CN102240889B - Manufacturing method for continuously rolling seamless steel pipe by using hollow mandril - Google Patents
Manufacturing method for continuously rolling seamless steel pipe by using hollow mandril Download PDFInfo
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- CN102240889B CN102240889B CN201110112245XA CN201110112245A CN102240889B CN 102240889 B CN102240889 B CN 102240889B CN 201110112245X A CN201110112245X A CN 201110112245XA CN 201110112245 A CN201110112245 A CN 201110112245A CN 102240889 B CN102240889 B CN 102240889B
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Abstract
The invention provides a method for manufacturing a hollow mandril of a continuously rolling seamless steel pipe. The method comprises the following steps of: designing the steel grade and the specification of the hollow mandril; performing continuous casting, cogging, and forging; rolling a mandril material, performing tempering heat treatment; and detecting the performance of the mandril material, and processing and connecting the mandril material. The method has the advantages that: the problem that the retained mandril depends on import for a long time is solved, so that the production localization of the retained madril is realized; the service life of the mandril is close to or the same as that of the solid mandril of the same specification which is imported from foreign countries or bought in China; and the quality of the inner and outer surfaces of a seamless steel pipe product in the production process is good, 1.5 to 1.7kg of steel is consumed for one ton of mandrils, the cost of one ton of steel is 30 yuan which is only one third the original cost, and the production cost is greatly reduced. Due to the development and use of the hollow mandril, the consumption cost of a tool is reduced, and the market competitiveness of a steel pipe product is improved; the technology promotion of the mandril manufacturing industry in China is driven, and the method has a profound and lasting significance for the top potential and consumption reduction of metallurgical industry.
Description
Technical field
The invention belongs to the steel pipe rolling technology of metallurgical industry, particularly a kind of manufacturing approach of producing the hollow plug of tandem rolling seamless steel pipe.
Background technology
The hot continuous rolling unit of producing hot rolled seamless steel tube both at home and abroad all uses solid mandrel; Mostly this kind plug is the H13 steel grade of external import, and single average price is more than 200,000 yuan, and the plug cost accounts for hot rolling instrument cost more than 40% in steel pipe's production; Loss per ton steel is at 60 yuan/ton; Cost is high, and procurement price is lasting high simultaneously, and the delivery cycle also reached more than 1 year.
Variation along with Market Situation, reducing production costs, improve tube quality is that the raising product competitiveness is the matter of great urgency.But through with the negotiation of external plug manufacturer, also do not have novel plug to satisfy the requirement of our factory at present, have only independent research in this case, adopt the hollow plug of extra strong pipe processing and fabricating can reach the purpose that reduces cost.But adopt H13 with the rolling thick walled steel tube of steel grade, steel grade smelting on the one hand, Technology for Heating Processing more complicated, the domestic and international in addition record that does not also have rolling H 13 steel pipes, the especially production of extra strong pipe, mill load is big, is difficult to satisfy batch production requirement.
Need adopt a kind of novel steel grade should satisfy performance requirements such as mandril strength for this reason, can on milling train, realize difficult problems such as batch process again, realize reducing the purpose of hot rolling instrument cost with hollow plug substituting import one plug.
Summary of the invention
For solving the problem that exists in the above-mentioned technology, the purpose of this invention is to provide a kind of manufacturing approach of producing the hollow plug of tandem rolling seamless steel pipe, meet the needs of production, reduce production costs.
