CN113373379A - Continuous casting billet for petroleum valve body and preparation method thereof - Google Patents

Continuous casting billet for petroleum valve body and preparation method thereof Download PDF

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Publication number
CN113373379A
CN113373379A CN202110686215.3A CN202110686215A CN113373379A CN 113373379 A CN113373379 A CN 113373379A CN 202110686215 A CN202110686215 A CN 202110686215A CN 113373379 A CN113373379 A CN 113373379A
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continuous casting
valve body
equal
petroleum valve
smelting
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CN113373379B (en
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李军龙
巩飞
尹修刚
任立坤
马小亮
杨磊
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Chengde Jianlong Special Steel Co Ltd
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Chengde Jianlong Special Steel Co Ltd
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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
    • 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
    • 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
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Continuous Casting (AREA)

Abstract

The invention provides a continuous casting billet for a petroleum valve body and a preparation method thereof, wherein the continuous casting billet for the petroleum valve body comprises the following components in percentage by mass: 0.28 to 0.33 wt% of C, 0.2 to 0.35 wt% of Si, 0.5 to 0.8 wt% of Mn, 1 to 1.1 wt% of Cr, 0.15 to 0.3 wt% of Mo, 0.2 to 0.5 wt% of Ni, 0.01 to 0.02 wt% of Nb, 0.01 to 0.02 wt% of V, the balance being Fe and unavoidable impuritiesThe impurities of (1). The continuous casting round billet for the petroleum valve body obtained by the preparation method meets the performance requirement of a new API standard sampling test, and when the round billet is sampled at the 1/4T position of a 200mm square, Rm is more than or equal to 700MPa, and Rp0.2More than or equal to 550MPa, and the impact energy at-60 ℃ is more than or equal to 65J.

Description

Continuous casting billet for petroleum valve body and preparation method thereof
Technical Field
The invention belongs to the technical field of metallurgy, relates to a continuous casting billet, and particularly relates to a continuous casting billet for a petroleum valve body and a preparation method thereof.
Background
The economic development promotes the increase of oil demand, the area of oil exploitation gradually expands, the oil exploitation shows the trend of increasing exploitation depth, turning from land to sea, from shallow sea to deep sea and from equator to two-stage transition, the use working condition of exploitation equipment is more and more severe, and the requirement on the exploitation equipment is more and more high.
The petroleum valve body is used as a key part of mining equipment, and needs to meet increasingly demanding working conditions such as high pressure, low temperature and the like, and higher requirements are put forward on steel used by the petroleum valve body. The valve is a control part in a fluid conveying system and has the functions of stopping, adjusting, guiding, preventing counter flow, stabilizing pressure, shunting or overflowing and relieving pressure and the like. The prior steel for the petroleum valve body is mainly carbon-chromium-molybdenum steel, the tensile strength Rel is 600-650MPa, the yield strength Rm is 430-470MPa, the elongation is 26-30%, the reduction of area is 26-30%, and the impact energy at-60 ℃ is 9-40J, so that the common carbon-chromium-molybdenum steel has lower strength and impact resistance, has shorter service life, and cannot meet the increasingly strict requirements on the petroleum valve body.
CN 109207862A discloses a wear-resistant special steel deep sea petroleum valve body and a manufacturing method thereof, wherein the valve body comprises the following chemical compositions in percentage by weight: 0.1-0.15 wt% of C, 0.4-0.6 wt% of Mn, less than or equal to 0.025 wt% of P, less than or equal to 0.025 wt% of S, 0.3-0.5 wt% of Si, 11.5-13.5 wt% of Cr, less than or equal to 0.6 wt% of Mo, 0.4-0.5 wt% of Ni, less than or equal to 1.5ppm of H, less than or equal to 15ppm of O, less than or equal to 50ppm of N, and the balance of Fe and inevitable impurities, wherein the main phase of the valve body is martensite, the second phase is austenite with a volume ratio of more than 8% and less than or equal to 12%, and contains pearlite with a volume ratio of more than 0% and less than or. Which improves the corrosion resistance and mechanical properties of the resulting valve body.
CN 112522604A discloses steel for a petroleum valve body and a preparation method thereof, wherein the steel comprises manganese steel, and the chemical parameter mixture ratio of the manganese steel comprises: 0.25 to 0.75 weight percent of Al, 0.25 weight percent of C, 0.25 weight percent of Si, 1.66 weight percent of Mn, 0.25 weight percent of Cr, 0.016 weight percent of Nb, 0.107 weight percent of V, less than or equal to 0.03 weight percent of S, less than or equal to 0.025 weight percent of P, 0.007 weight percent of O, 0.0284 weight percent of N and the balance of Fe. The Al and the oxide thereof form polymeric aluminum under the high-temperature condition by adding the Al with a certain proportion, and the polymeric aluminum is forged under the high-temperature condition for three times after the forming, so that the steel has the characteristic of quick oxidation of the surface in the working environment with lower oxygen content on the premise of not reducing the strength after the steel is formed, and the wear resistance of the steel in the grease environment is improved.
