CN102791895A - Cold rolled steel sheet for processing with excellent heat resistance, and preparation method thereof - Google Patents
Cold rolled steel sheet for processing with excellent heat resistance, and preparation method thereof Download PDFInfo
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- CN102791895A CN102791895A CN201080054949XA CN201080054949A CN102791895A CN 102791895 A CN102791895 A CN 102791895A CN 201080054949X A CN201080054949X A CN 201080054949XA CN 201080054949 A CN201080054949 A CN 201080054949A CN 102791895 A CN102791895 A CN 102791895A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
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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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/10—Ferrous alloys, e.g. steel alloys containing cobalt
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Abstract
The present invention relates to a cold rolled steel sheet for processing with excellent heat resistance, and a preparation method thereof. The cold rolled steel sheet for processing comprises C: 0.002~0.005%, Nb: 0.02~0.06%, Co: 0.02~0.20%, Mn: 0.10~0.35%, Al: 0.02~0.08%, P: 0.003~0.020%, N: 0.002~0.006%, S: less than or equal to 0.015%, the balance of Fe, and other inevitable impurities by weight%, or additionally comprises Sn: 0.05~0.25% to the composition, and thus has excellent processability and heat resistance, or additionally has excellent discoloration resistance and the like. According to the present invention, it is possible to prepare a highly heat resistant cold rolled steel sheet for processing which can be prepared with a low cost compared with known stainless steel sheets, has excellent room temperature processability due to various processing characteristics such as stretch flange formability, bendability and deep drawing property, shows excellent formability since yield point elongation does not appear due to the increase of anti-aging property by precipitation of dissolved alloy elements, has excellent high temperature strength to be able to extend the lifetime of equipment due to the shape freezing property of products applied at a high temperature, and has excellent discoloration resistance at a high temperature.
Description
Technical field
The present invention relates to a kind of high heat resistance cold-rolled steel sheet, be suitable for locomotive, household appliances and boiler (boiler) with high working property, with and method of manufacture; Relate more specifically to a kind of high heat resistance processing and use cold-rolled steel sheet; Wherein steel constituent and processing conditions are optimised, make it show excellent workability and thermotolerance, and in addition; Also can show anti-fadedness, and relate to its method of manufacture.
Background technology
Usually, cast iron (cast iron) is used to the parts that manufacture a product, for example locomotive exhaust system, baking oven, house chimney and boiler etc.Yet,, need high heat resistance because said iron continues to be exposed at least under up to a hundred degrees centigrade the hot conditions.For guaranteeing said high temperature properties, use finished Aludip, stainless steel plate etc.
So-called high-temperature behavior is meant a kind of product processed use one of characteristics showed under hot conditions.When using such as products such as locomotive exhaust system, the character of these products may increase deterioration because of local temperature, therefore needs high temperature properties, that is, and and sagging resistance (sagging resistance) and hot strength, and the anti-fadedness that possibly add.Wherein, sagging resistance is measured through the degree of sag of observing steel plate, and the material of said steel plate at high temperature changes owing to repeatedly exposing.If taken place said saggingly, then be difficult to keep the shape of moulded product.In addition, if thermal stresses is applied on the particular location thick and fast, then high-temperature yield strength may reduce, and the distortion or the destruction of shape of product is taken place.Therefore, in order to ensure the steadiness of shape, product should satisfy ys when about 700 ℃ of high temperature be 55MPa or higher; In addition; In order to prevent that steel plate from obtaining the adhesivity to coating material, possible demand schedule surface properties, promptly anti-fadedness in oxidation under the hot conditions and at coating the time.
Although stainless steel plate is mainly used in heat-resisting purpose, its production cost is very high, because added the alloying element of a large amount of costlinesses, for example Cr, Ni etc.In addition, when at high temperature heating, thereby can in the poor Cr district that crystal boundary place deposition chromium carbide forms, produce intergranular corrosion with the combining of Cr of crystal boundary, thereby cause erosion resistance to reduce via C.
In order to ensure the oxidation-resistance under the high temperature, can use Aludip.When this Aludip being heated to 400 ℃ or higher high temperature, Fe and Al may spread mutually and grow the alloy interface layer, thereby lose surface gloss at short notice and cause fading, and make the thermotolerance variation.The application of this steel plate is limited unfriendly.
In addition, be fabricated to such as products such as locomotive exhaust system, baking oven, house chimney and boilers and be contained in the finite space, thereby so steel plate formed through several different methods and given complicated shape, need extend then or procedure of processing such as bending.Like this, except above-mentioned high temperature properties, also need the room temperature processibility.
Therefore, Japanese uncensored public announcement of a patent application text spy opens flat No.9-176816 and discloses the steel plate of the N amount of Al amount and solid solution in a kind of steel through adjustment, and said steel plate is aluminized, and thermal treatment afterwards is with enhancing thermotolerance and processibility.Yet said steel plate is difficult to in the product component that is in application to 550 ℃ or higher temperature, and also is difficult for the amount of the steel constituent that adjustment adds, and causes the deterioration of processibility and produces manufacturing deficiency owing to wear out.
In addition, Japanese uncensored public announcement of a patent application text spy opens flat No.8-319548 and discloses a kind of Aludip, and it is formed with coating from the teeth outwards, thereby shows superior hot strength.Yet, because this patent provides the method for improvement coating condition rather than the method for enhancing steel plate character, be difficult to adjust the component of coating, can not obtain required thermotolerance.
