CN103276308A - Rare earth-containing high-strength atmospheric corrosion-resistant seamless steel pipe and production method thereof - Google Patents
Rare earth-containing high-strength atmospheric corrosion-resistant seamless steel pipe and production method thereof Download PDFInfo
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- CN103276308A CN103276308A CN2013101678703A CN201310167870A CN103276308A CN 103276308 A CN103276308 A CN 103276308A CN 2013101678703 A CN2013101678703 A CN 2013101678703A CN 201310167870 A CN201310167870 A CN 201310167870A CN 103276308 A CN103276308 A CN 103276308A
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Abstract
The invention relates to a rare earth-containing high-strength atmospheric corrosion-resistant seamless steel pipe and a production method thereof, and belongs to the technical fields of metallurgy and molding. According to the rare earth-containing high-strength atmospheric corrosion-resistant seamless steel pipe, the raw materials comprise 90 wt% of blast furnace molten iron and 10 wt% of high-quality waste steel; the pipe billet comprises the following chemical components: 0.05 to 0.10 wt% of C, 0.10 to 0.30 wt% of Si, 1.00 to 1.30 wt% of Mn, less than or equal to 0.020 wt% of P, less than or equal to 0.005 wt% of S, 0.70 to 1.00 wt% of Cr, 0.10 to 0.30 wt% of Mo, 0.20 to 0.40 wt% of Ni, 0.30 to 0.50 wt% of Cu, 0.01 to 0.03 wt% of Ti, 0.01 to 0.04 wt% of Al, 0.0005 to 0.0100 wt% of RE and the balance of Fe and trace elements which cannot be detected. The process flow comprises pretreatment of the molten iron, top and bottom combined blowing converter smelting, ladle furnace (LF) refining, vacuum distillation (VD) vacuum treatment, round billet continuous casting, cutting, pipe billet heating, perforation, tandem rolling, reheating, sizing, cooling, saw cutting, heat treatment, straightening and flaw detection. The rare earth-containing high-strength atmospheric corrosion-resistant seamless steel pipe comprises the following mechanical properties: the yield strength is 620-670 MPa; the tensile strength is 730-820 MPa; the yield ratio is less than or equal to 0.86; the extension ratio is more than or equal to 23 percent; the transverse impact value is more than or equal to 100 J/cm<2> (-40 DEG C); the shear ratio is 100 percent; the grain size is more than or equal to 8.5 level; the hardness is less than or equal to 22.0 HRC; and the residual stress is less than or equal to 30 MPa. The seamless steel pipe has the characteristics of high strength, good toughness, small grain size and good atmospheric corrosion resistance.
Description
One, affiliated technical field:
The invention belongs to ferrous metal smelting and stress metal manufacture field, relate to a kind of rare earth-containing high strength atmospheric corrosion resistance weldless steel tube and production method thereof.
Two, background technology:
China's complicated and changeableization of weather, the annual steel of scrapping because of atomospheric corrosion are quite a lot of, the spy develops the atmospheric corrosion resistance weldless steel tube for this reason, mainly for delivery of pipeline, oil derrick and engineering machinery etc., to satisfy the atmospheric corrosion resistance requirement, body should have the characteristics of intensity height, good toughness simultaneously.And atmospheric corrosion resistance and high grade of steel are conflicting.For this reason, developed the moisture-resistant atmosphere corrosion steel both at home and abroad in succession, the application of these materials has effectively prevented the destruction that atomospheric corrosion produces weldless steel tube.
By retrieval, Chinese invention patent " weather-resistant low alloy steel " (number of patent application: 02137308.6), it exists following problem and shortcoming:
1. the chemical ingredients scope is too wide, causes the mechanical property fluctuation too big, and operability is not strong;
2. adopt cooling controlling and rolling controlling process to be applicable to board materials production, but not strong to the reference of seamless steel tube production.
Three, summary of the invention:
The purpose of this invention is to provide that a kind of unrelieved stress is low, intensity is high, good toughness, good rare earth-containing high strength atmospheric corrosion resistance weldless steel tube and the production method thereof of atmospheric corrosion resistance.
The object of the present invention is achieved like this:
With the blast-melted of weight percent 90% and 10% high-quality steel scrap as raw material.
