CN1037700C - High strength hot rolled steel plates and sheets excellent in uniform elongation after cold working and process for producing the same - Google Patents
High strength hot rolled steel plates and sheets excellent in uniform elongation after cold working and process for producing the same Download PDFInfo
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Abstract
The present invention relates to a hot rolled steel plate having the tensile strength of 34 to 62 kgf/mm<2> after cold processing and good elongation and a productive technology thereof, and productive rate is not reduced. The hot rolled steel plate contains 0.04 to 0.25 % of C, 0.0050 to 0.0150 % of N, 0.003 to 0.050 % of Ti, 0.0008 to 0.015 % of TiN which has average sizes of particles of 1 mu m to 3 mu m, and is spread in basal bodies of the hot rolled steel plate, and 0.10% to 0.45 % of carbon equivalent. The technology comprises the steps that the steel plate billets are heated to the temperature of 1000 to 1300 DEG C, rolled, fine rolled at least at the transition point Ar3, cooled by air at least 500 DEG C, and coiled and cooled by the air at least 500 DEG C to obtain steel tissues having 5 to 20 % of perlite phases.
Description
The ordinary construction that the present invention relates to after cold machining process, to have fabulous uniform elongation and high tensile strength with and welded construction with hot-rolled steel sheet and thin plate, and relate to the technology of this kind of production product.
In recent years along with the quality improvement of structural hot rolled steel plate and thin plate and the major progress of production technology, demand to product made from steel with fabulous plastic deformation ability increases day by day, particularly all the more so from the viewpoint of seismic design in construction industry and field of civil engineering, and require steel plate to have high strength, low yielding ratio and high uniform elongation.
For adapting to this requirement, for example (disclose the technology that a kind of production is used for the low yielding ratio electric-welded pipe of oil well among the open No.57-16118 of Japanese unexamined patent at Kokai, wherein the carbon content of pipe is increased to 0.26% to 0.48%, and Kokai (Japanese unexamined patent is open) No.57-16119 to disclose a kind of production carbon content that is used for be 0.10% to 0.20% high tensile, the electric-welded pipe technology of low yielding ratio.In these two kinds of technologies, do not need the manufacturing of heat treated electric-welded pipe to finish by hot-rolled steel sheet or the thin plate of producing a kind of low yielding ratio, and when dependent variable is restricted the above-mentioned steel product of cold working, it is big that work hardening amount thus can not become.In addition, a kind of technology that is used for good round steel pipe of production anti-seismic performance or square steel pipe has been proposed among Kokai (Japanese unexamined patent the is open) No.4-176818, this method is by no strain ferrite-perlite double structure is carried out hot-work, its rate of cooling of control and heat-treat and realize after hot-work.But all above-mentioned technologies all greatly reduce productivity, and last technology has also reduced weldability significantly.Therefore, these technologies can not satisfy the requirement of industrial circle at present.
Except above-mentioned open file, Kokai (Japanese unexamined patent is open) No.4-48048 and KoKai (Japanese unexamined patent is open) No.4-99248 disclose in order to be mingled with the technology of improving welding heat influence area toughness by disperse oxide in steel matrix.The particle size of the oxide inclusion in last patent disclosure text is 0.5 μ m or littler and (Ti, Nb) (Q, N) composite junction crystalline phase arranged.The particle size of oxide inclusion is 1 μ m or littler and have Ti (O, N) a composite junction crystalline phase in the one patent disclosure text of back.The technology of these patent disclosures all has in essence different with the present invention the dispersion phase aspect purpose.
In general, the higher steel capital of intensity demonstrates higher yield ratio and lower ductility, and its uniform elongation is reduced.Especially when steel being cold worked into round steel pipe, square steel pipe, shaped steel, sheet pile etc., because the influence of the work hardening that the processing strain causes, its uniform elongation will significantly reduce.
The present invention has successfully solved the problems referred to above, even and purpose of the present invention just provide it being cold worked into pipe, square tube, shaped steel, sheet pile and wait until that productivity still has superior uniform elongation after not reducing a kind of like this O-level and has high tensile (333.2N/mm at least
2) hot-rolled steel sheet and thin plate.
