WO2007023873A1 - 焼入れ性、熱間加工性および疲労強度に優れた高強度厚肉電縫溶接鋼管およびその製造方法 - Google Patents
焼入れ性、熱間加工性および疲労強度に優れた高強度厚肉電縫溶接鋼管およびその製造方法 Download PDFInfo
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- 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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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G21/00—Interconnection systems for two or more resiliently-suspended wheels, e.g. for stabilising a vehicle body with respect to acceleration, deceleration or centrifugal forces
- B60G21/02—Interconnection systems for two or more resiliently-suspended wheels, e.g. for stabilising a vehicle body with respect to acceleration, deceleration or centrifugal forces permanently interconnected
- B60G21/04—Interconnection systems for two or more resiliently-suspended wheels, e.g. for stabilising a vehicle body with respect to acceleration, deceleration or centrifugal forces permanently interconnected mechanically
- B60G21/05—Interconnection systems for two or more resiliently-suspended wheels, e.g. for stabilising a vehicle body with respect to acceleration, deceleration or centrifugal forces permanently interconnected mechanically between wheels on the same axle but on different sides of the vehicle, i.e. the left and right wheel suspensions being interconnected
- B60G21/055—Stabiliser bars
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- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
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- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
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- 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
- C21D8/105—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of tubular bodies of ferrous alloys
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- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
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- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
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- 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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- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
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- 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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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2206/00—Indexing codes related to the manufacturing of suspensions: constructional features, the materials used, procedures or tools
- B60G2206/01—Constructional features of suspension elements, e.g. arms, dampers, springs
- B60G2206/40—Constructional features of dampers and/or springs
- B60G2206/42—Springs
- B60G2206/427—Stabiliser bars or tubes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2206/00—Indexing codes related to the manufacturing of suspensions: constructional features, the materials used, procedures or tools
- B60G2206/01—Constructional features of suspension elements, e.g. arms, dampers, springs
- B60G2206/80—Manufacturing procedures
- B60G2206/82—Joining
- B60G2206/8201—Joining by welding
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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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
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- 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
- C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
- C21D9/14—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes wear-resistant or pressure-resistant pipes
Definitions
- the present invention relates to a high strength thick electric resistance welded steel pipe excellent in hardenability, hot bright formability and fatigue strength, which is suitable for a hollow stainless steel pylizer for securing running stability of an automobile, and a method of manufacturing the same. . book
- Stabilizers which ease rolling of the vehicle body during cornering of the car and ensure vehicle stability during high-speed travel, are also listed as targets.
- stabilizers were manufactured by processing solid materials such as steel bars into desired shapes, but in order to reduce weight, they are manufactured using hollow materials such as seamless steel pipes and ERW welded steel pipes. Is increasing.
- an ERW welded steel pipe for use with Stabiraa in WO 2202/070767, by defining the composition, the metallographic structure of the ERW weld portion and the base material portion is uniform. Also disclosed is an ERW welded steel pipe for a hollow stabilizer which has a small difference in hardness between the ERW weld portion and the base material portion and which is excellent in processability, and is disclosed in Japanese Patent Application Laid-Open No. 2 0 0 4 0 1 0 0 9 The publication discloses a hollow-stabilized ERW welded steel pipe which secures hardenability by specifying the content of Ti, N.
- the ratio t ZD between the thickness t of the steel pipe and the outer diameter D is 20% or more, and the tensile strength is 4 0 0 to 7 5 5 N /
- An ERW welded steel pipe for hollow stabilizers with a size of 2 mm has been proposed, and it has been disclosed to increase the thickness by reducing diameter rolling.
- JP-A-2003-203 it is possible to reduce the diameter of an element tube and to obtain a high tensile strength of over 5800 MPa and a yield ratio of 70% or less.
- a high strength steel tube for automobile structural members excellent in workability that can withstand mouth forming has been proposed, and in addition, JP-A-2008-25992-2 describes a heating temperature in diameter reduction rolling.
- a method of manufacturing a high tensile steel pipe excellent in composite secondary workability such as bending, diameter reduction, pipe end flattening and the like has been proposed.
