CN111793768A - Production method of extremely-low-cost chromium-containing thick outlet pipeline steel - Google Patents

Production method of extremely-low-cost chromium-containing thick outlet pipeline steel Download PDF

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CN111793768A
CN111793768A CN202010411618.2A CN202010411618A CN111793768A CN 111793768 A CN111793768 A CN 111793768A CN 202010411618 A CN202010411618 A CN 202010411618A CN 111793768 A CN111793768 A CN 111793768A
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翟冬雨
吴俊平
方磊
姜金星
杜海军
员强鹏
殷杰
刘帅
刘梦冉
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Nanjing Iron and 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
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/064—Dephosphorising; Desulfurising
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/10—Handling in a vacuum
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • 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
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • 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
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • 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
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite

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Abstract

The invention discloses a production method of extremely-low-cost chromium-containing thick outlet pipeline steel, which relates to the technical field of steel smelting, and comprises the following chemical components in percentage by mass: c: 0.060% to 0.080%, Si: 0.25-0.35%, Mn: 1.35-1.70%, P is less than or equal to 0.018%, S is less than or equal to 0.0050%, Nb: 0.030 to 0.044 percent, Ti: 0.006-0.020%, Cr: 0.30-0.35%, Al: 0.015 to 0.050 percent, and the balance of Fe and inevitable impurities; the method comprises the steps of adopting converter smelting, LF desulfurization alloying, RH vacuum treatment, austenitizing technology, TMCP rolling technology and ACC cooling technology to obtain the thick pipeline steel product with the thickness specification of 20-40 mm, wherein the strength and the toughness of the product are matched.

Description

Production method of extremely-low-cost chromium-containing thick outlet pipeline steel
Technical Field
The invention relates to the technical field of steel smelting, in particular to a production method of chromium-containing thick outlet pipeline steel with extremely low cost.
Background
With the economic development of China, the steel consumption is increased day by day, and the scale of steel mills is increased day by day. At present, the crude steel yield of China reaches more than 10 hundred million tons, which accounts for about 60 percent of the steel yield of the world, the development of the steel industry promotes the competitive between steel plants of China, and simultaneously, the quality of steel products is stably improved. In order to improve the competitiveness of iron and steel enterprises in China worldwide, the state implements a tax refund policy on high-grade steel, particularly alloy steel of special variety types, and refunds according to 13% of the price of steel per ton, so that each enterprise deeply studies tax refunds, reduces the cost, improves the quality and strives to develop an international market.
The steel mills in the Yangtze river economic zone area have obvious geographic advantages, but lack of mines, raw material import and export transportation cost brings huge pressure to external competition of enterprises, and under the guidance of national preferential policies, the steel mills develop low-cost high-quality alloy steel varieties and are important for important environmental regulations in the steady world supply chain of the enterprises. Chromium element belongs to the cheapest element in the alloy, the high chromium element is adopted to design the export product with the lowest cost, the ultralow-cost manufacturing of chromium tax refurbishment is continuously researched and developed to produce the high-quality chromium-containing thick-specification low-cost pipeline steel, and the method can provide powerful guarantee for further development of enterprises in the international steel industry.
