CA2885696C - High-frequency straight welded pipe and manufacturing method thereof - Google Patents
High-frequency straight welded pipe and manufacturing method thereof Download PDFInfo
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
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- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/28—Normalising
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- 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
- C21D8/10—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of tubular bodies
-
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
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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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
Abstract
The present invention discloses a high-frequency straight welded pipe. The high-frequency straight welded pipe comprises the following chemical element percentages by mass: 0.042-0.056% of C, 0.18-0.22% of Si, 0.75-0.95% of Mn, 0.0064-0.015% of P, 0.0006-0.002% of S, 0.012-0.018% of Ti, 0.001-0.002% of V, 0.026-0.038% of Al, 0.080-0.13% of Ni, 0.020-0.029% of Nb, 0.125-0.135% of Cu, 0.018-0.03% of Cr, 0.004-0.008% of Mo, 0-0.0005% of B, 0.001-0.003% of Ca, and the balance of Fe and other inevitable impurities. Meanwhile, further disclosed is a manufacturing method for the high-frequency straight welded pipe.
Description
High-Frequency Straight Welded Pipe and Manufacturing Method Thereof Technical Field The invention relates to a steel pipe and a method for manufacturing the same, particularly to a high frequency welded pipe and a method for manufacturing the same.
Background Art In the field of production and transportation of petroleum and natural gas, high frequency straight welded pipes (HFW) are used widely owing to their advantages of low manufacture cost, high dimension precision, easy control over specified lengths, etc. They are employed mainly for transportation of petroleum, natural gas, ore slurry on the land and under the sea, and have a broad prospect in application.
Along with the ever growing global demand on petroleum and natural gas, the exploitation conditions in petroleum and natural gas wells tend to be worse and more complicated. As oil and gas fields characterized by badly corrosive environment with high contents of H and S are developed successively, it is urgent for steel pipe manufacturers to develop and produce pipes suitable for transporting petroleum and natural gas under this kind of acidic operation condition. At present, there are more than one hundred sets of high frequency straight welded pipe (HFW) machines in China. However, most manufacturers have to purchase plate volumes from large steel makers that mainly produce steel pipes of conventional steel grades. No domestic plant produces HIC
(hydrogen induced crack) resistant pipeline pipes of higher steel grades having superior properties that are needed raringly in the market. Up to now, there still remains a domestic blank area for HIC-resistant high-frequency straight welded pipes of grade L360MCS and a process of manufacturing the same.
Summary The object of the invention is to provide a high frequency straight welded pipe and a method for manufacturing the same, wherein the high frequency straight welded pipe possesses good HIC resistance, properties of steel grade L360MCS, high yield strength, high tensile strength, high impact toughness and good weldability.
In order to achieve the above object of the invention, there is provided a high frequency straight welded pipe, comprising the following chemical elements in mass percentages C: 0.042-0.056%;
Si: 0.18-0.22%;
Mn: 0.75-0.95%;
P: 0.0064-0.015%;
S: 0.0006-0.002%;
Ti: 0.012-0.018%;
V: 0.001-0.002%;
Al: 0.026-0.038%;
Ni: 0.080-0.13%;
Nb: 0.020-0.029%;
Cu: 0.125-0.135%;
Cr: 0.018-0.03%;
Mo: 0.004-0.008%;
B: 0-0.0005%;
Ca: 0.001-0.003%;
Background Art In the field of production and transportation of petroleum and natural gas, high frequency straight welded pipes (HFW) are used widely owing to their advantages of low manufacture cost, high dimension precision, easy control over specified lengths, etc. They are employed mainly for transportation of petroleum, natural gas, ore slurry on the land and under the sea, and have a broad prospect in application.
Along with the ever growing global demand on petroleum and natural gas, the exploitation conditions in petroleum and natural gas wells tend to be worse and more complicated. As oil and gas fields characterized by badly corrosive environment with high contents of H and S are developed successively, it is urgent for steel pipe manufacturers to develop and produce pipes suitable for transporting petroleum and natural gas under this kind of acidic operation condition. At present, there are more than one hundred sets of high frequency straight welded pipe (HFW) machines in China. However, most manufacturers have to purchase plate volumes from large steel makers that mainly produce steel pipes of conventional steel grades. No domestic plant produces HIC
(hydrogen induced crack) resistant pipeline pipes of higher steel grades having superior properties that are needed raringly in the market. Up to now, there still remains a domestic blank area for HIC-resistant high-frequency straight welded pipes of grade L360MCS and a process of manufacturing the same.