CN 110512134A discloses a smelting process of petroleum machinery valve body 4130 steel, which comprises the working procedures of smelting, LF refining, VD vacuum treatment and continuous casting. In the LF refining process, the aluminum content of molten steel is 0.02-0.04% when the molten steel is refined in place, and the refining white slag is kept for 25-40 min; in the VD treatment process, 7-10kg/t of rare earth is added in the VD vacuum treatment process, the vacuum degree of the VD vacuum treatment is less than or equal to 30Pa, the vacuum maintaining time is 10-15min, soft argon blowing is carried out after the vacuum breaking, the argon blowing flow is 20-60L/min, and the soft argon blowing time is 15-25 min. The indexes of the quantity level of the D-type inclusions in the obtained steel are as follows: 1-3% of more than or equal to 13 mu m, 42-45% of more than or equal to 7 mu m and 47-51% of more than or equal to 4 mu m, thus improving the purity of the steel.
However, the sampling standard of the petroleum valve body steel prepared by the method in the test is the old standard. Taking the petroleum valve body steel 4130 as an example, the performance requirements of the product are that the tensile strength is more than or equal to 655MPa, the yield strength is more than or equal to 520MPa, and the impact energy at minus 60 ℃ is more than or equal to 30J. When a sample is taken at the 1/4T position of a square billet with the thickness of 100 multiplied by 100mm, the obtained structure can meet the requirements that the tensile strength is more than or equal to 680MPa, the yield strength is more than or equal to 550MPa, and the impact energy at minus 60 ℃ is more than or equal to 50J.
However, the new API standard needs to sample the 1/4T position of a square billet of 200X 200mm, at the moment, the tensile strength of the petroleum valve body steel 4130 is only about 575MPa, the yield strength is about 485MPa, and the impact energy at-60 ℃ is only about 20J, so that the performance requirements are difficult to meet.
In order to meet the detection requirement of the new API standard, the components of the steel for the petroleum valve body need to be adjusted, and the obtained continuous casting blank for the petroleum valve body is forged into the steel200mm square billet, the 1/4T position is sampled to meet the condition that Rm is more than or equal to 700MPa and Rp0.2More than or equal to 550MPa, and the impact energy at-60 ℃ is more than or equal to 65J.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a continuous casting billet for a petroleum valve body and a preparation method thereof, wherein the continuous casting round billet for the petroleum valve body obtained by the preparation method meets the performance requirement of a new API standard sampling test, and when a sample is taken at the 1/4T position of a 200mm square, Rm is more than or equal to 700MPa, and Rp0.2More than or equal to 550MPa, and the impact energy at-60 ℃ is more than or equal to 65J.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a continuous casting slab for a petroleum valve body, comprising, by mass: 0.28 to 0.33 wt% of C, 0.2 to 0.35 wt% of Si, 0.5 to 0.8 wt% of Mn, 1 to 1.1 wt% of Cr, 0.15 to 0.3 wt% of Mo, 0.2 to 0.5 wt% of Ni, 0.01 to 0.02 wt% of Nb, 0.01 to 0.02 wt% of V, and the balance of Fe and inevitable impurities.
The amount of C in the petroleum valve strand is, for example, 0.28 to 0.33 wt%, and may be, for example, 0.28 wt%, 0.29 wt%, 0.3 wt%, 0.31 wt%, 0.32 wt%, or 0.33 wt%, in terms of mass%, but is not limited to the values listed, and other values not listed in the numerical range are also applicable, and preferably 0.28 to 0.3 wt%.
The Si content in the continuous casting slab for a petroleum valve body is 0.2 to 0.35 wt%, for example, 0.2 wt%, 0.21 wt%, 0.24 wt%, 0.25 wt%, 0.27 wt%, 0.28 wt%, 0.3 wt%, 0.31 wt%, 0.32 wt%, 0.33 wt%, 0.34 wt%, or 0.35 wt%, in terms of mass%, but is not limited to the values listed, and other values not listed in the numerical range are also applicable, preferably 0.31 to 0.35 wt%.
The Mn content of the petroleum valve strand is 0.5 to 0.8 wt%, for example, 0.5 wt%, 0.55 wt%, 0.6 wt%, 0.65 wt%, 0.7 wt%, 0.75 wt%, or 0.8 wt%, in terms of mass%, but is not limited to the values listed, and other values not listed in the numerical range are also applicable, preferably 0.6 to 0.7 wt%.