Disclosure of Invention
In order to solve the technical problems, the invention provides a production method of an extremely low-cost chromium-containing thick outlet pipeline steel, which comprises the following chemical components in percentage by mass: c: 0.060% to 0.080%, Si: 0.25-0.35%, Mn: 1.35-1.70%, P is less than or equal to 0.018%, S is less than or equal to 0.0050%, Nb: 0.030 to 0.044 percent, Ti: 0.006-0.020%, Cr: 0.30-0.35%, Al: 0.015 to 0.050 percent, and the balance of Fe and inevitable impurities;
the method specifically comprises the following steps:
s1, performing molten iron pretreatment desulfurization operation after the molten iron is poured into a tank, ensuring that slag is removed completely after desulfurization, and ensuring that S in the molten iron fed into the furnace is less than or equal to 0.010%;
s2, converter smelting is carried out by adopting a top-bottom combined blowing technology, the tapping temperature is 1640-1680 ℃, the tapping C is less than or equal to 0.050%, and the tapping P is less than or equal to 0.016%;
s3, carrying out desulfurization and alloying operation in an LF furnace to ensure that the components meet the design requirements of products;
s4, carrying out vacuum treatment operation in an RH furnace, wherein the vacuum degree is less than or equal to 0.3mbar, the vacuum treatment time is more than or equal to 15min, carrying out calcium treatment by adopting a seamless calcium line after the vacuum treatment is finished, and the static stirring time after the calcium treatment is more than or equal to 15 min;
s5, carrying out continuous casting on the molten steel after vacuum treatment, and ensuring that the macroscopic structure adopts a Raman standard grade 2 or better by adopting a dynamic soft reduction and electromagnetic stirring technology;
s6, austenitizing temperature is 1100 +/-10 ℃, and soaking time is more than or equal to 40 min;
s7, rolling by adopting a two-stage rolling process, wherein the water inlet temperature is controlled to be 735-760 ℃, the red returning temperature is controlled to be 400-600 ℃, the roller speed is controlled to be 0.4-0.9 m/S, and the acceleration is controlled to be 0.003-0.010 m/S2。
The technical effects are as follows: the invention adopts converter smelting, LF desulfurization alloying, RH vacuum treatment, and continuous casting to obtain the aluminum killed steel with macrostructure meeting the Mandarin standard grade 2 or better; by a high-temperature austenitizing technology, the grain size of the structure is effectively refined, a multi-phase structure type which takes the quasi-polymorphic ferrite iron as a main part and bainite and acicular ferrite as well as certain martensite-austenite-island as an auxiliary part is obtained by adopting a TMCP rolling process and an ACC cooling technology, the matching of the strength and the toughness of the product is met, and the performance requirement of a client product is met.
The technical scheme of the invention is further defined as follows:
the production method of the chromium-containing thick outlet pipeline steel with extremely low cost has the product thickness specification of 20-40 mm.
The production method of the chromium-containing thick outlet pipeline steel with extremely low cost is used for producing X60M, L415M, X65M, L450M, X70M and L485M grade pipeline steel plates.
The production method of the extremely-low-cost chromium-containing thick-specification outlet pipeline steel is used for producing X60M pipeline steel, and comprises the following chemical components in percentage by mass: c: 0.060% to 0.080%, Si: 0.25-0.35%, Mn: 1.35-1.45%, P is less than or equal to 0.018%, S is less than or equal to 0.0050%, Nb: 0.030 to 0.044 percent, Ti: 0.006-0.020%, Cr: 0.30-0.35%, Al: 0.015 to 0.050 percent, and the balance of Fe and inevitable impurities;
the method specifically comprises the following steps:
s1, performing molten iron pretreatment desulfurization operation after the molten iron is poured into a tank, ensuring that slag is removed completely after desulfurization, and ensuring that S in the molten iron fed into the furnace is less than or equal to 0.010%;
s2, converter smelting is carried out by adopting a top-bottom combined blowing technology, the tapping temperature is 1640-1680 ℃, the tapping C is less than or equal to 0.050%, and the tapping P is less than or equal to 0.016%;
s3, carrying out desulfurization and alloying operation in an LF furnace to ensure that the components meet the design requirements of products;
