CN111809113B

CN111809113B - TC-50 steel grade petroleum pipe blank containing rare earth

Info

Publication number: CN111809113B
Application number: CN202010588146.8A
Authority: CN
Inventors: 苏忠贵; 苏小东; 黄岩岗; 刘文红; 秦进; 李亮
Original assignee: YANAN JIASHENG PETROLEUM MACHINERY CO Ltd
Current assignee: YANAN JIASHENG PETROLEUM MACHINERY CO Ltd
Priority date: 2020-06-24
Filing date: 2020-06-24
Publication date: 2021-12-14
Anticipated expiration: 2040-06-24
Also published as: CN111809113A

Abstract

The invention provides a rare earth-containing TC-50 steel grade petroleum tube blank, which is composed of chemical components in the following mass percentages: C 0.28-0.32%; Si 0.15-0.30%; Mn 1.45-1.60%; P≤0.018%; S≤0.008%; Cr 0.15-0.25%; Al 0.015-0.040%; Ce 0.0005-0.0020%; Ni<0.10%;Cu<0.10%; the balance is Fe and impurities. A method for producing a rare earth-containing TC-50 steel grade petroleum pipe blank, producing a rare earth-containing TC-50 steel grade petroleum pipe blank, a rare earth-containing TC-50 steel grade petroleum casing, using a rare earth-containing TC-50 steel grade petroleum pipe blank. Made of rare earth TC‑50 steel grade oil tube blanks. A method for producing a rare earth-containing TC-50 steel grade petroleum casing, producing a rare earth-containing TC-50 steel grade petroleum casing. The beneficial effects of the invention are: high tensile strength, high yield strength and high lateral impact resistance.

Description

TC-50 steel grade petroleum pipe blank containing rare earth

Technical Field

The invention relates to production of petroleum casings, in particular to a TC-50 steel grade petroleum pipe blank containing rare earth.

Background

The TC-50 steel grade petroleum casing belongs to a high value-added product, is usually used for oil wells and gas wells with medium depth of about 3000 meters, can also be used for heavy oil thermal recovery wells with about 2000 meters, and is mainly used as a technical casing and a surface casing. With the increasing of oil and gas drilling and production strength of all countries in the world, J55 steel-grade oil casings cannot meet drilling and production requirements, and N80 steel-grade oil casings have the disadvantages of being high in cost and not economical enough.

For example, the steel for 80ksi steel grade straight welded oil casing disclosed in Chinese patent CN101376943A adopts components such as C, Si, Mn, Al, residual Fe and the like to obtain a coiled plate with yield strength of 600-645MPa by adopting a straight welding process, and an N80 oil casing with tensile strength of 550-560MPa and transverse impact of 65-90J. The casing has high cost and is not beneficial to popularization and application.

For example, chinese patent CN101328559A discloses a low yield strength petroleum casing pipe, which uses C, Si, Mn, P, S, Al, and the rest Fe. In addition, it is also possible to refine the crystal grains by adding an RE component.

For example, chinese patent CN108374121A discloses a method for producing a rare earth-containing C110 steel grade petroleum casing, which comprises keeping the bottom soft blowing of argon gas after the completion of the refining in the LF furnace, and feeding a proper amount of rare earth filaments according to the addition of 0.02%. However, in the scheme, the tensile strength is insufficient, the yield strength is low, and the lateral impact is insufficient to support the use scene of the TC-50 steel-grade oil casing.

For example, chinese patent CN201910196594.0 discloses an oil casing and a method for manufacturing the same, which adopts components such as C, Si, Mn, P, S, v, Ti, Al, RE, and residual Fe, and greatly improves the plasticity of steel by adding a small amount of rare earth components into basic components, however, in this scheme, the tensile strength is insufficient, the yield strength is low, and the lateral impact is insufficient to support the use scenario of TC-50 steel grade oil casing, which only provides a solution for J55 steel grade oil pipe blank.

In the design of the petroleum casing pipe with high transverse impact value, the Chinese patent CN103436787A discloses that the impurities in the pipe are removed by adding Ca,thereby improving the lateral impact value. Although 200J/cm at 0 ℃ was obtained²Transverse impact value of the order of magnitude, but requires additional addition of Ca as a cost, and 200J/cm²The technical requirements are far beyond, and for the general stratum structure, Ca adding cost is not particularly necessary to increase the transverse impact value to be as high as 200J/cm 2.