The amount of Cr in the slab for a petroleum valve body is 1 to 1.1 wt%, for example, 1 wt%, 1.01 wt%, 1.02 wt%, 1.03 wt%, 1.04 wt%, 1.05 wt%, 1.06 wt%, 1.07 wt%, 1.08 wt%, 1.09 wt%, or 1.1 wt%, in terms of mass%, but is not limited to the recited values, and other values not recited in the numerical range are also applicable, preferably 1.02 to 1.07 wt%.
The Mo content in the continuous casting slab for a petroleum valve body is 0.15 to 0.3 wt%, for example, 0.15 wt%, 0.16 wt%, 0.18 wt%, 0.2 wt%, 0.21 wt%, 0.24 wt%, 0.25 wt%, 0.26 wt%, 0.27 wt%, 0.28 wt%, 0.29 wt%, or 0.3 wt%, in terms of mass%, but is not limited to the values listed, and other values not listed in the numerical range are also applicable, preferably 0.25 to 0.3 wt%.
The Ni content in the continuous casting slab for a petroleum valve body is 0.2 to 0.5 wt%, for example, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, 0.4 wt%, 0.45 wt%, or 0.5 wt%, in terms of mass%, but is not limited to the values listed, and other values not listed in the numerical range are also applicable, and 0.3 to 0.4 wt%.
The Nb content in the continuous casting slab for petroleum valve bodies is 0.01 to 0.02 wt%, for example, 0.01 wt%, 0.012 wt%, 0.015 wt%, 0.018 wt%, or 0.02 wt%, but is not limited to the recited values, and other values not recited in the numerical range are also applicable, preferably 0.015 to 0.02 wt%.
In the continuous casting slab for a petroleum valve body, V is 0.01 to 0.02 wt% in mass percent, and may be, for example, 0.01 wt%, 0.012 wt%, 0.015 wt%, 0.018 wt%, or 0.02 wt%, but is not limited to the enumerated values, and other unrecited values within the numerical range are also applicable, and are preferably 0.012 to 0.015 wt%.
The invention strengthens the low-temperature impact toughness and the mechanical property by adjusting the composition of elements such as C, Si, Mn, Cr, Mo, Ni, Nb, V and the like and adjusting the contents of Ni, Mn, V and Nb on the basis of original steel, so that the invention can meet the requirement of the mechanical property of a continuous casting round billet with the specification of phi 400-plus 600mm in continuous casting.
Preferably, the inevitable impurities include P.ltoreq.0.015 wt%, S.ltoreq.0.01 wt% in mass percentage.
Preferably, the inevitable impurities include P.ltoreq.0.01 wt% and S.ltoreq.0.005 wt% in mass percentage.
In a second aspect, the invention provides a preparation method of the continuous casting billet for the petroleum valve body, which comprises the steps of molten iron pretreatment, converter smelting, LF refining, VD smelting, continuous casting and pit entering slow cooling which are sequentially carried out.
Preferably, the molten iron pretreatment is to add a desulfurizing agent into a semisteel tank, and then perform desulfurization and stirring.
Preferably, the desulfurizing agent is a combination of lime powder, fluorite powder and aluminum powder.
Preferably, the addition amount of the lime powder is 8-10kg/t, the addition amount of the fluorite powder is 2-3kg/t, and the addition amount of the aluminum powder is 0.8-1.2 kg/t.
The addition amount of the desulfurizer is based on semisteel, for example, the addition amount of lime powder is 8-10kg of lime powder added in each ton of semisteel.
The amount of lime powder added in the present invention is 8 to 10kg/t, and may be, for example, 8kg/t, 8.5kg/t, 9kg/t, 9.5kg/t or 10kg/t, but is not limited to the values listed, and other values not listed in the numerical range are also applicable.
The amount of the fluorite powder added in the present invention is 2 to 3kg/t, and may be, for example, 2kg/t, 2.4kg/t, 2.5kg/t, 2.7kg/t, 2.8kg/t or 3kg/t, but is not limited to the values listed, and other values not listed in the numerical range are also applicable.
The powdery aluminum can be added in an amount of 0.8 to 1.2kg/t, for example, 0.8kg/t, 0.9kg/t, 1kg/t, 1.1kg/t or 1.2kg/t, but the present invention is not limited to the above-mentioned values, and other values not shown in the above-mentioned numerical ranges are also applicable.
Preferably, the speed of the desulfurization stirring is 50-60r/min, such as 50r/min, 52r/min, 55r/min, 56r/min, 58r/min or 60r/min, but not limited to the recited values, and other values not recited in the numerical range are also applicable; the time is 8-10min, for example 8min, 8.5min, 9min, 9.5min or 10min, but is not limited to the values listed, and other values not listed in the numerical ranges are equally applicable.