Summary of the invention
Technical problem
Therefore, contriver of the present invention has carried out many researchs and the problem of test to exist in the solution prior art, and has proposed the present invention based on test result; One object of the present invention is; Provide the processing of a kind of high heat resistance with cold-rolled steel sheet with and method of manufacture, wherein, in order to use it for the purposes that needs high temperature properties and room temperature processibility simultaneously; As be used in locomotive exhaust system, baking oven, house chimney and the boiler; Can reduce and add expensive alloying element, and steel constituent can be optimised with processing conditions, therefore can make the steel plate of said processibility, thermotolerance and anti-fadedness excellence at low cost.
Technical scheme
In order to realize above-mentioned target; One aspect of the present invention provides a kind of high heat resistance processing to use cold-rolled steel sheet; It comprises the N, 0.015% or iron and other unavoidable impurities of S still less and surplus of P, the 0.002-0.006% of Al, the 0.003-0.020% of Mn, the 0.02-0.08% of Co, the 0.10-0.35% of Nb, the 0.02-0.20% of C, the 0.02-0.06% of 0.002-0.005%, in weight %.
Another aspect of the present invention provides a kind of high heat resistance processing to use cold-rolled steel sheet; It comprises the N, 0.015% or iron and other unavoidable impurities of S still less and surplus of P, the 0.002-0.006% of Al, the 0.003-0.020% of Mn, the 0.02-0.08% of Sn, the 0.10-0.35% of Co, the 0.05-0.25% of Nb, the 0.02-0.20% of C, the 0.02-0.06% of 0.002-0.005%, in weight %.
In addition, among the present invention, ((value of Nb * Co)/C) is 0.6-3.0, and in addition, (Nb, Co) C base carbide composite precipitation is formed on the cold-rolled steel sheet with respect to effective interpolation ratio of C for said Nb and Co.In addition, said cold-rolled steel sheet is made up of polygonal ferrite and acicular ferrite.
In addition, among the present invention, the volume(tric)fraction of said acicular ferrite is 5-15%, and Sn-base oxide layer is formed on the surface of cold-rolled steel sheet, and said Sn-base oxide layer can be Sn
2O
3Layer.
In addition; Another aspect of the present invention provides the method for manufacture of a kind of high heat resistance processing with cold-rolled steel sheet; Comprise this steel billet heating, hot rolling, batch (winding) and cold rolling; Thereby make cold-rolled steel sheet; Said steel billet comprises the N, 0.015% or iron and other unavoidable impurities of S still less and surplus of P, the 0.002-0.006% of Al, the 0.003-0.020% of Mn, the 0.02-0.08% of Co, the 0.10-0.35% of Nb, the 0.02-0.20% of C, the 0.02-0.06% of 0.002-0.005%; In weight %, with said cold-rolled steel sheet in the annealing of 800 ℃ or higher temperature, and with this annealed sheet steel with 30 ℃/second or higher rate of cooling cooling.
In addition; Another aspect of the present invention provides a kind of method of making high heat resistance processing with cold-rolled steel sheet; Comprise this steel billet heating, hot rolling, batch and cold rolling; Thereby make cold-rolled steel sheet; Said steel billet comprises the N, 0.015% or iron and other unavoidable impurities of S still less and surplus of P, the 0.002-0.006% of Al, the 0.003-0.020% of Mn, the 0.02-0.08% of Sn, the 0.10-0.35% of Co, the 0.05-0.25% of Nb, the 0.02-0.20% of C, the 0.02-0.06% of 0.002-0.005%; In weight %, with said cold-rolled steel sheet in the annealing of 800 ℃ or higher temperature, and with this annealed sheet steel with 30 ℃/second or higher rate of cooling cooling.
In addition, among the present invention, ((value of Nb * Co)/C) is 0.6-3.0 with respect to effective interpolation ratio of C for Nb and Co in steel billet.Said hot rolling is included in 900-950 ℃ and carries out finish rolling, and said hot rolling may further include the rate of cooling refrigerative step of hot-rolled steel sheet with 20-80 ℃/second.
In addition, said batching can be carried out at 560-680 ℃, and said annealing can be carried out at 800-900 ℃.
The invention effect
According to the present invention; Cold-rolled steel sheet can be with comparing the cost manufacturing low with traditional stainless steel plate; And can be endowed multiple processing characteristics; For example stretch flangeability (stretch flangeability), toughness and deep drawing quality (deep drawability), thereby show superior room temperature processibility.In addition, because the deposition of the alloying element of solid solution, anti-aging character can increase, thereby elongation at yield does not take place (yield elongation), thereby obtains high formability.And hot strength is very high, thus the shape steadiness of the product of guaranteeing under hot conditions, to use, thereby prolong work-ing life of equipment, and anti-fadedness at high temperature is excellent.
Description of drawings
Fig. 1 is the photo that the microtexture to the invention plate of embodiment 13 and contrast plate 10 compares.
Fig. 2 is the photo that the microtexture to the invention plate of embodiment 23 and contrast plate 6 compares.
Embodiment
Hereinafter, will describe cold-rolled steel sheet of the present invention in detail.
Contriver of the present invention has repeated repeatedly to study and test; The present invention finally not only satisfies multiple processing characteristics; For example stretch flangeability, toughness and deep drawing quality etc.; And anti-aging character and erosion resistance, but also guaranteed that ys is 55MPa or bigger in the time of 700 ℃, and at high temperature possibly add anti-fadedness.