For realizing above-mentioned purpose, technical solution of the present invention provides a kind of manufacturing approach of producing the hollow plug of tandem rolling seamless steel pipe, and this method may further comprise the steps:
1., the design of hollow plug steel grade, specification
Confirm that the used steel grade of hollow plug is that 30Cr3MoV forges base; The used plug of tandem rolling seamless steel pipe on the equipment of ASSEL unit; Confirm that forging the base specification is Φ 250 * 3850mm, the rolling mother metal that is the steel pipe of Φ 176 * 41 * 10650mm and 186 * 36 * 10900mm specification as the hollow plug of making through the ASSEL unit;
Finally, the mother metal of Φ 176 * 41 * 10650mm is processed into the plug of Φ 171 * 35 * 10500mm, and the mother metal of 186 * 36 * 10900mm is processed into 176.4 * 32 * 10500mm and 174.3 * 30 * 10500mm size mandril;
The component of said 30Cr3MoV steel grade in quality % proportioning is: C:0.28～0.33%, Si:0.65～0.80%, Mn:0.65～0.85%, Cr:3.20～3.50%; Mo:0.48～0.58%, V:0.25～0.35%, P≤0.012%, S≤0.005%; Ni≤0.20%, Al≤0.020%, Cu≤0.20%, N≤0.010%; O≤0.003%, H≤0.00015%, all the other are iron, the impurity element trace;
2., continuous casting, cogging, forging
1. steel grade component weight item batching is smelted set by step, and electric furnace steel making is after the molten steel process VD vacuum outgas after refining is intact; Last continuous casting platform carries out continuous casting; Carry out cogging then, forge base, forging the high temperature homogenizing temperature is 1230～1250 ℃, and final forging temperature is >=850 ℃;
3., the plug material is rolling
4., modified heat treatment
The Technology for Heating Processing of tempering again after adopt quenching is heated to complete austenitizing temperature AC with rolling above-mentioned plug material earlier
3More than 20 ℃～25 ℃, be incubated 120 minutes, the back water hardening of coming out of the stove, the control water yield and water temperature reenter 635 ℃ of processing of tempering furnace then, the stable insulation 160 minutes under temperature of plug material;
5., through the said plug material Performance Detection after the modified heat treatment:
Yield strength: >=900MPa
Tensile strength: 1050～1200MPa
Hardness: 315-360HB
Percentage elongation: >=10%;
6., the processing of plug material be connected
The plug material is processed as hollow plug; This hollow plug includes plug front end, plug active section, plug active section joint, plug extension rod and caudal peduncle; Plug active section after modified heat treatment is carried out rough turn, be preheated to plug front end, plug active section, plug active section joint respectively >=150 ℃ after, be welded to connect plug front end, plug active section, plug active section joint successively with alloy welding wire again; After again the outer surface of plug active section being comprised the finish turning of tapering, plug active section joint is carried out screw thread processing; Polish chromium plating, dehydrogenation is handled the back phosphatization, connects plug extension rod and plug active section joint are stubborn at last; Caudal peduncle and plug extension rod are twisted and are connect, and form to be used in the hollow plug on the retained mandrel tandem rolling tube machine.
The invention has the beneficial effects as follows that this method has solved the long-term dependence on import of retained mandrel, greatly reduce production cost, be reduced to present 20 yuan for 60 yuan by loss per ton steel in the past; Realized retained mandrel production production domesticization; Because the exploitation of hollow plug is used, and has reduced the instrument consuming cost, has improved the market competitiveness of company's tube product; Driven domestic plug and made the lifting of industry technology, metallurgy industry is taped the latent power to lower consumption has profound significance.
Description of drawings
Fig. 1 is the hollow plug syndeton of a present invention sketch map.
Among the figure:
1, plug front end 2, plug active section 3, plug active section joint
4, plug extension rod 5, caudal peduncle
The specific embodiment
In conjunction with embodiment the manufacturing approach of the hollow plug of production tandem rolling seamless steel pipe of the present invention is explained.
