CN104480404A - Steel for high-pressure pipeline valve and manufacturing method of steel - Google Patents
Steel for high-pressure pipeline valve and manufacturing method of steel Download PDFInfo
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- CN104480404A CN104480404A CN201410805283.7A CN201410805283A CN104480404A CN 104480404 A CN104480404 A CN 104480404A CN 201410805283 A CN201410805283 A CN 201410805283A CN 104480404 A CN104480404 A CN 104480404A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
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Abstract
The invention discloses steel for a high-pressure pipeline valve and a manufacturing method of the steel. The steel for the high-pressure pipeline valve comprises components in percentage by weight as follows: 0.19%-0.23% of C, 0.15%-0.25% of Si, 0.95%-1.10% of Mn, smaller than or equal to 0.30% of Cr, smaller than or equal to 0.40% of Cu, smaller than or equal to 0.020% of S, smaller than or equal to 0.020% of P, smaller than or equal to 0.40% of Ni, smaller than or equal to 0.12% of Mo, 0.010%-0.040% of Ti, smaller than or equal to 0.03% of V, smaller than or equal to 0.02% of Nb, 0.015%-0.025% of Al, smaller than or equal to 15*10<-6> of O, smaller than or equal to 90*10<-6> of N and the balance of Fe and inevitable impurities. Through content control of carbon and manganese elements, the mechanical property requirements of steel are guaranteed, meanwhile, the content of residual elements is controlled, the material welding property requirement is guaranteed, the fatigue strength of steel is enhanced, and the valve stability is guaranteed. Through control of molten iron (or pig iron) mixing proportion, furnace slag refining amount, VD (vacuum degassing) furnace operation and reinforced water gap protection and casting effect, titanium is added for nitrogen fixation, and the nitrogen content can be controlled below 90 ppm.
Description
Technical field
The invention belongs to metallurgical technology field, be specifically related to a kind of for the manufacture of pressure piping valve steel and manufacture method thereof.
Background technology
Valve main rising on pipeline is cut off and throttling action.High pressure valve performance directly affects the reliability of whole system work, security, working efficiency and work-ing life.In the system of the frequent supercharging release of those palpuses, seem particularly important.The dominant failure reason of high pressure valve is, cavitation erosion and erosive wear, and the factor of impact cavitation erosion and erosion is a lot, mainly contains the mechanical property of material, hydrodynamic factor and environmental influence.In order to improve the ability of high pressure valve Anti-erosion wearing and tearing, pressure piping valve steel generally has following requirement: material hardness is high; Yield-point is high, good stability; Fatigue strength is high.
Pressure piping valve is mainly used in temperature :-29 ~ 427 DEG C, for controlling the flowing of all kinds fluids such as water, liquefied gas, steam, oil product, Sweet natural gas.
Patent documentation CN102383065A discloses a kind of high-performance valve steel and preparation method thereof, it is mainly by constitutive material: matrix is Fe element, Cr, W, Sn, Ta, Mn, Al and C, by certain part by weight mixing, then obtain high-performance valve steel through melting, thermal treatment and vacuum pouring.The technical scheme of this application is applicable to fusion reactor, and can not be applicable to pressure piping valve, and there is the higher problem of cost.
Summary of the invention
The present invention is directed to the service requirements of pressure piping valve steel, Development and Production pressure piping valve steel, by appropriate design steel grades, improve preparation method; Solve the problem of steel product ingredient design, performance, tissue, surface quality, provide a kind of pressure piping valve steel that can meet consumers' demand and manufacture method thereof.
The invention provides a kind of pressure piping valve steel, it forms percentage ratio by weight and is:
C:0.19 ~ 0.23%, Si:0.15 ~ 0.25%, Mn:0.95 ~ 1.10%, Cr :≤0.30%, Cu≤0.40%, S≤0.020%, P≤0.020%, Ni≤0.40%, Mo :≤0.12%, Ti:0.010 ~ 0.040%, V :≤0.03%, Nb :≤0.02%, Al:0.015 ~ 0.025%, [O]≤15 × 10
-6, [N]≤90 × 10
-6, remaining is Fe and inevitable impurity.