Like this, one embodiment of the invention (hereinafter being called " first invention ") disclose the production of high heat resistance processing with cold-rolled steel sheet, wherein in the steel plate component; The carbon that contains minute quantity, and the Nb of control adding and amount and the ratio of Co, thus meticulous (Nb formed; Co) C-base carbide composite precipitation; Optimize annealing and cooling conditions, with the volume(tric)fraction of the acicular ferrite guaranteeing to be scheduled to, thereby the steel plate that obtains not only at high temperature has excellent thermotolerance and erosion resistance; And have fabulous resistance to deterioration and processibility in room temperature, therefore be applicable to the for example product component of locomotive exhaust system, baking oven, house chimney and boiler etc.
Another embodiment of the invention (hereinafter being called " second invention ") discloses the production of high heat resistance processing with cold-rolled steel sheet; Wherein in the steel plate component, contain the carbon of minute quantity, and the Nb of control adding and amount and the ratio of Co; Thereby form meticulous (Nb; Co) C-base carbide composite precipitation is optimized annealing and cooling conditions, with the volume(tric)fraction of the acicular ferrite guaranteeing to be scheduled to; And add Sn to form Sn-base oxide layer at surface of steel plate; Thereby the steel plate that obtains not only at high temperature has superior thermotolerance, erosion resistance and anti-fadedness, and has superior resistance to deterioration and processibility in room temperature, therefore is applicable to the for example product component of locomotive exhaust system, baking oven, house chimney and boiler etc.
At first, the reason that limits component in first invention is described (in whole specification sheets, weight % is expressed as % simply).
In the present invention, add the intensity of carbon (C), and mainly consume because of generating Nb carbide base deposition with the Nb reaction with the enhancing steel plate.Along with the amount increase of the C that adds, tension force and ys can increase, but the excessive affiliation that adds reduces processibility.The upper limit of therefore, adding this component preferably is set to 0.005%.But (particle size can increase, thereby causes the great variety in the steel for Nb, the Co) strengthening effect of C-base composite precipitation if the amount of C less than 0.002%, can't obtain.Therefore, the amount of C is restricted to 0.002-0.005%.
Manganese (Mn) is a kind of solution hardening element, and it can increase the intensity and the hot workability of steel, can deterioration ductility and processibility yet form MnS.If add excessive Mn, ductility can descend, and to add a large amount of alloying elements be unhelpful, and can cause center segregation.Therefore, the upper limit that adds this component preferably is set to 0.35%.If the amount of Mn less than 0.10%, though processibility increases, is difficult to guarantee required intensity.Therefore, the amount of Mn is restricted to 0.10-0.35%.
Add aluminium (Al) and combine with the alloying element of solid solution, thereby improve ageing property with deoxygenation in molten steel and in steel.Therefore, its consumption preferably is set to 0.02% or more.If the amount that this component adds surpasses 0.08%, the amount of inclusion increases and the generation surface imperfection in the steel, reduces processibility.Therefore, the amount of Al is restricted to 0.02-0.08%.
Add phosphorus (P) to increase the intensity and the erosion resistance of steel.For guaranteeing said character, the amount that contains P is preferably 0.003% or more.Yet,, possibly when casting, produce center segregation, and processibility reduces if said amount surpasses 0.020%.Therefore, the amount of P is restricted to 0.003-0.020%.
Nitrogen (N) exists with solid solution condition in steel, and it can strengthen steel effectively.If its consumption less than 0.002%, can't obtain enough hardness, form sedimentary position and tail off.On the contrary, if its consumption surpasses 0.006%,, cause sclerosis, thereby become the major cause of deterioration plasticity because excessive solid solution alloy element may wear out.Therefore, the amount of N is restricted to 0.002-0.006%.
Sulphur (S) combines with Mn in steel, thereby forms non-metallic inclusions, and it has the effect of the corrosive of initiation and can cause red brittleness, and the amount that therefore contains is preferably the least possible.The amount of S is restricted to 0.015% or still less.For guaranteeing above effect, the amount of preferred S is controlled at 0.010% or still less.
Niobium (Nb) is effective to the raising and the grain refining of the intensity of steel plate.In the present invention, its combine with the C of solid solution in the steel and form (Nb, Co) C-base carbide composite precipitation, thereby improve ageing property and formability.(intensity can increase and suppress ferrite crystal grain growth at high temperature for Nb, the Co) formation of C-base carbide composite precipitation, thereby acquisition is to the thinning effect of ferrite particles through said.Therefore, the amount that preferably adds of Nb is 0.02% or more.If its consumption surpasses 0.06%, steel may harden, and processibility can reduce in the anneal that continues, and the surface properties of steel plate also maybe deterioration.Therefore, the amount of Nb is restricted to 0.02-0.06%.
Cobalt (Co) promotes sedimentary formation in the steel, thereby gains in strength and erosion resistance.For reaching above effect, the amount that contains Co is preferably 0.02% or more.If its consumption surpasses 0.20%, then the elongation of steel descends, and can increase manufacturing cost owing to add a large amount of expensive alloying elements, but not helps lend some impetus to deposition.Therefore, the amount of Co is restricted to 0.02-0.20%.