The manufacturing approach of the hollow plug of production tandem rolling seamless steel pipe of the present invention, this method may further comprise the steps:
1., the design of hollow plug steel grade, specification
Confirm that the used steel grade of hollow plug is that 30Cr3MoV forges base; The used plug of tandem rolling seamless steel pipe on the equipment of ASSEL unit; Confirm that forging the base specification is Φ 250 * 3850mm; The rolling mother metal that is the steel pipe of Φ 176 * 41 * 10650mm and 186 * 36 * 10900mm specification as the hollow plug of making through the ASSEL unit, final, the mother metal of Φ 176 * 41 * 10650mm is processed into the plug of Φ 171 * 35 * 10500mm; The mother metal of 186 * 36 * 10900mm is processed into 176.4 * 32 * 10500mm and 174.3 * 30 * 10500mm size mandril, accomplishes whole manufacturing process of hollow plug again through polishing chromium plating;
The component of said 30Cr3MoV steel grade in quality % proportioning is: C:0.28～0.33%, Si:0.65～0.80%, Mn:0.65～0.85%, Cr:3.20～3.50%; Mo:0.48～0.58%, V:0.25～0.35%, P≤0.012%, S≤0.005%; Ni≤0.20%, Al≤0.020%, Cu≤0.20%, N≤0.010%; O≤0.003%, H≤0.00015%, all the other are iron, the impurity element trace;
2., continuous casting, cogging, forging
Smelt by above-mentioned steel grade component weight item batching, electric furnace steel making is after the molten steel process VD vacuum outgas after refining is intact; Last continuous casting platform carries out continuous casting; Carry out cogging then, forge base, forging the high temperature homogenizing temperature is 1230～1250 ℃, and final forging temperature is >=850 ℃;
3., the plug material is rolling
Above-mentioned forging stock heats in rotary heating furnace through scale forging stock after the assay was approved, and furnace temperature of heating furnace is controlled to be 1230～1260 ℃, and through perforation, ASSEL mill milling and sizing, finishing temperature is 1000～1060 ℃ again, behind aligning, becomes to be rolled into the plug material;
4., modified heat treatment
The Technology for Heating Processing of tempering again after adopt quenching is heated to complete austenitizing temperature AC with rolling above-mentioned plug material earlier
3More than 20 ℃～25 ℃, be incubated 120 minutes, the back water hardening of coming out of the stove, the control water yield and water temperature reenter 635 ℃ of processing of tempering furnace then, the stable insulation 160 minutes under temperature of plug material;
5., through the said plug material Performance Detection after the modified heat treatment:
Yield strength: >=900MPa
Tensile strength: 1050～1200MPa
Hardness: 315-360HB
Percentage elongation: >=10%;
6., the processing of plug material be connected
The plug material is processed as hollow plug; This hollow plug includes plug front end 1, plug active section 2, plug active section joint 3, plug extension rod 4 and caudal peduncle 5; Plug active section after modified heat treatment 2 is carried out rough turn, be preheated to plug front end 1, plug active section 2, plug active section joint 3 respectively >=150 ℃ after, be welded to connect plug front end 1, plug active section 2, plug active section joint 3 successively with alloy welding wire again; After again the outer surface of plug active section 2 being comprised the finish turning of tapering, plug active section joint 3 is carried out screw thread processing; Polish chromium plating, dehydrogenation is handled the back phosphatization, plug extension rod 4 is twisted with plug active section joint 3 to connect at last; Caudal peduncle 5 is twisted with plug extension rod 4 and is connect, and forms and is used in the hollow plug on the retained mandrel tandem rolling tube machine.
The manufacturing approach of the hollow plug of production tandem rolling seamless steel pipe of the present invention is achieved in that
1, according to service condition, the processing technology of plug, combine the production equipment ability simultaneously, designing and developing the used steel grade of hollow plug is that 30Cr3MoV forges base, and the component of this steel grade in quality % proportioning is: C:0.28～0.33%; Si:0.65～0.80%, Mn:0.65～0.85%, Cr:3.20～3.50%, Mo:0.48～0.58%; V:0.25～0.35%, P≤0.012%, S≤0.005%, Ni≤0.20%; Al≤0.020%, Cu≤0.20%, N≤0.010%, O≤0.003%; H≤0.00015%, all the other are iron, the impurity element trace.Shorten the construction cycle, reduced development cost.
2, according to plug stress and instructions for use in the operation of rolling, in conjunction with the capacity of equipment of ASSEL unit, steel mill, electric furnace steel making; After the molten steel process VD vacuum outgas after refining is intact, last continuous casting platform carries out continuous casting, carries out cogging then; Final design and definite forging stock specification are Φ 250x3850mm, and through heating in the ASSEL unit rotary heating furnace, furnace temperature of heating furnace is controlled to be 1230～1260 ℃; Through perforation, ASSEL mill milling and sizing, finishing temperature is 1000～1060 ℃ again, and the steel pipe that behind aligning, becomes Φ 176 * 41 * 10650mm and 186 * 36 * 10900mm specification is as the mother metal of making hollow plug; Through after the modified heat treatment, yield strength >=900MPa, tensile strength 1050～1200MPa; Hardness 315-360HB, percentage elongation >=10%.