Produce with following technical process: at first to the above-mentioned blast-melted pre-treatment of carrying out, together adding top and bottom combined blown converter with above-mentioned high-quality steel scrap then smelts, to smelt the good molten steel ladle of packing into again enters furnaceman LF position and carries out refining, enter the VD station after refining is finished and carry out the vacuum outgas processing, justify bad continuous casting again, and it is the bad pipe that cuts into of continuous casting is bad, heat the continuous casting pipe is bad then, make it become the tandem rolling pipe to bad perforation of the pipe that heats with tandem rolling, steel pipe is carried out the reheat temperature raising, through sending into the cold bed cooling after the sizing, implement sawing then, the steel pipe that cuts is heat-treated, align then, finally by carrying out flaw detection, eligible is high-strength weather-resistant weldless steel tube finished product.
Its brief description of the process is: the bad heating → perforation → tandem rolling of hot metal pretreatment → top and bottom combined blown converter smelting → LF stove refining → VD vacuum-treat → bad continuous casting of circle → cutting → pipe → reheat → sizing → cooling → sawing → thermal treatment → aligning → flaw detection.
The production process of continuous casting circular tube blank is as described below:
1, with blast-melted through pre-treatment, make that the S amount (weight percent) that contains in the molten iron is reduced to below 0.010%.
2, pretreated molten iron is blended into top and bottom combined blown converter, add (weight percent) 10% high-quality steel scrap, adopt single slag technology to smelt, control finishing slag basicity and terminal point target, carry out deoxidation alloying in the tapping process, final deoxygenation adopts aluminium deoxidation technology, and tapping process must pushing off the slag or skimmed adding lime piece after the tapping process interalloy adds.
3, carry out concise at the LF stove: the refining whole process is normally blown Ar on request, adopts from rudimentary and counts to the mode that senior number improves heat-up rate gradually and heat temperature raising; Carry out slag making desulfurization, composition adjustment and warming temperature according to converter molten steel composition and temperature; The white slag operation is made in employing.
4, the refining of LF stove finishes back maintenance bottom soft blow Ar, by predetermined add-on feeding rare-earth wires.
5, carry out VD vacuum-treat: vacuum tightness≤0.10KPa, dark vacuum time 〉=13 minutes.
6, feeding fixed length silico-calcium silk carries out blowing in 8-10 minute Ar behind hello the silk; To justify bad continuous casting through the molten steel after the VD vacuum-treat, adopt constant speed control and the induction stirring technology of low pulling rate; The control molten steel overheat; Casting is bad at behind the aligning, and flame cutting is that pipe is bad.
To managing the bad chemical ingredients chemical examination of carrying out, manage bad chemical ingredients and should meet following requirement (weight percent %): C0.05-0.10; Si0.10-0.30; Mn1.00-1.30; P≤0.020; S≤0.005; Cr0.70-1.00; Mo0.10-0.30; Ni0.20-0.40; Cu0.30-0.50; Ti0.01-0.03; Al0.01-0.04; Rare earth elements RE 0.0005-0.0100; Surplus is matrix Fe and the micro impurity element that can't detect.
Described rare earth elements RE is the norium of Ce, La, and their weight percent is respectively: Ce67%, La33%.
Add rare earth element and can play effects such as improving non-metallic inclusion form, reinforcement crystal boundary, thereby obtain the effect that improves corrosion resistance nature and impelling strength.
Composition is chemically examined qualified and sufur printing be not more than that 2.0 grades continuous casting circular tube is bad to carry out tubulation, the tubulation process is as follows:
To manage and bad put into process furnace and heat, continuous review and the temperature of each sections such as process furnace preheating section, heating zone, soaking zone controlled well, each section temperature controlling scope sees Table 1;
The control of each section of table 1 rotary heating furnace temperature (℃)
Each section of process furnace temperature is controlled automatically and automatic record with microcomputer.
Hot tool must be measured before use, must check before rolling, handle roller-way, avoids scratching tube wall.
After the bad perforation of the pipe that heats, be rolled into the weldless steel tube of the required specification of user at corresponding tube rolling unit, every batch is carried out once heat sampling at least when rolling, checks geometrical dimension; Steel pipe behind the tandem rolling enters reheating furnace, and the reheating furnace temperature is controlled between 900-930 ℃, and the control of body temperature is between 830-890 ℃ behind the sizing; The steel pipe of geometrical dimension passed examination is heat-treated, and the furnace temperature of strict control quenching process furnace, adds thermostability and cooling water flow, guarantees the quenching quality; Furnace temperature and the temper resistance of strict control tempering process furnace.
