CN103233161B - A kind of low yield strength ratio high-strength hot-rolled Q & P steel and manufacture method thereof - Google Patents
A kind of low yield strength ratio high-strength hot-rolled Q & P steel and manufacture method thereof Download PDFInfo
- Publication number
- CN103233161B CN103233161B CN201310121587.7A CN201310121587A CN103233161B CN 103233161 B CN103233161 B CN 103233161B CN 201310121587 A CN201310121587 A CN 201310121587A CN 103233161 B CN103233161 B CN 103233161B
- Authority
- CN
- China
- Prior art keywords
- steel
- rolled
- hot
- yield strength
- strength
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Abstract
A kind of low yield strength ratio high-strength hot-rolled Q & amp; P steel and manufacture method thereof, its chemical composition content is: C:0.20% ~ 0.40%, Si:1.0% ~ 2.0%, Mn:1.5% ~ 3.0%, P≤0.015%, S≤0.005%, Al:0.02 ~ 0.08%, N≤0.006%, Ti:0.005% ~ 0.015%, all the other are Fe and inevitable impurity.The present invention is by low cost Composition Design, on the component base of plain C-Mn steel, the precipitation of cementite is suppressed by carrying high Si content, micro-Ti process fining austenite grains, adopt hot continuous rolling process simultaneously, coordinate sub-sectional cooling technique can obtain containing proeutectoid ferrite+martensite+residual austenite body tissue; Its yield strength at below 700MPa, more than tensile strength 1000MPa, yield tensile ratio is 0.50 ~ 0.60; And cost of alloy significantly reduces.
Description
Technical field
The invention belongs to wear resisting steel field, relate to a kind of low yield strength ratio high-strength hot-rolled Q & P steel and manufacture method thereof, the yield strength of this hot rolling Q & P steel at below 700MPa, more than tensile strength 1000MPa, yield tensile ratio 0.50 ~ 0.60.
Background technology
Quenching-partition steel and Q & P steel are the study hotspots in nearly ten years high-strength steel fields, and its topmost object is while the intensity improving steel, improves the plasticity of steel, namely improves the strength and ductility product of steel.At present, Q & P steel has been known as the important new steel grade of a class in the advanced high-strength steel of the automobile steel field third generation.
The main technique of Q & P steel is: steel is heated to complete austenitic area or partial austenitic district, after Homogenization Treatments for some time, a certain temperature between rapid quench to Ms and Mf (Ms and Mf represents Ms (martensite start) point and end temp respectively) has the martensite+residual austenite body tissue of a certain amount of residual austenite to obtain, stop cold temperature in quenching or make carbon atom in residual austenite, spread enrichment from oversaturated martensite a little more than held for some time under stopping cold temperature subsequently, thus stable residual austenite, and then be quenched to room temperature.
The initial investigation and application of Q & P steel is mainly conceived to the demand of automobile industry to high-strength high-plasticity steel.Be not difficult to find out from the technique implementation procedure of Q & P steel, its operational path is comparatively complicated, and steel plate, after first time quenching, needs be rapidly heated to a certain temperature and stay for some time.This two-step approach Q & P technique is difficult to realize for hot rolling production process, but has good reference to the production of hot-rolling high-strength steel.In the hot rolling, after single stage method Q & P technique and finish to gauge can be adopted to terminate, press quenching batches to below Ms certain temperature.Q & P steel typical organization is martensite+a certain amount of residual austenite, therefore has high strength and good plasticity.
Chinese patent CN102226248A discloses a kind of carbon silicomanganese hot rolling Q & P steel, but design of alloy does not carry out micro-Ti process; Chinese patent CN101775470A discloses a kind of production technique of complex phase Q & P steel, is actually the technique that a kind of two-step approach produces Q & P steel; Chinese patent CN101487096A discloses one two-step thermal processing method and produces C-Mn-Al system Q & P steel, and its principal feature is that unit elongation is very high, but intensity is lower.
Above-mentioned patent adopts heat-treating methods, by in two-phase region, heating can relatively easily control ferritic volume fraction, but for Hot Strip Rolling, Heating temperature usually in complete austenitic area and finishing temperature generally more than 780 DEG C, and ferritic beginning Precipitation Temperature is mostly below 700 DEG C.Therefore, obtain a certain amount of ferrite by reduction finishing temperature to be difficult to realize in hot rolling actual production.
Summary of the invention
The object of the present invention is to provide a kind of low yield strength ratio high-strength hot-rolled Q & P steel and manufacture method thereof, its yield strength is at below 700MPa, tensile strength is at more than 1000MPa, yield tensile ratio is 0.50-0.60, and cost of alloy significantly reduces, there is the advantage of low yield strength ratio and high strength, can be applicable to require yielding and wear-resisting field.