In order to achieve the above object, the present inventor carefully studied the Chemical Composition of steel and crystalline structure and the mechanical property that obtains thus between relation, relation between the mechanical property of the mechanical property of the cold worked steel of process and the steel of rolling state, or the like.Thus, the present inventor has obtained following understanding: with regard to ordinary construction with and steel for welded structures, the particularly maximum tensile strength that has that is used for construction industry and field of civil engineering be 333.2 to 607.6N/mm
2Hot-rolled steel sheet or thin plate, the tensile strength of hot-rolled state product (its uniform elongation reduces with the raising of tensile strength) is roughly consistent with relation and their relations after cold working between the uniform elongation, and the relation under two kinds of situations can be come approximate representation with same curve; Though hot-rolled state steel and cold work steel both demonstrate the increase along with N in the steel, intensity improves and the characteristic of uniform elongation reduction, but by further increasing Ti, even when steel has high intensity, also can recover uniform elongation, and can obtain high uniform elongation, above-mentioned relation no longer keeps at this moment.
This understanding can further specify as follows with reference to figure 2.
Fig. 2 is a graphic representation, and it is represented by hot-rolled state product made from steel and the resulting TS of cold work steel product (square steel pipe) (tensile strength, N/mm
2) and Elu (uniform elongation, relation %), used steel is S-1 (comparative example), S-2 (comparative example), T-1 (giving an example) and T-2 (giving an example) listed in the table 1, and S-1, T-1 and T-2 press the production technique B shown in the table 2 production, and S-2 produces by production technique C.Ti among the S-1 and the content of N all are lower than lower limit of the present invention.Though the N content among the S-2 within the scope of the present invention, the content of Ti is lower and be lower than lower limit of the present invention.In production technique C, final rolling temperature is lower and be lower than transition point Ar
3
In Fig. 2, with regard to the relation between TS and the Elu, hot-rolled state steel plate or the thin plate of S-1 demonstrate high TS and Elu.But along with the increase of TS, the square steel pipe of S-1 demonstrates the rapid reduction of Elu.
Under the situation of S-2, above-mentioned relation is more obvious.When TS was higher, hot-rolled state steel plate or thin plate demonstrated 10% or littler Elu, though they can demonstrate higher Elu when TS is low.The square tube made from cold working demonstrates 10% or littler Elu as a rule, and increases with TS Elu is further reduced.
In other words, under the situation of S-1 and S-2, the cold work steel product demonstrates the trend that Elu sharply reduces with the increase of TS.
In contrast, under the situation of T-1 and T-2, even hot-rolled state steel plate or thin plate demonstrate the characteristic that Elu also reduces hardly when TS increases.The cold production that obtains thus demonstrates its Elu the seldom reduction of degree, and the influence that increased by TS.
In other words, even contain the N of an amount of interpolation and the steel of the present invention of Ti demonstrates after cold working, along with the raising of tensile strength, the characteristic that uniform elongation also reduces hardly.A kind of TS of having particularly of the present invention is at least 460.6N/mm
2Steel can demonstrate effect of the present invention.As mentioned above, use and steel for welded structures as ordinary construction, steel of the present invention has remarkable performance.
Based on the above-mentioned fact, the present invention has reached purpose of the present invention, and theme of the present invention is to have 333.2 to 607.6/mm after cold shaping
2Tensile strength and the high tensile hot rolled steel sheet and the thin plate of superior uniform elongation, above-mentioned steel plate and thin plate contain 0.040% to 0.25% C, 0.0050% to 0.0150% N and 0.003% to 0.050% Ti, contain 0.0008% to 0.015% simultaneously, mean sizes is by 1 μ m to 30 μ m and the TiN of disperse in steel matrix, and contain 0.10% to 0.45% carbon equivalent (WES), when preparation steel plate and thin plate, the slab that will contain mentioned component is heated to 1000 to 1300 ℃ hot-rolled temperature, rolled slab is being at least transition point Ar
3Temperature finish rolling, then the rolled products air cooling is formed its total amount to be converted to the area percentage be 5% to 20% perlite phase to being at least 500 ℃ temperature or thereby rolled products being batched and will batch in the tissue of product air cooling at steel in the temperature that is at least 500 ℃, theme of the present invention also is to produce the production technique of the said products.