Therefore, the market needs a TC-50 steel grade petroleum pipe blank, sleeve and production process thereof which do not contain Mo, Nb and Ca, contain less Cu and Ni, have low cost, and have high tensile strength, high yield strength and high transverse impact resistance.

Disclosure of Invention

In order to solve the technical problems, the invention discloses a rare earth-containing TC-50 steel grade petroleum pipe blank, a sleeve and a production process thereof, wherein the petroleum pipe blank does not contain Mo, Nb and Ca, contains less Cu and Ni, is low in cost, and can have high tensile strength, high yield strength and high transverse impact resistance. The technical scheme of the invention is implemented as follows:

a TC-50 steel grade petroleum pipe blank containing rare earth is characterized in that: the method is characterized in that calcium is not added, the transverse impact value is adjusted by adjusting the Mn/C mass ratio, and the transverse impact value comprises the following chemical components in percentage by mass: c (0.28-0.32 wt%); si (0.15-0.30 wt%); mn (1.45-1.60 wt%); p is less than or equal to 0.018wt percent; s is less than or equal to 0.008 wt%; cr (0.15-0.25 wt%); al (0.015-0.040 wt%); ce (0.0005-0.0020 wt%); ni is less than 0.10 wt%; cu is less than 0.10 wt%; the balance of Fe and impurities; wherein the Mn/C mass ratio satisfies 79/16-157/30.

Preferably, the TC-50 steel grade petroleum pipe blank containing rare earth is characterized in that: the composite material comprises the following chemical components in percentage by mass: 0.28 wt% of C; si0.16 wt%; mn 1.46 wt%: p0.013 wt%; 0.005wt% of S; 0.17 wt% of Cr; 0.038 wt% of Al; 0.0011 wt% of Ce; ni 0.005 wt%; 0.005 wt% of Cu; the balance being Fe and impurities.

Preferably, the TC-50 steel grade petroleum pipe blank containing rare earth is characterized in that: the composite material comprises the following chemical components in percentage by mass: 0.30 wt% of C; si0.23 wt%; mn 1.57 wt%: p0.012 wt%; s0.006wt%; 0.21 wt% of Cr; 0.025 wt% of Al; 0.0015 wt% of Ce; ni 0.005 wt%; 0.005 wt% of Cu; the balance being Fe and impurities.

Preferably, the TC-50 steel grade petroleum pipe blank containing rare earth is characterized in that: the composite material comprises the following chemical components in percentage by mass: 0.32 wt% of C; si0.28 wt%; mn 1.58 wt%: 0.016 wt% of P; 0.005wt% of S; 0.23 wt% of Cr; 0.017wt percent of Al; 0.0018 wt% of Ce; ni 0.005 wt%; 0.005 wt% of Cu; the balance being Fe and impurities.

A production method of a TC-50 steel grade petroleum pipe blank containing rare earth is used for producing the TC-50 steel grade petroleum pipe blank containing rare earth, and is characterized in that: the method comprises the following steps: s1: pretreatment of blast furnace molten iron: after the blast furnace molten iron is subjected to the pretreatment, the sulfur content of the blast furnace molten iron is less than 0.01 wt%; magnesium powder is used for pretreatment in the pretreatment process; s2: smelting by a top-bottom combined blown converter to produce molten steel: and (3) adding the blast furnace molten iron into a top-bottom re-blowing converter, and mixing the blast furnace molten iron and the scrap steel 9: 1, adding the scrap steel; the smelting process of the top-bottom combined blown converter adopts a single slag process, and the alkalinity of final slag is controlled to be 3.0; during tapping, silicon-manganese, ferromanganese and ferrochromium are adopted for deoxidation alloying, and an aluminum deoxidation process is adopted for final deoxidation; slag is required to be removed in the tapping process, and slag is required to be removed when slag removal fails; in the tapping process, according to the ratio of molten steel to white ash blocks 1: 2, adding the white ash block; s3: refining in an LF furnace: putting the molten steel into a ladle and putting the ladle into an LF furnace station for refining; in the refining process of the LF furnace, normally blowing argon according to requirements, and heating and raising the temperature by gradually increasing the temperature raising speed from a low level to a high level; carrying out slagging desulfurization, component adjustment and heating operation according to the components and the temperature of the molten steel of the converter, and additionally carrying out white slag making operation in the refining process; s4: adding rare earth alloy: keeping the bottom to be subjected to soft blowing Ar, and adding the rare earth alloy, wherein the rare earth alloy is Ce-Fe alloy; s5: VD vacuum treatment: in the VD vacuum treatment process, the deep vacuum degree is less than or equal to 0.10KPa, and the deep vacuum time is more than or equal to 13 minutes; s6: adding a calcium silicate wire: and after adding, soft argon blowing is carried out for 10-12 minutes; s7: round billet continuous casting to produce a casting blank: hoisting the ladle to a ladle turret to perform 5-machine 5-flow round billet continuous casting; in the continuous casting process, a constant-speed control of low drawing speed, electromagnetic stirring and whole-process protection pouring process are adopted; the superheat degree delta T of the molten steel is 25 ℃ in the continuous casting process; s8: cutting to length: straightening the casting blank, and cutting the casting blank into a tube blank by flame sizing; s9: and stacking and slowly cooling the tube blank.