Mentality of designing of the present invention is as follows:
The present invention is by low cost Composition Design, on the component base of plain C-Mn steel, the precipitation of cementite is suppressed by carrying high Si content, micro-Ti process fining austenite grains, adopt hot continuous rolling process, cooperation employing sub-sectional cooling technique can obtain the proeutectoid ferrite+martensite+residual austenite body tissue containing a certain amount of volume fraction simultaneously.By controlling three kinds of out of phase relative contents, can obtain yield strength at below 700MPa, tensile strength is at the low yield strength ratio of more than 1000MPa high-strength hot-rolled Q & P steel.
To achieve these goals, the present invention adopts following technical scheme:
A kind of low yield strength ratio high-strength hot-rolled Q & P steel, the weight percentage of its chemical composition is: C:0.20% ~ 0.40%, Si:1.0% ~ 2.0%, Mn:1.5% ~ 3.0%, P≤0.015%, S≤0.005%, Al:0.02 ~ 0.08%, N≤0.006%, Ti:0.005% ~ 0.015%, all the other are Fe and other inevitable impurity, and the yield strength of described low yield strength ratio high-strength hot-rolled Q & P steel is at below 700MPa, tensile strength is at more than 1000MPa, and its yield tensile ratio is 0.50-0.60.
Preferably, in the chemical composition of described hot rolling Q & P steel, Si:1.3 ~ 1.7%wt.%; Mn:1.8 ~ 2.5wt.%; Al:0.03 ~ 0.06wt.%; N≤0.004wt.%; Ti:0.008 ~ 0.012wt.%; O≤30ppm.
In the design of low yield strength ratio of the present invention high-strength hot-rolled Q & P steel chemical composition:
Carbon: carbon is element the most basic in steel is also one of most important element in low yield strength ratio of the present invention high-strength hot-rolled Q & P steel simultaneously.Carbon, as the interstitial atom in steel, plays very important effect to improving the intensity of steel, has the greatest impact to the yield strength of steel and tensile strength.Under normal circumstances, the intensity of steel is higher, and unit elongation is lower.The present invention is in order to ensure the high tensile steel plate obtaining more than tensile strength 1000MPa, in steel, the content of carbon is not less than 0.2wt.% usually, too low carbon content can not ensure steel plate after quenching is batched in Slow cooling process carbon fully spread to residual austenite from oversaturated martensite, thus affect the stability of residual austenite.Carbon content in steel is also unsuitable too high, if carbon content is greater than 0.4wt.%, although the high strength of steel can be ensured, but owing to the object of the invention is to obtain a certain amount of proeutectoid ferrite+martensite+residual austenite body tissue, the precipitation of proeutectoid ferrite must cause rich carbon in the remaining change austenite do not turned, the high carbon martensite unit elongation that this part austenite obtains after quenching is too low, thus the unit elongation of final steel plate is reduced.Therefore, carbon content proper in steel should control at 0.2 ~ 0.4wt.%, can ensure that steel plate has good intensity and good plasticity coupling.
Silicon: silicon is element the most basic in steel is also one of most important element in steel of the present invention simultaneously.Compared with traditional hot-rolling high-strength steel, current hot rolling high-strength Q & P base steel is originally all the Composition Design principle adopting high Si.Except C, Si, Mn, substantially do not add or only add other alloying elements a small amount of.Si can suppress the precipitation of cementite in certain temperature range, but more limited to the restraining effect of ε-carbide.Si suppresses cementite to be separated out carbon atom to be diffused in residual austenite from martensite thus stable residual austenite.Although add the precipitation that higher Al and P also can suppress cementite, the high molten steel that makes of Al content compares thickness, is easy to block the mouth of a river during continuous casting, reduces and waters steel efficiency; And P content height easily causes crystal boundary fragility, the impelling strength of steel plate is very low.Therefore, in general, the Composition Design of high Si is still one of most important Composition Design principle of current hot rolling Q & P steel.The content of Si is generally not less than 1.0wt.%, otherwise cementite can not be suppressed to separate out; The content of Si is general also no more than 2.0wt.%, otherwise easily occurs hot tearing during Plate Welding, cause difficulty, therefore in steel of the present invention, the content of Si controls usually at 1.0 ~ 2.0wt.%, be preferably 1.3 ~ 1.7%wt.% to the application of steel plate.