Preferably, the contents of Mn, Cr, No, Ni, Nb and V are adjusted in the process of smelting and tapping by the converter.
Preferably, the liquid level is controlled to be positioned above the inner edge of the outlet in the tapping process of the converter treatment, and the sliding plate is adopted for blocking slag to prevent tapping and slag discharging.
Preferably, S is less than or equal to 0.01 wt% in the LF refining process, and S is less than or equal to 0.005 wt% preferably.
Preferably, after the VD smelting breaks the vacuum, the wire feeding line deforms the inclusions and performs soft blowing treatment, the soft blowing treatment time is 20-30min, for example, 20min, 22min, 24min, 25min, 27min, 28min or 30min, but not limited to the values listed, and other values not listed in the numerical range are also applicable.
Preferably, the continuous casting adopts an integral water gap, the large ladle to the middle ladle adopt a long water gap, a sealing gasket and argon seal, and argon is filled before the middle ladle is cast to reduce air suction in the continuous casting process.
Preferably, the pit entry temperature for pit entry annealing is 500-.
The pit entry slow cooling time is 36-48h, for example, 36h, 38h, 40h, 42h, 45h or 48h, but is not limited to the values listed, and other values not listed in the range of values are also applicable.
The pit exit temperature for pit entry and annealing is 120-150 ℃, for example, 120 ℃, 125 ℃, 130 ℃, 135 ℃, 140 ℃, 145 ℃ or 150 ℃, but not limited to the values listed, and other values not listed in the range of values are also applicable.
Preferably, the continuous casting billet for the petroleum valve body obtained by the preparation method is a continuous casting round billet with the specification of phi 400-600mm, such as phi 400mm, phi 450mm, phi 500mm, phi 540mm or phi 600mm, but not limited to the values listed, and other values not listed in the numerical range are also applicable.
As a preferable technical solution of the preparation method of the second aspect, the preparation method comprises the steps of:
(1) pretreating molten iron: adding a desulfurizing agent into the semisteel tank, and then desulfurizing and stirring for 8-10min at the speed of 50-60 r/min; the desulfurizer is a combination of lime powder, fluorite powder and aluminum powder; the addition amount of the lime powder is 8-10kg/t, the addition amount of the fluorite powder is 2-3kg/t, and the addition amount of the aluminum powder is 0.8-1.2 kg/t;
(2) smelting in a converter: adjusting the contents of Mn, Cr, No, Ni, Nb and V in the smelting and tapping process of the converter; in the tapping process of the converter treatment, the liquid level is controlled to be positioned above the inner edge of the outlet, and a sliding plate is adopted for blocking slag to prevent tapping and slag discharging;
(3) LF refining: carrying out deep deoxidation and alloying of molten steel in the LF refining process, blowing argon in the whole LF refining process, and controlling white slag to enable S to be less than or equal to 0.01 wt% in the LF refining process;
(4) VD smelting: carrying out vacuum degassing and impurity removal on VD smelting, after the VD smelting breaks vacuum, deforming the impurities by a wire feeding line, and carrying out soft blowing treatment, wherein the soft blowing treatment time is 20-30min, so that P is less than or equal to 0.015 wt%, S is less than or equal to 0.01 wt%, H is less than or equal to 0.00016 wt%, and O is less than or equal to 0.002 wt%;
(5) continuous casting: the continuous casting adopts an integral water gap, a long water gap is used for adding a sealing gasket and argon sealing from a large ladle to a medium ladle, and argon is filled for casting before casting the medium ladle, so that the air suction in the continuous casting process is reduced;
(6) entering a pit for slow cooling: the pit entry temperature for pit entry slow cooling is 500-550 ℃, the pit entry slow cooling time is 36-48h, and the pit exit temperature is 120-150 ℃;
the continuous casting billet for the petroleum valve body is a phi 400-plus 600mm specification continuous casting round billet.
The recitation of numerical ranges herein includes not only the above-recited numerical values, but also any numerical values between non-recited numerical ranges, and is not intended to be exhaustive or to limit the invention to the precise numerical values encompassed within the range for brevity and clarity.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a continuous casting billet for a petroleum valve body, which is prepared by adjustingThe element composition ensures that the performance requirement of the sampling test of a new API standard is met, Rm is more than or equal to 700MPa and Rp is met when the sampling is carried out at the 1/4T position with the square of 200mm0.2More than or equal to 550MPa, and the impact energy at-60 ℃ is more than or equal to 65J.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments.
