 DEG C.Then, hollow blank is sent back to heating furnace and carry out second time heating, and make hollow ingot temperature reach deformation temperature range, such as 1150 DEG C ~ 1250 DEG C, subsequently the hollow ingot heated is hung out and carry out the second passage forging, by the drafts of 25mm, hollow steel ingot is carried out to the pulling of the second passage, forging and stamping are stopped when hollow ingot temperature reaches 870 ± 20 DEG C, hollow ingot is sent back to heating furnace and carry out third time heating, heating-up temperature hangs out when reaching 1150 ~ 1250 DEG C carries out the 3rd passage forging, first by the drafts of 20mm, forging is carried out to hollow steel ingot, again drafts is transferred to 10mm and carries out forging.Through after different drafts carries out the forging of several time, the hollow bloom that formation external diameter is 577mm, internal diameter is 349mm and wall thickness 114mm.
Finally with the circular anvil mould of endoporus 580 ~ 590mm, hollow bloom is peeped circle to be shaped, reduce the processing capacity of steel tube surface, improve recovery rate of iron, reduce production cost.The steel pipe of forging send heating furnace to anneal, and steel pipe two end-grain cutting after annealing is put down, and machining surface is processed into the steel pipe of 559mm (external diameter) × 95mm (thickness), becomes qualified tubing after Overheating Treatment.
embodiment 3
In example 2,91 steel are adopted to carry out alloying seamless steel pipe.Carry out electric arc furnace smelting to first steel-making water, tap when carbon≤0.03%, phosphorus≤0.004%, temperature >=1650 ~ 1680 DEG C in molten steel, tapping process carries out liquid steel pre-deoxidizing and alloying.Then, make molten steel through LF external refining, carry out deoxidation, desulfurization, removal of inclusions, adjustment alloying component at LF stove.Hang out LF stove when liquid steel temperature reaches 1680 DEG C ~ 1700 DEG C and chemical composition meets standard-required, the molten steel of using LF stove carries out VD application of vacuum, removes gas and field trash.Subsequently, the molten steel after the application of vacuum of electric furnace smelting and external refining is molded into the hollow steel ingot of internal diameter Φ 295mm and external diameter Φ 880mm.
The hollow steel ingot be cast into is delivered to gas-fired heater heat, and hollow steel ingot is heated to deformation temperature range, for chrome molybdenum high alloy steel ingot, deformation temperature range is 1150 DEG C ~ 1250 DEG C.Then the hollow steel ingot heated is placed on the anvil of forging press, feeder clamps the endoporus of the plug insertion hollow steel ingot of external diameter Φ 280mm, water flowing cooling in plug simultaneously, forging machine carries out the pulling of the first passage to hollow steel ingot by the drafts of 50mm, stop forging and stamping when hollow ingot temperature reaches 870 ± 20 DEG C.Then, hollow blank is sent back to heating furnace and carry out second time heating, and make hollow ingot reach deformation temperature range, such as 1150 DEG C ~ 1250 DEG C, subsequently the hollow ingot heated is hung out and carry out the second passage forging, by the drafts of 30mm, hollow steel ingot is carried out to the pulling of the second passage, forging and stamping are stopped when hollow ingot temperature reaches 870 ± 20 DEG C, hollow ingot is sent back to heating furnace and carry out third time heating, heating-up temperature hangs out when reaching 1150 ~ 1250 DEG C carries out the 3rd passage forging, carries out forging by the drafts of 18mm to hollow steel ingot.Through after different drafts carries out the forging of several time, the hollow bloom that formation external diameter is 482mm, internal diameter is 319mm and wall thickness 81.5mm.
Finally with the circular anvil mould of endoporus 470 ~ 480mm, hollow bloom is peeped circle to be shaped, reduce the processing capacity of steel tube surface, improve recovery rate of iron, reduce production cost.The steel pipe of forging send heating furnace to anneal, and steel pipe two end-grain cutting after annealing is put down, and machining surface is processed into the steel pipe of 457mm (external diameter) × 60mm (thickness), becomes qualified tubing after Overheating Treatment.
In the method for wrought alloys of the present invention (such as chrome molybdenum high alloy) seamless steel pipe, the surfaces externally and internally of hollow steel ingot does not need to carry out machined, steel ingot is directly delivered to heating furnace and is heated, according to chrome molybdenum high-alloy steel such as P91, the deformation temperature range of P92 heats, temperature send hydraulic press to forge after reaching requirement, during forging, plug is inserted hollow steel ingot endoporus, preferably, plug size 10 ~ 25mm less of hollow steel ingot endoporus, plug water flowing cools, hollow steel ingot does not need to weld " chuck material ", steel ingot is forged into the steel pipe of needs through 2 ~ 3 passages, wherein, the drafts of the first passage forging is 40 ~ 60mm, the drafts of the second passage forging is 25 ~ 35mm, the drafts of the 3rd passage forging is 5 ~ 20mm, final forging temperature controls more than the Ac3 at steel grade.Steel pipe after forging carries out annealing in process again, and end to end, carry out surfaces externally and internally machined, the Steel Pipe Heat after processing is processed into production tube to the steel pipe excision after annealing.