The following is content and the Action Specification of each component in steel of the present invention:
In order to ensure the weldability of material, the carbon equivalent of the present invention to this material specifies: CEV=C+Mn/6+ (Cr+Mo+V)/5+ (Ni+Cu)/15≤0.43%.C is very remarkable to the mechanical impact of steel, and very large to the heart portion intensity effect of steel, the content of C is too low, and intensity does not reach requirement, and too high meeting makes the plasticity of steel and toughness decline.For ensureing that steel performance stability contorting carbon content is 0.19 ~ 0.23%.
Manganese is a kind of weak reductor.Appropriate manganese effectively can improve steel strength, eliminates sulphur, oxygen to the hot-short impact of steel, improves steel heat processing characteristics, and improve the cold short tendency of steel, significantly do not reduce plasticity, the impelling strength of steel simultaneously.In the present invention, control Mn content is 0.95 ~ 1.10%.
Si can improve the hardening capacity of infiltration layer strongly, but in cementation process, easily grain boundary oxidation occurs and form the netted defect of black; With the increase of alloying element addition, the martensite point of steel declines, and contain abundant residues austenite in infiltration layer after making quenching, affect fatigue property and the wear resistance of part, control Si content is 0.15 ~ 0.30%.
S, P are considered as harmful element in steel, therefore, and the present invention's control S≤0.020%, P≤0.020%.
Cr, Ni, Cu, V, Mo, Nb are residual element, according to the requirement of carbon equivalent and the demand of cost declining, and control Cr :≤0.30%, Cu≤0.40%, Ni≤0.40%, Mo :≤0.12%, V :≤0.03%, Nb :≤0.02%; For improving purity and the fatigue lifetime of steel.
The present invention also proposes control overflow to oxygen, nitrogen and aluminium, titanium: [O]≤15 × 10-6, [N]≤60 × 10-6, [Al]: 0.015 ~ 0.025%, [Ti]: 0.010 ~ 0.040%.
Preferably, pressure piping valve steel of the present invention forms percentage ratio by weight and is
C:0.20 ~ 0.23%, Si:0.17 ~ 0.25%, Mn:0.95 ~ 1.00%, Cr:0.10 ~ 0.15%, Cu≤0.25%, S≤0.015%, P≤0.020%, Ni≤0.25%, Mo :≤0.12%, Ti:0.010 ~ 0.040%, V :≤0.03%, Nb :≤0.02%, Al:0.015 ~ 0.025%, [O]≤15 × 10-6, [N]≤90 × 10-6, remaining is Fe and inevitable impurity.
The invention provides a kind of preparation method of pressure piping valve steel, comprise smelting and alloying, cast, rolling, slow cooling, and the chemical component weight degree controlling steel is: C:0.20 ~ 0.23%, Si:0.17 ~ 0.25%, Mn:0.95 ~ 1.00%, Cr:0.10 ~ 0.15%, Cu≤0.25%, S≤0.015%, P≤0.020%, Ni≤0.25%, Mo :≤0.12%, Ti:0.010 ~ 0.040%, V :≤0.03%, Nb :≤0.02%, Al:0.015 ~ 0.025%, [O]≤15 × 10-6, [N]≤90 × 10-6, remaining is Fe and inevitable impurity.
The smelting that the present invention is degassed by the deoxidation that ladle argon-blown, Fruit storage strengthen steel controls, final deoxygenation feeding aluminum steel, and before the tapping of LF stove, feeding titanium wire controls titanium content; Employing whole process protection is poured into a mould; For improving homogeneity of steel structure, design steel billet is 1130 ~ 1250 DEG C in the soaking temperature of process furnace, Ф 500mm hot base heat-up time >=4.5h, cold base heat-up time >=5.5h; Ф 650mm hot base heat-up time >=5.0h, cold base heat-up time >=7.0h; Start rolling temperature 1090 ~ 1190 DEG C, the steps such as finishing temperature 850 ~ 1000 DEG C ensure that product has certain composition.