- a forming step of forming a raw material pipe into a stainless steel shape by cold bending, and hardening and tempering of the formed steel pipe In the manufacturing method of the hollow stabilizer which heat-treats, after heat-processing the said raw material to a mother steel pipe, rolling temperature 600-850.
- a manufacturing method of a hollow expander having excellent fatigue resistance, which is subjected to reduction rolling with a cumulative diameter reduction of 40% or more, is disclosed.
- an ERW steel pipe for quenching is excellent in workability with the balance being Fe and having a high residual strength after penetration of hydrogen due to corrosion.
- STEEL VALIER 1 further reduces the diameter of ERW welded steel pipe and reduces the thickness to the required thickness outer diameter ratio.
- Curved ERW welded steel pipe Form it into the required shape by cold forming such as
- B-added steel with high hardenability As a stabilizer steel, but B-added steel is poor in hot workability and is prone to cracking during hot forming. Is a major issue.
- B-added steel may have low fatigue strength, which is an important characteristic for stainless steel.
- welded steel pipes and high-strength steel pipes are useful as steel pipes for automobile structural members, as described above, they can not sufficiently cope with the problems caused by process changes in the manufacturing process of automobile structural members. In addition, it can not be said that it is sufficient in terms of fatigue characteristics. In view of the above problems, the present invention has sufficient hardenability and
- An object of the present invention is to provide a high strength thick electric resistance welded steel pipe excellent in inter-row workability and fatigue strength, and a method of manufacturing the same.
- the thick electric resistance welded steel pipe of the present invention has been made to solve the above-mentioned problems, and by increasing c as much as possible without deteriorating the weldability and toughness, and improving the strength (hardness), N
- N By strictly limiting the range of the content, it is possible to improve the hot workability and the fatigue strength and further to adjust the composition of the steel material so that the critical cooling rate V c falls within a specific range. Therefore, in the manufacture of the thick electric resistance welded steel pipe according to the present invention, reduction resistance rolling is applied to the electric resistance welded steel pipe with the heating temperature and the reduction rate of the cross section as a specific range.
- the critical cooling rate V c represented by the formula ⁇ 1> is less than 30 ° CZ s
- the thickness t and the outer diameter D A high strength thick electric resistance welded welded steel pipe excellent in hardenability, hot workability and fatigue strength characterized in that the ratio t ZD is in the range of from 0.15 or more to 0.30.
- composition according to any one of (1) to (3) characterized in that it contains, in mass%, Ca: 0.000-0. 05%.
- the electric resistance welded steel pipe having the component according to any one of (1) to (4) is heated to 800 to 120 ° C., and the reduction in area is 40 to 80
- the thick electric resistance welded steel pipe of the present invention is extremely excellent in hardenability, it is sufficient, for example, to carry out a hardening process immediately after performing a hot forming process in the manufacture of a member for an automobile structure such as a stabilizer.
- the quenching effect can be obtained, and the quenching means is not limited to water cooling, and a sufficient quenching effect can be obtained by oil quenching having a smaller cooling rate than water cooling.
- Fig. 1 is a diagram showing the relationship between the hardening and the amount of hardness after tempering of steel materials for thick-walled ERW welded steel pipes.
- FIG. 2 is a view showing the relationship between the shear stress value at 850 ° C. and the N content, and is a view for explaining the method of the fatigue test.
- the inventors examined a method of further strengthening the strength while improving the hardenability, the hot workability and the fatigue strength of the thick electric resistance welded steel pipe for stainless steel.
- the hardness increases with an increase in the amount of C.
- Fig. 1 also shows the relationship between the hardness of the 100% and 90% martensite ⁇ structure and the amount of C at the same time, but if the test material 8 and BC at least 90% martensite structure is baked, the conventional material It can be seen that a hardness of 10% or more of the above can be secured. Therefore, as an index of hardenability, for example, the critical cooling which can obtain 90% martensite structure conventionally known from iron and steel 7 4 (1 9 8 8) P 1 0 7 3 Speed V c
- the components are selected such that the critical cooling rate V c shown by ⁇ 1> is less than 30 ° C.Zsec.