s4, carrying out vacuum treatment operation in an RH furnace, wherein the vacuum degree is less than or equal to 0.3mbar, the vacuum treatment time is more than or equal to 15min, carrying out calcium treatment by adopting a seamless calcium line after the vacuum treatment is finished, and the static stirring time after the calcium treatment is more than or equal to 15 min;
s5, carrying out continuous casting on the molten steel after vacuum treatment, and ensuring that the macroscopic structure adopts a Raman standard grade 2 or better by adopting a dynamic soft reduction and electromagnetic stirring technology;
s6, austenitizing temperature is 1100 +/-10 ℃, and soaking time is more than or equal to 40 min;
s7, rolling by adopting a two-stage rolling process, controlling the water inlet temperature at 750-760 ℃, the red returning temperature at 500-600 ℃, the roller speed at 0.4-0.9 m/S and the acceleration at 0.003-0.010 m/S2。
The production method of the extremely-low-cost chromium-containing thick-specification outlet pipeline steel is used for producing X65M pipeline steel, and comprises the following chemical components in percentage by mass: c: 0.060% to 0.080%, Si: 0.25-0.35%, Mn: 1.45-1.55 percent of Nb, less than or equal to 0.018 percent of P, less than or equal to 0.0050 percent of S, and the mass percent of Nb: 0.030 to 0.044 percent, Ti: 0.006-0.020%, Cr: 0.30-0.35%, Al: 0.015 to 0.050 percent, and the balance of Fe and inevitable impurities;
the method specifically comprises the following steps:
s1, performing molten iron pretreatment desulfurization operation after the molten iron is poured into a tank, ensuring that slag is removed completely after desulfurization, and ensuring that S in the molten iron fed into the furnace is less than or equal to 0.010%;
s2, converter smelting is carried out by adopting a top-bottom combined blowing technology, the tapping temperature is 1640-1680 ℃, the tapping C is less than or equal to 0.050%, and the tapping P is less than or equal to 0.016%;
s3, carrying out desulfurization and alloying operation in an LF furnace to ensure that the components meet the design requirements of products;
s4, carrying out vacuum treatment operation in an RH furnace, wherein the vacuum degree is less than or equal to 0.3mbar, the vacuum treatment time is more than or equal to 15min, carrying out calcium treatment by adopting a seamless calcium line after the vacuum treatment is finished, and the static stirring time after the calcium treatment is more than or equal to 15 min;
s5, carrying out continuous casting on the molten steel after vacuum treatment, and ensuring that the macroscopic structure adopts a Raman standard grade 2 or better by adopting a dynamic soft reduction and electromagnetic stirring technology;
s6, austenitizing temperature is 1100 +/-10 ℃, and soaking time is more than or equal to 40 min;
s7, rolling by adopting a two-stage rolling process, controlling the water inlet temperature at 750-760 ℃ and the red returning temperature at 500-600 ℃,the roller speed is controlled to be 0.4-0.9 m/s, and the acceleration is controlled to be 0.003-0.010 m/s2。
The production method of the extremely-low-cost chromium-containing thick-specification outlet pipeline steel is used for producing X70M pipeline steel, and comprises the following chemical components in percentage by mass: c: 0.060% to 0.080%, Si: 0.25-0.35%, Mn: 1.60-1.70%, P is less than or equal to 0.018%, S is less than or equal to 0.0050%, Nb: 0.030 to 0.044 percent, Ti: 0.006-0.020%, Cr: 0.30-0.35%, Al: 0.015 to 0.050 percent, and the balance of Fe and inevitable impurities;
the method specifically comprises the following steps:
s1, performing molten iron pretreatment desulfurization operation after the molten iron is poured into a tank, ensuring that slag is removed completely after desulfurization, and ensuring that S in the molten iron fed into the furnace is less than or equal to 0.010%;
s2, converter smelting is carried out by adopting a top-bottom combined blowing technology, the tapping temperature is 1640-1680 ℃, the tapping C is less than or equal to 0.050%, and the tapping P is less than or equal to 0.016%;
s3, carrying out desulfurization and alloying operation in an LF furnace to ensure that the components meet the design requirements of products;