The processing respectively of Nb and Co is very important, but control Nb and Co for the effective weight of C than ((Nb * Co)/C) remain in the predetermined scope, also very important to guarantee at room temperature not only have anti-aging character but also to have hot strength.
That is, (when the value of Nb * Co)/C is 0.6-3.0, by (Nb, Co) C-base carbide composite precipitation forms and the fixing C of solid solution in the steel, guarantees anti-aging character and processibility under the room temperature thus.In addition, control annealing and cooling conditions suitably, meticulous (growth that suppresses crystal grain under the high temperature is thus finally guaranteed fabulous high temperature properties to control ferritic microtexture for Nb, Co) C-base carbide composite precipitation thereby form.
Yet, if (value of Nb * Co)/C is lower than 0.6, in steel, has excessive solid solution element, cause anti-aging character and the deterioration of processibility under the room temperature, and (Nb, Co) amount of C-base carbide composite precipitation is not remarkable, makes and can not guarantee hot strength.On the other hand, if its numerical value surpasses 3.0, steel may harden, and recrystallization temperature sharply increases, surface properties possibility deterioration, thus be reduced in the processibility in the aftertreatment.Therefore, (value of Nb * Co)/C is restricted to 0.6-3.0.
Equally, for realizing second invention of the present invention, add tin (Sn) extraly.Sn exists with solid solution condition in steel, and it increases high temperature properties and erosion resistance, and is heated and oxidation through thermal treatment, therefore forms for example Sn of Sn-base oxide on the surface of steel plate
2O
3Thereby, be suppressed at surface of steel plate and form alloy layer, to strengthen erosion resistance and anti-fadedness.For reaching this effect, the amount that this component preferably adds is 0.05% or more.If its consumption surpasses 0.25%, manufacturing cost can increase, but not helps to increase erosion resistance or anti-fadedness.Therefore, the amount of Sn is restricted to 0.05-0.25%.
Cold-rolled steel sheet of the present invention comprises said components, also comprises the iron and the unavoidable impurities of surplus.As required, also can other alloying elements of extra interpolation to increase the character of cold-rolled steel sheet of the present invention.Add the alloying element of not putting down in writing in embodiments of the present invention, be not considered to exceed scope of the present invention.
Simultaneously, cold-rolled steel sheet of the present invention comprises polygonal ferrite (polygonal ferrite) and acicular ferrite.Thus, acicular ferrite is a kind of bainite of growing via nucleation in the austenite particle before conversion.Since this structure be by the meticulous non-metallic inclusions of dispersive in the steel via nucleating growth, thereby its forms random structure, wherein ferritic bar (lath) has superior relatively ductility or toughness transforming the crystal boundary that the time point of accomplishing forms high angle.
According to the present invention,, form the microtexture of high-density type like this through controlling the volume(tric)fraction that annealing and cooling conditions are guaranteed the said acicular ferrite of 5-15% aptly.Therefore, at high temperature suppress the misgrowth of crystal grain, thereby guarantee hot strength, strengthen thermotolerance.If the volume(tric)fraction of said acicular ferrite is lower than 5%, then be difficult to guarantee hot strength, make to be difficult to obtain needed thermotolerance.On the contrary, if the volume(tric)fraction of acicular ferrite surpasses 15%, then cause the deterioration of processibility owing to hardened material.Therefore, the volume(tric)fraction of acicular ferrite is restricted to 5-15%.
Below, high heat resistance processing of the present invention is carried out detailed explanation with the method for manufacture of cold-rolled steel sheet.
The steel billet that will have above-mentioned composition is warm again, and hot rolling is batched; Cold rolling, then at 800 ℃ or higher annealing temperature, thereby process a kind of steel plate; And cool off said steel plate with 30 ℃/second or higher rate of cooling; Thereby make a kind of high heat resistance processing and use cold-rolled steel sheet, it has superior processibility and thermotolerance, and possibly add anti-fadedness.
When in typical temperature, the steel billet of said components carried out heat again after, final rolling temperature is 900-950 ℃ during hot rolling.If final rolling temperature is lower than 900 ℃, then hot rolling stops in low relatively TR, makes the final crystal grain that forms be easy to mix, and causes the deterioration of processibility and rollability.On the contrary, if final rolling temperature surpasses 950 ℃, then can't on whole thickness, carry out hot rolling equably, the refinement of crystal grain is insufficient thus, the crystal grain roughening, thus impelling strength reduces.Therefore, final rolling temperature is restricted to 900-950 ℃.
After above-mentioned hot finishing finished, the steel of hot rolling was gone up cooling with 20-80 ℃/second speed at runoff table (run-out table).If rate of cooling is lower than 20 ℃/second, the growth meeting of crystal grain is formed comparatively coarse particle by promotion, thereby reduces intensity and processibility.On the contrary, if rate of cooling surpasses 80 ℃/second, because uneven cooling on the direction of width possibly depart from mechanical properties.
After cooling on the runoff table, batch hot-rolled steel sheet at 560-680 ℃.If coiling temperature is lower than 560 ℃, hot rolled plate possibly slightly harden, and increases the load in cold rolling subsequently, thereby is difficult to guarantee rollability.In addition, the inhomogeneous rolling degree on width increases, and the difference of sedimentary at low temperatures production behavior possibly cause departing from of mechanical properties, causes the deterioration of processibility and high temperature properties.On the contrary, if coiling temperature is higher than 680 ℃, the structure of the finished product becomes coarse, causes the deterioration of processibility and erosion resistance.Therefore, coiling temperature is restricted to 560-680 ℃.