Preferred further, pressure piping valve steel is prepared with following processing condition:
(1) smelt: control molten iron (or pig iron) and be blended into ratio 55% ~ 65%, eaf tapping point carbon content control is ≤0.10%; Adopt aluminium deoxidation, control steel-core-aluminium add-on at 1.5 ~ 2.5kg/t steel.Electric furnace steel tapping temperature controls at 1600 ~ 1640 DEG C.
In refining process, select refining slag system and soft blow argon system, remove steel inclusion, reduce total oxygen content, improve the purity of steel.Feed aluminum steel 1.0 ~ 1.5m/ ton steel and control aluminium in molten steel and be in 0.015 ~ 0.025% and calcium line 1.5 ~ 2.0m/ ton steel (φ 13mm).Add titanium 2-4 rice/ton steel fixed nitrogen, nitrogen content can be controlled in below 80ppm.VD stove vacuum tightness is less than the 67Pa hold-time and is not less than 15min.Ensure after VD process that the soft blow time is not less than 12min.In control, steel temperature is 1575 ± 5 DEG C.
(2) cast, adopt full guard casting, controlling tundish superheating temperature is 20 ~ 30 DEG C, and liquidus temperature is 1510 DEG C.Control Ф 500mm continuous casting casting speed is 0.35 ± 0.01m/min; Control Ф 650mm continuous casting casting speed is 0.25 ± 0.01m/min.
(3) rolling, steel billet is 1130 ~ 1250 DEG C in the soaking temperature of process furnace, start rolling temperature 1090 ~ 1190 DEG C, finishing temperature 850 ~ 1000 DEG C.
Preferably, step 1) described in refining slag system be control the consisting of of refining slag: CaO%:45 ~ 50, SiO2%:2 ~ 3, MgO%:8 ~ 10, Al2O3%:30 ~ 40, TFe%:1 ~ 2, (FeO)+(MnO)≤1.0% weight ratio; Described soft blow argon system is: argon flow amount 150L/min ~ 300L/min, pressure 0.25MPa ~ 0.30MPa.
Preferably, step 1) described in suitable liquid steel temperature be 1570 ± 5 DEG C; Preferably, step 1) described in rational argon pressure 0.25MPa ~ 0.30MPa.；
Step 1) in strengthening deoxidation and deformation processing of inclusion.The gas content reduced further in steel by VD stove Fruit storage improves the purity of steel.
Step 1) described in VD stove be vacuum degassing furnace; VD vacuum outgas removes nitrogen in steel gas for being used for;
Per-cent of the present invention or other ratios, not specified is weight ratio.
Compared with prior art, technical scheme of the present invention has following advantages:
(1) steel of the present invention controls the content of carbon, manganese element, ensure that the mechanical property requirements of steel, controls simultaneously to residual element, ensure that the welding property requirement of material.Invention enhances the fatigue strength of steel; Ensure that the stability of valve.
(2) control techniques of nitrogen, oxygen level: be blended into ratio, the refining furnace quantity of slag, VD furnace operating and strengthening mouth of a river protective casting effect by controlling molten iron (or pig iron), add titanium fixed nitrogen, nitrogen content can be controlled in below 90ppm.
Accompanying drawing explanation
The metallograph of the product that Fig. 1, the present invention obtain.
Embodiment
The present invention adopts UHP (uhp electric arc furnace) → LF (external refining) → VD (vacuum outgas) → continuous casting (induction stirring) → enter to cheat slow cooling → rolling → finishing process to produce steel.
Following embodiment illustrates the present invention with the production technique of Φ 190mm specification steel and how to implement.
Concrete technology step is:
1) electric furnace is metallurgical: burden structure is steel scrap+molten iron, and control molten iron (or pig iron) and be blended into ratio 55% ~ 65%, 4 wall lance oxygen decarburizations are main, and 1 furnace door oxygen lance oxygen decarburization is auxiliary; Combine with oxygen blast, winding-up carbon dust making foamed slag; With addition of 35 ㎏/t ~ 40 ㎏/t lime slag making dephosphorizations; Eccentric bottom tapping, stays steel remaining slag operation; Tapping process, argon bottom-blowing stirs, slag charge add-on 13 ㎏/t ~ 16 ㎏/t in ladle.Eaf tapping point carbon content control is ≤0.10%; Adopt aluminium deoxidation, control steel-core-aluminium add-on at 1.5 ~ 2.5kg/t steel.Electric furnace steel tapping temperature controls at 1600 ~ 1640 DEG C.