Summary The object of the invention is to provide a high frequency straight welded pipe and a method for manufacturing the same, wherein the high frequency straight welded pipe possesses good HIC resistance, properties of steel grade L360MCS, high yield strength, high tensile strength, high impact toughness and good weldability.
In order to achieve the above object of the invention, there is provided a high frequency straight welded pipe, comprising the following chemical elements in mass percentages C: 0.042-0.056%;
Si: 0.18-0.22%;
Mn: 0.75-0.95%;
P: 0.0064-0.015%;
S: 0.0006-0.002%;
Ti: 0.012-0.018%;
V: 0.001-0.002%;
Al: 0.026-0.038%;
Ni: 0.080-0.13%;
Nb: 0.020-0.029%;
Cu: 0.125-0.135%;
Cr: 0.018-0.03%;
Mo: 0.004-0.008%;
B: 0-0.0005%;
Ca: 0.001-0.003%;
2 the balance of Fe and other unavoidable impurities.
The main chemical elements in the high frequency straight welded pipe of the invention are designed according to the following principles:
C: Carbon is the main solid solution strengthening element in the pipeline pipe. A good number of experiments conducted by the researchers demonstrate that the sensitivity of strip steel to hydrogen induced crack (HIC) increases as the carbon content in the strip steel increases. Thus, it is necessary to control the carbon content appropriately to an acceptable low range that will not affect the strength of the strip steel. The carbon content in the composition of the invention is reduced suitably, from about 0.07wt% which is generally used in the prior art to not more than 0.056wt%. As such, the carbon in the technical solution of the invention is controlled in the range of 0.042-0.056wt%.
S: In low sulfur steel, the crack length ratio is reduced and MnS appears at the fracture face, indicating that the generation of cracks may be controlled effectively by reduction of N, S in strip steel. Nevertheless, it is unnecessary to seek reduction of the sulfur content blindly because cracks in the strip steel cannot be avoided completely even if the sulfur content is reduced to an extremely low level. The inventors have carried out a lot of experiments and found that, when the mass percentage of sulfur is controlled in the range of 0.0006-0.002%, not only the requirement of corrosion resistance can be fulfilled, but also cracking in the strip steel can be prevented.
Ca: Calcium treatment has an important influence on the hydrogen induced crack (HIC) resistance of strip steel. In the technical solution of the invention, a suitable amount of calcium is added into the composition. CaS precipitated at the final solidification position is converted into spherical inclusions after rolling, so that the hydrogen induced crack (HIC) resistance of the strip steel is improved. Yet, control over the calcium content is related with the sulfur
The main chemical elements in the high frequency straight welded pipe of the invention are designed according to the following principles:
C: Carbon is the main solid solution strengthening element in the pipeline pipe. A good number of experiments conducted by the researchers demonstrate that the sensitivity of strip steel to hydrogen induced crack (HIC) increases as the carbon content in the strip steel increases. Thus, it is necessary to control the carbon content appropriately to an acceptable low range that will not affect the strength of the strip steel. The carbon content in the composition of the invention is reduced suitably, from about 0.07wt% which is generally used in the prior art to not more than 0.056wt%. As such, the carbon in the technical solution of the invention is controlled in the range of 0.042-0.056wt%.
S: In low sulfur steel, the crack length ratio is reduced and MnS appears at the fracture face, indicating that the generation of cracks may be controlled effectively by reduction of N, S in strip steel. Nevertheless, it is unnecessary to seek reduction of the sulfur content blindly because cracks in the strip steel cannot be avoided completely even if the sulfur content is reduced to an extremely low level. The inventors have carried out a lot of experiments and found that, when the mass percentage of sulfur is controlled in the range of 0.0006-0.002%, not only the requirement of corrosion resistance can be fulfilled, but also cracking in the strip steel can be prevented.
Ca: Calcium treatment has an important influence on the hydrogen induced crack (HIC) resistance of strip steel. In the technical solution of the invention, a suitable amount of calcium is added into the composition. CaS precipitated at the final solidification position is converted into spherical inclusions after rolling, so that the hydrogen induced crack (HIC) resistance of the strip steel is improved. Yet, control over the calcium content is related with the sulfur
3 content. Hence, the calcium content in the technical solution of the invention is controlled in the range of 0.001-0.003wt%.