Preferably, it further comprises S10: and sampling the tube blank to carry out low power inspection, and if the sulfur imprint experiment result does not exceed 1.0 level, carrying out the low power inspection to be qualified.

The TC-50 steel grade petroleum casing pipe containing the rare earth is characterized by being manufactured by using the TC-50 steel grade petroleum casing pipe containing the rare earth.

The production method of the TC-50 steel grade petroleum casing pipe containing the rare earth is characterized by comprising the following steps of: the method comprises the following steps: s11: heating the tube blank: putting the tube blank into an annular heating furnace for heating; in the heating process, the temperature of the preheating section I is controlled to be 1000-1100 ℃, the temperature of the preheating section II is controlled to be 1120-1230 ℃, the temperature of the heating section I is controlled to be 1220-1290 ℃, the temperature of the heating section II is controlled to be 1260-1300 ℃, the temperature of the soaking section I is controlled to be 1260-1300 ℃, and the temperature of the soaking section II is controlled to be 1250-1290 ℃; s12: performing bacterial perforation; s13: continuously rolling the tube blank to produce a seamless steel tube; s14: straightening operation: cooling the seamless steel pipe, and straightening when the temperature of the seamless steel pipe is reduced to 517 ℃; s15: and (3) thread machining: and carrying out thread machining on two ends of the seamless steel pipe.

Preferably, before S11, S11-0: thermal tool quality control; the hot tool must be measured before use and the roller bed must be inspected and processed before rolling.

Preferably, between S15 and S14, S14-0 and S14-1 are also included; s14-0: measuring the residual stress of the seamless steel tube by adopting a circular cutting method; s14-1: and carrying out nondestructive inspection and hydrostatic test on the seamless steel pipe.

According to the TC-50 steel grade petroleum pipe blank containing the rare earth, the addition of calcium is not considered, but the Mn/C mass ratio is directly considered to modulate the transverse impact value, so that the requirement of petroleum exploitation is met, and the addition cost of the calcium is further reduced. Because the Mn/C mass ratio meets 79/16-157/30, the influence of overhigh Mn/C on the transverse impact property can be avoided on the basis of ensuring the quenching property.

The TC-50 steel grade petroleum pipe blank containing rare earth does not contain M_ONb and Ca contain less Cu and Ni, so the production cost is low.

In conclusion, according to the technical scheme of the invention, the technical problems of insufficient tensile strength, low yield strength and low transverse impact in the prior art can be solved with lower cost; by implementing the technical scheme of the invention, the technical effects of high tensile strength, high yield strength and high transverse impact can be realized.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only one embodiment of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is an overall flow chart of a production method of a TC-50 steel grade petroleum pipe blank containing rare earth and a TC-50 steel grade petroleum casing pipe containing rare earth.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Those skilled in the art will appreciate that in steel products of various steel grades, chemical components are often added to improve various properties of the steel.

Such as carbon (C), as the amount of carbon in steel increases, the yield point and tensile strength thereof increase, cold brittleness increases, and, at the same time, plasticity and impact properties thereof decrease, and weldability deteriorates.

Such as silicon (Si), which is added as a reducing agent and a deoxidizer during steel making. Silicon increases yield point and tensile strength, while increasing the amount of silicon decreases the weldability of the steel.