In refining process, select refining slag system and soft blow argon, remove steel inclusion, reduce total oxygen content, adopt SiC diffusive deoxidation, feed aluminum steel deep deoxidation before analyzing a sample, improve the purity of steel.Feed aluminum steel 1.0 ~ 1.5m/ ton steel and control aluminium in molten steel and be in 0.015 ~ 0.025% and calcium line 1.5 ~ 2.0m/ ton steel (φ 13mm).Add titanium 2-4 rice/ton steel fixed nitrogen, nitrogen content can be controlled in below 80ppm.Before ladle enters VD stove, remove the slag of about 50%; VD stove vacuum tightness is less than the 67Pa hold-time and is not less than 15min.Ensure after VD process that the soft blow time is not less than 12min.In control, steel temperature is 1575 ± 5 DEG C.
(2) cast, adopt full guard casting, controlling tundish superheating temperature is 20 ~ 30 DEG C, and liquidus temperature is 1510 DEG C.Control Ф 500mm continuous casting casting speed is 0.35 ± 0.01m/min; Control Ф 650mm continuous casting casting speed is 0.25 ± 0.01m/min.
(3) rolling, steel billet is 1130 ~ 1250 DEG C in the soaking temperature of process furnace, start rolling temperature 1090 ~ 1190 DEG C, finishing temperature 850 ~ 1000 DEG C.
The related process parameters of preparation process is in table 1 ~ table 5, and Chemical Composition and carbon equivalent are in table 6; Nitrogen, oxygen level are in table 7; Low power is in table 8; Mechanics examination table 9, its metallograph is shown in Fig. 1.
Table 1 molten iron adds situation
Table 2 electrosmelting
Table 3 refining is smelted
Table 4 refining slag composition
| Heat (batch) number | ΣFe | SiO <sub>2</sub> | MgO | CaO | Al <sub>2</sub>O <sub>3</sub> | MnO <sub>2</sub> |
| 1 | 1.97 | 2.12 | 8.16 | 45.07 | 38.40 | 0.34 |
| 2 | 1.78 | 2.00 | 9.0 | 47.42 | 39.07 | 0.32 |
| 3 | 1.73 | 2.00 | 9.00 | 46.90 | 37.28 | 0.29 |
The process of all heat VD stoves all meets technological process requirement, (16 minutes hold-times); Minimum vacuum tightness 40Pa.
Table 5 continuous casting working procedure controls
Three stream M-EMS actual parameters: 208A, 1.0Hz; End induction stirring actual parameter: 182A, 1.0Hz.Omnidistance normal use, operational excellence.
Table 6 embodiment Chemical Composition (weight, %)
Table 7 nitrogen, Control for Oxygen Content (weight, ppm)
Table 8 macrostructure
Table 9 mechanical property
Preparation technology of the present invention is simple, stable components, cost are low, and the present invention with the addition of multiple alloying element on raw material, has the various features such as good mechanical property, high temperature resistant, radioprotective, is applicable to the application of fusion reactor.
Claims (7)
1. a pressure piping valve steel, is characterized in that, described valve steel forms percentage ratio by weight and is:
C:0.19 ~ 0.23%, Si:0.15 ~ 0.25%, Mn:0.95 ~ 1.10%, Cr :≤0.30%, Cu≤0.40%, S≤0.020%, P≤0.020%, Ni≤0.40%, Mo :≤0.12%, Ti:0.010 ~ 0.040%, V :≤0.03%, Nb :≤0.02%, Al:0.015 ~ 0.025%, [O]≤15 × 10
-6, [N]≤90 × 10
-6, remaining is Fe and inevitable impurity.