Fig. 1 (A) represents a photomicrography picture (amplifying 400 times), and the metallographic structure of the planar section of the square tube of producing with steel of the present invention (T-2 in the table 4 (middle portion) steel contains 15.2% perlite phase) is described.
Fig. 1 (B) represents a photomicrography picture (amplifying 400 times), illustrates with relatively using the steel (metallographic structure of the planar section of the square tube that the S-2 steel in the table 4 (thickness (t)=3.2mm) contains 4% perlite phase) is produced.
Fig. 2 represents various hot-rolled steel sheets and the tensile strength of square tube and the relation between the uniform elongation in the table 4.
Describe below the present invention in detail.
In the present invention, at first with traditional production stage make a kind of by 0.040% to-0.25% C, 0.0050% to 0.0150% N, 0.003% to 0.050% Ti form, and the scope of its carbon equivalent (Ceq) is 0.10% to 0.45%, and all the other be Fe and not The alloy steel sheet billet of evitable impurity, it is by the melting furnace such as converter or electric furnace That the molten steel of producing is made through continuous casting or molten steel made steel ingot and with the steel ingot warp Be rolled at the beginning of crossing.
In the present invention, the composition in the steel is stipulated as mentioned above its reason explanation As follows.
C be the intensity that determines steel with structure of steel in the important composition of pearlite total amount mutually. Be at least 333.2N/mm when having hot strength2Hot rolled steel plate or thin plate in the group of steel Contain the area occupied rate in knitting and be less than 5% pearlite phase time, after its cold forming evenly Percentage elongation will significantly reduce. This is because pearlite can guarantee the intensity of steel, prevents that dislocation is close Degree increases, and can keep the plastic deformation ability.
In addition, be 20% or more pearlite phase when hot rolled steel plate contains the area occupied rate The time, the hardness of steel is increased, the plastic deformation ability reduces. In order to obtain thisly having it Total amount accounts for the structure of steel that the area percentage is 5% to 20% pearlite phase, just needs steel Contain at least 0.04% C. But, when the content of C surpasses 0.25%, can weaken steel Welding performance, so the upper limit of C content is defined as 0.25%.
The N that is added in the steel is dissolved in the ferritic matrix, and it can improve the intensity of steel And reduction plastic deformation ability. But, when N adds fashionablely with Ti, just form TiN. This formation not only makes the N that is dissolved in the steel reduce, and the plastic deformation ability is changed Kind, and its dispersion is strengthened steel. Therefore N is a kind of important element, It gives steel with high intensity and big uniform elongation.
In order to give steel with this performance, just must make to have the average of 1 μ m to 30 μ m The TiN disperse of particle size in matrix, its total amount convert by weight be 0.0008% to 0.015%. In other words, when the average particle size particle size of TiN during less than 1 μ m, disperse increases Pretend with just very ineffective.
Certainly, when the average particle size particle size of TiN surpasses 30 μ m, in the cold working process In between thick TiN particle and matrix, can produce buffer action. With plastic deformation Increase consistently, micro-crack can occur, and the plastic deformation ability of steel is descended.
In order to obtain above-mentioned TiN, the content of Ti is preferably in 0.003% to 0.050% In the scope.
In addition, although the necessary amounts of N is at least 0.0050%, preferably be at least 0. 0080%, but when the content of N surpassed 0.0150%, humidification was excessive, and makes Uniform elongation reduces. Therefore the upper limit of N content is defined as 0.0150%. In addition, for In steel, effectively form above-mentioned TiN, be preferably in adding Ti and in steel, add before Al makes it deoxidation.