Manganese: manganese is element the most basic in steel is also one of most important element in steel of the present invention simultaneously.As everyone knows, Mn is the important element expanding austenite phase field, can reduce the critical quenching rate of steel, stable austenite, crystal grain thinning, postpones austenite to pearlitic transformation.The present invention is in order to ensure the intensity of steel plate, and Mn content generally should control at more than 1.5wt.%, and Mn content is too low, and when the first stage air cooling of sub-sectional cooling, supercooled austenite is unstable, easily changes the tissue of perlite type into; Meanwhile, the content of Mn is general during more than 3.0wt.%, easily there is Mn segregation during steel-making also no more than 3.0wt.%, easily hot tearing occurs simultaneously, be unfavorable for the raising of production efficiency during sheet billet continuous casting.Therefore, in steel of the present invention, the content general control of Mn is at 1.5 ~ 3.0wt.%, is preferably 1.8 ~ 2.5wt.%.
Phosphorus: phosphorus is the impurity element in steel.P very easily segregation, on crystal boundary, in steel time the content of P higher (>=0.1%), forms Fe
2p separates out around crystal grain, reduce the plasticity of steel and toughness, therefore its content is more low better, general control within 0.015wt.% better and do not improve steel-making cost.
Sulphur: sulphur is the impurity element in steel.S in steel is usually combined with Mn and forms MnS and be mingled with, especially, when the content of S and Mn is all higher, more MnS will be formed in steel, and MnS itself has certain plasticity, in the follow-up operation of rolling, MnS is along rolling to deforming, and reduces the transverse tensile property of steel plate.Therefore in steel of the present invention, the content of S is more low better, usually controls within 0.005wt.% during actual production.
Aluminium: the effect of aluminium in steel mainly carries out deoxidation in steelmaking process.In addition, Al also can be combined formation AlN by the N in steel, and AlN can crystal grain thinning.The grain fineness number size of steel is directly related with Al content, and Al content is lower than 0.02wt.%, and grain refinement effect is not obvious; When Al content is greater than 0.08wt.%, not only can not crystal grain thinning, and easily make steel generation greying, thus cause the inefficacy of steel plate.Therefore, in steel of the present invention, the content of Al will control, in suitable scope, usually to control at 0.02 ~ 0.08wt.%, and preferable range is 0.03 ~ 0.06wt.%.
Nitrogen: nitrogen belongs to impurity element in steel of the present invention, its content is more low better.N is also inevitable element in steel, and under normal circumstances, in steel, the residual content of N is between 0.002 ~ 0.004wt.%, and these solid solutions or free N element can be fixed by being combined with acid-soluble Al.In order to not improve steel-making cost, in steel of the present invention, the content of N controls within 0.006wt.%, and preferable range is for being less than 0.004wt.%.
Titanium: the add-on of titanium is corresponding with the add-on of nitrogen in steel.In steel, the content of Ti and N controls in lower scope, can form the TiN particle of a large amount of small and dispersed during hot rolling in steel; In steel, Ti/N need control below 3.42 to ensure that Ti all forms TiN simultaneously.Tiny and the nano level TiN particle with good high-temperature stability can effective fining austenite grains in the operation of rolling; If Ti/N is greater than 3.42, then easily form thicker TiN particle in steel, cause disadvantageous effect to the impelling strength of steel plate, thick TiN particle can become the formation of crack of fracture.On the other hand, the content of Ti can not be too low, otherwise the TiN quantity formed very little, do not have the effect of fining austenite grains.Therefore, in steel of the present invention, the content of titanium will control in suitable scope, and the add-on of usual titanium is at 0.005 ~ 0.015wt.%, and preferable range is 0.008 ~ 0.012wt.%.
Oxygen: oxygen is inevitable element in steelmaking process, and for the purpose of the present invention, in steel, the content of O is by generally reaching below 30ppm after Al deoxidation, significant adverse can not be caused to affect on the performance of steel plate.Therefore, the O content in steel of the present invention is controlled within 30ppm.