- the present inventors investigated the cause of the poor hot workability of the B-added steel in the temperature range of 600 ° C. to 900 ° C. where hot forming is performed, and as a result, the N content in the steel is a thermal It was found that the inter-deformation resistance was greatly affected. That is, the inventors found that the N content in the 0.3 C-1.1 M n-0. 0 2 0 T i-0. 0 0 1 3 B steel is 0.1 0 1% to 0. 0. 0. 0. The test material changed in the range of 0. 1% was manufactured, and a uniaxial tensile test was performed at 8500 which is a temperature range actually hot formed, and the reduction value at that time was measured.
- Figure 2 shows the relationship between the aperture value at 850 ° C and the N content.
- the reduction value increases, that is, it can be seen that the hot workability is improved.
- the reduction value increases to 40%, which is the standard at which hot forming can be carried out generally, and when the content of N is less than 0.040%, The squeeze value has reached 50% or more where hot forming can be performed without problems. It has been found that the reason for this is that the amount of T i N precipitated in the temperature range in which hot forming is performed is reduced by the reduction of the N content.
- the B-added steel in order to suppress the precipitation of BN, which reduces the hardenability improving effect of B, the B-added steel generally contains Ti having a high effect of fixing N, which is why In steel, it was found that the hot workability was not good because of the precipitation of TiN in the temperature range where hot forming was performed.
- the thick-walled ERW welded steel pipe of the present invention improves the strength and improves the hot workability and the fatigue strength.
- the critical cooling rate V c is lowered and the hardenability is improved.
- C is an element that precipitates as a solid solution or carbide in the matrix to increase the strength of the steel.
- HV 400 As a structural member for automobile structural strength higher than before, at least a hardness of HV 400 is required for a 90% martensite ⁇ structure and at least 0.52% C should be contained. Although it is necessary, if it is contained in excess of 0.4%, the adhesivity and weldability will be degraded, so the content is made in the range of 0.25 0.5%.
- S 1 is an alloying element that contributes to solid solution strengthening, and it is necessary to contain 0.01% or more in order to obtain the effect. Further, it has an effect of enhancing the resistance to temper softening, To get the effect 0.2
- the content is more than 0. 0%, the toughness decreases. For this reason, the content is in the range of 0.010%. Preferably, it is 0.205%.
- Mn is an element improving the hardenability, and if the content is less than 0.8%, the effect of improving the hardenability can not be sufficiently ensured, and if it exceeds 1.5%, welding is performed. And the soundness of welds are adversely affected.
- the content should be in the range of 0.8 to 1.5% in order to
- a 1 is an element necessary as a deoxidizing material for molten steel and is also an element for fixing N, its amount greatly affects the grain size and mechanical properties. If the content exceeds 0.5%, the crystal grain size is coarsened and the toughness is lowered, and the content of non-metallic inclusions is apt to generate surface defects in the product. Not less than 5%. Preferably, it is not more than 0.3%.
- B is an element that significantly improves the hardenability of steel with a small amount of addition, and also has the effect of grain boundary strengthening. If the content is less than 0.000%, the effect of improving hardenability can not be expected, while if it exceeds 0.01%, a coarse B-containing phase tends to be formed, and embrittlement It becomes easy to get up. For this reason, its content is set to from 0. 0 0 0 5% to 0. 0 1%. In addition, Preferably, it is more than 0. 0 0 1 0-0. 0 0 2 0%.
- N is an element having the effect of precipitating nitride or carbonitride and enhancing the strength.
- T i N also has the effect of suppressing the coarsening of the grain size at high temperatures and improving the toughness. Therefore, in order to optimize the balance of hot workability, fatigue strength and toughness, the content is made in the range of 0.01 to 0. 05%. In addition, Preferably, it is less than 0. 0 0 2-0. 0 0 4%.
- T i acts to stably and effectively improve hardenability by the addition of B by fixing N in steel as T i N to suppress the precipitation of BN. Therefore, in order to meet the stoichiometry of TIN, the addition of at least 3.42 times the N content is at least necessary, and the N content described above A range of amounts to a range of Ti content is also determined automatically. However, because there is also a portion that precipitates as a carbonate, in order to ensure the fixation of N, the value should be 0.50 or higher, which is higher than the theoretical value, while if it exceeds 0.5% Since the toughness tends to deteriorate, the range is from 0. 0 0 5 to 0. 0 5%. In addition, Preferably, it is 0. 0 1-0. 0 2%.