The reason of in steel of the present invention, adding Ti as mentioned above, and its content is preferably 0.01% to 0.03%.
Carbon equivalent (Ceq) obtains (according to WES) by following formula:
Ceq＝C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14。
Determining of the total amount of Ceq is relevant with intensity and weldability.When total amount is less than 0.10%, can not guarantee enough intensity.When total amount surpassed 0.45%, though can obtain high intensity, weldability was weakened.Therefore Ceq. is limited in 0.10% in 0.45% scope.
Steel can contain to be useful on and improves intensity and flexible effective ingredient, chooses a kind of element the component that can form from the V by 0.01% to 0.7% Si, 0.1% to 2.0% Mn, 0.05% to 1.0% Ni, 0.05% to 1.0% Cr, 0.02% to 0.5% Mo and 0.005% to 0.2% at least.
In addition, P that is contained in the plate slab of the present invention and S are the detrimental impurity that reduces the toughness of steel and weldability etc.Therefore, the content of the content of P and S is limited in 0.025% or still less respectively, and the content of P+S is limited in 0.04% or still less.
In addition, steel of the present invention can contain a kind of be used to improve intensity and flexible effective ingredient, can choose a kind of at least from the component of being made up of the REM of 0.05% to 1.0% Cu, 0.005% to 0.05% Nb, 0.001% to 0.1% Al, 0.0005% to 0.0020% B, 0.0005% to 0.0070% Ca and 0.001% to 0.050% (comprising the rare earth metal the lanthanon of Y).
Its composition is adjusted at alloy steel sheet billet in the above-mentioned scope is heated to and is used for 1000 to 1300 ℃ of hot rolled and is rolled, the temperature at steel is at least transition point Ar then
3Shi Jinhang finish rolling.Resulting steel air cooling to the temperature that is at least 500 ℃, obtaining steel plate, or is batched resulting steel and air cooling being at least under 500 ℃ the coiling temperature, to obtain hot rolled band.
The lower limit of the Heating temperature that hot rolling is used is defined as 1000 ℃, and improve and the reduction of plastic deformation ability with the intensity that prevents to be caused by following situation: according to the thickness of steel, the final rolling temperature of steel can be lower than transition point Ar
3Its result will force ferrite wherein to be subject to processing, so the dislocation desity in the matrix increases.When the board briquette of steel surpasses 1300 ℃, the productivity of product will significantly descend owing to the oxidation of product.Therefore, its upper temperature limit is defined as 1300 ℃.Final rolling temperature is limited to is at least transition point Ar
3, its reason as mentioned above.In addition, for fear of the unnecessary raising of steel plate of the present invention and thin plate intensity, the air cooling starting temperature after rolling and coiling temperature be limited to be at least 500 ℃.
In steel plate produced according to the invention, will to have average particle size particle size be the good disperse of TiN of 1 μ m to 30 μ m and be deposited in the matrix, and its ratio is 0.0008% to 0.015%.Consequently, steel demonstrates a kind of close grain ferrite one pearlitic structure (part contains bainite structure), wherein contain just like shown in Fig. 1 (A), the conversion of its content is 5% to 20% perlite phase for the area percentage.Because steel plate of the present invention and thin plate have the tissue of this steel, they have superior uniform elongation after cold working, and have 333.2 to 607.6N/mm
2High intensity.
The following describes embodiments of the invention.
Having the plate slab that contains TiN of Chemical Composition shown in the table 1 and relatively all being rolled into thickness with steel is 3.0 to 22.2mm steel plate and thin plate, and the mechanical property of finished product steel plate is studied.Its production technique is illustrated in the table 2.Hot-rolled state or the performance that is machined to 10% strained product made from steel all are illustrated in the table 3.