Heat treating regime is: carry out shrend behind 870～920 ℃ of insulation 30～50min, 620～670 ℃ of laggard line spaces of insulation 60～80min are cold; It is straight to carry out the band temperature correction after the tempering, straightening temperature 〉=500 ℃.
Then steel pipe is pursued the Zhi Jinhang carrying out flaw detection.
Through above-mentioned technological process, can produce " rare earth-containing high strength atmospheric corrosion resistance weldless steel tube " of the present invention.
The beneficial effect of the invention:
1. add proper C u, improved the atmospheric corrosion resistance of material, Ni can improve the toughness that the red brittleness of Cu in steel improved material again;
2. owing to be with temperature correction straight more than 500 ℃, the unrelieved stress of steel pipe is lower, unrelieved stress :≤30MPa (adopting the ring cutting method);
3. because " the unique component design+modifier treatment technology that contains rare earth element ", makes every excellent performance of steel pipe in conjunction with ripe production technique, the specific performance index is as follows:
Yield strength: 620～700MPa; Tensile strength: 730～820MPa; Yield tensile ratio :≤0.86; Unit elongation: 〉=23%; Traverse impact value: a
KV〉=100J/cm
2(40 ℃); Shear ratio: 100%; Hardness :≤22.0HRC.
4. atmospheric corrosion resistance
Because unique composition design+modifier treatment technology makes the average corrosion rate of material of the present invention only reach 48% of contrast material, shows that atmospheric corrosion resistance is good.
The present invention is directed to the problem that exists in the background technology, by technical measures such as " unique chemical compositions design and be the unique production technique of raw material with blast-melted ", solved the problems referred to above well, obtained obvious improvement.
Four, embodiment:
Be described in further detail below in conjunction with the present invention of embodiment.
Embodiment 1:
Raw material is by weight percentage: blast-melted 90%, and high-quality steel scrap 10%.
The technological process of production is in proper order: the bad heating → perforation → tandem rolling of hot metal pretreatment → top and bottom combined blown converter smelting → LF stove refining → VD vacuum-treat → bad continuous casting of circle → cutting → pipe → reheat → sizing → cooling → sawing → thermal treatment → aligning → flaw detection.
The concrete technological process of production is summarized as follows:
90 tons of blast-melted usefulness " metal magnesium powder " are done the desulfating and deoxidation pre-treatment, make the S amount that contains in the molten iron be reduced to (weight percent) below 0.010%;
Described 90 tons of preprocessed molten irons are blended in 100 tonnes the top and bottom combined blown converter, add 10 tons of high-quality steel scraps again, adopt single slag technology to smelt then, finishing slag basicity is by 3.0 controls, adopt silicomanganese, ferromanganese and ferrochrome to carry out deoxidation alloying during tapping, final deoxygenation adopts aluminium deoxidation technology, the necessary pushing off the slag of tapping process, the pushing off the slag failure must be skimmed, and adds 200kg lime piece after the tapping process interalloy adds.
Enter furnaceman LF position and carry out refining smelting the good molten steel ladle of packing into: normal Argon on request during refining, adopt from rudimentary and count to the mode heat temperature raising that senior number improves heat-up rate gradually; Carry out slag making desulfurization, composition adjustment and warming temperature according to converter molten steel composition and temperature; The white slag operation is made in employing, and copper coin, nickel plate, molybdenum-iron and ferro-titanium added in the middle and later periods.
After finishing, the refining of LF stove to keep bottom soft blow Ar, by the rare-earth wires of predetermined add-on feeding certain-length.
Then the good molten steel of refining is carried out the VD vacuum-treat again: dark vacuum tightness≤0.10KPa, dark vacuum time 〉=13 minutes; Feed the silicon-calcium wire of certain-length again, feed the silk back and keep 8～10 minutes soft blow Ar.
Will be through the molten steel after the VD vacuum-treat big bag hang on ladle turret and carry out 5 machines, 5 bad continuous castings of stream circle, adopt constant speed control and the induction stirring technology of low pulling rate during continuous casting; Molten steel overheat Δ T≤30 ℃; Casting is aligned after badly going out the secondary cooling zone territory, is that pipe is bad with flame cutting then.