Such as manganese (Mn), which is used as a deoxidizer and a desulfurizer in a steel-making process, manganese steel has sufficient toughness, high strength and high hardness, and improves the quenching property, the hot workability and the yield point of the steel.

Such as phosphorus (P), is destructive to the steel and the content of P should be minimized.

Such as sulfur (S), are destructive to the steel and the amount of S should be minimized.

Such as chromium (Cr), can significantly improve the strength, hardness, and wear resistance of the steel, and improve the oxidation resistance and corrosion resistance of the steel, but at the same time reduce the plasticity and toughness.

Such as nickel (Ni), can increase the strength of the steel while maintaining good plasticity and toughness.

Such as copper (Cu), can increase the strength and toughness of the steel, but can reduce the plasticity.

Such as aluminum (Al), as a deoxidizer in steel making, the addition of a small amount of aluminum to steel can refine grains and improve impact toughness, but affects hot workability and weldability at the same time.

Such as cerium (Ce), the addition of a small amount of lanthanum cerium alloy to austenitic and austenitic-ferritic stainless steels can significantly improve the forging properties.

However, if the content of these chemical components is high, other properties of the steel material are affected, and if the content is low, the effects cannot be obtained. In the conventional pipe-making process, carbon (C) is generally considered to be the most effective element for improving strength and hardenability, but in general, Mn/C must be increased as much as possible in order to improve the requirement for impact resistance of the sleeve. In order to find the best balance point, the research and development team of the invention is diligent, and as a result, the conventional knowledge is wrong. While increasing the contents of Mn and C at the same time, as long as their mass ratio is maintained at 5: about 1 (concretely, Mn/C mass ratio satisfying 79/16. ltoreq. Mn/C. ltoreq. 157/30)But effectively improves the hardenability of the steel and also improves the impact resistance of the sleeve, which is not the trade-off of the conventional knowledge, so that the carbon content can be increased to 0.32 wt% and the Mn content can be correspondingly increased in the present application, and at this time, the transverse impact value at 0 ℃ is not less than 63J/cm in the impact resistance of the sleeve²Therefore, the invention not only overcomes the traditional technical bias and improves the technical effect of the product, but also does not contain M in the invention_ONb and Ca contain less Cu and Ni, and the effect of at least not less than that of La, Re and the like can be obtained without using expensive rare earth elements such as La and the like, so that the cost is lower.

The TC-50 steel grade petroleum pipe blank containing the rare earth in a specific embodiment 1 of the invention comprises the following chemical components in percentage by mass: c (0.28-0.32 wt%); si (0.15-0.30 wt%); mn (1.45-1.60 wt%); p is less than or equal to 0.018wt percent; s is less than or equal to 0.008 wt%; cr (0.15-0.25 wt%); al (0.015-0.040 wt%); ce (0.0005-0.0020 wt%); ni is less than 0.10 wt%; cu is less than 0.10 wt%; the balance of Fe and impurities, wherein the Mn/C mass ratio satisfies 79/16-157/30.

In this specific example, Si has a deoxidizing effect while being capable of improving strength, but its content is controlled to be between 0.15 and 0.30 wt% in order to consider the impact performance requirements of the bushing; mn has the effect of solid solution strengthening, can enlarge an austenite region, reduce the transformation temperature from austenite to ferrite, further refine ferrite grains and improve the toughness of steel, but the Mn content is excessively high and can generate segregation, so the Mn content is controlled within 1.45-1.60 wt%; cr can improve the strength and hardenability of steel, and can form a passive film on the surface of steel, and has hydrogen sulfide corrosion resistance and oxidation resistance, so that the content thereof is set between Cr (0.15-0.25 wt%); p causes micro segregation, and easily causes quenched martensite to form fiber cracks, so the content of P is controlled to be less than 0.018 wt%; the increase of S content can cause the hot brittleness of steel, in order to ensure that the sleeve has good toughness, the S content is less than 0.008 wt%, Al has good deoxidation capability, and austenite grains can be refined, so the S content is controlled to be (0.015-0.040 wt%);

in a preferred embodiment 2, the material comprises the following chemical components in percentage by mass: 0.28 wt% of C; si0.16wt%; mn 1.46 wt%: p0.013 wt%; 0.005 wt% of S; 0.17 wt% of Cr; 0.038 wt% of Al; 0.0011 wt% of Ce; ni 0.005 wt%; 0.005 wt% of Cu; the balance being Fe and impurities.