- P is an element that adversely affects weld cracking resistance and toughness, so it is limited to not more than 0.5%. Preferably, it is not more than 0.33%.
- S affects the formation of non-metallic inclusions in steel, degrades the workability such as bendability and flatness of steel pipe, and causes deterioration of toughness and increase in anisotropy and reheat cracking susceptibility.
- the soundness of welds is adversely affected. Therefore, its content is limited to 0.5% or less. Preferably, it is not more than 0.1%.
- the thick electric resistance welded steel pipe of the present invention can contain one or more of C r, M o, V, and N i and one or more of no or C a and N b according to need. .
- Cr is an element improving the hardenability, and also has the effect of precipitating M 2 3 C 6 type carbides in the matrix, and has the action of increasing the strength and refining the carbide. If the content is less than 0.1%, these effects and effects can not be expected sufficiently, and if it exceeds 1%, defects tend to occur during electric resistance welding. Therefore, its content is in the range of 0.;! To 1%. Preferably, it is from 0.:! To 0.6%.
- Mo is an element having an effect of improving hardenability, and an element having an effect of causing solid solution strengthening. If the content is less than 0.5%, these effects can not be expected sufficiently, while if it exceeds 1%, coarse carbides are easily precipitated and the toughness is deteriorated. Amount shall be in the range of 0.51%. Preferably, it is 0.:! 0.5%.
- N 1 is an element having an effect of improving hardenability and toughness. If the content is less than 0.1%, the effect can not be expected. On the other hand, if it exceeds 1%, residual r may be present even after quenching, which degrades fatigue durability. Therefore, its content is in the range of 0.1%. In addition, Preferably, it is 0.50 0.5%.
- V is an element having an effect of improving hardenability, and is an element having an effect of precipitation strengthening by V carbon nitride. If the content is less than 0.01%, these effects can not be sufficiently expected. On the other hand, if the content exceeds 0.5%, coarse carbides are easily precipitated and the toughness is deteriorated. 0 1 0. 5% range. Preferably, it is 0. 0 2 0. 0 5%.
- Nb In addition to the effect of precipitation strengthening by Nb carbonitrides, Nb has the effect of refining the old austenite grain size and improving the toughness. Furthermore, it has the effect of suppressing surface decarburization.
- the content is less than 0.01%, the effect of improving the strength and toughness is not sufficient, and if it is contained in excess of 0.1%, the carbide increases and the toughness decreases, so the content is 0.1%. It shall be in the range of 0.1%. Preferably, it is 0. 0 2 0. 0 4%
- C a is an element having an effect of improving the formability by making the shape of the oxide sulfide spherical. If the content is less than 0 • 00 0 2%, these effects can not be expected sufficiently. On the other hand, if the content exceeds 0. 0 0 5%, oxides in the steel increase and the toughness is deteriorated. 0. 0
- the thickness t (mm) of the steel pipe The reason why the range of t ZD, which is the ratio of) and the outside diameter D (mm) of the steel pipe, is from 0.15 to 0.30 will be explained.
- t z D In order to reduce the weight of the stabilizer, it is desirable that t z D be as small as possible. However, the smaller the tD, the larger the main stress applied at the time of use, and the fatigue characteristics deteriorate. On the other hand, as t / D increases, the effect of weight reduction decreases, and it becomes difficult to manufacture ERW steel pipe. In order to secure the minimum fatigue strength, the lower limit of t ZD is set to over 0.15, and the upper limit is set to 0.30 from the viewpoint of manufacturability and weight reduction.
- the molten steel that has been melted so as to have the required chemical composition is either formed into flakes or after being formed into steel ingots, it is hot-rolled into steel flakes and this flakes or steel flakes are hot-rolled. And hot-rolled steel plate.
- This hot-rolled steel sheet is made into an electric resistance welded steel pipe by an ordinary method for producing an electric resistance welded steel pipe, for example, electric resistance welding in hot or cold.