s4, carrying out vacuum treatment operation in an RH furnace, wherein the vacuum degree is less than or equal to 0.3mbar, the vacuum treatment time is more than or equal to 15min, carrying out calcium treatment by adopting a seamless calcium line after the vacuum treatment is finished, and the static stirring time after the calcium treatment is more than or equal to 15 min;
s5, carrying out continuous casting on the molten steel after vacuum treatment, and ensuring that the macroscopic structure adopts a Raman standard grade 2 or better by adopting a dynamic soft reduction and electromagnetic stirring technology;
s6, austenitizing temperature is 1100 +/-10 ℃, and soaking time is more than or equal to 40 min;
s7, rolling by adopting a two-stage rolling process, controlling the water inlet temperature at 735-745 ℃, the red returning temperature at 490-500 ℃, the roller speed at 0.4-0.9 m/S and the acceleration at 0.003-0.010 m/S2。
The invention has the beneficial effects that:
(1) according to the invention, the strength of steel can be effectively improved, and meanwhile, the toughness and the surface quality of steel can be improved by adopting a low-carbon design, so that the welding performance of a product is improved; mn can play a role in solid solution strengthening, can form sulfides, reduces the harm of sulfur, and can be gathered in austenite to improve the stability of the austenite; nb can remarkably improve the austenite recrystallization temperature, increase the deformation of a non-recrystallization region, form the grain size of a niobium carbonitride refined tissue and improve the drop hammer performance of a product; cr can improve hardenability and product strength, but the Cr content is higher, which can cause unstable structure transformation and fluctuation of mechanical properties;
(2) the invention meets the national alloy tax refunding requirement of chromium tax refunding by adopting the low-carbon manganese design concept, and the component design is a cost design mode with the lowest cost in export products, thereby effectively reducing the alloy cost design, reducing the manufacturing cost of the products and ensuring the quality requirement of the products;
(3) according to the invention, according to the element characteristics, the water inlet temperature of the steel plate is effectively controlled, the structure is promoted to develop towards a single quasi-polygonal ferrite structure, the stability of the mechanical property of the product is ensured, and the stability of the toughness of the product is ensured;
(4) the smelting process ensures the cleanliness of products and the low-power quality of casting blanks, the stable components are the basic requirements for ensuring the performance of the products, and the stability of the performance of the products is realized through the control of the smelting process;
(5) the austenitizing process effectively refines the texture grain size, improves the product strength, simultaneously effectively reduces the consumption of high-cost ferrocolumbium, effectively reduces the secondary opening temperature through a two-stage rolling technology, refines the texture grain size and the texture uniformity again, obtains the quasiporphism ferrite iron with the content of not less than 50 percent of the main content through lower water inlet temperature, effectively improves the product toughness, meets the-30-degree drop hammer toughness requirement of API standard, simultaneously forms bainite and acicular ferrite through rapid cooling of alloy elements such as manganese, chromium and the like precipitated in the texture under the condition of rapid water cooling, contains a certain amount of multi-phase texture assisted by Maroza, not only ensures the product strength, but also improves the texture toughness, and meets the universality requirement of the performance application of the product.
Drawings
FIG. 1 is a thickness-wise metallographic structure of the product of example 1;
FIG. 2 is a thickness-wise metallographic structure of the product of example 2;
FIG. 3 is a thickness-wise metallographic structure of the product of example 3.
Detailed Description
Example 1
The production method of the extra-low-cost chromium-containing thick outlet pipeline steel provided by the embodiment is used for producing X60M pipeline steel, the thickness of the product is 30mm, and the chemical components and the mass percentage are as follows: c: 0.071%, Si: 0.28%, Mn: 1.37%, P: 0.011%, S: 0.0030%, Nb: 0.033%, Ti: 0.016%, Cr: 0.32%, Al: 0.018%, and the balance of Fe and inevitable impurities.