Example 1
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, which comprises the following steps:
(1) pretreating molten iron: adding a desulfurizing agent into the semisteel tank, and then desulfurizing and stirring at 55r/min for 9 min; the desulfurizer is a combination of lime powder, fluorite powder and aluminum powder; the addition amount of the lime powder is 9kg/t, the addition amount of the fluorite powder is 2.5kg/t, and the addition amount of the aluminum powder is 1 kg/t;
(2) smelting in a converter: adjusting the contents of Mn, Cr, No, Ni, Nb and V in the smelting and tapping process of the converter; in the tapping process of the converter treatment, the liquid level is controlled to be positioned above the inner edge of the outlet, and a sliding plate is adopted for blocking slag to prevent tapping and slag discharging;
(3) LF refining: carrying out deep deoxidation and alloying of molten steel in the LF refining process, blowing argon in the whole LF refining process, and controlling white slag to enable S to be less than or equal to 0.01 wt% in the LF refining process;
(4) VD smelting: carrying out vacuum degassing and impurity removal on VD smelting, after the VD smelting breaks vacuum, deforming the impurities by a wire feeding line, and carrying out soft blowing treatment, wherein the soft blowing treatment time is 25min, so that P is less than or equal to 0.015 wt%, S is less than or equal to 0.01 wt%, H is less than or equal to 0.00016 wt%, and O is less than or equal to 0.002 wt%;
(5) continuous casting: the continuous casting adopts an integral water gap, a long water gap is used for adding a sealing gasket and argon sealing from a large ladle to a medium ladle, and argon is filled for casting before casting the medium ladle, so that the air suction in the continuous casting process is reduced;
(6) entering a pit for slow cooling: the pit entering temperature for pit entering and slow cooling is 520 ℃, the pit entering and slow cooling time is 42h, and the pit discharging temperature is 140 ℃;
the obtained continuous casting billet for the petroleum valve body is a phi 500mm continuous casting round billet.
The continuous casting billet for the petroleum valve body comprises the following components in percentage by mass: 0.29 wt% of C, 0.32 wt% of Si, 0.65 wt% of Mn, 1.05 wt% of Cr, 0.27 wt% of Mo, 0.35 wt% of Ni, 0.018 wt% of Nb, 0.014 wt% of V, and the balance of Fe and inevitable impurities.
The inevitable impurities in the continuous casting billet for the petroleum valve body prepared by the method comprise less than or equal to 0.01 wt% of P and less than or equal to 0.005 wt% of S.
The petroleum valve body obtained by the embodiment is forged into a 200mm square by using a continuous casting round billet, and after heat treatment, when a sample is taken at the 1/4T position (namely, 50mm under the skin), Rm is more than or equal to 700MPa, and Rp0.2More than or equal to 550MPa, and the impact energy at-60 ℃ is more than or equal to 65J.
Example 2
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The continuous casting billet for the petroleum valve body comprises the following components in percentage by mass: 0.28 wt% of C, 0.31 wt% of Si, 0.6 wt% of Mn, 1.02 wt% of Cr, 0.3 wt% of Mo, 0.4 wt% of Ni, 0.015 wt% of Nb, 0.015 wt% of V, and the balance of Fe and inevitable impurities.
The rest is the same as in example 1.
The petroleum valve body obtained by the embodiment is forged into a 200mm square by using a continuous casting round billet, and after heat treatment, when a sample is taken at the 1/4T position (namely, 50mm under the skin), Rm is more than or equal to 700MPa, and Rp0.2More than or equal to 550MPa, and the impact energy at-60 ℃ is more than or equal to 65J.
Example 3
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The continuous casting billet for the petroleum valve body comprises the following components in percentage by mass: 0.3 wt% of C, 0.35 wt% of Si, 0.7 wt% of Mn, 1.07 wt% of Cr, 0.25 wt% of Mo, 0.3 wt% of Ni, 0.02 wt% of Nb, 0.012 wt% of V, and the balance of Fe and inevitable impurities.
The rest is the same as in example 1.
The continuous casting round billet for the petroleum valve body obtained in the embodiment is forged into a 200mm square and is subjected to heat treatmentAfter treatment, when the sample is taken at the 1/4T position (namely subcutaneous 50mm), Rm is equal to or more than 700MPa, and Rp is satisfied0.2More than or equal to 550MPa, and the impact energy at-60 ℃ is more than or equal to 65J.
Example 4
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The procedure was as in example 1 except that the amount of C in the continuously cast slab for a petroleum valve body was 0.32% by weight.
Example 5
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The procedure was as in example 1 except that the amount of C in the continuously cast slab for a petroleum valve body was 0.33% by weight.
Example 6
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The same as example 1 except that Si in the continuously cast slab for a petroleum valve body was 0.28 wt% in terms of mass%.
Example 7
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The same as example 1 except that Si in the continuously cast slab for a petroleum valve body was 0.2 wt% in terms of mass%.
Example 8
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The same as example 1 except that the Mn content in the continuous casting slab for a petroleum valve body was 0.5 wt% in terms of mass%.