In a preferred embodiment 3, the material comprises the following chemical components in percentage by mass: 0.30 wt% of C; si0.23wt%; mn 1.57 wt%: p0.012 wt%; 0.006 wt% of S; 0.21 wt% of Cr; 0.025 wt% of Al; 0.0015 wt% of Ce; ni 0.005 wt%; 0.005 wt% of Cu; the balance being Fe and impurities.

In a preferred embodiment 4, the material comprises the following chemical components in percentage by mass: 0.32 wt% of C; 0.28wt% of Si; mn 1.58 wt%: 0.016 wt% of P; 0.005 wt% of S; 0.23 wt% of Cr; 0.017wt percent of Al; 0.0018 wt% of Ce; ni 0.005 wt%; 0.005 wt% of Cu; the balance being Fe and impurities.

In a specific embodiment, as shown in fig. 1, a method for producing a rare earth-containing TC-50 steel grade petroleum pipe billet produces the rare earth-containing TC-50 steel grade petroleum pipe billet, which comprises: s1: pretreatment of blast furnace molten iron: after the blast furnace molten iron is subjected to the pretreatment, the sulfur content of the blast furnace molten iron is less than 0.01 wt%; the pretreatment process uses magnesium powder for pretreatment, and the sulfur content of the blast furnace molten iron can be effectively reduced through the magnesium powder.

S2: smelting by a top-bottom combined blown converter to produce molten steel: and (3) adding the blast furnace molten iron into a top-bottom re-blowing converter, and mixing the blast furnace molten iron and the scrap steel 9: 1, the scrap steel is added, and it is pointed out that, in the invention, because the scrap steel with relatively less impurities is used as the raw material, compared with the method of completely using the molten steel, the impurity elements in the molten steel can be effectively reduced, and the cost can be saved, meanwhile, because the scrap steel does not contain precious elements of Mo and Nb, and only contains a small amount of even does not contain Cu and Ni, the production difficulty is small, and the production cost is low;

it is emphasized that, in the invention, the smelting process of the top-bottom combined blown converter adopts a single slag process, the alkalinity of the final slag is controlled to be 3.0 (compared with the traditional process of 3.2), and the contents of Si and Al in the molten steel are further reduced.

During tapping, silicon-manganese, ferromanganese and ferrochromium are adopted for deoxidation alloying, and an aluminum deoxidation process is adopted for final deoxidation; slag is required to be removed in the tapping process, and slag is required to be removed when slag removal fails; in the tapping process, according to the ratio of molten steel to white ash blocks 1: 2, adding the white ash block;

s3: refining in an LF furnace: putting the molten steel into a ladle and putting the ladle into an LF furnace station for refining; in the refining process of the LF furnace, normally blowing argon according to requirements, and heating and raising the temperature by gradually increasing the temperature raising speed from a low level to a high level; carrying out slagging desulfurization, component adjustment and heating operation according to the components and the temperature of the molten steel of the converter, and additionally carrying out white slag making operation in the refining process;

s4: adding rare earth alloy: keeping bottom soft blowing Ar, adding the rare earth alloy, wherein the rare earth alloy is Ce-Fe alloy, and the Ce element can play a role in improving the form of nonmetallic inclusions, strengthening crystal boundaries, refining grains and the like, so that the effects of fine grain strengthening and impact toughness improvement are achieved;

s5: VD vacuum treatment: in the VD vacuum treatment process, the deep vacuum degree is less than or equal to 0.10KPa, and the deep vacuum time is more than or equal to 13 minutes;

s6: adding a calcium silicate wire: and after adding, soft argon blowing is carried out for 10-12 minutes;

s7: round billet continuous casting to produce a casting blank: hoisting the ladle to a ladle turret to perform 5-machine 5-flow round billet continuous casting; in the continuous casting process, a constant-speed control of low drawing speed, electromagnetic stirring and whole-process protection pouring process are adopted; the superheat degree delta T of the molten steel is 25 ℃ in the continuous casting process; it is emphasized that, in the present invention, the equiaxed crystals and columnar crystals of the cast slab are improved by reducing the degree of superheat, and the quality of the cast slab is improved.