Accomplish the said steel plate that batches and be cold-rolled to desired thickness then, continue annealing with control recrystallization and microtexture 800 ℃ or higher temperature afterwards by pickling (pickling).Said 800 ℃ or higher annealing temperature are the required temperature of motivating force for guaranteeing that fully acicular ferrite transforms.If annealing temperature is lower than 800 ℃; The required volume(tric)fraction of the acicular ferrite that can't obtain to exist in the steel plate microtexture, thus be difficult to guarantee superior high temperature properties, when high temperature annealing, increase the generation of the surface imperfection of steel plate; Therefore, annealing temperature preferably is set to 900 ℃ or lower.
Above-mentioned annealed steel plate can be guaranteed the volume(tric)fraction of the acicular ferrite of needs through cooling.For this reason, rate of cooling remains on 30 ℃/second or higher.If rate of cooling is lower than 30 ℃/second, can be because slowly cooling and can not reach the volume(tric)fraction of required acicular ferrite.
Below, through embodiment, the present invention is explained more specifically.
[embodiment 1]
Make invention steel 1,2 and compared steel 1 to 5 through listed component in the fusing following table 1, and under the processing conditions shown in the table 2, process, thereby obtain invention plate 1 to 4 and contrast plate 1 to 10 as cold-rolled steel sheet.Each cold-rolled steel sheet to said manufacturing carries out the evaluation of acicular ferrite volume(tric)fraction and room temperatures properties and high temperature properties, and the result is listed in the table below in 3.
In the character of table 3, the elongation at yield phenomenon is assessed as follows, and according to the elongation at yield rate of being surveyed, the situation that elongation takes place is with " generation " expression, and the situation that elongation does not take place is with " not producing " expression.Equally, resistance to bending according to the face bend degree of finished steel plate with five crooked level evaluations.Particularly, the grade 1 and 2 that degree of crook is low relatively is assessed as " good ", and naked-eye observation is assessed as " poor " to crooked grade 3-5.
Equally, sagging resistance is assessed as follows, with total length be 250mm and width 30mm steel plate with HTFX 700 ℃ again heat 100 hours, measure the sagging of steel plate afterwards, sag is that 5mm or bigger assessment of scenario are " poor " thus.Equally, when the ys under 700 ℃ during less than 55MPa, high-temperature yield strength is evaluated as " poor ", when it is 55MPa or when bigger, is evaluated as " good ".In addition, add when producing the crack man-hour in room temperature, processibility is assessed as " poor ".
Table 1
The component of invention steel and compared steel
Table 2
The manufacturing processing conditions of steel plate
Table 3
The assessment of steel plate character
| Steel plate | Acicular ferrite | Elongation at yield | Counter-bending | Anti-sagging | High temperature yield | Processibility |
| Mark (%) | The property | The property | Intensity | |||
| Invention 1 | 9.6 | Do not produce | Good | Good | Good | Good |
| Invention 2 | 10.3 | Do not produce | Good | Good | | Good |
| Invention | ||||||
| 3 | 7.9 | Do not produce | Good | Good | Good | Good |
| Invention 4 | 10.1 | Do not produce | Good | Good | Good | Good |
| Contrast 1 | 6.4 | Do not produce | Difference | Good | Difference | Difference |
| Contrast 2 | 3.1 | Produce | Difference | Difference | | Difference |
| Contrast | ||||||
| 3 | 2.1 | Produce | Difference | Difference | Good | Difference |
| Contrast 4 | 0 | Do not produce | Difference | Difference | Difference | Difference |
| Contrast 5 | 3.4 | Do not produce | Good | Difference | | Good |
| Contrast | ||||||
| 6 | 2.5 | Do not produce | Good | Difference | Difference | Good |
| Contrast 7 | 1.5 | Produce | Difference | Difference | Difference | Difference |
| Contrast 8 | 2.1 | Produce | Difference | Difference | Difference | Difference |
| Contrast 9 | 4.2 | Produce | Difference | Good | Difference | Difference |
| Contrast 10 | 0 | Produce | Difference | Difference | Good | Difference |
As shown in table 3, the component of steel satisfies scope invention plate 1 to 4 of the present invention and does not produce elongation at yield, and has good resistance to bending and superior anti-aging character.In addition, and owing to produce (Nb, Co) C-base carbide composite precipitation and optimized the volume(tric)fraction of acicular ferrite, thereby the high-temperature yield strength after the thermal treatment and sagging resistance are all fine.At room temperature add man-hour, defective do not occur, show superior room temperature processibility.
Yet; Though the component of steel satisfies the scope of the invention in the table 1, the processing conditions in the table 2 departs from the contrast plate 1 to 5 of the scope of the invention, and the volume(tric)fraction of its acicular ferrite significantly reduces; Do not have excellent high temperature properties, processibility and anti-aging character are also poor.
And though the processing conditions in the table 2 satisfies the scope of the invention, C, Nb, Co etc. depart from the contrast plate 6 to 10 of the scope of the invention in the steel constituent in the table 1, and the volume(tric)fraction of its acicular ferrite is low, and room temperature and high temperature properties major part are all very poor.