Example 9
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The same as example 1 except that the Mn content in the continuous casting slab for a petroleum valve body was 0.8 wt% in terms of mass%.
Example 10
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The same as example 1 except that Mo in the continuously cast slab for a petroleum valve body was 0.23% by weight in terms of mass%.
Example 11
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The same as example 1 except that Mo in the continuously cast slab for a petroleum valve body was 0.2 wt% in terms of mass%.
Example 12
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The same as example 1 except that Mo in the continuously cast slab for a petroleum valve body was 0.15% by weight in terms of mass%.
Example 13
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The same as example 1 except that Ni was 0.42 wt% in the continuous casting slab for a petroleum valve body in terms of mass%.
Example 14
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The same as example 1 except that Ni was 0.44 wt% in the continuous casting slab for a petroleum valve body in terms of mass%.
Example 15
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The same as example 1 except that Ni was 0.5 wt% in the continuous casting slab for a petroleum valve body in terms of mass%.
Example 16
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The same as example 1 except that Nb in the continuously cast slab for a petroleum valve body was 0.01 wt% in terms of mass percentage.
Example 17
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The procedure was as in example 1 except that V in the continuously cast slab for a petroleum valve body was 0.01% by weight in terms of mass%.
Example 18
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, and the technological parameters of the preparation method are the same as those of embodiment 1.
The procedure was as in example 1 except that V in the continuously cast slab for a petroleum valve body was 0.02 wt% in terms of mass%.
Example 19
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, which comprises the following steps:
(1) pretreating molten iron: adding a desulfurizing agent into the semisteel tank, and then desulfurizing and stirring for 10min at the speed of 50 r/min; the desulfurizer is a combination of lime powder, fluorite powder and aluminum powder; the addition amount of the lime powder is 8kg/t, the addition amount of the fluorite powder is 3kg/t, and the addition amount of the aluminum powder is 1.2 kg/t;
(2) smelting in a converter: adjusting the contents of Mn, Cr, No, Ni, Nb and V in the smelting and tapping process of the converter; in the tapping process of the converter treatment, the liquid level is controlled to be positioned above the inner edge of the outlet, and a sliding plate is adopted for blocking slag to prevent tapping and slag discharging;
(3) LF refining: carrying out deep deoxidation and alloying of molten steel in the LF refining process, blowing argon in the whole LF refining process, and controlling white slag to enable S to be less than or equal to 0.01 wt% in the LF refining process;
(4) VD smelting: carrying out vacuum degassing and impurity removal on VD smelting, after the VD smelting breaks vacuum, deforming the impurities by a wire feeding line, and carrying out soft blowing treatment, wherein the soft blowing treatment time is 20min, so that P is less than or equal to 0.015 wt%, S is less than or equal to 0.01 wt%, H is less than or equal to 0.00016 wt%, and O is less than or equal to 0.002 wt%;
(5) continuous casting: the continuous casting adopts an integral water gap, a long water gap is used for adding a sealing gasket and argon sealing from a large ladle to a medium ladle, and argon is filled for casting before casting the medium ladle, so that the air suction in the continuous casting process is reduced;
(6) entering a pit for slow cooling: the pit entering temperature for pit entering and slow cooling is 500 ℃, the pit entering and slow cooling time is 36h, and the pit discharging temperature is 120 ℃;
the continuous casting billet for the petroleum valve body is a phi 400mm specification continuous casting round billet.
The element composition of the continuous casting billet for the petroleum valve body is the same as that of the embodiment 1.
Example 20
The embodiment provides a preparation method of a continuous casting billet for a petroleum valve body, which comprises the following steps:
(1) pretreating molten iron: adding a desulfurizing agent into the semisteel tank, and then desulfurizing and stirring for 8min at the speed of 60 r/min; the desulfurizer is a combination of lime powder, fluorite powder and aluminum powder; the addition amount of the lime powder is 10kg/t, the addition amount of the fluorite powder is 2kg/t, and the addition amount of the aluminum powder is 0.8 kg/t;
(2) smelting in a converter: adjusting the contents of Mn, Cr, No, Ni, Nb and V in the smelting and tapping process of the converter; in the tapping process of the converter treatment, the liquid level is controlled to be positioned above the inner edge of the outlet, and a sliding plate is adopted for blocking slag to prevent tapping and slag discharging;
(3) LF refining: carrying out deep deoxidation and alloying of molten steel in the LF refining process, blowing argon in the whole LF refining process, and controlling white slag to enable S to be less than or equal to 0.01 wt% in the LF refining process;
(4) VD smelting: carrying out vacuum degassing and impurity removal on VD smelting, after the VD smelting breaks vacuum, deforming the impurities by a wire feeding line, and carrying out soft blowing treatment, wherein the soft blowing treatment time is 30min, so that P is less than or equal to 0.015 wt%, S is less than or equal to 0.01 wt%, H is less than or equal to 0.00016 wt%, and O is less than or equal to 0.002 wt%;
(5) continuous casting: the continuous casting adopts an integral water gap, a long water gap is used for adding a sealing gasket and argon sealing from a large ladle to a medium ladle, and argon is filled for casting before casting the medium ladle, so that the air suction in the continuous casting process is reduced;
(6) entering a pit for slow cooling: the pit entering temperature for pit entering and slow cooling is 550 ℃, the pit entering and slow cooling time is 48 hours, and the pit discharging temperature is 150 ℃;
the continuous casting billet for the petroleum valve body is a phi 600mm specification continuous casting round billet.