- the ratio of outer diameter to outer diameter of the steel pipe, tZD is from 0.15 to 0.30, and the electric resistance welded steel pipe construction
- the hot-rolled steel pipe of the present invention of the present invention is directly Can be manufactured.
- ERW welded steel pipes with a thickness Z outer diameter ratio tZD of less than 0.15 can be manufactured using a conventional ERW welded steel pipe making machine, but t / D exceeds 0.15. It is difficult to directly manufacture the thick electric resistance welded steel pipe of the present invention having t ZD of more than 0.15 to 0.30 in a conventional ERW welded steel pipe pipe making machine because the production capacity is exceeded. Often.
- the thickness Z outer diameter ratio is 0.1 in a conventional ERW welded steel pipe making machine.
- Produce ERW welded steel pipe of 5 or less (this is also referred to as a mother pipe), and further subject it to hot reduction with a diameter reduction ratio, and the thickness-to-diameter ratio exceeds 0.15 to 0.3.3. It is intended to produce 0 thick electric resistance welded steel pipe.
- the diameter reduction rolling can be performed using a straight tire reducer or the like.
- the steel reducer is a rolling mill equipped with a plurality of rolling stands with 3 rolls or 4 rolls around the rolling axis in series on the rolling axis, and the roll rotation speed of each rolling stand of this rolling mill. Control the tension in the axial direction of the steel pipe (rolling direction) and the compressive force in the circumferential direction by adjusting the rolling force and the rolling force, thereby reducing the diameter to increase the thickness Z outer diameter ratio.
- Rolling direction Control the tension in the axial direction of the steel pipe (rolling direction) and the compressive force in the circumferential direction by adjusting the rolling force and the rolling force, thereby reducing the diameter to increase the thickness Z outer diameter ratio.
- the wall thickness is increased, while the wall thickness is reduced due to the tension acting in the axial direction of the steel pipe.
- the final thickness is determined by the balance between the two. Since the thickness of the steel tube rolled in this way is mainly determined by the tension between the above-mentioned rolling stands, the tension between the rolling stands for obtaining the target thickness can be determined from the rolling theory etc. It is necessary to set the roll rotation speed of each rolling stand so that the tension acts.
- the ERW welded steel pipe (base pipe) is heated to 800 to 120 ° C., and the reduction of diameter in hot rolling is performed at a reduction rate of 40 to 80%.
- the thickness Z outer diameter ratio is from 0.15 to 0.30.
- the cross-sectional reduction rate is (the outer diameter of the steel pipe before diameter reduction-the outer diameter of the steel pipe after diameter reduction)
- the heating temperature of ERW welded steel pipe during reduction rolling is less than 800 ° C, the deformation resistance is large, while if it exceeds 120 ° C, the generation of heating scale occurs And the surface properties deteriorate. Therefore, the heating temperature is in the range of 800 ° C. to 1200 ° C.
- the reduction in area during reduction rolling is less than 40%, the compressive force is insufficient, and the thickness outside diameter ratio is less than 0.15. It is difficult to obtain a thick electric resistance welded steel pipe with a ratio of more than 0.15 to 0.30.
- the reduction in area exceeds 80%, surface reduction of the surface of the steel pipe due to reduction rolling will be significant and it will be difficult to secure a uniform shape. For this reason, the cross-section reduction rate in diameter reduction rolling is set to 40 to 80%.
- a straight tire reducer used for reducing diameter rolling is a rolling mill equipped with a plurality of rolling stands having three or four rolls around the rolling axis in series on the rolling axis. , Normally, the rolls of the adjacent rolling stands (for example, N and N + 1 rolling stands) are out of phase, 60 ° for 3-roll rolling stand, for 4-roll rolling stand The arrangement is 45 degrees out of phase.
- the inner surface shape of the cross section (C cross section) perpendicular to the axial direction of the thick ERW welded steel pipe manufactured by reduction rolling is hexagonal when the Stresley Dedeuser has a three-roll rolling stand. If it is equipped with a four-roll rolling stand, it will be octagonal.
- the rolling phase is one of four continuous rolling stands (for example, N, N + l, N + 2 and N + 3 rolling stands) of one straight stripper. Shifted to 30 °, 60 °, 90 °, and 2 2.5 °, 45 °, for a 4-roll rolling stand. 6 7.