The method specifically comprises the following steps:
s1, after the molten iron is poured into a tank, performing molten iron pretreatment desulfurization operation, after desulfurization, ensuring that slagging-off is clean, and feeding molten iron into a furnace S: 0.008 percent;
s2, converter smelting is carried out by adopting a top-bottom combined blowing technology, the tapping temperature is 1646 ℃, and the tapping C: 0.036%, tapping P: 0.012%; s3, carrying out desulfurization and alloying operation in an LF furnace to ensure that the components meet the design requirements of products;
s4, carrying out vacuum treatment operation in an RH furnace, wherein the vacuum degree is 0.1mbar, the vacuum treatment time is 15min, carrying out calcium treatment by adopting a seamless calcium line after the vacuum treatment is finished, and carrying out static stirring for 15min after the calcium treatment, so that the purity of the molten steel is effectively improved;
s5, carrying out continuous casting on the molten steel after vacuum treatment, and ensuring that the macroscopic structure adopts a Mandarin rating level 1 by adopting a dynamic soft reduction and electromagnetic stirring technology;
s6, austenitizing at 1106 ℃, soaking for 42min to fully exert the strengthening effect of the alloy;
s7, rolling by adopting a two-stage rolling process, effectively refining the grain size of the structure, controlling the water inlet temperature at 751 ℃, the re-reddening temperature at 505 ℃, the roller speed at 0.6m/S and the acceleration at 0.005m/S2The complete tissue transformation is ensured, and the matching of the strength and the toughness is ensured.
Example 2
The production method of the extra-low-cost chromium-containing thick outlet pipeline steel provided by the embodiment is used for producing X65M pipeline steel, the thickness of the product is 28.6mm, and the chemical components and the mass percentage are as follows: c: 0.073%, Si: 0.27%, Mn: 1.51%, P: 0.013%, S: 0.0030%, Nb: 0.035%, Ti: 0.016%, Cr: 0.33%, Al: 0.018%, and the balance of Fe and inevitable impurities.
The method specifically comprises the following steps:
s1, after the molten iron is poured into a tank, performing molten iron pretreatment desulfurization operation, after desulfurization, ensuring that slagging-off is clean, and feeding molten iron into a furnace S: 0.008 percent;
s2, converter smelting is carried out by adopting a top-bottom combined blowing technology, the tapping temperature is 1646 ℃, and the tapping C: 0.036%, tapping P: 0.012%;
s3, carrying out desulfurization and alloying operation in an LF furnace to ensure that the components meet the design requirements of products;
s4, carrying out vacuum treatment operation in an RH furnace, wherein the vacuum degree is 0.1mbar, the vacuum treatment time is 15min, carrying out calcium treatment by adopting a seamless calcium line after the vacuum treatment is finished, and carrying out static stirring for 15min after the calcium treatment, so that the purity of the molten steel is effectively improved;
s5, carrying out continuous casting on the molten steel after vacuum treatment, and ensuring that the macroscopic structure adopts a Mandarin rating level 1 by adopting a dynamic soft reduction and electromagnetic stirring technology;
s6, austenitizing at 1106 ℃, soaking for 42min to fully exert the strengthening effect of the alloy;
s7, rolling by adopting a two-stage rolling process to effectively refine the grain size of the structure, controlling the water inlet temperature at 751 ℃, the re-reddening temperature at 510 ℃, the roller speed at 0.6m/S and the acceleration at 0.005m/S2The complete tissue transformation is ensured, and the matching of the strength and the toughness is ensured.
Example 3
The production method of the extra-low-cost chromium-containing thick outlet pipeline steel provided by the embodiment is used for producing X70M pipeline steel with the product thickness of 28.6mm and producing X70M pipeline steel, and comprises the following chemical components in percentage by mass: c: 0.075%, Si: 0.26%, Mn: 1.63%, P: 0.013%, S: 0.0030%, Nb: 0.033%, Ti: 0.016%, Cr: 0.33%, Al: 0.018%, and the balance of Fe and inevitable impurities.