Wherein, contrast plate 6 does not produce elongation at yield, and resistance to bending is excellent and anti-aging character and processibility are all good, and the sagging resistance and the hot strength that still are equivalent to high temperature properties are poor.This is because do not add the Co component, has therefore reduced (Nb, Co) C-base carbide composite precipitation and profitability thereof.In the contrast plate 7 to 10, the solid solution C content in the steel is many, so processibility and anti-aging character are poor.And the Nb of interpolation and the amount of Co or its adding proportion are low, and therefore (Nb, Co) C-base carbide composite precipitation is not remarkable, makes that the volume(tric)fraction of acicular ferrite is low, and high temperature properties is poor, is difficult to satisfy simultaneously processibility and high temperature properties.
Simultaneously, Fig. 1 is the photo that invention plate 3 and the microtexture that contrasts plate 10 are compared.In the invention plate 3 of Fig. 1 (a), the ferritic that approaches polygonal shape is a polygonal ferrite, and the ferritic that is elongated is an acicular ferrite.The volume(tric)fraction of the acicular ferrite that said invention plate 3 has is 7.9%, and the evaluation on room temperature and high temperature properties is all fine.Yet the contrast plate 10 of Fig. 1 (b) does not contain acicular ferrite and only is made up of polygonal ferrite, therefore from table 3, confirms anti-aging character, processibility and poor heat resistance.
Therefore; Condition (particularly annealing and cooling conditions) to steel constituent condition and manufacturing processed is carried out optimization and is formed meticulous (Nb; Co) C-base carbide composite precipitation; The volume(tric)fraction of control acicular ferrite is used cold-rolled steel sheet thereby make the high heat resistance processing of satisfying high temperature properties and processibility simultaneously with low cost.
Embodiment 2
Through listed component the invention steel 1,2 and the compared steel 1 to 5 that make in the fusing following table 4, these are processed under the processing conditions shown in the following table 5 and obtain the invention plate 1 to 5 and contrast plate 1 to 10 as cold-rolled steel sheet.Afterwards the acicular ferrite volume(tric)fraction of these cold-rolled steel sheets and room temperatures properties and high temperature properties are estimated, the result is listed in the table below in 6.
The elongation at yield phenomenon is assessed as follows, and according to the elongation at yield rate of being surveyed, the situation that elongation takes place is with " generation " expression, and the situation that elongation does not take place is with " not producing " expression.Equally, resistance to bending according to the face bend degree of finished steel plate with five crooked level evaluations.Particularly, be assessed as " good " in the low relatively grade 1 and 2 of degree of crook, naked-eye observation is assessed as " poor " to crooked grade 3-5.
Equally, sagging resistance is assessed as follows, with total length be 250mm and width 30mm steel plate with HTFX 700 ℃ again heat 100 hours, measure the sagging of steel plate afterwards, sag is that 5mm or bigger assessment of scenario are " poor " like this.In addition, when the ys under 700 ℃ was lower than 55MPa, high-temperature yield strength was evaluated as " poor ", when it is 55MPa or when bigger, was evaluated as " good ".When steel plate in 500 ℃ keep 48 hours after, surface gloss reduces by 30% or when bigger, the anti-fadedness of high temperature is evaluated as " poor ".
In addition, add in room temperature that processibility is assessed as " poor " when producing crack (crack) man-hour.
Table 4
The component of invention steel and compared steel
Table 5
The manufacturing processing conditions of steel plate
Table 6
The assessment of steel plate character
As shown in table 6, the component of steel and processing conditions satisfy in the invention plate 1 to 5 of scope of the present invention and do not produce elongation at yield, and have good resistance to bending and excellent anti-aging character.(its high-temperature yield strength and sagging resistance after thermal treatment is all fine for Nb, Co) C-base carbide composite precipitation and optimized the volume(tric)fraction of acicular ferrite owing to produce.And at high temperature the surface gloss reduced rate is less than 30%, and therefore anti-fadedness is good, and at room temperature adds man-hour, the crack do not occur, shows fabulous room temperature processibility.
Yet; The component of steel satisfies the scope of the invention in the table 4; But the processing conditions in the table 5 departs from the contrast plate 1 to 5 of the scope of the invention; The volume(tric)fraction major part of its acicular ferrite is all very low, cause failing to obtain good high-temperature character (sagging resistance, hot strength, anti-fadedness), and processibility and anti-aging character (elongation at yield, resistance to bending) is also very poor.
In addition, the processing conditions in the table 5 satisfies in the scope of the invention, but the steel constituent of table 4 departs from the contrast plate 6 to 10 in the scope of the invention, makes the back it is carried out the character evaluation.As a result of, the volume(tric)fraction of its acicular ferrite is zero or very low, and room temperature and high temperature properties major part are all very poor.Wherein, in contrast plate 7, do not produce elongation at yield, and obtained good resistance to bending and processibility, but the sagging resistance, hot strength and the anti-fadedness that are equivalent to high temperature properties are poor.This is because do not add the Co component, has therefore reduced (Nb, Co) formation and the profitability thereof of C-base carbide composite precipitation.And contrast plate 8 to 10 contains the C amount of solid solution in a large amount of steel, therefore represents the processibility and the anti-aging character of going on business.In addition, perhaps its adding proportion is low not add Nb or Co, so precipitation capacity is not enough, makes that the volume(tric)fraction of acicular ferrite is low, and sagging resistance and high-temperature yield strength are low.In addition, anti-fadedness is poor, makes it be difficult to satisfy simultaneously room temperature processibility and high temperature properties.