The element composition of the continuous casting billet for the petroleum valve body is the same as that of the embodiment 1.
Comparative example 1
The present comparative example provides a continuous casting slab manufacturing method having the same process parameters as in example 1.
The same procedure as in example 1 was repeated except that V in the slab was replaced with Nb in an equal mass percentage.
Comparative example 2
The present comparative example provides a continuous casting slab manufacturing method having the same process parameters as in example 1.
The same procedure as in example 1 was repeated except that Nb in the slab was replaced with V of equal mass in percentage by mass.
A sample 200mm long was cut out of a slab obtained from the continuous casting slabs obtained in examples 1 to 20 and comparative examples 1 to 2 at a forging ratio of 4:1 or more by forging into a 200mm square, and after heat treatment, the sample was sampled at the T/4 portion (i.e., 50mm below the skin) and processed into a standard sample according to ASTm A370. Mechanical properties were tested according to ASTM E8, ASTM E23.
The heat treatment was carried out by normalizing, quenching (water extraction after heating to 860 ℃ C.) and tempering (air cooling after heating to 680 ℃ C.) in this order, and the results are shown in Table 1.
TABLE 1
Figure BDA0003124786250000151
Figure BDA0003124786250000161
As can be seen from Table 1, the Rm of the slabs obtained in examples 1 to 3 and examples 19 to 20 was not less than 820MPa, Rp0.2More than or equal to 670MPa, and the impact energy at-60 ℃ is more than or equal to 130J.
As is clear from a comparison of examples 4 and 5 with example 1, an excessively high C content reduces the mechanical properties of the resulting strand.
As is clear from a comparison of examples 6 and 7 with example 1, too low a Si content reduces the mechanical properties of the resulting slab.
As is clear from comparison of examples 8 and 9 with example 1, when the Mn content is 0.5 wt% or 0.8 wt%, the mechanical properties of the resulting continuous cast slab are inferior to those of Mn in the range of 0.6 to 0.7 wt%.
As is clear from the comparison of examples 10, 11 and 12 with example 1, too low a Mo content reduces the mechanical properties of the resulting slab.
As is clear from comparison of examples 13, 14 and 15 with example 1, too much Ni content reduces the mechanical properties of the resulting slab.
As is clear from a comparison of example 16 with example 1, too low a Nb content reduces the mechanical properties of the resulting slab.
As is clear from a comparison of examples 17 and 18 with example 1, too high or too low a V content reduces the mechanical properties of the resulting slab.
As is clear from comparison of comparative examples 1 and 2 with example 1, replacing Nb with V or replacing V with Nb is not favorable for obtaining a continuous casting slab having excellent mechanical properties.
In conclusion, the continuous casting billet for the petroleum valve body provided by the invention meets the performance requirement of a new API standard sampling test by adjusting the element composition, and meets the conditions that Rm is more than or equal to 700MPa and Rp is equal to or more than Rp when sampling is carried out at the 1/4T position of a 200mm square0.2More than or equal to 550MPa, and the impact energy at-60 ℃ is more than or equal to 65J.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. The continuous casting billet for the petroleum valve body is characterized by comprising the following components in percentage by mass: 0.28 to 0.33 wt% of C, 0.2 to 0.35 wt% of Si, 0.5 to 0.8 wt% of Mn, 1 to 1.1 wt% of Cr, 0.15 to 0.3 wt% of Mo, 0.2 to 0.5 wt% of Ni, 0.01 to 0.02 wt% of Nb, 0.01 to 0.02 wt% of V, and the balance of Fe and inevitable impurities.
2. The continuous casting billet for the oil valve body according to claim 1, which comprises, in mass percent: 0.28 to 0.3 wt% of C, 0.31 to 0.35 wt% of Si, 0.6 to 0.7 wt% of Mn, 1.02 to 1.07 wt% of Cr, 0.25 to 0.3 wt% of Mo, 0.3 to 0.4 wt% of Ni, 0.01 to 0.02 wt% of Nb, 0.01 to 0.02 wt% of V, and the balance of Fe and inevitable impurities.