Cu: Among the variety of alloy elements, copper is the only element that is beneficial to the hydrogen induced crack (HIC) resistance. When an amount of copper is added into pipeline steel, the sensitivity to hydrogen induced crack is decreased remarkably. The main reason is that copper facilitates the formation of a passivation film which blocks invasion of hydrogen element and thus inhibits formation of hydrogen induced crack. According to the technical solution of the invention, an amount of copper is added to improve the hydrogen induced crack (HIC) resistance. Therefore, the copper content is controlled in the range of 0.125-0.135wt%.
Mn: The effect of manganese on the sensitivity of pipeline steel to hydrogen induced crack principally resides in the influence of manganese on the phase transition of the strip steel. If the manganese content exceeds 1.0wt%, the sensitivity to hydrogen induced crack (HIC) increases. Therefore, the manganese content in the technical solution of the invention is controlled in the range of 0.75-0.95wt%.
Accordingly, the invention also provides a method for manufacturing the above high frequency straight welded pipe, comprising the following steps:
in a shell forming step, the squeeze is controlled in the range of 2-3% of the outer diameter of the welded pipe;
in a welding step, the welding speed is controlled in the range of 18-20m/min;
in a post-welding heat treatment step, the welding line is normalized at 930-970 C, followed by air cooling to below 380 C and water cooling to below 80 C.
Cu: Among the variety of alloy elements, copper is the only element that is beneficial to the hydrogen induced crack (HIC) resistance. When an amount of copper is added into pipeline steel, the sensitivity to hydrogen induced crack is decreased remarkably. The main reason is that copper facilitates the formation of a passivation film which blocks invasion of hydrogen element and thus inhibits formation of hydrogen induced crack. According to the technical solution of the invention, an amount of copper is added to improve the hydrogen induced crack (HIC) resistance. Therefore, the copper content is controlled in the range of 0.125-0.135wt%.
Mn: The effect of manganese on the sensitivity of pipeline steel to hydrogen induced crack principally resides in the influence of manganese on the phase transition of the strip steel. If the manganese content exceeds 1.0wt%, the sensitivity to hydrogen induced crack (HIC) increases. Therefore, the manganese content in the technical solution of the invention is controlled in the range of 0.75-0.95wt%.
Accordingly, the invention also provides a method for manufacturing the above high frequency straight welded pipe, comprising the following steps:
in a shell forming step, the squeeze is controlled in the range of 2-3% of the outer diameter of the welded pipe;
in a welding step, the welding speed is controlled in the range of 18-20m/min;
in a post-welding heat treatment step, the welding line is normalized at 930-970 C, followed by air cooling to below 380 C and water cooling to below 80 C.
4 Further, in the shell forming step of the method for manufacturing a high frequency straight welded pipe according to the invention, the opening angle is controlled in the range of 3-4.2 .
In the technical solution of the invention, the squeeze measured before and after welding is controlled in the range of 2-3% of the outer diameter of the welded pipe, wherein the squeeze refers to the difference between the perimeter of the shell before squeezing and the perimeter after the squeezing. In a molten state, the molten pool at the welding line is exposed to air and susceptible to oxidation, wherein the product of the oxidation reaction is closely related with the chemical composition of the strip steel. Hence, a relatively large squeeze needs to be applied to squeeze the resulting product with high melting point to the surface of the welding line on the strip steel and remove the same by deburring. If the squeeze is lower than 2%, flaws such as cold welding will occur, such that the inclusions in the strip steel cannot be expelled to the surface of the welding line for removal, and the quality of the strip steel will be affected.
The welding speed is set in the range of 18-20m/min for the reason that the welding speed is generally inversely proportional to the welding power, such that a rapid welding speed tends to counteract the expellability of the inclusions resulted from a high welding power and a large squeeze, leading to decreased effect in expelling the inclusions. Therefore, the inventors control the welding speed in the range of 18-20m/min according to the technical solution of the invention.
According to the method for manufacturing a high frequency straight welded pipe in the invention, on the basis of the utilization of a manufacturing method of high frequency straight induction welding (HFW), a high frequency straight welded pipe that meets the requirements of HIC resistance, tensile property, impact toughness and microstructure is manufactured by reasonably regulating the squeeze and the forming process, setting the high frequency weld forming and welding parameters, and controlling the technical parameters of the subsequent heat treatment.