The steel of table 4 and table 5 expression rolling state and with the performance study result at each position on its square tube of making.Fig. 1 (A) has represented the photomicrography (amplifying 400 times) with the metallographic structure of the planar section (middle part) of the square tube of steel T-2 manufacturing of the present invention, and Fig. 1 (B) represents the photomicrography with the metallographic structure of the same area of the square tube of relatively using steel S-2 to make.In the steel of the present invention in Fig. 1 (A), the content by area percentage conversion of perlite phase is approximately 15.2%, and relatively using in the steel in Fig. 1 (B), only contains the perlite phase that is about 4% minute quantity.Fig. 2 represents steel of the present invention and is used for the tensile strength of steel of comparison and the relation between the uniform elongation that they have mainly utilized the result in the table 4.
According to these results, though its intensity is higher when relatively comparing with steel with each, steel of the present invention (C-4, C-6, T-1, T-2, T-3 T-4) has kept high uniform elongation, particularly after cold working.These results can well be understood from Fig. 2, the figure shows steel of the present invention and relatively use hot-rolled steel sheet and the uniform elongation of thin plate and the relation between the intensity of steel, and in the actual production line by the uniform elongation of the resulting square tube of the above-mentioned steel plate of cold shaping and the relation between the intensity.
As mentioned above, in the present invention, even can not reduce a kind of like this degree of ordinary student productive rate and still have 333.2 catching a cold to be formed into to 607.6/mm
2Tensile strength and the high tensile hot rolled steel sheet and the thin plate of extremely superior uniform elongation can have the bigger TiN particle that disperse strengthens ability to make it to form by the composition that limits in the steel, and produce mutually by forming effective perlite therein.As ordinary construction with and steel for welded structures system product and as the material of pipe and square tube, shaped steel, sheet pile etc., high tensile hot rolled steel sheet and thin plate are exceedingly useful.
Table 1
( ％ ) C Si Mn P S Cu Ni Cr Mo V Al Ti N CeqCS C-1 0.16 0.05 0.45 0.009 0.007--0.11 0.02-0.025-0.0027 0.26CS C-2 0.16 0.05 0.45 0.009 0.017--0.11 0.03-0.030-0.0034 0.26CS C-3 0.15 0.05 0.44 0.010 0.016--0.07 0.02-0.026-0.0071 0.24IS C-4 0.15 0.05 0.45 0.010 0.017--0.07 0.02-0.027 0.015 0.0071 0.24CS C-5 0.08 0.07 0.31 0.012 0.017 0.20 0.59 0.06 0.10 0.01 0.027 0.001 0.0058 0.19IS C-6 0.08 0.08 0.28 0.010 0.016 0.21 0.60 0.05 0.11 0.01 0.012 0.012 0.0092 0.18CS C-7 0.08 0.07 0.30 0.010 0.017 0.20 0.57 0.05 0.09 0.01 0.023 0.011 0.0167 0.18CS S-1 0.14 0.01 0.46 0.013 0.003-----0.032-0.0015 0.22CS S-2 0.12 0.09 0.29 0.016 0.022--0.05-0.005 0.038 0.001 0.0074 0.18CS S-3 0.15 0.39 1.40 0.012 0.013--0.05--0.033-0.0040 0.41CS S-4 0.06 0.04 0.33 0.009 0.010--0.03--0.034-0.0110 0.12IS T-1 0.15 0.09 0.27 0.014 0.019--0.05-0.006 0.039 0.016 0.0111 0.21IS T-2 0.17 0.09 0.28 0.011 0.015--0.06-0.007 0.030 0.021 0.0110 0.23IS T-3 0.15 0.38 1.39 0.013 0.013--0.06--0.031 0.022 0.0100 0.41IS T-4 0.05 0.05 0.39 0.010 0.010--0.06--0.031 0.027 0.0090 0.13