To managing bad samplingization, check, its chemical ingredients result of laboratory test (weight percent content) is as table 2:
The chemical ingredients of table 2 the present invention and contrast experiment's steel (weight %)
Sufur printing: all be no more than 1.0 grades, macroscopic examination is qualified.
The pipe of changing, being up to the standards is badly carried out tubulation, and the tubulation process is as follows:
Pipe is bad to have good rolling performance in order to make, and continuous detecting and controls preheating section, heating zone, the soaking zone temperature of process furnace, and it is thoroughly evenly and not overheated to guarantee to heat.
Each section of process furnace temperature is controlled automatically and automatic record with microcomputer.
Hot tool must be measured before use, must check before rolling, handle roller-way, avoids scratching tube wall.
After the pipe perforation that heats, be rolled into the weldless steel tube that specification is ф 168.3mm * 14.60mm at Φ 180mmMPM tube rolling unit, every batch is carried out once heat sampling, checks geometrical dimension; Steel pipe behind the tandem rolling enters reheating furnace, and the reheating furnace temperature is controlled between 900-930 ℃, and the control of body temperature is between 830-890 ℃ behind the sizing; The steel pipe of geometrical dimension passed examination is heat-treated, and the furnace temperature of strict control quenching process furnace, adds thermostability and cooling water flow, guarantees the quenching quality; Furnace temperature and the temper resistance of strict control tempering process furnace.
Heat treating regime is: come out of the stove behind 890 ± 10 ℃ of insulation 40min and carry out shrend, come out of the stove behind 640 ± 20 ℃ of insulation 70min and carry out air cooling; The steel pipe straightening temperature is 517 ℃, and the unrelieved stress that the ring cutting method is measured steel pipe is 22MPa.
Through above-mentioned explained hereafter and non-destructive test(ing)(NDT) process, the finished product that eligible namely becomes " rare earth-containing high strength atmospheric corrosion resistance weldless steel tube " of the present invention.Produce sample with it and carry out mechanical properties test.
Through check, the mechanical property detected value of embodiment 1 weldless steel tube that produces sees Table 3.
Embodiment 2:
The proportioning raw materials of embodiment 2, the technological process of production etc. and other technic index are all identical with embodiment 1, and difference is bad chemical composition content and straightening temperature of its pipe, and chemical ingredients detected result (weight %) sees Table 2:
The steel pipe straightening temperature is 522 ℃, and the unrelieved stress that the ring cutting method is measured steel pipe is 21MPa
Table 3 steel pipe mechanical property detected result
Annotate: impact specimen is that laterally experimental temperature is-40 ℃.
Table 4 weather-resistant test-results
The average corrosion rate that experiment records embodiment 1 and embodiment 2 is 1.14g/m
2/ h, the average corrosion rate of contrast material are 2.38g/m
2/ h, namely the average corrosion rate of embodiment only reaches 48% of contrast material, shows that material of the present invention has good atmospheric corrosion resistance.
Claims (10)
1. rare earth-containing high strength atmospheric corrosion resistance weldless steel tube is characterized in that raw material is that 90% high-quality steel scrap blast-melted and 10% is formed by weight percent, and its chemical ingredients is respectively by weight percentage: C0.05-0.10; Si0.10-0.30; Mn1.00-1.30; P≤0.020; S≤0.005; Cr0.70-1.00; Mo0.10-0.30; Ni0.20-0.40; Cu0.30-0.50; Ti0.01-0.03; Al0.01-0.04; Rare earth elements RE 0.0005-0.0100; Surplus is matrix Fe and the micro impurity element that can't detect; The mechanical property of product: yield strength 620～700MPa, unrelieved stress≤30MPa, traverse impact value 〉=100J/cm
2(40 ℃), grain fineness number 〉=8.5 grade; Atmospheric corrosion resistance is good.
2. a kind of rare earth-containing high strength atmospheric corrosion resistance weldless steel tube according to claim 1 is characterized in that RE is the norium of Ce and La, and its weight percent is: Ce67%, La33%.