Compared with the prior art, the high frequency straight welded pipe of the invention has good HIC resistance, properties of steel grade L360MCS, high yield strength, high tensile strength, high impact toughness and good weldability, and is suitable for use as a transporting pipe in a harsh operation environment where the contents of H and S are high or acidic corrosion exists.
Detailed Description of the Invention Examples 1-6 The high frequency straight welded pipe of the invention was manufactured in accordance with the following steps:
The head and tail portions of unrolled steel rolls were cut off, and cuts were formed flush at an angle of 30 relative to the traverse direction of the steel rolls. The tail of a preceding steel roll was welded to the head of a succeeding steel roll by carbon dioxide shielded welding. The steel strip was used to manufacture a high frequency straight welded pipe, wherein the edge of the plate was treated by edge milling to control the width of the steel strip and the plumbness of the plate edge precisely. The steel strip was formed into a shell by a cage roll forming process. The squeeze was controlled in the range of 2-3%
of the outer diameter of the welded pipe, and the opening angle was controlled in the range of 3-4.2 . The welding speed was controlled in the range of 18-20m/min during welding. After welding, the welding line was normalized at 930-970 C, followed by air cooling to below 380 C and water cooling to below 80 C. The wall thickness of the high frequency straight welded pipe obtained by the above process was 6.4mm-9.5mm, and the pipe diameter was 219.7mm-406.4mm.
Table 1 lists the chemical compositions of the high frequency straight welded pipes of Examples 1-6.
Table 1 (The balance is Fe and other unavoidable impurities, wt%) Ex. 1 2 3 4 5 6 C 0.0551 0.0553 0.0499 0.0494 0.0517 0.0421 Si 0.18 , 0.182 0.0182 0.182 0.183 0.22 Mn 0.886 0.886 0.0878 0.877 0.750 0.950 P 0.0136 0.0136 ., 0.0118 0.0121 0.0064 0.0149 S 0.002 0.0012 0.0014 0.0015 0.0006 0.0010 Ti 0.014 0.014 0.014 0.014 0.012 0.018 / 0.001 0.001 0.001 0.001 0.002 0.001 Al 0.031 0.026 0.030 0.030 0.028 0.038 Ni 0.096 0.096 0.096 0.096 0.08 0.128 Nb 0.027 0.027 0.026 0.027 0.020 0.029 Cu 0.132 0.129 0.13 0.129 0.125 0.135 Cr 0.026 0.026 0.026 0.027 0.030 0.018 Mo 0.005 0.005 0.005 0.005 0.004 0.008 B 0.0001 0.0002 0.0002 0.0002 0 0.0005 Ca 0.0018 0.0020 0.0020 0.0023 0.0029 0.0010 Table 2 lists the detailed process parameters for manufacturing the high frequency straight welded pipes of Examples 1-6.
Table 2 Water Air Cooling C ooling Strip Wall Welding Opening Normalizing Temperature Width Output Thickness Diameter Squeeze Ex. Speed Angle Temperature for the Temperaturefor t,ne After Power of Welded of Welded (%) (rnimin) ( ) ( C) Welding Milling (KW) Pipe Pipe (mm) Welding Line Line("C) ("C) (mm) (mm) 1 2.9 20 3.8 950 360 42 . 700 450 6.4 219.7 2 2 18 4 955 365 46 1285 840 8.7 406.4 3 2.7 18 4 960 370 50 1281 906 9.5 . 406.4 4 3 18 4 960 375 38 1024 772 9.1 323.9 2.62 20 3.8 950 350 35 1031 572 6.4 323.9 6 2.46 18 4 955 360 40 1289 698 7.1 406.4 Table 3 lists the performance parameters of the high frequency straight welded pipes of Examples 1-6.