Annotate: CS=relatively uses steel; IS=steel of the present invention
Ceq.(WES)＝C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14
Table 2
(temperature ℃) production technique plate slab adds final rolling temperature steel sheet volume air cooling to be risen
Hot temperature is got temperature beginning temperature IB A 1,200 950 680-IB B 1,230 980 630-CB C 1,230 790 490-IB D 1,180 900-700
Annotate: (1) TS=steel of the present invention; CS=relatively uses steel
(2) temperature is lower than transition point Ar
3
Table 3
Amount to into area steel grade technology thickness YSl
*TS
*El
*ELu
*The flat percentile pearly-lustre of the TiN of TiN is annotated
(mm) (N/mm
2) (N/mm
2) (%) the equal particle size body phase of (%) weight (%)
(μ m) be CS C-1 A 5.7 305.0 421.7 42.0 22.2 0-16.9 hot-rolled states (%)
5.4 475.6 475.6 28.0 7.2---10% strain CS C-2 A, 5.7 286.3 428.5 43.5 21.6 0-17.1 hot-rolled states
5.4 483.4 488.4 26.0 5.2---10% strain CS C-3 A, 5.7 306.0 439.3 40.5 21.0 0-16.6 hot-rolled states
5.4 510.9 517.8 23.0 2.0---10% strain IS C-4 A, 5.7 319.7 451.1 44.0 20.0 0.0051 3.82 16.8 hot-rolled states
5.4 515.5 522.7 31.0 9.0---10% strain CS C-5 A, 8.5 240.3 339.3 47.0 22.8 0-10.7 hot-rolled states
6.9 415.8 424.6 21.0 1.2---10% strain IS C-6 A, 8.7 245.2 347.1 45.5 22.0 0.0041 3.44 10.9 hot-rolled states
6.9 426.6 454.0 26.0 6.4---10% strain CS C-7 C, 8.5 407.0 478.5 34.0 17.5 0.0038 3.20 4.5 hot-rolled states
6.9 559.0 566.8 20.1 1.4---10% strains
Annotate: IS=steel of the present invention; CS=relatively uses steel
*The YSI=yield strength; The TS=tensile strength; The El=unit elongation;
The Elu=uniform elongation
Tensile test specimen is according to the test specimen specification preparation of JIS Z22015
Table 4 steel grade technology thickness YSl
*TS
*El
*ELu
*The flat area of amounting to into of TiN TiN is annotated
(mm) (N/mm
2) (N/mm
2) (%) the percentile pearly-lustre of the equal particle size of the weight of (%)
(%) body phase (%)
(μ m) be CS S-1 B 3.2 306.9 444.2 39.0 19.2 0-9.3 hot-rolled states (%)
3.3 441.3 468.7 33.2 11.6 - - - sq.tube?F
B 3.2 311.8 450.1 39.2 18.8--9.5 hot-rolled state
3.2 376.6 454.0 36.0 17.3 - - - sq.tube?F
B 6.0 312.8 438.3 40.6 19.7--9.7 hot-rolled state
6.1 396.2 444.2 37.0 14.5---sq.tube FCS S-2 C 3.2 333.4 437.4 34.8 16.3 0-4.4 hot-rolled states
3.2 471.7 505.0 20.4 4.0 - - - sq.tube?F
C 6.0 390.3 471.7 29.0 9.8--4.2 hot-rolled state
6.0 454.0 498.2 23.6 4.9 - - - sq.tube?F
C 5.7 310.9 433.4 38.0 18.7--4.3 hot-rolled state
5.8 423.6 477.6 29.0 5.5 - - - sq.tube?F
Table 4 (continuing) steel grade technology thickness YSl
*TS
*El
*ELu
*The flat area of amounting to into of TiN TiN is annotated
(mm) (N/mm
2) (N/mm
2) (%) the percentile pearly-lustre of the equal particle size of the weight of (%)
(%) (μ m) body phase (%) IS T-1 B 3.0 314.8 444.2 39.5 19.5 0.0055 6.50 14.7 hot-rolled states (top)
3.1 330.5 458.9 36.0 16.6---sq.tube F (top)
B 3.0 297.1 455.0 40.0 20.0--14.9 hot-rolled state (middle part)
3.1 373.6 461.9 36.5 17.0---sq.tube F (middle part)
B 3.1 337.3 502.1 34.0 17.5--14.1 hot-rolled state (bottom)
3.1 419.7 508.0 31.0 13.6---sq.tube F (bottom)
B 3.1 640.3 705.1 28.0 6.2---sq.tube C (bottom)
3.1 597.2 642.3 32.0 7.9---sq.tube C (bottom) IS T-2 B 3.0 340.7 479.5 40.0 19.8 0.0072 6.21 15.5 hot-rolled states (top)