- the inner surface shape of the section (C section) perpendicular to the pipe axis direction of thick-walled ERW welded steel pipe after reduction rolling has a 3-roll rolling stand respectively If it is equipped with a dodecagon, 4-roll rolling stand, it becomes a dodecagon.
- the obtained thick electric resistance welded steel pipe was heated to 90.degree. C., water cooled and quenched, and tempering was carried out at 300: x i h r and 350 ° C. x l h r. Test pieces were collected from this steel pipe and subjected to various tests to confirm the characteristics of the thick electric resistance welded steel pipe of the present invention.
- the hardness was measured at 5 points at the center of the thickness at HV 9.8 N and the average value was obtained.
- the hot workability was evaluated by the reduction rate of the cross-sectional area of the fractured part at a temperature of 800 ° C. using a uniaxial tensile test piece having a diameter of parallel part of 6 mm.
- the steels of No. ! to 11 having the chemical composition of the present invention shown in Table 2 have excellent properties in hardness, hot workability and fatigue strength.
- the steel of No. 12 has a large critical cooling rate V c so that it can not be sufficiently fired, and the amount of C is as low as 0.22%, in an example where sufficient hardness can not be obtained. is there .
- the steel of No. 13 is an example in which the amount of N was too high, so the hot-rollability was less, ⁇ , and the fatigue characteristics were slightly lower.
- steel tube N o. a to e is found to have sufficient fatigue strength to rupture repetition number exceeds 5 0 X 1 0 3 times.
- steel tubes with N o ⁇ f are examples where t ZD is too small to obtain sufficient fatigue strength.
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Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/990,477 US20090250146A1 (en) | 2005-08-22 | 2006-08-17 | High Strength Thick-Gauge Electric-Resistance Welded Steel Pipe Excellent in Hardenability, Hot Workability and Fatigue Strength and Method of Production of the Same |
ES06796702T ES2745078T3 (es) | 2005-08-22 | 2006-08-17 | Tubería de acero soldada de alta resistencia de calibre grueso y resistencia eléctrica excelente en la capacidad de endurecimiento, la trabajabilidad en caliente y la resistencia a la fatiga y método de producción de la misma |
EP06796702.6A EP1923477B1 (en) | 2005-08-22 | 2006-08-17 | Highly strong, thick electric resistance-welded steel pipe excellent in quenching property, hot forming processability and fatigue strength, and method for manufacture thereof |
JP2007532156A JP5005543B2 (ja) | 2005-08-22 | 2006-08-17 | 焼入れ性、熱間加工性および疲労強度に優れた高強度厚肉電縫溶接鋼管およびその製造方法 |
Applications Claiming Priority (4)
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JP2005-239953 | 2005-08-22 | ||
JP2005-240130 | 2005-08-22 | ||
JP2005240130 | 2005-08-22 | ||
JP2005239953 | 2005-08-22 |
Publications (1)
Publication Number | Publication Date |
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WO2007023873A1 true WO2007023873A1 (ja) | 2007-03-01 |
Family