Table 3 Welding Line of Welded Welded Pipe BodyWhole Pipe Impact Impact Toughness/Char Toughness/Char I-Iydrogen Induced Crack Ex. Yield Tensile Elong- Yield py Impact Ener gy (J) Tensile r Impact (IIIC) Resistance Strength Strength ation Ratio Strength ergy (J) (MPa) (MPa) (%) (MPa) Crack Crack Crack AveAve Sensitiv Length Thickne Minimum Mini mum rage rage e Rate Rate ss Rate (CSR) (CLR) (CLR) I 478 545 28 0.877 119 127 475 139 145 0 0 0 2 399 505 37 0.790 198 259 480 284 318 0 0 0 3 422 520 37 0.812 293 301 487 266 268 0 0 0 4 455 540 24 0.843 231 241 510 225 239 0 0 0
In the technical solution of the invention, the squeeze measured before and after welding is controlled in the range of 2-3% of the outer diameter of the welded pipe, wherein the squeeze refers to the difference between the perimeter of the shell before squeezing and the perimeter after the squeezing. In a molten state, the molten pool at the welding line is exposed to air and susceptible to oxidation, wherein the product of the oxidation reaction is closely related with the chemical composition of the strip steel. Hence, a relatively large squeeze needs to be applied to squeeze the resulting product with high melting point to the surface of the welding line on the strip steel and remove the same by deburring. If the squeeze is lower than 2%, flaws such as cold welding will occur, such that the inclusions in the strip steel cannot be expelled to the surface of the welding line for removal, and the quality of the strip steel will be affected.
The welding speed is set in the range of 18-20m/min for the reason that the welding speed is generally inversely proportional to the welding power, such that a rapid welding speed tends to counteract the expellability of the inclusions resulted from a high welding power and a large squeeze, leading to decreased effect in expelling the inclusions. Therefore, the inventors control the welding speed in the range of 18-20m/min according to the technical solution of the invention.
According to the method for manufacturing a high frequency straight welded pipe in the invention, on the basis of the utilization of a manufacturing method of high frequency straight induction welding (HFW), a high frequency straight welded pipe that meets the requirements of HIC resistance, tensile property, impact toughness and microstructure is manufactured by reasonably regulating the squeeze and the forming process, setting the high frequency weld forming and welding parameters, and controlling the technical parameters of the subsequent heat treatment.
Compared with the prior art, the high frequency straight welded pipe of the invention has good HIC resistance, properties of steel grade L360MCS, high yield strength, high tensile strength, high impact toughness and good weldability, and is suitable for use as a transporting pipe in a harsh operation environment where the contents of H and S are high or acidic corrosion exists.
Detailed Description of the Invention Examples 1-6 The high frequency straight welded pipe of the invention was manufactured in accordance with the following steps:
The head and tail portions of unrolled steel rolls were cut off, and cuts were formed flush at an angle of 30 relative to the traverse direction of the steel rolls. The tail of a preceding steel roll was welded to the head of a succeeding steel roll by carbon dioxide shielded welding. The steel strip was used to manufacture a high frequency straight welded pipe, wherein the edge of the plate was treated by edge milling to control the width of the steel strip and the plumbness of the plate edge precisely. The steel strip was formed into a shell by a cage roll forming process. The squeeze was controlled in the range of 2-3%
of the outer diameter of the welded pipe, and the opening angle was controlled in the range of 3-4.2 . The welding speed was controlled in the range of 18-20m/min during welding. After welding, the welding line was normalized at 930-970 C, followed by air cooling to below 380 C and water cooling to below 80 C. The wall thickness of the high frequency straight welded pipe obtained by the above process was 6.4mm-9.5mm, and the pipe diameter was 219.7mm-406.4mm.
Table 1 lists the chemical compositions of the high frequency straight welded pipes of Examples 1-6.
Table 1 (The balance is Fe and other unavoidable impurities, wt%) Ex. 1 2 3 4 5 6 C 0.0551 0.0553 0.0499 0.0494 0.0517 0.0421 Si 0.18 , 0.182 0.0182 0.182 0.183 0.22 Mn 0.886 0.886 0.0878 0.877 0.750 0.950 P 0.0136 0.0136 ., 0.0118 0.0121 0.0064 0.0149 S 0.002 0.0012 0.0014 0.0015 0.0006 0.0010 Ti 0.014 0.014 0.014 0.014 0.012 0.018 / 0.001 0.001 0.001 0.001 0.002 0.001 Al 0.031 0.026 0.030 0.030 0.028 0.038 Ni 0.096 0.096 0.096 0.096 0.08 0.128 Nb 0.027 0.027 0.026 0.027 0.020 0.029 Cu 0.132 0.129 0.13 0.129 0.125 0.135 Cr 0.026 0.026 0.026 0.027 0.030 0.018 Mo 0.005 0.005 0.005 0.005 0.004 0.008 B 0.0001 0.0002 0.0002 0.0002 0 0.0005 Ca 0.0018 0.0020 0.0020 0.0023 0.0029 0.0010 Table 2 lists the detailed process parameters for manufacturing the high frequency straight welded pipes of Examples 1-6.