3. the production method of the rare earth-containing high strength atmospheric corrosion resistance weldless steel tube of feature according to claim 1 is characterized in that technological process of production summary is: hot metal pretreatment → top and bottom combined blown converter smelting → LF stove refining → VD vacuum-treat → bad continuous casting of circle → cutting → pipe evil idea heating → perforation → tandem rolling → reheat → sizing → cooling → sawing → thermal treatment → aligning → flaw detection.
4. the production method of a kind of rare earth-containing high strength atmospheric corrosion resistance weldless steel tube according to claim 3 is characterized in that blast-melted through pre-treatment, makes that S content is reduced to weight percent below 0.010% in the molten iron; Pretreated molten iron and high-quality steel scrap are added top and bottom combined blown converter by design proportion respectively, adopt single slag technology to smelt, control finishing slag basicity and terminal point target; Carry out deoxidation alloying in the tapping process, final deoxygenation adopts aluminium deoxidation technology, and tapping process must pushing off the slag or skimmed adding lime piece after the tapping process interalloy adds.
5. the production method of a kind of rare earth-containing high strength atmospheric corrosion resistance weldless steel tube according to claim 3 is characterized in that carrying out concise at the LF stove; The refining whole process is normal Argon on request, adopts from rudimentary and counts to the mode heat temperature raising that senior number improves heat-up rate gradually; Carry out slag making desulfurization, composition adjustment and warming temperature according to converter molten steel composition and temperature; The white slag operation is made in employing.
6. according to the production method of claim 3 or 5 described a kind of rare earth-containing high strength atmospheric corrosion resistance weldless steel tubes, it is characterized in that the refining of LF stove finishes the back and keeps bottom soft blow Ar, by predetermined add-on feeding rare-earth wires.
7. the production method of a kind of rare earth-containing high strength atmospheric corrosion resistance weldless steel tube according to claim 3 is characterized in that carrying out the vacuum treated vacuum tightness≤0.10KPa of VD, dark vacuum time 〉=13 minutes.
8. according to the production method of claim 3 or 7 described a kind of rare earth-containing high strength atmospheric corrosion resistance weldless steel tubes, feeding fixed length silico-calcium silk carries out blowing in 8～10 minutes Ar behind hello the silk when it is characterized in that the VD vacuum-treat.
9. the production method of a kind of rare earth-containing high strength atmospheric corrosion resistance weldless steel tube according to claim 3 when it is characterized in that justifying bad continuous casting, adopts constant speed control and the induction stirring technology of low pulling rate and controls molten steel overheat≤30 ℃; Casting is bad aligns after going out the secondary cooling zone territory, and it is bad to be cut into pipe then.
10. the production method of a kind of rare earth-containing high strength atmospheric corrosion resistance weldless steel tube according to claim 3, it is characterized in that adopting modifier treatment technology: carry out shrend behind 870～920 ℃ of insulation 30～50min, 620～670 ℃ of laggard line spaces of insulation 60～80min are cold; It is straight to carry out the band temperature correction after the tempering, straightening temperature 〉=500 ℃.
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| CN108504933A (en) * | 2018-05-10 | 2018-09-07 | 江阴兴澄钢管有限公司 | 07CrCuAlMoTi seamless steel pipes and its production technology |
| CN109778060A (en) * | 2019-03-26 | 2019-05-21 | 内蒙古锦和稀土功能材料有限公司 | Rare earth alloy and its preparation method and application |
| CN110760753A (en) * | 2019-10-25 | 2020-02-07 | 鞍钢股份有限公司 | Low-yield-ratio seamless steel pipe and manufacturing method thereof |
| CN110923572A (en) * | 2019-11-27 | 2020-03-27 | 上海大学 | Rare earth weathering steel rich in alloying rare earth elements and manufacturing method thereof |
| CN110983156A (en) * | 2019-11-27 | 2020-04-10 | 上海大学 | Rare earth corrosion-resistant steel rich in alloying rare earth elements and manufacturing method thereof |
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| CN108504933A (en) * | 2018-05-10 | 2018-09-07 | 江阴兴澄钢管有限公司 | 07CrCuAlMoTi seamless steel pipes and its production technology |
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| CN110983156A (en) * | 2019-11-27 | 2020-04-10 | 上海大学 | Rare earth corrosion-resistant steel rich in alloying rare earth elements and manufacturing method thereof |
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Application publication date: 20130904 |