3.1 327.5 472.7 35.0 16.0---sq.tube F (top)
B 3.0 303.0 463.8 37.0 19.4--15.3 as rolled (middle part)
3.1 380.5 471.7 35.0 16.2---sq.tube F (middle part)
B 3.1 326.5 518.7 35.0 17.6--16.0 hot-rolled state (bottom)
3.1 386.4 480.5 35.0 16.0---sq.tube F (bottom)
B 3.1 596.2 660.9 33.0 12.0---sq.tube C (bottom)
3.1 581.5 652.1 35.0 12.3---sq.tube C (bottom)
Annotate: (1) IS=steel of the present invention; CS=relatively uses steel
(2)
*The YSl=yield strength; The TS=tensile strength; The El=unit elongation; The Elu=uniform elongation
(3) planar section of Sq.tube F=square tube; The bight of Sq.tube C=square tube
(4) tensile test specimen has only bight test specimen root according to the test specimen specification preparation of JIS Z 2,201 5
Test specimen specification preparation according to JIS Z2201 12B.
(5) size of every class steel pipe is 75mm * 75mm
Table 5 steel grade technology thickness 0.2%PS
*TS
*El
*ELu
*The area of on average amounting to into of TiN TiN is annotated
(mm) (N/mm
2) (N/mm
2) (%) the percentile pearly-lustre of weight particles size of (%)
(%) (μ m) body phase (%) CS S-3 D 22.2 353.0 538.4 28.4 20.0 0-5.5 hot-rolled states
22.0 373.6 549.1 24.7 16.6 - - - sq.tube?F
22.1 559.9 649.2 15.0 5.2---sq.tube CCS S-4 C 9.0 294.2 421.7 40.0 17.5 0-3.8 hot-rolled states
9.1 374.6 449.1 35.0 9.5 - - - sq.tube?F
9.0 479.5 530.5 26.0 4.2---sq.tube CIS T-3 D 22.1 355.0 540.3 29.0 21.3 0.0076 5.77 5.5 hot-rolled states
22.0 377.5 551.1 27.1 18.7---sq.tube CIS T-4 B 8.9 287.3 441.3 38.5 20.5 0.0093 4.06 6.2 hot-rolled states
9.0 335.4 444.2 38.0 19.6 - - - sq.tube?F
9.0 493.3 554.1 36.0 16.0---sq.tube C notes: (1) Prodn=product
(2) IS=steel of the present invention; CS=relatively uses steel
(3)
*The yield-point of 0.2%PS=0.2%, the TS=tensile strength; El=extends 1 rate;
The Elu=uniform elongation
(4) planar section of gq.tube F=square tube; The bight of Sq.tube C=square tube
(5) S-3, T-3: every kind of square tube has the size of 350mm * 350mm, stretches
Test specimen is according to the test specimen specification preparation of JIS Z2201 1B.
(6) S-4, T-4: every kind of square tube has the size of 250mm * 250mm, stretches
Test specimen is according to the test specimen specification preparation of JIS Z2201 5.
Claims (5)
1. high tensile hot rolled steel sheet and thin plate that superior uniform elongation is arranged after cold working, contain weight percent and be 0.04% to 0.25% C, 0.0050% to 0.0150% N and 0.003% to 0.050% Ti, described steel plate and thin plate have 0.10% to 0.45% the carbon equivalent of determining by following formula (Ceq.), it also contain have average particle size particle size be 1 μ m and 30 μ m and disperse therein, weight percent is 0.0008% to 0.015% TiN:
Ceq.＝C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/14。
2. high tensile hot rolled steel sheet according to claim 1 and thin plate, it is characterized by, steel plate and thin plate also contain at least a composition of choosing from following combination, this combination is that 0.01% to 0.7% Si, weight percent are that 0.1% to 2.0% Mn, weight percent are that 0.05% to 1.0% Ni, weight percent are that 0.05% to 1.0% Cr, weight percent are that 0.02% to 0.5% Mo and weight percent are that 0.005% to 0.2% V forms by weight percent.