2. valve steel according to claim 1, is characterized in that, described valve steel forms percentage ratio by weight and is:
C:0.20 ~ 0.23%, Si:0.17 ~ 0.25%, Mn:0.95 ~ 1.00%, Cr:0.10 ~ 0.15%, Cu≤0.25%, S≤0.015%, P≤0.020%, Ni≤0.25%, Mo :≤0.12%, Ti:0.010 ~ 0.040%, V :≤0.03%, Nb :≤0.02%, Al:0.015 ~ 0.025%, [O]≤15 × 10
-6, [N]≤90 × 10
-6, remaining is Fe and inevitable impurity.
3. the manufacture method of the arbitrary valve steel of claim 1 or 2, comprising:
1) smelt: control molten iron or the pig iron in electric furnace and be blended into ratio 55% ~ 65%, eaf tapping point carbon content control is ≤0.10%; Adopt aluminium deoxidation, and control steel-core-aluminium add-on at 1.5 ~ 2.5kg/t steel; Electric furnace steel tapping temperature controls at 1600 ~ 1640 DEG C;
2) cast: controlling tundish superheating temperature when building is 20 ~ 30 DEG C, and liquidus temperature is 1510 DEG C;
3) rolling: steel billet is 1130 ~ 1250 DEG C in the soaking temperature of process furnace, start rolling temperature 1090 ~ 1190 DEG C, finishing temperature 850 ~ 1000 DEG C.
4. method according to claim 3, it is characterized in that, step 1) deoxidation time feed aluminum steel 1.0 ~ 1.5m/ ton steel and to control aluminium content in molten steel be 0.015 ~ 0.025, calcium line add-on is 1.5 ~ 2.0m/ ton steel, and add titanium 2-4 rice/ton steel fixed nitrogen, make Control of Nitrogen Content at below 80ppm.
5. the method according to claim 3 or 4, is characterized in that, step 1) refining slag that obtains has following quality composition: CaO%:45 ~ 50, SiO2%:2 ~ 3, MgO%:8 ~ 10, Al
2o
3%:30 ~ 40, TFe%:1 ~ 2, (FeO)+(MnO)≤1.0%.
6. method according to claim 3, is characterized in that, step 1) in also comprise the soft blow time after VD process and be not less than 12min, and to control upper steel temperature be 1575 ± 5 DEG C.
7. the method according to claim 3 or 6, is characterized in that, step 1) also comprise the steps: that argon pressure when controlling Argon is 0.25 ~ 0.30MPa.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101358316A (en) * | 2007-07-31 | 2009-02-04 | 辽阳石化机械设计制造有限公司 | Steel of large-sized high-pressure pipe member for oil gas conveying, steel pipe pipe fitting and weld material prepared by thereof |
| CN102002600A (en) * | 2010-11-29 | 2011-04-06 | 昆明理工大学 | Environmentally-friendly chlorine water gold-extracting process |
| CN102605274A (en) * | 2012-03-26 | 2012-07-25 | 宝山钢铁股份有限公司 | Steel for blade of turbine and manufacturing method of the steel |
| CN103695785A (en) * | 2013-12-11 | 2014-04-02 | 莱芜钢铁集团有限公司 | Steel for low-temperature and high-pressure pipeline connector and manufacturing method of continuous casting round billet thereof |
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- 2014-12-22 CN CN201410805283.7A patent/CN104480404B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101358316A (en) * | 2007-07-31 | 2009-02-04 | 辽阳石化机械设计制造有限公司 | Steel of large-sized high-pressure pipe member for oil gas conveying, steel pipe pipe fitting and weld material prepared by thereof |
| CN102002600A (en) * | 2010-11-29 | 2011-04-06 | 昆明理工大学 | Environmentally-friendly chlorine water gold-extracting process |
| CN102605274A (en) * | 2012-03-26 | 2012-07-25 | 宝山钢铁股份有限公司 | Steel for blade of turbine and manufacturing method of the steel |
| CN103695785A (en) * | 2013-12-11 | 2014-04-02 | 莱芜钢铁集团有限公司 | Steel for low-temperature and high-pressure pipeline connector and manufacturing method of continuous casting round billet thereof |
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