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/JP2006/316539 WO2007023873A1 (ja) | 2005-08-22 | 2006-08-17 | 焼入れ性、熱間加工性および疲労強度に優れた高強度厚肉電縫溶接鋼管およびその製造方法 |
Country Status (6)
Country | Link |
---|---|
US (1) | US20090250146A1 (ja) |
EP (1) | EP1923477B1 (ja) |
JP (1) | JP5005543B2 (ja) |
KR (1) | KR20080034958A (ja) |
ES (1) | ES2745078T3 (ja) |
WO (1) | WO2007023873A1 (ja) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2013175821A1 (ja) | 2012-05-25 | 2013-11-28 | 新日鐵住金株式会社 | 中空スタビライザ並びに中空スタビライザ用鋼管及びその製造方法 |
JP2015168845A (ja) * | 2014-03-06 | 2015-09-28 | 新日鐵住金株式会社 | 疲労特性に優れた中空材とその製造方法 |
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JP5303842B2 (ja) * | 2007-02-26 | 2013-10-02 | Jfeスチール株式会社 | 偏平性に優れた熱処理用電縫溶接鋼管の製造方法 |
US20110253265A1 (en) * | 2010-04-15 | 2011-10-20 | Nisshin Steel Co., Ltd. | Quenched and tempered steel pipe with high fatigue life, and its manufacturing method |
KR101271781B1 (ko) | 2010-12-23 | 2013-06-07 | 주식회사 포스코 | 내마모성, 내식성 및 저온인성이 우수한 오일샌드 슬러리 파이프용 강판 및 그 제조방법 |
JP5892267B2 (ja) * | 2013-01-31 | 2016-03-23 | Jfeスチール株式会社 | 電縫鋼管 |
CN103938098A (zh) * | 2014-04-21 | 2014-07-23 | 河北钢铁股份有限公司唐山分公司 | 一种超高强度钢管及其连续生产方法 |
JP6465249B2 (ja) | 2016-10-24 | 2019-02-06 | Jfeスチール株式会社 | 高強度薄肉中空スタビライザー用電縫鋼管およびその製造方法 |
KR102526496B1 (ko) * | 2018-12-19 | 2023-04-26 | 제이에프이 스틸 가부시키가이샤 | 전봉 강관 |
KR20200136722A (ko) * | 2019-05-28 | 2020-12-08 | 현대자동차주식회사 | 차체 멤버 성형방법 |
CN112359278B (zh) * | 2020-10-19 | 2021-08-24 | 中天钢铁集团有限公司 | 一种工程机械齿轮用钢的制备法及其锻件的制备方法 |
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JP4485148B2 (ja) * | 2003-05-28 | 2010-06-16 | Jfeスチール株式会社 | 冷間鍛造加工性と転造加工性に優れた高炭素鋼管およびその製造方法 |
JP4379085B2 (ja) * | 2003-11-07 | 2009-12-09 | Jfeスチール株式会社 | 高強度高靭性厚鋼板の製造方法 |
-
2006
- 2006-08-17 KR KR1020087004225A patent/KR20080034958A/ko not_active Application Discontinuation
- 2006-08-17 JP JP2007532156A patent/JP5005543B2/ja active Active
- 2006-08-17 ES ES06796702T patent/ES2745078T3/es active Active
- 2006-08-17 US US11/990,477 patent/US20090250146A1/en not_active Abandoned
- 2006-08-17 EP EP06796702.6A patent/EP1923477B1/en not_active Not-in-force
- 2006-08-17 WO PCT/JP2006/316539 patent/WO2007023873A1/ja active Application Filing
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JPS58123858A (ja) * | 1982-01-16 | 1983-07-23 | Nisshin Steel Co Ltd | 中空状スタビライザ−用電縫鋼管用鋼 |
JPH05302119A (ja) * | 1992-03-27 | 1993-11-16 | Sumitomo Metal Ind Ltd | 高強度自動車部品の製造方法 |
JP2004011009A (ja) * | 2002-06-11 | 2004-01-15 | Nippon Steel Corp | 中空スタビライザー用電縫溶接鋼管 |
JP2005076047A (ja) * | 2003-08-28 | 2005-03-24 | Jfe Steel Kk | 耐疲労特性に優れた中空スタビライザの製造方法 |
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WO2013175821A1 (ja) | 2012-05-25 | 2013-11-28 | 新日鐵住金株式会社 | 中空スタビライザ並びに中空スタビライザ用鋼管及びその製造方法 |
JP2015168845A (ja) * | 2014-03-06 | 2015-09-28 | 新日鐵住金株式会社 | 疲労特性に優れた中空材とその製造方法 |
Also Published As
Publication number | Publication date |
---|---|
KR20080034958A (ko) | 2008-04-22 |
ES2745078T3 (es) | 2020-02-27 |
JP5005543B2 (ja) | 2012-08-22 |
JPWO2007023873A1 (ja) | 2009-03-26 |
EP1923477B1 (en) | 2019-07-24 |
EP1923477A4 (en) | 2015-04-01 |
EP1923477A1 (en) | 2008-05-21 |
US20090250146A1 (en) | 2009-10-08 |
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