The manufacture method of low yield strength ratio of the present invention high-strength hot-rolled Q & P steel, comprises the steps:
1) smelting, secondary refining, casting:
Converter or electrosmelting, vacuum oven secondary refining, casting formation strand or ingot casting is adopted by following compositions, the weight percentage of chemical composition is: C:0.20% ~ 0.40%, Si:1.0% ~ 2.0%, Mn:1.5% ~ 3.0%, P≤0.015%, S≤0.005%, Al:0.02 ~ 0.08%, N≤0.006%, Ti:0.005% ~ 0.015%, all the other are Fe and other inevitable impurity;
2) heating, hot rolling:
The strand obtain step 1) or ingot casting are heated to 1100 ~ 1200 DEG C and are incubated 1 ~ 2h, and start rolling temperature is 1000 ~ 1100 DEG C, multi-pass rolling and accumulative deflection >=50%, and main purpose is fining austenite grains; 3 ~ 5 passes are carried out subsequently and accumulative deflection >=70% when intermediate blank temperature is down to 900 ~ 950 DEG C;
3) sub-sectional cooling:
The cooling rate rapid water of rolled piece after hot rolling with >50 DEG C/s between 800 ~ 900 DEG C is chilled to 500 ~ 600 DEG C, then air cooling 5 ~ 10s, continue again to be cooled to a certain temperature between 100 ~ 300 DEG C (namely between Ms-Mf) to obtain proeutectoid ferrite+martensite+residual austenite body tissue with the cooling rate of >50 DEG C/s, slowly cool to room temperature after finally batching, obtain described low yield strength ratio high-strength hot-rolled Q & P steel.
Preferably, step 2) in multi-pass rolling be 5 ~ 7 rollings; The speed of batching rear Slow cooling in step 3) is 8 ~ 12 DEG C/h.
In above-mentioned proeutectoid ferrite+martensite+residual austenite body tissue, the volume percent of its proeutectoid ferrite body tissue is 10 ~ 20%, and the volume percent of residual austenite body tissue is greater than 5% and is less than 10%.
Low yield strength ratio of the present invention high-strength hot-rolled Q & P steel, designed by reasonable component, coordinate the novel process of the hot rolling+sub-sectional cooling of novelty can obtain the steel plate of excellent combination property simultaneously, namely yield strength is obtained at below 700MPa, tensile strength is at more than 1000MPa, and its yield tensile ratio is the low yield strength ratio high-strength hot-rolled Q & P steel of 0.50 ~ 0.60.
In sub-sectional cooling of the present invention, the main purpose of first stage quick water-cooled is the phase driving force improving supercooled austenite, is convenient to separate out enough proeutectoid ferrites (10 ~ 20wt%), to ensure the low yield strength of steel plate in the follow-up air cooling stage.The Composition Design of test steel needs higher carbon and manganese so that the carbon after coiler plate distributes and stable residual austenite, but then, carbon and manganese are also that austenite stabilizer element is unfavorable for that the air cooling stage after first stage quick water-cooled separates out ferrite, therefore, the proportioning of the composition of alloy and hot rolling, process for cooling must obtain and control well, The faster the better for the water-cooled speed of this one-phase, and this is also one of innovative point of patent of the present invention;
Steel plate after first stage water-cooled needs through 5 ~ 10s air cooling, its main purpose separates out a certain amount of proeutectoid ferrite, for ensureing the low yield strength of steel plate, the quantity of proeutectoid ferrite should control can ensure lower yield strength between 10 ~ 20wt%; After air cooling terminates, subordinate phase quenching stops cold temperature and must to control in certain temperature range but not room temperature, otherwise cannot complete the distribution of carbon atom and residual austenite quantity is too low, causes steel plate unit elongation to reduce.Press quenching technique conventional is at present all that direct quenching is to room temperature, and another innovative point of the present invention to be oiler temperature control in certain low temperature range: more residual austenite (> 5wt%) can be retained on the one hand, but residual austenite is now unstable, if be cooled to room temperature, residual austenite will change its hetero-organization into, therefore on Composition Design, add the precipitation that a certain amount of Si element can suppress carbide in residual austenite, reduce the consumption of carbon; On the other hand, because the partial potential of carbon atom in martensite is higher than the partial potential in residual austenite, the difference of the partial potential of the two is that carbon atom spreads from martensite and provides motivating force to residual austenite, carbon content in residual austenite is significantly increased, thus residual austenite is at room temperature existed Absorbable organic halogens.By the ingenious cooperation of composition proportion and process for cooling, the steel plate of a certain amount of ferrite+martensite+residual austenite body tissue can be obtained, thus obtain the low yield strength ratio high-strength hot-rolled Q & P steel of excellent performance.
In addition, if the Heating temperature of steel billet lower than 1100 DEG C and soaking time too short, be then unfavorable for the homogenizing of alloying element; And when temperature is higher than 1200 DEG C, not only increase manufacturing cost, and the heating quality of steel billet is declined to some extent.Therefore, the heating and temperature control of steel billet is proper at 1100 ~ 1200 DEG C.
Equally, the soaking time of heating also needs to control within the specific limits.Soaking time is too short, and solute atoms is as abundant not in the diffusion of Si, Mn etc., and the heating quality of steel billet can not be guaranteed; Soaking time is long, makes austenite crystal thick and improve manufacturing cost, therefore the soaking time of heating should control between 1 ~ 2 hour.Heating temperature is higher, and corresponding soaking time can suitably shorten.
