CN111118410A

CN111118410A - Thick-wall large-caliber high-steel grade pipeline pipe with thickness of 40-60 mm and manufacturing method thereof

Info

Publication number: CN111118410A
Application number: CN202010045011.7A
Authority: CN
Inventors: 李艳; 刘金海; 张哲平; 丛国元; 赵兴亮; 刘江成; 赵春辉; 张传友; 张国柱; 赵苏娟; 陈燕; 胡希达; 田琨
Original assignee: Tianjin Steel Tube Manufacturing Co ltd
Current assignee: Tianjin Steel Tube Manufacturing Co ltd
Priority date: 2020-01-16
Filing date: 2020-01-16
Publication date: 2020-05-08

Abstract

The invention provides a manufacturing method of a thick-wall large-caliber high-grade steel pipeline pipe with the thickness of 40 mm-60 mm, which is characterized in that four-stream continuous casting is carried out to form billets with the sections of phi 450mm and phi 500mm through the treatment of an electric furnace, a refining furnace and a vacuum furnace VD and Ti; then, cold centering, heating by an annular heating furnace, hot perforating, continuous rolling by a continuous rolling unit, sizing and cold straightening are carried out to prepare a steel pipe; and finally, respectively carrying out immersion rotary type inner-spraying and outer-spraying water quenching and tempering, thermal straightening and air cooling in a stepping high-temperature furnace and a stepping low-temperature furnace to finish the manufacture of the seamless pipeline pipe. The invention has the beneficial effects that: the high-precision rolling is utilized to provide a high-dimensional precision pipe, the pipe is immersed into a rotary type internal spraying and external spraying heat treatment technology to obtain a 40mm to 60mm thick wall, 406.4mm to 508mm large-caliber, high-strength, low-yield ratio, high-ductility and high-elongation excellent low-temperature impact performance pipeline pipe with uniform and stable performance, and the conveying requirements of gathering, long-distance conveying and special-purpose pipelines are met.

Description

Thick-wall large-caliber high-steel grade pipeline pipe with thickness of 40-60 mm and manufacturing method thereof

Technical Field

The invention relates to the field of oil and gas transportation and seamless pipe manufacturing, in particular to a thick-wall large-caliber high-steel grade pipeline pipe with the thickness of 40mm or more and a manufacturing method thereof.

Background

With the increasing demand of petroleum and natural gas, the development of oil and gas fields in severe environments such as extremely cold environment, deep sea environment and the like, high-pressure, large-caliber and thick-wall development has become the trend of oil and gas development and design. In order to meet the mining requirements, the large-wall-thickness large-caliber high-strength steel is the first choice in design from the perspective of safe and reliable operation. The seamless pipe is superior to a welded steel pipe in the aspects of thick wall, corrosion resistance and the like. The problems of component design, performance design, welding and the like exist when the strength is improved or the wall thickness is improved, and the requirements on the performance of the pipe are very strict. The thickness of the thick-wall pipe is usually 25.4-36 mm, and with the design requirement of higher collapse strength, the requirement of thick-wall large-caliber pipeline pipe with the thickness of 40mm and above is increasing day by day. And simultaneously, new requirements are provided for the rolling process and the heat treatment process, and according to the design capability of 406PQF and 508PQF rolling mills, the rolling mill can produce 60mm of the maximum wall thickness with the outer diameter of 406.4mm, 50mm of the outer diameter of 457.2mm, 50mm of the outer diameter of 508mm and the like. 460PQF and 508PQF have different maximum outer diameters in different units, even though casting blank specifications, pass designs and the like adopted for producing the same specifications are different, 460PQF unit produces a specification with a lower rolling ratio than 508PQF unit, and has the problems of interlayer, low performance and the like, and for line pipes with large diameter, large thickness and thick wall, a unit capable of realizing a rolling ratio larger than 3 is preferentially selected, and a 508PQF unit is preferentially selected.