Table 2 Water Air Cooling C ooling Strip Wall Welding Opening Normalizing Temperature Width Output Thickness Diameter Squeeze Ex. Speed Angle Temperature for the Temperaturefor t,ne After Power of Welded of Welded (%) (rnimin) ( ) ( C) Welding Milling (KW) Pipe Pipe (mm) Welding Line Line("C) ("C) (mm) (mm) 1 2.9 20 3.8 950 360 42 . 700 450 6.4 219.7 2 2 18 4 955 365 46 1285 840 8.7 406.4 3 2.7 18 4 960 370 50 1281 906 9.5 . 406.4 4 3 18 4 960 375 38 1024 772 9.1 323.9 2.62 20 3.8 950 350 35 1031 572 6.4 323.9 6 2.46 18 4 955 360 40 1289 698 7.1 406.4 Table 3 lists the performance parameters of the high frequency straight welded pipes of Examples 1-6.
Table 3 Welding Line of Welded Welded Pipe BodyWhole Pipe Impact Impact Toughness/Char Toughness/Char I-Iydrogen Induced Crack Ex. Yield Tensile Elong- Yield py Impact Ener gy (J) Tensile r Impact (IIIC) Resistance Strength Strength ation Ratio Strength ergy (J) (MPa) (MPa) (%) (MPa) Crack Crack Crack AveAve Sensitiv Length Thickne Minimum Mini mum rage rage e Rate Rate ss Rate (CSR) (CLR) (CLR) I 478 545 28 0.877 119 127 475 139 145 0 0 0 2 399 505 37 0.790 198 259 480 284 318 0 0 0 3 422 520 37 0.812 293 301 487 266 268 0 0 0 4 455 540 24 0.843 231 241 510 225 239 0 0 0
5 400 510 34 0.784 170 180 490 160 166 0 0 0
6 420 520 24 0.808 150 162 505 202 214 0 0 0 As shown by Table 3, the high frequency straight welded pipe of the invention possesses superior mechanical properties and HIC resistance.
Specifically, the welded pipe body exhibits a yield strength >399MPa, a tensile strength >505MPa, an elongation >24%, and the welding line of the welded pipe has a tensile strength >475MPa, indicating that the high frequency straight welded pipe as a whole meets the requirement of high strength and possesses high tensile capability. With respect to impact toughness, the Charpy impact energy of the welded pipe body has a minimum >119J and an average >127J, and that of the welding line of the welded pipe has a minimum >139J and an average >145J, indicating that the high frequency straight welded pipe has good toughness and weldability. The crack sensitive rate (CSR), the crack length rate (CLR) and the crack thickness rate (CTR), which are used for evaluating the hydrogen induced crack (HIC) resistance of a strip steel material, are all 0%
as shown in Table 3, demonstrating the good hydrogen induced crack (HIC) resistance of the high frequency straight welded pipe.
It is to be noted that the above specific examples of the invention are only exemplary. Obviously, the invention is not limited to the above examples.
Rather, a number of variations can be made. All variations derived directly or contemplated from the disclosure of the invention by one skilled in the art fall within the protection scope of the invention.
Specifically, the welded pipe body exhibits a yield strength >399MPa, a tensile strength >505MPa, an elongation >24%, and the welding line of the welded pipe has a tensile strength >475MPa, indicating that the high frequency straight welded pipe as a whole meets the requirement of high strength and possesses high tensile capability. With respect to impact toughness, the Charpy impact energy of the welded pipe body has a minimum >119J and an average >127J, and that of the welding line of the welded pipe has a minimum >139J and an average >145J, indicating that the high frequency straight welded pipe has good toughness and weldability. The crack sensitive rate (CSR), the crack length rate (CLR) and the crack thickness rate (CTR), which are used for evaluating the hydrogen induced crack (HIC) resistance of a strip steel material, are all 0%
as shown in Table 3, demonstrating the good hydrogen induced crack (HIC) resistance of the high frequency straight welded pipe.