S8: cutting to length: straightening the casting blank, and cutting the casting blank into a tube blank by flame sizing;

s9: and stacking and slowly cooling the tube blanks, and improving the tempering temperature and prolonging the heat preservation time, thereby being beneficial to the homogenization of the steel structure and the stress relief, and further improving the mechanical property of the steel.

In a preferred embodiment, the method further comprises the step of S10: and sampling the tube blank to carry out low power inspection, and if the sulfur imprint experiment result does not exceed 1.0 level, the low power inspection is qualified, so that the quality of the pipeline is qualified, and the tube blank can be used for tube manufacturing.

In a specific embodiment, the TC-50 steel grade petroleum casing pipe containing the rare earth is manufactured by using the TC-50 steel grade petroleum casing pipe containing the rare earth.

In a specific embodiment, as shown in fig. 1, a method for producing a TC-50 steel grade petroleum casing containing rare earth produces the TC-50 steel grade petroleum casing containing rare earth, which is characterized in that: the method comprises the following steps: s11: heating the tube blank: putting the tube blank into an annular heating furnace for heating; in the heating process, the temperature of the preheating section I is controlled to be 1000-1100 ℃, the temperature of the preheating section II is controlled to be 1120-1230 ℃, the temperature of the heating section I is controlled to be 1220-1290 ℃, the temperature of the heating section II is controlled to be 1260-1300 ℃, the temperature of the soaking section I is controlled to be 1260-1300 ℃, the temperature of the soaking section II is controlled to be 1250-1290 ℃, and the overheating temperature is different along with different components of the tube blank in the heating process. In the present invention, in order to ensure thorough heating, the temperature at each heating stage is set slightly higher, so that the tube blank has good rolling properties.

S12: performing bacterial perforation; s13: continuously rolling the tube blank to produce a seamless steel tube; s14: straightening operation: cooling the seamless steel pipe, and straightening when the temperature of the seamless steel pipe is reduced to 517 ℃; s15: and (3) thread machining: and (3) carrying out thread machining on two ends of the seamless steel pipe, and obtaining a usable product after the machining is finished.

In a preferred embodiment, before S11, the method further comprises S11-0: thermal tool quality control; the hot tool must be measured before use, and the roller way must be checked and processed before rolling, so that the pipe wall is prevented from being scratched.

In a preferred embodiment, between S15 and S14, S14-0 and S14-1 are also included; s14-0: measuring the residual stress of the seamless steel tube by adopting a circular cutting method; s14-1: and carrying out nondestructive flaw detection and hydrostatic test on the seamless steel pipe, wherein if the two test results are qualified, the pipeline can be used if the quality is qualified.

90 tons of blast furnace molten ironFor example, 90 tons of blast furnace molten iron is subjected to desulfurization and deoxidation pretreatment by using metal magnesium powder, so that the content of S element in the molten iron is reduced to be below 0.010 percent; adding 90 tons of pretreated molten iron into a top-bottom combined blown converter of 100 tons, adding 10 tons of high-quality scrap steel, smelting by adopting a single slag process, controlling the alkalinity of final slag according to 3.0, deoxidizing and alloying by adopting silicomanganese, ferromanganese and ferrochromium during tapping, adopting an aluminum deoxidation process for final deoxidation, stopping slag during tapping, pushing off slag when the slag stopping fails, and adding 200kg of white ash blocks after the alloy is completely added during tapping. Filling the smelted molten steel into a ladle, and feeding the molten steel into an LF furnace station for refining: blowing argon normally according to requirements during refining, and heating and raising the temperature by gradually increasing the temperature raising speed from a low level to a high level; carrying out slagging desulfurization, component adjustment and heating operation according to the components and the temperature of the molten steel of the converter; and adding the additional alloy in the middle and later periods by adopting the white slag making operation. And (3) keeping the bottom to be subjected to soft blowing Ar after the refining of the LF furnace, and adding a predetermined amount of rare earth alloy, wherein the rare earth alloy is Ce-Fe alloy. Then carrying out VD vacuum treatment on the refined molten steel: deep vacuum, wherein the vacuum degree is less than or equal to 0.10KPa, and the deep vacuum time is more than or equal to 13 minutes; and feeding a certain length of calcium silicon wire, and keeping soft blowing Ar for 10-12 minutes after wire feeding. Hoisting a ladle subjected to VD vacuum treatment on a ladle turret to perform 5-machine 5-flow round billet continuous casting, wherein a constant-speed control, electromagnetic stirring and whole-process protection pouring process of low drawing speed is adopted during continuous casting; the superheat degree delta T of the molten steel is 25 ℃; straightening the casting blank after the casting blank is discharged from a secondary cooling area, and cutting the casting blank into the specification of