The method specifically comprises the following steps:
s1, after the molten iron is poured into a tank, performing molten iron pretreatment desulfurization operation, after desulfurization, ensuring that slagging-off is clean, and feeding molten iron into a furnace S: 0.008 percent;
s2, converter smelting is carried out by adopting a top-bottom combined blowing technology, the tapping temperature is 1646 ℃, and the tapping C: 0.036%, tapping P: 0.012%;
s3, carrying out desulfurization and alloying operation in an LF furnace to ensure that the components meet the design requirements of products;
s4, carrying out vacuum treatment operation in an RH furnace, wherein the vacuum degree is 0.1mbar, the vacuum treatment time is 15min, carrying out calcium treatment by adopting a seamless calcium line after the vacuum treatment is finished, and carrying out static stirring for 15min after the calcium treatment, so that the purity of the molten steel is effectively improved;
s5, carrying out continuous casting on the molten steel after vacuum treatment, and ensuring that the macroscopic structure adopts a Mandarin rating level 1 by adopting a dynamic soft reduction and electromagnetic stirring technology;
s6, austenitizing at 1106 ℃, soaking for 42min to fully exert the strengthening effect of the alloy;
s7, rolling by adopting a two-stage rolling process to effectively refine the grain size of the structure, controlling the water inlet temperature at 738 ℃, the red returning temperature at 466 ℃, the roller speed at 0.8m/S and the acceleration at 0.006m/S2The complete tissue transformation is ensured, and the matching of the strength and the toughness is ensured.
The products obtained from example 1, example 2 and example 3 were subjected to mechanical tests, the results of which are given in the following table:
Figure BDA0002493486300000061
the invention adopts the design idea of niobium-chromium low-carbon and manganese-less alloy, adopts a pure steel smelting process and a TMCP rolling technology, obtains a multiphase structure type which takes the quasi-pleomorphic ferrite iron as the main component and contains bainite and acicular ferrite and a certain amount of martensite islands as the auxiliary component as shown in figures 1-3, has good matching between the strength and the toughness after the performance test of the product, meets the performance requirements of API and other international petroleum steel pipes, and reduces the production cost.
In addition to the above embodiments, the present invention may have other embodiments. All technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the claims of the present invention.

Claims (6)

1. A production method of an extremely low-cost chromium-containing thick outlet pipeline steel is characterized by comprising the following steps:
the chemical components and the mass percentage are as follows: c: 0.060% to 0.080%, Si: 0.25-0.35%, Mn: 1.35-1.70%, P is less than or equal to 0.018%, S is less than or equal to 0.0050%, Nb: 0.030 to 0.044 percent, Ti: 0.006-0.020%, Cr: 0.30-0.35%, Al: 0.015 to 0.050 percent, and the balance of Fe and inevitable impurities;
the method specifically comprises the following steps:
s1, performing molten iron pretreatment desulfurization operation after the molten iron is poured into a tank, ensuring that slag is removed completely after desulfurization, and ensuring that S in the molten iron fed into the furnace is less than or equal to 0.010%;
s2, converter smelting is carried out by adopting a top-bottom combined blowing technology, the tapping temperature is 1640-1680 ℃, the tapping C is less than or equal to 0.050%, and the tapping P is less than or equal to 0.016%;
s3, carrying out desulfurization and alloying operation in an LF furnace to ensure that the components meet the design requirements of products;
s4, carrying out vacuum treatment operation in an RH furnace, wherein the vacuum degree is less than or equal to 0.3mbar, the vacuum treatment time is more than or equal to 15min, carrying out calcium treatment by adopting a seamless calcium line after the vacuum treatment is finished, and the static stirring time after the calcium treatment is more than or equal to 15 min;
s5, carrying out continuous casting on the molten steel after vacuum treatment, and ensuring that the macroscopic structure adopts a Raman standard grade 2 or better by adopting a dynamic soft reduction and electromagnetic stirring technology;
s6, austenitizing temperature is 1100 +/-10 ℃, and soaking time is more than or equal to 40 min;
s7, rolling by adopting a two-stage rolling process, wherein the water inlet temperature is controlled to be 735-760 ℃, the red returning temperature is controlled to be 400-600 ℃, the roller speed is controlled to be 0.4-0.9 m/S, and the acceleration is controlled to be 0.003-0.010 m/S2。
2. The method for producing the chromium-containing thick-gauge outlet pipeline steel with extremely low cost according to claim 1, is characterized in that: the thickness specification of the product is 20-40 mm.