Production technique of the present invention can be used for manufacturing yield strength≤700MPa, tensile strength >=1000MPa, and thickness is at the low yield strength ratio of 3 ~ 12mm high-strength hot-rolled Q & P wear-resisting steel plate, there is good unit elongation (> 8%) simultaneously, this steel plate shows excellent strong plasticity coupling, brings the beneficial effect of the following aspects thus:
1, low yield strength ratio of the present invention high-strength hot-rolled Q & P steel plate, its cost of alloy significantly reduces.Compared with traditional low-alloy high-strength steel, do not add any noble metal element as Nb, V, Cu, Ni, Mo etc., greatly reduce cost of alloy.Adopt hot continuous rolling process to produce the production of ratio slab line and also can reduce production cost further, therefore, the production cost of steel plate is very low;
2, low yield strength ratio of the present invention high-strength hot-rolled Q & P steel plate, its excellent in mechanical performance, the comprehensive use cost of user reduces.Because the yield strength of steel plate is lower, and tensile strength is high, and yield tensile ratio is low, and the largest benefit brought thus is, many high-strength steel users just can carry out the techniques such as bending without the need to transforming existing processing units to steel plate, eliminates the expense of reforming equipment; Decrease the loss of grinding tool simultaneously, extend the work-ing life etc. of grinding tool;
3, steel plate of the present invention is adopted to have low cost, low yield strength ratio and high strength advantage, be particularly suitable for needing carry out bending and forming to steel plate and require wear-resisting field, the metastable state residual austenite retained in steel, martensite can be changed under the conditions such as abrasive wear, improve the wear resistance of steel plate further.
Accompanying drawing explanation
Fig. 1 is the production technological process of low yield strength ratio of the present invention high-strength hot-rolled Q & P steel;
Fig. 2 is the rolling technology figure of low yield strength ratio of the present invention high-strength hot-rolled Q & P steel;
Fig. 3 is the roller repairing artwork of low yield strength ratio of the present invention high-strength hot-rolled Q & P steel;
Fig. 4 is the typical metallograph that embodiment of the present invention 1# tests steel;
Fig. 5 is the typical metallograph that embodiment of the present invention 3# tests steel;
Fig. 6 is the typical metallograph that embodiment of the present invention 5# tests steel;
Fig. 7 is the typical metallograph that embodiment of the present invention 7# tests steel.
Embodiment
Below in conjunction with specific embodiment, technical scheme of the present invention is described in further detail.
The manufacture method of low yield strength ratio of the present invention high-strength hot-rolled Q & P steel, its technological process of production is: converter or electrosmelting → vacuum oven secondary refining → strand (ingot) → steel billet (ingot) reheat → hot rolling+sub-sectional cooling technique → coil of strip, as shown in Figure 1.
Embodiment
The manufacture of the low yield strength ratio high-strength hot-rolled Q & P steel of embodiment 1-9, specifically comprises the steps:
1) smelting, secondary refining, casting:
Converter or electrosmelting, vacuum oven secondary refining, casting formation strand or ingot casting is adopted according to the chemical composition of steel each in table 1; Slab thickness 120mm;
2) heating, hot rolling:
The strand obtain step 1) or ingot casting are heated to 1100 ~ 1200 DEG C and are incubated 1 ~ 2h, start rolling temperature is 1000 ~ 1100 DEG C, 5 ~ 7 passage hot rollings and accumulative deflection >=50% of large pressure, carry out 3 ~ 5 passes and accumulative deflection >=70% subsequently when intermediate blank temperature is down to 900 ~ 950 DEG C; Its hot rolling technology as shown in Figure 2; The heating that each embodiment is concrete and hot-rolled process parameter as shown in table 2;
3) sub-sectional cooling:
Rolled piece after hot rolling is chilled to 500 ~ 600 DEG C with the cooling rate rapid water of > 50 DEG C/s between 800 ~ 900 DEG C, then air cooling 5 ~ 10s, continue again to be cooled to a certain temperature between 100 ~ 300 DEG C (namely between Ms-Mf) to obtain a certain amount of ferrite+martensite+a certain amount of residual austenite body tissue with the cooling rate of > 50 DEG C/s, slowly cool to room temperature (cooling rate is 8 ~ 12 DEG C/h) after finally batching, obtain the low yield strength ratio high-strength hot-rolled Q & P steel of each embodiment; Its roller repairing technique as shown in Figure 3; The roller repairing processing parameter that each embodiment is concrete is as shown in table 2.