3. according to claim 1 or 3 described high tensile hot rolled steel sheet and thin plates, it is characterized by, also further contain at least a composition of from following combination, choosing in steel plate and the thin plate, this combination is by by weight percentage, is respectively 0.05% to 1.0% Cu, 0.005% to 0.05% Nb, 0.001% to 0.1% Al, 0.0005% to 0.0020% B, 0.0005% to 0.0070% Ca and 0.001% to 0.050% REM and forms.
4. high tensile hot rolled steel sheet according to claim 1 and thin plate is characterized in that, will control to satisfy following condition the content of P and S:
P≤0.025%, weight %,
S≤0.025%, weight %, and
P+S≤0.04%, weight %.
5. technology that is used for after cold working, producing the high tensile hot rolled steel sheet and the thin plate of excellent in uniform elongation, it comprises that with containing weight % be that 0.04% to 0.25% C, weight % are that 0.0050% to 0.0150% N and weight % are that 0.003% to 0.050% Ti and the plate slab with carbon equivalent (Ceq.) 0.10% to 0.45% are heated to 1000 to 1300 ℃, begin rolling through heating hot plate slab and be at least transition point Ar
3Temperature under carry out finish rolling, begin air cooling from the temperature that is at least 500 ℃ then.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN94102515A CN1037700C (en) | 1994-02-25 | 1994-02-25 | High strength hot rolled steel plates and sheets excellent in uniform elongation after cold working and process for producing the same |
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| Application Number | Priority Date | Filing Date | Title |
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| CN94102515A CN1037700C (en) | 1994-02-25 | 1994-02-25 | High strength hot rolled steel plates and sheets excellent in uniform elongation after cold working and process for producing the same |
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| CN1107521A CN1107521A (en) | 1995-08-30 |
| CN1037700C true CN1037700C (en) | 1998-03-11 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100392131C (en) * | 2003-09-24 | 2008-06-04 | 新日本制铁株式会社 | Hot rolled steel sheet for working |
| CN100400679C (en) * | 2004-02-19 | 2008-07-09 | 住友金属工业株式会社 | High strength seamless steel pipe and its manufacturing method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100434560C (en) * | 2006-12-26 | 2008-11-19 | 宋立华 | Following steering axle for air suspension of automobile |
| CN102021493A (en) * | 2009-09-21 | 2011-04-20 | 宝山钢铁股份有限公司 | Hot rolled steel plate for precision stamping and manufacturing method thereof |
| CN105734422B (en) * | 2016-03-24 | 2018-06-05 | 攀钢集团攀枝花钢铁研究院有限公司 | The production method of the effective hot rolled strip of cold rolling thin-walled |
| CN107304458B (en) * | 2016-04-21 | 2019-06-25 | 北大方正集团有限公司 | A kind of hot-rolled steel and its manufacturing method, mooring cable and its manufacturing method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02267222A (en) * | 1989-04-10 | 1990-11-01 | Nippon Steel Corp | Production of thick hot-rolled dual phase-type high tensile steel plate having low yield ratio |
-
1994
- 1994-02-25 CN CN94102515A patent/CN1037700C/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02267222A (en) * | 1989-04-10 | 1990-11-01 | Nippon Steel Corp | Production of thick hot-rolled dual phase-type high tensile steel plate having low yield ratio |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100392131C (en) * | 2003-09-24 | 2008-06-04 | 新日本制铁株式会社 | Hot rolled steel sheet for working |
| CN100400679C (en) * | 2004-02-19 | 2008-07-09 | 住友金属工业株式会社 | High strength seamless steel pipe and its manufacturing method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1107521A (en) | 1995-08-30 |
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