In addition, Fig. 2 shows the microtexture of plate 3 of the present invention and contrast plate 6.In the plate of the present invention 3 of Fig. 2 (a), the ferritic that approaches polygonal shape is a polygonal ferrite, and the ferritic that is extended is an acicular ferrite.The volume(tric)fraction of the acicular ferrite that invention plate 3 has is 7.9%, and is all fine aspect room temperature and high temperature properties.Yet, confirm in the table 6 that Fig. 2 (b) shows that 6 of plates of contrast have formed polygonal ferrite and do not contained acicular ferrite, so room temperatures properties and high temperature properties are all poor.
In a word; Condition (particularly annealing and cooling conditions) to steel constituent and manufacturing processed is optimized, and can form meticulous (Nb, Co) C-base carbide composite precipitation thus; And the volume(tric)fraction of may command acicular ferrite; And can form Sn-base oxide layer at surface of steel plate, thereby show fabulous anti-fadedness, can make the high heat resistance processing of satisfying processibility, high temperature properties and anti-fadedness simultaneously with low cost thus and use cold-rolled steel sheet.
Above-mentioned embodiment is an illustration only, and the present invention is not limited thereto.Through with claim scope of the present invention in the substantive identical formation of the technological thought put down in writing, bring into play any other technology of identical action effect, include in technical scope of the present invention.
Claims (15)
1. cold-rolled steel sheet is used in a high heat resistance processing; The N, 0.015% or iron and other unavoidable impurities of S still less and surplus that comprises P, the 0.002-0.006% of Al, the 0.003-0.020% of Mn, the 0.02-0.08% of Co, the 0.10-0.35% of Nb, the 0.02-0.20% of C, the 0.02-0.06% of 0.002-0.005% is in weight %.
2. cold-rolled steel sheet is used in a high heat resistance processing; The N, 0.015% or iron and other unavoidable impurities of S still less and surplus that comprises P, the 0.002-0.006% of Al, the 0.003-0.020% of Mn, the 0.02-0.08% of Sn, the 0.10-0.35% of Co, the 0.05-0.25% of Nb, the 0.02-0.20% of C, the 0.02-0.06% of 0.002-0.005% is in weight %.
3. cold-rolled steel sheet is used in claim 1 or the processing of 2 described high heat resistances, and wherein said Nb and Co are for effective adding proportion of C ((Nb * Co)/C) be 0.6-3.0.
4. cold-rolled steel sheet is used in claim 1 or 2 described high heat resistance processing, wherein in said cold-rolled steel sheet, forms (Nb, Co) C-base carbide composite precipitation.
5. cold-rolled steel sheet is used in claim 1 or 2 described high heat resistance processing, and wherein said cold-rolled steel sheet contains polygonal ferrite and acicular ferrite.
6. to use cold-rolled steel sheet, the volume(tric)fraction of wherein said acicular ferrite be 5-15% to the processing of the described high heat resistance of claim 5.
7. cold-rolled steel sheet is used in the described high heat resistance processing of claim 2, and the surface of wherein said cold-rolled steel sheet forms Sn-base oxide layer.
8. cold-rolled steel sheet is used in the described high heat resistance processing of claim 7, and wherein Sn-base oxide layer is Sn
2O
3Layer.
9. a high heat resistance is processed the method for manufacture with cold-rolled steel sheet; Comprise steel billet heating, hot rolling, batch with cold rolling; Thereby obtain a kind of cold-rolled steel sheet; Said steel billet contains the N, 0.015% or iron and other unavoidable impurities of S still less and surplus of P, the 0.002-0.006% of Al, the 0.003-0.020% of Mn, the 0.02-0.08% of Co, the 0.10-0.35% of Nb, the 0.02-0.20% of C, the 0.02-0.06% of 0.002-0.005%, in weight %; With said cold-rolled steel sheet at 800 ℃ or higher annealing temperature, thereby obtain a kind of annealed steel plate; And with said annealed sheet steel with 30 ℃/second or the cooling of higher rate of cooling.
10. a high heat resistance is processed the method for manufacture with cold-rolled steel sheet; Comprise steel billet heating, hot rolling, batch with cold rolling; Thereby obtain a kind of cold-rolled steel sheet; Said steel billet contains the N, 0.015% or iron and other unavoidable impurities of S still less and surplus of P, the 0.002-0.006% of Al, the 0.003-0.020% of Mn, the 0.02-0.08% of Sn, the 0.10-0.35% of Co, the 0.05-0.25% of Nb, the 0.02-0.20% of C, the 0.02-0.06% of 0.002-0.005%, in weight %; With said cold-rolled steel sheet at 800 ℃ or higher annealing temperature, thereby obtain a kind of annealed sheet steel; And with said annealed sheet steel with 30 ℃/second or the cooling of higher rate of cooling.
11. claim 9 or the processing of 10 described high heat resistances is with the method for manufacture of cold-rolled steel sheet, wherein in said steel billet Nb and Co for effective adding proportion of C ((Nb * Co)/C) be 0.6-3.0.
12. claim 9 or 10 described high heat resistance processing are with the method for manufacture of cold-rolled steel sheet, wherein said hot rolling is included in 900-950 ℃ and carries out finish rolling.
13. the described high heat resistance processing of claim 12 is with the method for manufacture of cold-rolled steel sheet, wherein finish rolling comprises that also the steel plate with hot rolling carries out the refrigerative step with 20-80 ℃/second rate of cooling.