Then the specification is

The tube blanks are stacked and slowly cooled. Will be specified as

The tube blank is put into an annular heating furnace for heating, the temperature of each section of a preheating section, a heating section, a soaking section and the like of the annular heating furnace is continuously checked and controlled, and the heating penetration is ensuredThe temperature of each section of the annular heating furnace is automatically controlled and recorded by a microcomputer thoroughly and uniformly without overheating. The hot tool must be measured before use, and the roller way must be checked and processed before rolling, so as to avoid scratching the pipe wall. The heated specification is

The tube blank is subjected to bacterial perforation and then to

Continuously rolling the tube on a PQF tube rolling mill, sizing and forming the tube into a finished product with the specification

The seamless steel pipe of (1) is subjected to thermal sampling once per batch, and the geometric dimension is checked. And when the temperature of the seamless steel pipe is reduced to 517 ℃, straightening, and measuring the residual stress of the seamless steel pipe by adopting a circular cutting method. The specification of the production process is

The seamless steel pipe is subjected to nondestructive flaw detection and hydrostatic test in sequence, and the qualified seamless steel pipe is subjected to thread machining at two ends to obtain a final product.

Through the above-mentioned process, the chemical composition test results of the tube blanks formed in the preferred embodiments 2, 3 and 4 are shown in table 1, the mechanical property test of the seamless steel tubes manufactured in the preferred embodiments 2, 3 and 4 is shown in table 2, and the mechanical property test of the seamless steel tubes manufactured in the preferred embodiments 2, 3 and 4 is shown in table 3.

TABLE 1 chemical composition test results (mass%) of tube blanks

	C	Si	Mn	P	S	Cr	Al	RE	Ni	Cu
											Example 2	0.28	0.16	1.46	0.013	0.005	0.17	0.038	0.0011	0.005	0.005
Example 3	0.30	0.23	1.57	0.012	0.006	0.21	0.025	0.0015	0.005	0.005
											Example 4	0.32	0.28	1.58	0.016	0.005	0.23	0.017	0.0018	0.005	0.005

TABLE 2 mechanical Property test results of seamless steel pipes

	R_t0.5(MPa)	R_m(MPa)	R_t0.5/R_m	A(％)	a_KV(0 ℃, transverse, J ^ er)cm²)	Residual stress
							Example 2	462	663	0.70	25.0	95	21MPa
Example 3	471	681	0.69	24.0	75	23MPa
							Example 4	495	712	0.70	22.0	63	25MPa

TABLE 3 metallographic examination of the seamless steel tubes (grade)

As can be seen from the above test results, in the present invention, since the Mn/C mass ratio is set to 79/16. ltoreq. Mn/C. ltoreq. 157/30, it is possible to realize as high as 0.032 wt% as compared with conventional J55-grade or N80-grade petroleum pipe blanksThe carbon content can reach 1.58 wt% and the quenching performance and impact performance of the steel can reach ideal effect. Therefore, the examples 2, 3 and 4 have better lateral impact under the conditions of high carbon content and low Mn/C, which is contrary to the conventional knowledge that Mn/C generally must be improved as much as possible, thereby overcoming the original technical bias and achieving the equivalent technical effect. And we found that, instead of the smaller Mn/C, the more excellent the lateral impact value, we need to satisfy 79/16. ltoreq. Mn/C. ltoreq. 157/30, within which we found 73/14 the best point of example 2, obtaining nearly 100J/cm²The transverse impact value of the steel can completely meet the requirements of oil exploitation. The invention can achieve the technical effect not lower than that of the case of adding La or Re on the premise of not containing La, Re and other elements.