After meeting above-mentioned each item mechanical performance index and meeting the requirements, the processing of carrying out the plug material be connected, concrete steps are following:
As shown in Figure 1, the structure that the plug material is processed as hollow plug includes plug front end 1, plug active section 2, plug active section joint 3, plug extension rod 4 and caudal peduncle 5.Carry out rough turn to the plug active section after modified heat treatment 2; Be preheated to plug front end 1, plug active section 2, plug active section joint 3 respectively >=150 ℃ after; Be welded to connect plug front end 1, plug active section 2, plug active section joint 3 successively with alloy welding wire again; After again the outer surface of plug active section 2 being comprised the finish turning of tapering, plug active section joint 3 is carried out screw thread processing; Again the plug front end 1 after being welded to connect, plug active section 2, plug active section joint 3 are polished chromium plating, dehydrogenation is handled the back phosphatization, plug extension rod 4 is twisted with plug active section joint 3 to connect at last; Caudal peduncle 5 is twisted with plug extension rod 4 and is connect, and forms and is used in the hollow plug on the retained mandrel tandem rolling tube machine.
Finally be processed into Φ 171x35x10500mm, 176.4 * 32 * 10500mm and the hollow plug of 174.3 * 30 * 10500mm specification, accomplished the preparation of plug material.
3, in the development process of hollow plug, according to 30Cr3MoV steel grade characteristic, formulated each item technological requirement, include the heat treating regime of steel grade smelting process, plug material rolling mill practice, plug material, finally make plug material performance reach instructions for use.
4, the connection and the processing technology of plug material have been formulated.
The rolled steel tube number on average can reach 1200 in the hollow plug practical application; Compare with the same specification solid mandrel life-span of external import or domestic purchase; Its service life is approaching or fair, and the seamless steel pipe product surfaces externally and internally quality in the production process is good, and loss per ton steel is at the 1.5-1.7Kg/ ton; 30 yuan/ton of ton steel costs are merely original 1/3.
Claims (1)
1. manufacturing approach of producing the hollow plug of tandem rolling seamless steel pipe, this method may further comprise the steps:
1., the design of hollow plug steel grade, specification
Confirm that the used steel grade of hollow plug is that 30Cr3MoV forges base; The used plug of tandem rolling seamless steel pipe on the equipment of ASSEL unit; Confirm that forging the base specification is Φ 250 * 3850mm, the rolling mother metal that is the steel pipe of Φ 176 * 41 * 10650mm and 186 * 36 * 10900mm specification as the hollow plug of making through the ASSEL unit;
Finally, the mother metal of Φ 176 * 41 * 10650mm is processed into the plug of Φ 171 * 35 * 10500mm, and the mother metal of 186 * 36 * 10900mm is processed into 176.4 * 32 * 10500mm and 174.3 * 30 * 10500mm size mandril;
The component of said 30Cr3MoV steel grade in quality % proportioning is: C:0.28～0.33%, Si:0.65～0.80%, Mn:0.65～0.85%, Cr:3.20～3.50%; Mo:0.48～0.58%, V:0.25～0.35%, P≤0.012%, S≤0.005%; Ni≤0.20%, Al≤0.020%, Cu≤0.20%, N≤0.010%; O≤0.003%, H≤0.00015%, all the other are iron, the impurity element trace;
2., continuous casting, cogging, forging
1. steel grade component weight item batching is smelted set by step, and electric furnace steel making is after the molten steel process VD vacuum outgas after refining is intact; Last continuous casting platform carries out continuous casting; Carry out cogging then, forge base, forging the high temperature homogenizing temperature is 1230～1250 ℃, and final forging temperature is >=850 ℃;
3., the plug material is rolling