Chinese patent publication No. CN101287853A discloses a seamless steel pipe for pipeline and a manufacturing method thereof, which mainly aims at thick-wall pipes, high strength, toughness and corrosion resistance are realized by adding 0.4-1.2% of Mo element in a large amount, and the welding performance of materials is considered for pipeline pipes, so that the maximum value of the industry standard cannot exceed 0.5%, and the seamless steel pipe does not belong to the field of the same pipeline pipe; chinese patent publication No. CN101417296A discloses a method for manufacturing a large-caliber high-steel-grade corrosion-resistant seamless tube with the diameter of phi 219.0-460 mm, which only designs the range of a 460PQF rolling unit within the range of 219.1-460 mm; chinese patent publication No. CN2008101512321 discloses a high-strength high-toughness X70 thick-wall seamless pipeline steel and a manufacturing method thereof, which mainly aims at seamless pipeline pipes with the wall thickness of less than or equal to 36mm and below the range of 460PQF rolling mills, and has limited wall thickness range and different rolling units.

Disclosure of Invention

In order to solve the above problems, it is a first object of the present invention to provide a thick-walled large-caliber high-grade steel line pipe of 40mm or more; the second purpose is to provide a method for manufacturing thick-wall large-caliber high-steel grade pipeline pipes of 40mm or more. The production problems of smelting, rolling, heat treatment and the like of the pipeline pipe with the wall thickness of more than 40mm are solved, a safe and reliable thick-wall pipeline is provided, and the safety design problem in the oil and gas conveying process is solved.

In order to achieve the first purpose, the invention adopts the technical scheme that: a thick-wall large-caliber high-steel grade pipeline pipe with the thickness of 40 mm-60 mm comprises the following components in percentage by weight: 0.06 to 0.16 percent of C, 0.10 to 0.45 percent of Si, 1.25 to 1.80 percent of Mn, 0.020 to 0.060 percent of Al, 0.020 to 0.050 percent of Nb, 0.03 to 0.09 percent of V, 0.20 to 0.50 percent of Ni, 0.20 to 0.50 percent of Mo, 0.20 to 0.50 percent of Cr0.20, less than or equal to 0.006 percent of Ca, 0.003 to 0.010 percent of N, less than or equal to 0.20 percent of CEpcm, less than or equal to 0.28 percent of Ti, less than or equal to 0.005 percent of Ti, less than or equal to 0.020 percent of CE, less than or equal to 0_ΠWNot more than 0.44 percent, Al/N not less than 2, V + Nb + Ti not more than 0.15 percent, and the balance of Fe and inevitable impurities.

The thick wall and the large caliber are more than or equal to 406.4 mm.

The invention adopts another technical scheme that: a manufacturing method of a 40 mm-60 mm thick-wall large-caliber high-steel grade pipeline pipe comprises the following steps:

(1) electric furnace smelting: the weight percentages are as follows: 0.06 to 0.16 percent of C, 0.10 to 0.45 percent of Si, 1.25 to 1.80 percent of Mn, 0.020 to 0.060 percent of Al, 0.020 to 0.050 percent of Nb, 0.03 to 0.09 percent of V, 0.20 to 0.50 percent of Ni, 0.20 to 0.50 percent of Mo0.20, 0.20 to 0.50 percent of Cr0.20, less than or equal to 0.006 percent of Ca, 0.003 to 0.010 percent of N, less than or equal to 0.20 percent of CEpcm, less than or equal to 0.28 percent of Ti, less than or equal to 0.005 percent of Ti, less than or equal to 0.020 percent of CE, less than or_ΠWEqual to or less than 0.44 percent, Al/N equal to or more than 2 percent, V + Nb + Ti equal to or less than 0.15 percent and the balance of Fe and inevitable impurity seamless steel pipe components are processed by a 100T electric furnace EAF, a refining LF furnace, a vacuum furnace VD and a Ti, and then four-flow continuous casting is carried out to obtain sections with phi 450mm and phi 500mmA steel billet;

(2) rolling by a PQF rolling mill: carrying out cold centering, heating by a ring heating furnace, hot piercing, continuous rolling by a phi 508PQF continuous rolling unit, sizing and cold straightening on the steel billet obtained in the step (1) to prepare a steel pipe;