3. The continuous casting billet for petroleum valve bodies according to claim 2, wherein Nb in the continuous casting billet for petroleum valve bodies is 0.015 to 0.02 wt% in terms of mass percentage.
4. The continuous casting billet for petroleum valve bodies according to claim 2 or 3, wherein V in the continuous casting billet for petroleum valve bodies is 0.012 to 0.015 wt% in terms of mass percentage content.
5. The continuous casting billet for an oil valve body according to any one of claims 1 to 4, wherein the inevitable impurities include P.ltoreq.0.015 wt%, S.ltoreq.0.01 wt%;
preferably, the inevitable impurities include P.ltoreq.0.01 wt% and S.ltoreq.0.005 wt% in mass percentage.
6. A method for preparing a continuous casting billet for a petroleum valve body as defined in any one of claims 1 to 5, which comprises molten iron pretreatment, converter smelting, LF refining, VD smelting, continuous casting and pit entry slow cooling which are sequentially carried out.
7. The preparation method according to claim 6, wherein the molten iron pretreatment is to add a desulfurizing agent into a semisteel tank, and then to perform desulfurization stirring;
preferably, the desulfurizing agent is a combination of lime powder, fluorite powder and aluminum powder;
preferably, the addition amount of the lime powder is 8-10kg/t, the addition amount of the fluorite powder is 2-3kg/t, and the addition amount of the aluminum powder is 0.8-1.2 kg/t;
preferably, the rotation speed of the desulfurization stirring is 50-60r/min, and the time is 8-10 min.
8. The preparation method according to claim 6 or 7, characterized in that the contents of Mn, Cr, No, Ni, Nb and V are adjusted during the smelting and tapping process of the converter;
preferably, the liquid level is controlled to be positioned above the inner edge of the outlet in the tapping process of the converter treatment, and the sliding plate is adopted for blocking slag to prevent tapping and slag discharging.
9. The method of any one of claims 6 to 8, wherein S is 0.01 wt% or less, preferably 0.005 wt% or less, during the LF refining process;
preferably, after the VD smelting breaks vacuum, the wire feeding line deforms the inclusions and performs soft blowing treatment, wherein the soft blowing treatment time is 20-30 min;
preferably, the continuous casting adopts an integral water gap, a long water gap is adopted from a large ladle to a middle ladle for adding a sealing gasket and argon sealing, argon is filled before the middle ladle is cast for casting, and air suction in the continuous casting process is reduced;
preferably, the pit entering temperature for pit entering slow cooling is 500-550 ℃, the pit entering slow cooling time is 36-48h, and the pit outlet temperature is 120-150 ℃;
preferably, the continuous casting billet for the petroleum valve body obtained by the preparation method is a phi 400-600mm specification continuous casting round billet.
10. The method according to any one of claims 6 to 9, characterized by comprising the steps of:
(1) pretreating molten iron: adding a desulfurizing agent into the semisteel tank, and then desulfurizing and stirring for 8-10min at the speed of 50-60 r/min; the desulfurizer is a combination of lime powder, fluorite powder and aluminum powder; the addition amount of the lime powder is 8-10kg/t, the addition amount of the fluorite powder is 2-3kg/t, and the addition amount of the aluminum powder is 0.8-1.2 kg/t;
(2) smelting in a converter: adjusting the contents of Mn, Cr, No, Ni, Nb and V in the smelting and tapping process of the converter; in the tapping process of the converter treatment, the liquid level is controlled to be positioned above the inner edge of the outlet, and a sliding plate is adopted for blocking slag to prevent tapping and slag discharging;
(3) LF refining: carrying out deep deoxidation and alloying of molten steel in the LF refining process, blowing argon in the whole LF refining process, and controlling white slag to enable S to be less than or equal to 0.01 wt% in the LF refining process;
(4) VD smelting: carrying out vacuum degassing and impurity removal on VD smelting, after the VD smelting breaks vacuum, deforming the impurities by a wire feeding line, and carrying out soft blowing treatment, wherein the soft blowing treatment time is 20-30min, so that P is less than or equal to 0.015 wt%, S is less than or equal to 0.01 wt%, H is less than or equal to 0.00016 wt%, and O is less than or equal to 0.002 wt%;
(5) continuous casting: the continuous casting adopts an integral water gap, a long water gap is used for adding a sealing gasket and argon sealing from a large ladle to a medium ladle, and argon is filled for casting before casting the medium ladle, so that the air suction in the continuous casting process is reduced;
(6) entering a pit for slow cooling: the pit entry temperature for pit entry slow cooling is 500-550 ℃, the pit entry slow cooling time is 36-48h, and the pit exit temperature is 120-150 ℃;
the continuous casting billet for the petroleum valve body is a phi 400-plus 600mm specification continuous casting round billet.
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