In addition, adopt the high-alloy steel hollow steel ingot that die casting is produced, through the forging of hydraulic forging press cored bar, overcome the problem that blank needs surfaces externally and internally machined, processing charges increase and recovery rate of iron to reduce; Adopt hollow steel ingot forging steel pipe not need to weld " chuck material ", decrease processing chuck material process and welding sequence; Adopt hollow steel ingot forging steel pipe not by the restriction of Ingot Type, outer diameter of steel pipes and length are not particularly limited, and thickness of steel pipe is thicker, and the recovery rate of metal is higher, and cost is lower.Therefore, the method of employing hollow steel ingot forging seamless steel pipe of the present invention has the advantages such as recovery rate of iron is high, with short production cycle, production cost is low, and product specification, length are unrestricted, can forging external diameter at more than Φ 450mm, wall thickness at the seamless steel pipe of more than 60mm, be particularly suitable for high-alloy steel heavy caliber thick wall seamless steel tube and produce.
Claims (7)
1. by a method for forging alloy seamless steel pipe by die cast hollow ingot, it is characterized in that, described method comprises the steps:
Alloy molten steel through smelting and refining is molded into hollow steel ingot;
Hollow steel ingot is heated to its deformation temperature range, through the forging and stamping of 2-3 passage, forging is carried out to hollow steel ingot; When forging and pressing, in hollow steel ingot, be provided with plug;
With circular anvil mould, the hollow steel ingot after forging is peeped circle to be shaped, is reprocessed into the steel pipe of expectation,
Wherein, described alloy molten steel is chrome molybdenum high alloy molten steel, and obtained steel pipe is external diameter at more than Φ 450mm, wall thickness at the high-alloy steel heavy caliber thick wall seamless steel tube of more than 60mm.
2. method according to claim 1, is characterized in that, the deformation temperature range of hollow steel ingot is 1150 DEG C-1250 DEG C.
3. method according to claim 1, is characterized in that, when carrying out every time forging and stamping, stopping forging and stamping, and again hollow steel ingot is heated to its deformation temperature range, until each passage has forged and pressed when hollow steel ingot temperature reaches 870 ± 20 DEG C.
4. method according to claim 1, is characterized in that, the diameter 10mm to 25mm less of the endoporus of hollow steel ingot of plug, and plug water flowing cools.
5. method according to claim 1, is characterized in that, the drafts of the first passage is 40mm to 60mm.
6. method according to claim 1, is characterized in that, the drafts of the second passage is 25mm to 35mm.
7. method according to claim 2, is characterized in that, the drafts of the 3rd passage is 5mm to 20mm.
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| CN103056183B (en) * | 2013-01-24 | 2015-08-19 | 太原科技大学 | A kind of thick-walled seamless steel pipes short-flow casting squeezes the method for progressive forming |
| CN103386587B (en) * | 2013-07-08 | 2015-11-25 | 甘肃酒钢集团西部重工股份有限公司 | A kind ofly grind the method for large ring processed with centrifugal hollow steel ingot |
| CN106756500B (en) * | 2016-12-26 | 2018-10-02 | 天津钢管集团股份有限公司 | High-intensity and high-tenacity seamless steel pipe for gas cylinder and production method |
| CN106862549B (en) * | 2017-04-18 | 2018-07-20 | 南通盛立德金属材料科技有限公司 | Integrated type stainless steel tube production line |
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| CN102179478A (en) * | 2011-01-24 | 2011-09-14 | 江苏兴盛风能科技有限公司 | Cold iron drying device and using method thereof during casting of cold iron |
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| US4714498A (en) * | 1986-06-27 | 1987-12-22 | National Forge Company | Process for producing large section, large mass forged sleeves from large diameter ingots of alloy 625 |
| KR20060095032A (en) * | 2005-02-25 | 2006-08-30 | 대우조선해양 주식회사 | Pressure hull manufacture method for submarine using hollow forging technique |
| CN101376204B (en) * | 2007-08-30 | 2010-07-28 | 北京首宏钢科技开发有限公司 | Novel technique for producing seamless steel pipe |
| CN101439365B (en) * | 2008-11-21 | 2011-09-14 | 攀钢集团成都钢铁有限责任公司 | Method for rolling seamless steel pipe from die-casting hollow steel ingot |
| CN101633115A (en) * | 2009-08-06 | 2010-01-27 | 刘怀文 | Novel method for producing high-grade alloy steel seamless steel tube |
| CN201558924U (en) * | 2009-11-23 | 2010-08-25 | 北京首宏钢科技开发有限公司 | Tube blank for producing large-caliber alloy steel seamless steel tube on radial forging machine |
| CN101722262B (en) * | 2009-11-23 | 2012-07-18 | 北京首宏钢科技开发有限公司 | New method for producing medium and large caliber alloy steel seamless pipe by utilizing radial forging technology |
| CN101811149B (en) * | 2010-04-14 | 2012-05-23 | 新兴铸管股份有限公司 | Manufacturing method of high alloy seamless steel tube |
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| CN102179478A (en) * | 2011-01-24 | 2011-09-14 | 江苏兴盛风能科技有限公司 | Cold iron drying device and using method thereof during casting of cold iron |
Non-Patent Citations (1)
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| 南昌航空专科学校.锻后整形.《自由锻造工艺学》.1961,307. * |
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