It is to be noted that the above specific examples of the invention are only exemplary. Obviously, the invention is not limited to the above examples.
Rather, a number of variations can be made. All variations derived directly or contemplated from the disclosure of the invention by one skilled in the art fall within the protection scope of the invention.
Claims (3)
1. A high frequency straight welded pipe, comprising the following chemical elements in rnass percentages:
C: 0.042~0.056%;
Si: 0.18~0.22%;
Mn: 0.75~0.95%;
P: 0.0064~0.015%;
S 0.0006~0.002%;
Ti 0.012~0.018%;
V 0.001~0.002%;
Al 0.026~0.038%;
Ni 0.080~0.13%;
Nb 0.020~0.029%;
Cu 0.125~0.135%;
Cr 0.018~0.03%;
Mo 0.004~0.008%;
B 0~0.0005%;
Ca 0.001~0.003%;
the balance of Fe and other unavoidable impurities.
C: 0.042~0.056%;
Si: 0.18~0.22%;
Mn: 0.75~0.95%;
P: 0.0064~0.015%;
S 0.0006~0.002%;
Ti 0.012~0.018%;
V 0.001~0.002%;
Al 0.026~0.038%;
Ni 0.080~0.13%;
Nb 0.020~0.029%;
Cu 0.125~0.135%;
Cr 0.018~0.03%;
Mo 0.004~0.008%;
B 0~0.0005%;
Ca 0.001~0.003%;
the balance of Fe and other unavoidable impurities.
2. A method for rnanufacturing the high frequency straight welded pipe of claim 1, wherein:
in a shell forming step, the squeeze is controlled to be 2-3% of the outer diameter of the welded pipe;
in a welding step, the welding speed is controlled in the range of 18-20m/min;
in a post-welding heat treatment step, the welding line is normalized at 930-970°C, followed by air cooling to below 380°C and water cooling to below 80°C.
in a shell forming step, the squeeze is controlled to be 2-3% of the outer diameter of the welded pipe;
in a welding step, the welding speed is controlled in the range of 18-20m/min;
in a post-welding heat treatment step, the welding line is normalized at 930-970°C, followed by air cooling to below 380°C and water cooling to below 80°C.
3. The method for manufacturing the high frequency straight welded pipe according to claim 2, wherein in the shell forrning step, the opening angle is controlled in the range of 3~4.2°.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201210378301.9 | 2012-09-29 | ||
| CN201210378301.9A CN102912253B (en) | 2012-09-29 | 2012-09-29 | High-frequency straight welded pipe and manufacturing method thereof |
| PCT/CN2013/084267 WO2014048337A1 (en) | 2012-09-29 | 2013-09-26 | High-frequency straight welded pipe and manufacturing method thereof |
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| CA2885696A1 CA2885696A1 (en) | 2014-04-03 |
| CA2885696C true CA2885696C (en) | 2021-04-20 |
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| CN (1) | CN102912253B (en) |
| AU (1) | AU2013324845B2 (en) |
| CA (1) | CA2885696C (en) |
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| CN106670743B (en) * | 2016-12-14 | 2019-06-11 | 安徽楚江特钢有限公司 | A kind of manufacturing method of precision gas spring straight seam welded pipe |
| CN114535939B (en) * | 2022-03-22 | 2023-02-28 | 湖南胜利湘钢钢管有限公司 | Method for manufacturing longitudinal submerged arc welded pipe |
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| CN101898295B (en) * | 2010-08-12 | 2011-12-07 | 中国石油天然气集团公司 | Manufacturing method of high-strength and high-plasticity continuous tube |
| CN102330034B (en) * | 2011-09-30 | 2013-04-24 | 中国石油集团渤海石油装备制造有限公司 | X65MS steel-grade spiral welded tube for acidic corrosion environment and manufacturing method thereof |
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| CN102912253B (en) * | 2012-09-29 | 2014-07-23 | 宝山钢铁股份有限公司 | High-frequency straight welded pipe and manufacturing method thereof |
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| CN102912253B (en) | 2014-07-23 |
| AU2013324845B2 (en) | 2018-03-08 |
| SA515360196B1 (en) | 2015-12-22 |
| CA2885696A1 (en) | 2014-04-03 |
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