3. The method for producing the chromium-containing thick-gauge outlet pipeline steel with extremely low cost according to claim 1, is characterized in that: the method is used for producing X60M, L415M, X65M, L450M, X70M and L485M grade pipeline steel plates.
4. The method for producing the chromium-containing thick-gauge outlet pipeline steel with extremely low cost according to claim 1, is characterized in that:
the X60M pipeline steel is produced by the following chemical components in percentage by mass: c: 0.060% to 0.080%, Si: 0.25-0.35%, Mn: 1.35-1.45%, P is less than or equal to 0.018%, S is less than or equal to 0.0050%, Nb: 0.030 to 0.044 percent, Ti: 0.006-0.020%, Cr: 0.30-0.35%, Al: 0.015 to 0.050 percent, and the balance of Fe and inevitable impurities;
the method specifically comprises the following steps:
s1, performing molten iron pretreatment desulfurization operation after the molten iron is poured into a tank, ensuring that slag is removed completely after desulfurization, and ensuring that S in the molten iron fed into the furnace is less than or equal to 0.010%;
s2, converter smelting is carried out by adopting a top-bottom combined blowing technology, the tapping temperature is 1640-1680 ℃, the tapping C is less than or equal to 0.050%, and the tapping P is less than or equal to 0.016%;
s3, carrying out desulfurization and alloying operation in an LF furnace to ensure that the components meet the design requirements of products;
s4, carrying out vacuum treatment operation in an RH furnace, wherein the vacuum degree is less than or equal to 0.3mbar, the vacuum treatment time is more than or equal to 15min, carrying out calcium treatment by adopting a seamless calcium line after the vacuum treatment is finished, and the static stirring time after the calcium treatment is more than or equal to 15 min;
s5, carrying out continuous casting on the molten steel after vacuum treatment, and ensuring that the macroscopic structure adopts a Raman standard grade 2 or better by adopting a dynamic soft reduction and electromagnetic stirring technology;
s6, austenitizing temperature is 1100 +/-10 ℃, and soaking time is more than or equal to 40 min;
s7, rolling by adopting a two-stage rolling process, controlling the water inlet temperature at 750-760 ℃, the red returning temperature at 500-600 ℃, the roller speed at 0.4-0.9 m/S and the acceleration at 0.003-0.010 m/S2。
5. The method for producing the chromium-containing thick-gauge outlet pipeline steel with extremely low cost according to claim 1, is characterized in that:
the X65M pipeline steel is produced by the following chemical components in percentage by mass: c: 0.060% to 0.080%, Si: 0.25-0.35%, Mn: 1.45-1.55 percent of Nb, less than or equal to 0.018 percent of P, less than or equal to 0.0050 percent of S, and the mass percent of Nb: 0.030 to 0.044 percent, Ti: 0.006-0.020%, Cr: 0.30-0.35%, Al: 0.015 to 0.050 percent, and the balance of Fe and inevitable impurities;
the method specifically comprises the following steps:
s1, performing molten iron pretreatment desulfurization operation after the molten iron is poured into a tank, ensuring that slag is removed completely after desulfurization, and ensuring that S in the molten iron fed into the furnace is less than or equal to 0.010%;
s2, converter smelting is carried out by adopting a top-bottom combined blowing technology, the tapping temperature is 1640-1680 ℃, the tapping C is less than or equal to 0.050%, and the tapping P is less than or equal to 0.016%;
s3, carrying out desulfurization and alloying operation in an LF furnace to ensure that the components meet the design requirements of products;