14. claim 9 or 10 described high heat resistance processing are with the method for manufacture of cold-rolled steel sheet, wherein said batching at 560-680 ℃ carried out.
15. claim 9 or 10 described high heat resistance processing are with the method for manufacture of cold-rolled steel sheet, wherein said annealing is carried out at 800-900 ℃.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020090120143A KR101263790B1 (en) | 2009-12-04 | 2009-12-04 | High heat-resistance cold-rolled steel sheet having excellent formability, heat resistance for working and manufacturing method thereof |
| KR10-2009-0120143 | 2009-12-04 | ||
| KR10-2009-0120150 | 2009-12-04 | ||
| KR1020090120150A KR101263792B1 (en) | 2009-12-04 | 2009-12-04 | High heat-resistance cold-rolled steel sheet having excellent formability, heat resistance, surface properties for working and manufacturing method thereof |
| PCT/KR2010/008376 WO2011068328A2 (en) | 2009-12-04 | 2010-11-25 | Cold rolled steel sheet for processing with excellent heat resistance, and preparation method thereof |
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| CN102791895A true CN102791895A (en) | 2012-11-21 |
| CN102791895B CN102791895B (en) | 2014-12-24 |
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| CN201080054949.XA Expired - Fee Related CN102791895B (en) | 2009-12-04 | 2010-11-25 | Cold rolled steel sheet for processing with excellent heat resistance, and preparation method thereof |
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| JP (1) | JP5586704B2 (en) |
| CN (1) | CN102791895B (en) |
| WO (1) | WO2011068328A2 (en) |
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| KR102045654B1 (en) * | 2017-12-26 | 2019-11-15 | 주식회사 포스코 | Cold rolled steel sheet having excellent high temperature mechanical properties as well as room temperature workability and method of manufacturing the same |
Citations (5)
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|---|---|---|---|---|
| JP2001342549A (en) * | 2000-03-30 | 2001-12-14 | Sumitomo Metal Ind Ltd | Heat resisting steel with low and medium cr content |
| WO2006048034A1 (en) * | 2004-11-03 | 2006-05-11 | Thyssenkrupp Steel Ag | High-strength steel strip or sheet exhibiting twip properties and method for producing said strip by direct strip casting ' |
| CN1878882A (en) * | 2003-11-10 | 2006-12-13 | Posco公司 | Cold rolled steel sheet having aging resistance and superior formability, and process for producing the same |
| CN101243198A (en) * | 2005-08-25 | 2008-08-13 | Posco公司 | Steel sheet for galvanizing with excellent workability, and method for manufacturing the same |
| CN101558178A (en) * | 2006-12-12 | 2009-10-14 | Posco公司 | Cold-rolled steel sheet with high yield ratio and excellent weather resistance |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP3552322B2 (en) * | 1995-02-07 | 2004-08-11 | Ｊｆｅスチール株式会社 | Method of manufacturing pipe with excellent workability |
| JPH09176816A (en) * | 1995-12-22 | 1997-07-08 | Nisshin Steel Co Ltd | Production of hot-dip aluminum plated steel sheet excellent in heat resistance, workability or the like |
| JP3958921B2 (en) * | 2000-08-04 | 2007-08-15 | 新日本製鐵株式会社 | Cold-rolled steel sheet excellent in paint bake-hardening performance and room temperature aging resistance and method for producing the same |
| US20040170518A1 (en) * | 2001-07-05 | 2004-09-02 | Manabu Oku | Ferritic stainless steel for member of exhaust gas flow passage |
| US20070122650A1 (en) * | 2003-11-14 | 2007-05-31 | Nippon Steel Corporation | Steel for exhaust gas processing equipment and exhaust gas duct excellent in wear resistance or wear resistance and gas cutting property |
| EP1951922B1 (en) * | 2005-10-25 | 2016-05-18 | Posco | Corrosion resistance improved steel sheet for automotive muffler and method of producing the steel sheet |
-
2010
- 2010-11-25 CN CN201080054949.XA patent/CN102791895B/en not_active Expired - Fee Related
- 2010-11-25 WO PCT/KR2010/008376 patent/WO2011068328A2/en active Application Filing
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001342549A (en) * | 2000-03-30 | 2001-12-14 | Sumitomo Metal Ind Ltd | Heat resisting steel with low and medium cr content |
| CN1878882A (en) * | 2003-11-10 | 2006-12-13 | Posco公司 | Cold rolled steel sheet having aging resistance and superior formability, and process for producing the same |
| WO2006048034A1 (en) * | 2004-11-03 | 2006-05-11 | Thyssenkrupp Steel Ag | High-strength steel strip or sheet exhibiting twip properties and method for producing said strip by direct strip casting ' |
| CN101243198A (en) * | 2005-08-25 | 2008-08-13 | Posco公司 | Steel sheet for galvanizing with excellent workability, and method for manufacturing the same |
| CN101558178A (en) * | 2006-12-12 | 2009-10-14 | Posco公司 | Cold-rolled steel sheet with high yield ratio and excellent weather resistance |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102791895B (en) | 2014-12-24 |
| JP5586704B2 (en) | 2014-09-10 |
| WO2011068328A2 (en) | 2011-06-09 |
| JP2013512337A (en) | 2013-04-11 |
| WO2011068328A3 (en) | 2011-11-03 |
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