After testing, the mechanical property of the low yield strength ratio high-strength hot-rolled Q & P steel of embodiment 1-9 acquisition is as shown in table 3; The typical metallograph of the low yield strength ratio high-strength hot-rolled Q & P steel of embodiment 1,3,5 and 7 respectively as shown in Figure 4 to 7.
Can clearly be seen that from the typical metallograph of the low yield strength ratio of Fig. 4 ~ Fig. 7 high-strength hot-rolled Q & P steel, the tissue of steel plate be mainly needle-like or etc. shaft-like proeutectoid ferrite+martensite+residual austenite.According to X-ray diffraction result, the content of embodiment 1,3,5 and No. 7 detecting residual austenite in steel plates is respectively 5.47%, 6.14%, 5.56% and 6.82%.Needle-like or etc. the volumn concentration of shaft-like proeutectoid ferrite all between 10 ~ 20%.In the temperature range of 500 ~ 600 DEG C, it is lower to stop cold temperature, more easily forms needle-like proeutectoid ferrite; Stop cold temperature higher, more easily the shaft-like proeutectoid ferrite such as formation, the two all can meet performance requriements.Therefore, the microtexture of steel plate of the present invention be needle-like or etc. shaft-like proeutectoid ferrite+martensite+residual austenite.Due to the existence of residual austenite, make steel plate undergo phase transition induced plastic (TRIP) effect in stretching or wear process, thus improve the wear resistance of steel plate.
As known from Table 3, low yield strength ratio of the present invention high-strength hot-rolled Q & P steel plate, its yield strength≤700MPa, tensile strength >=1000MPa, its yield tensile ratio is 0.50 ~ 0.60, have the good unit elongation of > 8%, this steel plate shows excellent strong plasticity coupling simultaneously.
Table 1 unit: weight percent
| Embodiment | C | Si | Mn | P | S | Al | N | Ti | O |
| 1 | 0.20 | 1.77 | 2.95 | 0.005 | 0.0033 | 0.043 | 0.0033 | 0.011 | 0.0028 |
| 2 | 0.23 | 1.98 | 2.81 | 0.008 | 0.0032 | 0.028 | 0.0038 | 0.012 | 0.0023 |
| 3 | 0.25 | 1.37 | 2.25 | 0.006 | 0.0034 | 0.051 | 0.0042 | 0.013 | 0.0027 |
| 4 | 0.27 | 1.01 | 2.63 | 0.007 | 0.0035 | 0.035 | 0.0044 | 0.010 | 0.0025 |
| 5 | 0.30 | 1.54 | 2.24 | 0.010 | 0.0029 | 0.022 | 0.0058 | 0.014 | 0.0028 |
| 6 | 0.32 | 1.25 | 2.05 | 0.015 | 0.0030 | 0.079 | 0.0033 | 0.012 | 0.0024 |
| 7 | 0.35 | 1.63 | 1.74 | 0.013 | 0.0027 | 0.065 | 0.0041 | 0.010 | 0.0029 |
| 8 | 0.38 | 1.16 | 1.88 | 0.009 | 0.0023 | 0.073 | 0.0046 | 0.005 | 0.0026 |
| 9 | 0.40 | 1.42 | 1.55 | 0.011 | 0.0031 | 0.058 | 0.0040 | 0.008 | 0.0030 |
Table 2
The mechanical property of table 3 steel plate
Claims (5)
1. a low yield strength ratio high-strength hot-rolled Q & P steel, the weight percentage of its chemical composition is: C:0.20% ~ 0.40%, Si:1.0% ~ 2.0%, Mn:1.5% ~ 3.0%, P≤0.015%, S≤0.005%, Al:0.02 ~ 0.08%, N≤0.006%, Ti:0.005% ~ 0.015%, all the other are Fe and other inevitable impurity; The yield strength of described hot rolling Q & P steel is at below 700MPa, and tensile strength is at more than 1000MPa, and its yield tensile ratio is 0.50 ~ 0.60; It is organized as proeutectoid ferrite+martensite+residual austenite body tissue.
2. low yield strength ratio high-strength hot-rolled Q & P steel as claimed in claim 1, is characterized in that, in the chemical composition of described hot rolling Q & P steel, and Si:1.3 ~ 1.7%wt.%; Mn:1.8 ~ 2.5wt.%; Al:0.03 ~ 0.06wt.%; N≤0.004wt.%; Ti:0.008 ~ 0.012wt.%; O≤30ppm.