s4, carrying out vacuum treatment operation in an RH furnace, wherein the vacuum degree is less than or equal to 0.3mbar, the vacuum treatment time is more than or equal to 15min, carrying out calcium treatment by adopting a seamless calcium line after the vacuum treatment is finished, and the static stirring time after the calcium treatment is more than or equal to 15 min;
s5, carrying out continuous casting on the molten steel after vacuum treatment, and ensuring that the macroscopic structure adopts a Raman standard grade 2 or better by adopting a dynamic soft reduction and electromagnetic stirring technology;
s6, austenitizing temperature is 1100 +/-10 ℃, and soaking time is more than or equal to 40 min;
s7, rolling by adopting a two-stage rolling process, controlling the water inlet temperature at 750-760 ℃, the red returning temperature at 500-600 ℃, the roller speed at 0.4-0.9 m/S and the acceleration at 0.003-0.010 m/S2。
6. The method for producing the chromium-containing thick-gauge outlet pipeline steel with extremely low cost according to claim 1, is characterized in that:
the X70M pipeline steel is produced by the following chemical components in percentage by mass: c: 0.060% to 0.080%, Si: 0.25-0.35%, Mn: 1.60-1.70%, P is less than or equal to 0.018%, S is less than or equal to 0.0050%, Nb: 0.030 to 0.044 percent, Ti: 0.006-0.020%, Cr: 0.30-0.35%, Al: 0.015 to 0.050 percent, and the balance of Fe and inevitable impurities;
the method specifically comprises the following steps:
s1, performing molten iron pretreatment desulfurization operation after the molten iron is poured into a tank, ensuring that slag is removed completely after desulfurization, and ensuring that S in the molten iron fed into the furnace is less than or equal to 0.010%;
s2, converter smelting is carried out by adopting a top-bottom combined blowing technology, the tapping temperature is 1640-1680 ℃, the tapping C is less than or equal to 0.050%, and the tapping P is less than or equal to 0.016%;
s3, carrying out desulfurization and alloying operation in an LF furnace to ensure that the components meet the design requirements of products;
s4, carrying out vacuum treatment operation in an RH furnace, wherein the vacuum degree is less than or equal to 0.3mbar, the vacuum treatment time is more than or equal to 15min, carrying out calcium treatment by adopting a seamless calcium line after the vacuum treatment is finished, and the static stirring time after the calcium treatment is more than or equal to 15 min;
s5, carrying out continuous casting on the molten steel after vacuum treatment, and ensuring that the macroscopic structure adopts a Raman standard grade 2 or better by adopting a dynamic soft reduction and electromagnetic stirring technology;
s6, austenitizing temperature is 1100 +/-10 ℃, and soaking time is more than or equal to 40 min;
s7, rolling by adopting a two-stage rolling process, controlling the water inlet temperature at 735-745 ℃, the red returning temperature at 490-500 ℃, the roller speed at 0.4-0.9 m/S and the acceleration at 0.003-0.010 m/S2。
CN202010411618.2A 2020-05-15 2020-05-15 Production method of extremely-low-cost chromium-containing thick outlet pipeline steel Pending CN111793768A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118086780A (en) * 2024-04-17 2024-05-28 江苏省沙钢钢铁研究院有限公司 Acid-resistant pipeline steel and manufacturing method thereof

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110016626A (en) * 2019-05-07 2019-07-16 南京钢铁股份有限公司 A kind of production method improving low Grade Pipeline Steel surface quality

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110016626A (en) * 2019-05-07 2019-07-16 南京钢铁股份有限公司 A kind of production method improving low Grade Pipeline Steel surface quality

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118086780A (en) * 2024-04-17 2024-05-28 江苏省沙钢钢铁研究院有限公司 Acid-resistant pipeline steel and manufacturing method thereof

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