Step 2. forging stock warp scale forging stock after the assay was approved heats in rotary heating furnace; Furnace temperature of heating furnace is controlled to be 1230～1260 ℃; Through perforation, ASSEL mill milling and sizing, finishing temperature is 1000～1060 ℃ again, behind aligning, becomes to be rolled into the plug material;
4., modified heat treatment
The Technology for Heating Processing of tempering again after adopt quenching is heated to complete austenitizing temperature AC with rolling above-mentioned plug material earlier
3More than 20 ℃～25 ℃, be incubated 120 minutes, the back water hardening of coming out of the stove, the control water yield and water temperature reenter 635 ℃ of processing of tempering furnace then, the stable insulation 160 minutes under temperature of plug material;
5., through the said plug material Performance Detection after the modified heat treatment:
Yield strength: >=900MPa
Tensile strength: 1050～1200MPa
Hardness: 315-360HB
Percentage elongation: >=10%;
6., the processing of plug material be connected
The plug material is processed as hollow plug; This hollow plug includes plug front end (1), plug active section (2), plug active section joint (3), plug extension rod (4) and caudal peduncle (5); Plug active section (2) to after modified heat treatment carries out rough turn; Be preheated to plug front end (1), plug active section (2), plug active section joint (3) respectively >=150 ℃ after; Be welded to connect plug front end (1), plug active section (2), plug active section joint (3) successively with alloy welding wire again, after again the outer surface of plug active section (2) being comprised the finish turning of tapering, plug active section joint (3) is carried out screw thread processing, polish chromium plating; Dehydrogenation is handled the back phosphatization; At last plug extension rod (4) and plug active section joint (3) are twisted and connect, caudal peduncle (5) is twisted with plug extension rod (4) and is connect, and forms and is used in the hollow plug on the retained mandrel tandem rolling tube machine.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104998905A (en) * | 2015-08-03 | 2015-10-28 | 山东墨龙石油机械股份有限公司 | Alloy steel, retained mandrel and production method of retained mandrel |
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| CN102601130B (en) * | 2012-03-15 | 2013-11-27 | 天津钢管集团股份有限公司 | Method for adjusting new mandrel of retained mandrel mill at first use |
| CN102965581B (en) * | 2012-10-25 | 2015-04-22 | 安徽蓝博旺机械集团精密液压件有限责任公司 | Preparation method of cylinder body of oil feed pump |
| CN103521523A (en) * | 2013-10-25 | 2014-01-22 | 江苏南山冶金机械制造有限公司 | Mandrel extension rod of tandem rolling machine |
| CN103555912B (en) * | 2013-11-01 | 2016-02-17 | 中原特钢股份有限公司 | A kind of 30Cr3MoV steel that utilizes is for the method for raw material production plug |
| CN103740918B (en) * | 2013-12-13 | 2015-09-16 | 攀钢集团成都钢钒有限公司 | For the heat treating method of the hollow core rod of Continuous mill train |
| CN106694768B (en) * | 2015-11-15 | 2018-05-08 | 内蒙古北方重工业集团有限公司 | A kind of manufacture method of H13 hollow core rods |
| CN106391713B (en) * | 2016-10-31 | 2019-03-12 | 太原科技大学 | A kind of mandrel rolling method of metal pipe material |
| CN107779583A (en) * | 2017-12-15 | 2018-03-09 | 江苏建中新材料科技有限公司 | Seamless steel pipe Technology for Heating Processing |
| CN112846659B (en) * | 2020-12-31 | 2023-04-11 | 上海久砾不锈钢管有限公司 | Seamless method for stainless steel welded pipe and application thereof |
| CN114425682B (en) * | 2021-12-08 | 2024-01-30 | 江苏新长江无缝钢管制造有限公司 | Manufacturing method of seamless steel tube for smoke tube |
| CN115625206B (en) * | 2022-12-21 | 2023-03-17 | 张家港嘉园钢铁制品有限公司 | Production method of high-precision seamless steel tube |
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Effective date of registration: 20190621 Address after: No. 396 Jintang Highway, Dongli District, Tianjin 300301 Patentee after: Tianjin Steel Tube Manufacturing Co., Ltd. Address before: No. 396 Jintang Highway, Dongli District, Tianjin 300301 Patentee before: Tianjin Steel Pipe Group Co., Ltd. |