(3) quenching and tempering: respectively carrying out immersion rotary type inner-spraying and outer-spraying water quenching and tempering, thermal straightening and air cooling on the steel pipe in the step type high-temperature furnace and the step type low-temperature furnace to finish the manufacture of the seamless pipeline;

the manufacturing method of the 40 mm-60 mm thick-wall large-caliber high-steel-grade pipeline pipe can obtain the pipeline pipe meeting the steel grade of X65Q and above, the yield strength is not less than 455MPa, the tensile strength is not less than 535MPa, the impact property is not less than 250J at 0 ℃, and the hardness is not more than 250HV 10.

The heating temperature in the stepping high-temperature furnace is 900-980 ℃, the heat preservation time is 15-45 min, high-pressure water descaling is carried out, quenching water cooling is carried out, then heating is carried out in the stepping low-temperature furnace for heat preservation at 600-710 ℃ for 20-60 min, and tempering air cooling is carried out.

The hot straightening adopts high temperature of 500-630 ℃, the tolerance of the outer diameter is less than or equal to +/-0.5 percent D, the tolerance of the wall thickness is-3.0 mm-3.7 mm, the out-of-roundness is less than or equal to 1.5 percent D, and the straightness is less than 0.15 percent L as a whole.

The invention has the beneficial effects that: 1) the low-carbon high-manganese high-carbon equivalent is added with Cr, Mo and Ni alloy, the smelting process adopts micro Ti treatment and pure calcium wire inclusion spheroidization treatment, and the powder spraying process is carried out to reduce the content of the impurity S. 2) The phi 508PQF rolling unit is combined with a high-end hot rolling control technology to obtain high-quality pipe bodies with different sizes, the accuracy of the outer diameter size is +/-0.5 percent OD, and the accuracy of the wall thickness is minus 3.0mm to 3.7 mm. 3) The immersed rotary inner-spraying outer-spraying water quenching and tempering air cooling tempering process ensures the performance of the pipe body, selects reasonable heat straightening temperature to be more than or equal to 450 ℃, and reduces the residual stress of the steel pipe to the maximum extent. 4) The pipeline pipe with the thick wall of 40mm or more, the large caliber of 406.4mm or more, high strength, low yield ratio, high ductility, high elongation and excellent low-temperature impact performance is produced, and the conveying requirements of gathering and conveying, long-distance conveying and special-purpose pipelines are met.

Drawings

FIG. 1 is a schematic metallographic structure of an X70Q steel grade line pipe according to the present invention;

FIG. 2 is a low temperature series toughness curve for an X70Q steel grade line pipe of the present invention.

Detailed Description

The invention provides a thick-wall large-caliber high-steel grade pipeline pipe with the thickness of 40mm or more and a manufacturing method thereof, which are described by combining the accompanying drawings and embodiments.

The thick-wall large-caliber high-steel grade pipeline pipe with the thickness of 40 mm-60 mm comprises the following components in percentage by weight: 0.06 to 0.16 percent of C, 0.10 to 0.45 percent of Si, 1.25 to 1.80 percent of Mn, 0.020 to 0.060 percent of Al, 0.020 to 0.050 percent of Nb, 0.03 to 0.09 percent of V, 0.20 to 0.50 percent of Ni, 0.20 to 0.50 percent of Mo, 0.20 to 0.50 percent of Cr0.20, less than or equal to 0.006 percent of Ca, 0.003 to 0.010 percent of N, less than or equal to 0.20 percent of CEpcm, less than or equal to 0.28 percent of Ti, less than or equal to 0.005 percent of Ti, less than or equal to 0.020 percent of CE, less than or equal to 0_ΠWNot more than 0.44 percent, Al/N not less than 2 percent, V + Nb + Ti not more than 0.15 percent, and the balance of Fe and inevitable impurities, as shown in a schematic diagram of the metallographic structure of an X70Q steel-grade pipeline pipe in figure 1.