3. the manufacture method of low yield strength ratio high-strength hot-rolled Q & P steel as claimed in claim 1 or 2, specifically comprises the steps:
1) smelting, secondary refining, casting:
According to chemical composition adopt converter or electrosmelting, vacuum oven secondary refining, casting formation strand or ingot casting;
2) heating, hot rolling:
By step 1) strand that obtains or ingot casting be heated to 1100 ~ 1200 DEG C and be incubated 1 ~ 2h, start rolling temperature is 1000 ~ 1100 DEG C, multi-pass rolling and accumulative deflection >=50%, carry out 3 ~ 5 passes and accumulative deflection >=70% subsequently when intermediate blank temperature is down to 900 ~ 950 DEG C;
3) sub-sectional cooling:
The cooling rate rapid water of rolled piece after hot rolling with >50 DEG C/s between 800 ~ 900 DEG C is chilled to 500 ~ 600 DEG C, then air cooling 5 ~ 10s, continue again to be cooled to a certain temperature between 100 ~ 300 DEG C to obtain proeutectoid ferrite+martensite+residual austenite body tissue with the cooling rate of >50 DEG C/s, slowly cool to room temperature after finally batching, obtain described low yield strength ratio high-strength hot-rolled Q & P steel.
4. the manufacture method of low yield strength ratio high-strength hot-rolled Q & P steel as claimed in claim 3, is characterized in that, step 2) in multi-pass rolling be 5 ~ 7 rollings; Step 3) in the speed of batching rear Slow cooling be 8 ~ 12 DEG C/h.
5. the manufacture method of low yield strength ratio high-strength hot-rolled Q & P steel as claimed in claim 3, it is characterized in that, in the low yield strength ratio high-strength hot-rolled Q & P steel obtained, the volume percent of its proeutectoid ferrite body tissue is 10 ~ 20%, and the volume percent of residual austenite body tissue is greater than 5% and is less than 10%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310121587.7A CN103233161B (en) | 2013-04-09 | 2013-04-09 | A kind of low yield strength ratio high-strength hot-rolled Q & P steel and manufacture method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310121587.7A CN103233161B (en) | 2013-04-09 | 2013-04-09 | A kind of low yield strength ratio high-strength hot-rolled Q & P steel and manufacture method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103233161A CN103233161A (en) | 2013-08-07 |
| CN103233161B true CN103233161B (en) | 2016-01-20 |
Family
ID=48881224
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310121587.7A Active CN103233161B (en) | 2013-04-09 | 2013-04-09 | A kind of low yield strength ratio high-strength hot-rolled Q & P steel and manufacture method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103233161B (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105441814A (en) * | 2014-09-26 | 2016-03-30 | 宝山钢铁股份有限公司 | Hot rolled Q&P steel with 700MPa grade yield strength and ultralow yield ratio and manufacturing method thereof |
| CN104532126B (en) * | 2014-12-19 | 2017-06-06 | 宝山钢铁股份有限公司 | A kind of super high strength hot rolled Q＆P steel of low yield strength ratio and its manufacture method |
| EP3686296A4 (en) | 2017-09-20 | 2020-07-29 | Baosteel Zhanjiang Iron & Steel Co., Ltd. | Softening method for high-strength q p steel hot roll |
| CN108165890B (en) * | 2018-01-09 | 2020-08-11 | 北京科技大学 | Preparation method of low-cost high-strength nano bainite wear-resistant steel ball |
| CN108411200B (en) * | 2018-04-02 | 2020-07-10 | 武汉科技大学 | Hot-rolled Q & P steel plate with high work hardening rate and preparation method thereof |
| CN108396225B (en) * | 2018-04-17 | 2019-12-03 | 马钢(集团)控股有限公司 | A kind of 700MPa grades of titaniferous hot rolling biphase plate and its manufacturing method |
| CN109355573B (en) * | 2018-12-03 | 2020-08-14 | 东北大学 | One-steel multi-stage hot rolled steel plate based on carbon distribution technology and manufacturing method thereof |
| CN109402355B (en) * | 2018-12-29 | 2020-12-15 | 首钢集团有限公司 | 600 MPa-grade hot-rolled TRIP type dual-phase steel and preparation method thereof |
| CN109554616B (en) * | 2018-12-29 | 2021-01-15 | 首钢集团有限公司 | 700 MPa-grade hot-rolled TRIP auxiliary type dual-phase steel and preparation method thereof |
| CN109881107B (en) * | 2019-04-01 | 2021-08-31 | 山东钢铁集团日照有限公司 | Hot-rolled Q & P980 steel with different yield ratios and production method thereof |
| CN109972036B (en) * | 2019-04-01 | 2021-09-10 | 山东钢铁集团日照有限公司 | Hot-rolled Q & P1180 steel with different yield ratios and manufacturing method thereof |