It should be understood that the above-described embodiments are merely exemplary of the present invention, and are not intended to limit the present invention, and that any modification, equivalent replacement, or improvement made without departing from the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. a TC-50 steel grade petroleum tube blank containing rare earth, is characterized in that: do not add calcium element, be 73/14 by adjusting Mn/C mass ratio to modulate the size of transverse impact value, by the chemical of lower mass percentage Composition: C 0.28wt%; Si0.16wt%; Mn 1.46wt%; P 0.013wt%; S 0.005wt%; Cr

0.17wt%; Al 0.038wt%; Ce 0.0011wt%; Ni 0.005wt%; Cu 0.005wt%; the balance is Fe and impurities;

The steps of generating the tube blank are as follows:

S1: blast furnace molten iron pretreatment: after the blast furnace molten iron is subjected to the pretreatment, the sulfur content of the blast furnace molten iron is less than 0.01%; the pretreatment process uses magnesium powder for pretreatment;

S2: molten steel produced by smelting in the top-bottom double-blowing converter: mixing the blast furnace molten iron into the top-bottom double-blowing converter, and adding the scrap according to the mass ratio of the blast furnace molten iron to the scrap steel of 9:1; the top-bottom double-blowing converter The smelting process adopts a single-slag process, and the final slag basicity is controlled at 3.0; during tapping, silicon-manganese, ferromanganese and ferrochromium are used for deoxidation and alloying, and the final deoxidation adopts an aluminum deoxidation process; the tapping process must block slag, and the slag blocking fails. The slag must be removed; during the tapping process, the white ash block is added according to the mass ratio of the molten steel and the white ash block of 1:2;

S3: LF furnace refining: put the molten steel into the ladle and put it into the LF furnace station for refining; during the refining process of the LF furnace, argon is normally blown as required, and the method of gradually increasing the heating rate from the low level to the high level is adopted Heating and heating up; additional white slag making operation in the refining process;

S4: Add rare earth alloy: keep soft blowing of Ar at the bottom, add the rare earth alloy, and the rare earth alloy is Ce-Fe alloy;

S5: VD vacuum treatment: in the process of VD vacuum treatment, the deep vacuum degree is less than or equal to 0.10kPa, and the deep vacuum time is greater than or equal to 13 minutes;

S6: Add silicon calcium wire, and blow argon softly for 10-12 minutes after adding;

S7: Round billet continuous casting to generate casting billets: the ladle is hoisted onto the ladle turntable for 5-machine 5-stream round billet continuous casting; in the continuous casting process, the constant speed control of low pulling speed, electromagnetic stirring and The whole casting process is protected; in the continuous casting process, the superheat degree of molten steel ΔT=25°C;

S8: Cut to length: straighten the casting billet, and then cut it into a tube billet by using flame to cut to length;

S9: slowly cooling the tube blanks by stacking;

S10: Sampling the tube blank for low magnification inspection, if the result of the sulfur mark test does not exceed level 1.0, the low magnification inspection is qualified;

S11: Tube blank heating: Put the tube blank into an annular heating furnace for heating; during the heating process, the temperature of the preheating stage I is controlled at 1000-1100 °C, and the temperature of the preheating stage II is controlled at 1120-1120 °C. 1230℃, the temperature of the heating section I is controlled at 1220~1290℃, the heating section II is controlled at 1260~1300℃, the soaking section I is controlled at 1260~1300℃, and the soaking section II is controlled at 1250~1290℃;

S12: bacterial perforation;

S13: Continuously rolling the tube blank to produce a seamless steel tube;

S14: Straightening operation: cooling the seamless steel pipe, and straightening when the temperature of the seamless steel pipe drops to 517°C;

S15: Threading: Threading is performed on both ends of the seamless steel pipe.

2. The rare earth-containing TC-50 steel grade petroleum tube blank according to claim 1, characterized in that: before S11, it also includes S11-0: hot tool quality control; the hot tool must be measured before use, rolling The roller table must be inspected and treated before it.

3. A kind of TC-50 steel grade petroleum tube blank containing rare earth according to claim 2, is characterized in that: between S15 and S14, also comprises S14-0 and S14-1;

S14-0: measure the residual stress of the seamless steel pipe by the ring cutting method;

S14-1: Perform non-destructive testing and hydrostatic test on the seamless steel pipe.

4. A rare earth-containing TC-50 steel grade petroleum pipe, characterized in that: it is made from a rare earth-containing TC-50 steel grade petroleum pipe blank according to claim 1.