The chemical components for preparing the steel grade components are described as follows:

c: the steel is a strengthening element, the influence and cost of the carbon content on the strength and toughness of the steel and the corrosion resistance are comprehensively considered, and the C content is controlled to be 0.06-0.16%. C content as in the examples in table 1.

Si: si is an element necessary for deoxidation, and the strength of the steel is improved, so that the content thereof is limited to 0.10 to 0.45%. As in the examples in table 1.

Mn: mn is an essential strengthening element, ensures the performance of the pipe body, belongs to low-carbon high-manganese design, and therefore the content of Mn is limited to be within the range of 1.25-1.80%. Mn content as in the examples in Table 1.

Al: al is an element which must be added to refine grains, and the content of Al is limited to the range of 0.020 to 0.060% considering Al/N ratio, inclusion content, toughness and workability.

Nb: nb is added microalloying element, and has obvious effect on strength and grain size refinement. Controlling Nb0.020-0.050%. Nb content as in the examples in table 1.

V: v has higher precipitation strengthening effect and grain refining effect, and when Nb and V microalloy elements are used in a composite way, V is simultaneously precipitated and strengthened in ferrite by VC to improve the strength of steel. Controlling V to be 0.03-0.09%. As in the examples in table 1.

Ni, Cr, Mo: the hardenability of the material can be improved by Ni, Cr and Mo elements, so that the performance of the large-diameter thick-wall pipe body is ensured, and the hardenability improving alloy Ni is properly added according to different wall thicknesses of the pipe body, wherein the hardenability improving alloy Ni is 0.05-0.50%, Mo is 0.15-0.50%, and Cr0.20-0.50%. The contents of Cr, Mo and Ni elements in the examples shown in Table 1.

Cu: the residual elements in the steel grade are beneficial to impact toughness and corrosion resistance, but the content is controlled in a low range considering the contribution of cost and carbon equivalent, and the maximum content is not allowed to exceed 0.25%.

N, O, H element is gas element in steel, and its content is controlled in low range, considering welding performance and mechanical property, the maximum is not allowed to exceed N less than 0.0100%, O less than 0.0030% and H less than 0.0002%.

P, S: p and S are harmful impurity elements, and the content of the P and S is reduced as much as possible. But the steel-making cost cannot be considered, and P is preferably less than or equal to 0.020% and S is preferably less than or equal to 0.008%.

The steel pipe is characterized by low-carbon high-manganese Nb + V series microalloying, and 0.05-0.50% of alloy Ni, 0.15-0.50% of Mo and 0.20-0.50% of Cr0 are properly added to improve hardenability according to different wall thicknesses of a pipe body. The trace elements Nb and V are alloyed, Cr, Mo and Ni are alloyed, the content of the impurity element P, S and the content of the gas element are limited, and reasonable component proportion is selected through a large number of tests, so that the large thick-wall steel pipe has good comprehensive mechanical resistance.

The manufacturing method of the thick-wall large-caliber high-steel grade pipeline pipe with the thickness of 40 mm-60 mm is realized by the following steps:

(1) component design and electric furnace smelting: the weight percentages are as follows: 0.06 to 0.16 percent of C, 0.10 to 0.45 percent of Si, 1.25 to 1.80 percent of Mn, 0.020 to 0.060 percent of Al, 0.020 to 0.050 percent of Nb, 0.03 to 0.09 percent of V, 0.20 to 0.50 percent of Ni, 0.20 to 0.50 percent of Mo, 0.20 to 0.50 percent of Cr0.20, less than or equal to 0.006 percent of Ca, 0.003 to 0.010 percent of N, less than or equal to 0.28 percent of CEpcmm and less than or equal to 0.005 percent of Ti and less than or equal to 0.020 percent of Ti,0.36％≤CE_ΠWequal to or less than 0.44 percent, Al/N equal to or more than 2 percent, V + Nb + Ti equal to or less than 0.15 percent, and the balance of Fe and inevitable impurity seamless steel tube components are processed by a 100T electric furnace EAF, a refining LF furnace, a vacuum furnace VD, pure Ca wires and Ti wires by adopting a short-flow process route, and then four-flow continuous casting is carried out to obtain phi 450mm and phi 500mm section steel billets;

(2) rolling by a PQF rolling mill: and (2) carrying out cold centering, heating by a ring heating furnace, hot piercing, continuous rolling by a phi 508PQF continuous rolling unit, sizing and cold straightening on the steel billet obtained in the step (1) to obtain the steel pipe. The 508PQF mill is of the maximum caliber PQF mill type. The PQF retained mandrel three-roller continuous tube rolling mill avoids the bamboo joint phenomenon, and the wall thickness of the whole capillary tube is not more than +/-8% after the end part of the tube is removed.

(3) Quenching and tempering: and (3) respectively quenching and tempering the steel pipe in the step type high-temperature furnace and the step type low-temperature furnace by immersing the steel pipe in a rotary type internal spraying and external spraying water, thermally straightening and air cooling to finish the manufacture of the seamless pipeline pipe. Heating the steel plate in a stepping high-temperature furnace to 900-980 ℃ and preserving heat for 15-45 min, descaling with high-pressure water, quenching and water cooling, heating the steel plate in a stepping low-temperature furnace to 600-710 ℃ and preserving heat for 20-60 min, and tempering and air cooling; high-temperature hot straightening is carried out at 500-630 ℃, the tolerance of the outer diameter is less than or equal to +/-0.5 percent D, the tolerance of the wall thickness is-3.0 mm-3.7 mm, the out-of-roundness is less than or equal to 1.5 percent D, and the straightness is less than 0.15 percent L as a whole. The water quenching is carried out by accurately controlling the temperature of the high-temperature furnace and the low-temperature furnace and immersing the steel tube in an external spraying and internal spraying rotating mode, so that the uniform and stable performance of the whole wall thickness and length of the steel tube is ensured.

The manufacturing method of the 40 mm-60 mm thick-wall large-caliber high-steel grade pipeline pipe can obtain the pipeline pipe meeting the steel grade X65Q and above, the yield strength is more than or equal to 455MPa, the tensile strength is more than or equal to 535MPa, the impact property is more than or equal to 250J at 0 ℃, and the hardness is less than or equal to 250HV 10.

Taking the steel grades of X65Q and X70Q, the specifications of 508.00mmx41.14mm and 406.40mmx47.58mm as examples, the development dimensional requirements are as shown in the following table 1 and the mechanical properties are as shown in the following table 2:

TABLE 1 geometric dimensioning index

Serial number	Inspection item	Design requirements
			1	Outer diameter of pipe body	±0.5％D
2	Outside diameter of pipe end	±1.6mm
			3	Wall thickness	-3.0～+3.7mm
4	Ovality of pipe body	≤1.5％OD
			5	Ovality of pipe end	≤1％OD
6	Straightness of pipe body	≤0.15％L
			7	Straightness of pipe end	≤3mm/m

TABLE 2 mechanical Properties index

The chemical composition of the composition was actually controlled as shown in Table 3 below. The actual mechanical properties are shown in Table 4 below.

The chemical components of the pipe completely meet the requirements of claim 1, the deviation of the component content is small, and the stable component content is beneficial to temperature control during heat treatment, so that preconditions are provided for the pipe to have good structure and performance. As can be seen from Table 2, the invention can well meet the performance requirements of X65Q and X70Q pipeline pipes, has small yield ratio and high toughness, has the impact energy above-50 ℃ and is still higher than 200J, as shown in figure 2, the specification is 508mmx41.14mm yield strength is 540MPa, and the shear ratio is higher than 50% according to a series of impact energy distribution curves at different temperatures.

TABLE 3 chemical composition of examples of line pipes according to the invention

Note: when the content of C is less than or equal to 0.12 percent, the carbon equivalent CE_PcmC + Si/30+ Mn/20+ Cu/20+ Ni/60+ Cr/20+ Mo/15+ V/10+5B, B is less than or equal to 0.0005%, and the content of B in the formula is 0.

When the C content is more than 0.12%, the carbon equivalent, CE, is calculated_ⅡW＝C+Mn/6+Cu/15+Ni/15+Cr/5+Mo/5+V/5

TABLE 4 mechanical properties and metallographic phase of the line pipe examples of the invention

Claims

1. A40 mm-60 mm thick-wall large-caliber high-steel grade pipeline pipe is characterized in that: the pipeline pipe comprises the following components in percentage by weight: 0.06-0.16% of C, 0.10-0.45% of Si, 1.25-1.80% of Mn, 0.020-0.060% of Al, 0.020-0.050% of Nb, 0.03-0.09% of V, 0.20-0.50% of Ni, Mo 0.20～0.50％，Cr0.20～0.50％，Ca≤0.006％，N 0.003～0.010％，0.20％≤CEpcm≤0.28％，0.005％≤Ti≤0.020％，0.36％≤CE_ΠWNot more than 0.44 percent, Al/N not less than 2, V + Nb + Ti not more than 0.15 percent, and the balance of Fe and inevitable impurities.

2. The thick-wall large-caliber high-steel grade line pipe of 40-60 mm as claimed in claim 1, wherein: the thick wall and the large caliber are more than or equal to 406.4mm, the external diameter size precision is +/-0.5 percent OD, and the wall thickness precision is minus 3.0mm to 3.7 mm.

3. A method for manufacturing a 40 mm-60 mm thick-wall large-caliber high-steel grade pipeline pipe according to claim 1, comprising the following steps:

(1) electric furnace smelting: the weight percentages are as follows: 0.06 to 0.16 percent of C, 0.10 to 0.45 percent of Si, 1.25 to 1.80 percent of Mn, 0.020 to 0.060 percent of Al, 0.020 to 0.050 percent of Nb, 0.03 to 0.09 percent of V, 0.20 to 0.50 percent of Ni, 0.20 to 0.50 percent of Mo, 0.20 to 0.50 percent of Cr, less than or equal to 0.006 percent of Ca, 0.003 to 0.010 percent of N, less than or equal to 0.20 percent of CEpcm, less than or equal to 0.28 percent of 0.005 percent of Ti, less than or equal to 0.020 percent of Ti, less than or equal to 0.36 percent of CE_ΠWThe alloy steel is processed by a 100T electric furnace EAF, a refining LF furnace, a vacuum furnace VD and Ti, and then four-flow continuous casting is carried out to obtain billets with sections phi of 450mm and phi of 500 mm;

(3) quenching and tempering: and (3) respectively quenching and tempering the steel pipe in the step type high-temperature furnace and the step type low-temperature furnace by immersing the steel pipe in a rotary type internal spraying and external spraying water, thermally straightening and air cooling to finish the manufacture of the seamless pipeline pipe.

4. The method for manufacturing a 40 mm-60 mm thick-wall large-caliber high-steel grade line pipe according to claim 3, wherein the method comprises the following steps: the seamless line pipe has the yield strength of more than or equal to 455MPa, the tensile strength of more than or equal to 535MPa, the impact property of 0 ℃ of more than or equal to 250J and the hardness of less than or equal to 250HV10, and meets the requirements of X65Q and above steel grade line pipes.

5. The method for manufacturing a 40 mm-60 mm thick-wall large-caliber high-steel grade line pipe according to claim 3, wherein the method comprises the following steps: and heating the steel pipe to 900-980 ℃ in a stepping high-temperature furnace, preserving heat for 15-45 min, descaling with high-pressure water, quenching, cooling with water, heating to 600-710 ℃ in a stepping low-temperature furnace, preserving heat for 20-60 min, and tempering and air cooling.

6. The method for manufacturing a 40 mm-60 mm thick-wall large-caliber high-steel grade line pipe according to claim 3, wherein the method comprises the following steps: the hot straightening adopts high temperature of 500-630 ℃, the tolerance of the outer diameter is less than or equal to +/-0.5 percent D, the tolerance of the wall thickness is-3.0 mm-3.7 mm, the out-of-roundness is less than or equal to 1.5 percent D, and the straightness is less than 0.15 percent L as a whole.