| CN110093552B (en) * | 2019-05-30 | 2020-10-23 | 安徽工业大学 | High-strength-ductility Q & P steel plate with excellent welding performance and preparation method thereof |
| CN113802051A (en) * | 2020-06-11 | 2021-12-17 | 宝山钢铁股份有限公司 | Ultrahigh-strength steel with excellent plasticity and manufacturing method thereof |
| CN115233092B (en) * | 2022-06-24 | 2023-04-14 | 马鞍山钢铁股份有限公司 | 900 MPa-grade high-strength steel with excellent ductility and toughness and heat treatment method for improving residual austenite content of high-strength steel |
| CN115747656B (en) * | 2022-11-24 | 2023-10-31 | 湖南华菱涟源钢铁有限公司 | Economical hot-rolled high-strength steel with high plasticity and production process and application thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1293716A (en) * | 1999-01-28 | 2001-05-02 | 住友金属工业株式会社 | Machine structural steel product |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3468031B2 (en) * | 1997-06-24 | 2003-11-17 | 住友金属工業株式会社 | Martensite-bainite hot forged part and method of manufacturing the same |
-
2013
- 2013-04-09 CN CN201310121587.7A patent/CN103233161B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1293716A (en) * | 1999-01-28 | 2001-05-02 | 住友金属工业株式会社 | Machine structural steel product |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103233161A (en) | 2013-08-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103215516B (en) | A kind of 700MPa grade high-strength hot-rolled Q & P steel and manufacture method thereof | |
| CN103233161B (en) | A kind of low yield strength ratio high-strength hot-rolled Q & P steel and manufacture method thereof | |
| CN104532126B (en) | A kind of super high strength hot rolled Q＆P steel of low yield strength ratio and its manufacture method | |
| CN101638749B (en) | Automobile steel with low cost and high strength ductility balance and preparation method thereof | |
| CN103361547B (en) | A kind of production method of cold formability ultrahigh-strength steel plates and steel plate | |
| CN101713046B (en) | Preparation method of superfine grain martensitic steel reinforced and controlled by nano precipitated phase | |
| CN103255341B (en) | High-strength and high-toughness hot-rolled wear-resistant steel and preparation method thereof | |
| CN103805869B (en) | A kind of high-strength hot-rolled Q & P steel and manufacture method thereof | |
| WO2018036348A1 (en) | Thin thermoformed steel directly rolled using thin slabs and having tensile strength of ≥1500 mpa, and method for producing same | |
| CN109504900B (en) | A kind of superhigh intensity cold rolling transformation induced plasticity steel and preparation method thereof | |
| CN103805851B (en) | A kind of superstrength low cost hot rolling Q & P steel and production method thereof | |
| CN105648317A (en) | High-strength and high-plasticity medium-manganese Q and P steel cold-rolling annealing plate and preparing technology thereof | |
| CN106256918B (en) | A kind of the Automobile flywheel cold-strip steel and its manufacturing method of precision stamping processing | |
| WO2016095665A1 (en) | High-strength high-tenacity steel plate with tensile strength of 800 mpa and production method therefor | |
| CN110093552A (en) | A kind of high strength and ductility Q&P steel plate and preparation method thereof that welding performance is excellent | |
| CN102703803B (en) | Globular pearlite type hot rolled coil and production method thereof | |
| CN105274432A (en) | 600 MPa grade high-yield-ratio high-plasticity cold-rolled steel plate and manufacturing method thereof | |
| CN101717886A (en) | Hot rolled dual phase steel plate with 650MPa of tensile strength and manufacturing method thereof | |
| CN106811698A (en) | A kind of high strength steel plate and its manufacture method based on tissue precise controlling | |
| CN108486494A (en) | The production method of vanadium micro-alloying 1300MPa grade high-strengths hot rolled steel plate and cold-rolled biphase steel plate | |
| CN101363099A (en) | Cold rolled dual-phase sheet steel with 1000MPa grade tensile strength and preparation method thereof | |
| CN103422025A (en) | Steel for low-yield-ratio structure with yield strength larger than or equal to 690MPa and production method of steel | |
| CN105441814A (en) | Hot rolled Q&P steel with 700MPa grade yield strength and ultralow yield ratio and manufacturing method thereof | |
| CN110129673A (en) | A kind of 800MPa grades of high strength and ductility Q&P steel plate and preparation method thereof | |
| CN104313483A (en) | High-carbon cold-rolled automobile diaphragm spring steel and production method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |