CN102791895B - 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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- CN102791895B CN102791895B CN201080054949.XA CN201080054949A CN102791895B CN 102791895 B CN102791895 B CN 102791895B CN 201080054949 A CN201080054949 A CN 201080054949A CN 102791895 B CN102791895 B CN 102791895B
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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
-
- 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
-
- 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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- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Sheet Steel (AREA)
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 with high working property, be suitable for locomotive, household appliances and boiler (boiler), and its manufacture method, relate more specifically to a kind of high heat resistance processing cold-rolled steel sheet, wherein steel constituent and processing conditions optimised, make it show excellent workability and thermotolerance, and in addition, also can show fade resistance, and relate to its manufacture method.
Background technology
Usually, cast iron (cast iron) is used to the parts that manufacture a product, such as locomotive exhaust system, baking oven, house chimney and boiler etc.But, under described iron continues to be exposed to the hot conditions of at least up to a hundred degrees Celsius, need high heat resistance.For guaranteeing described high temperature properties, use finished Aludip, stainless steel plate etc.
So-called high-temperature behavior, refers to that a kind of product of processing uses one of characteristic shown under the high temperature conditions.When using the products such as such as locomotive exhaust system, the character of these products may be deteriorated because local temperature increases, and therefore needs high temperature properties, namely, sagging resistance (sagging resistance) and hot strength, and the fade resistance that may add.Wherein, sagging resistance measures by observing the degree of sag of steel plate, and the material of described steel plate changes owing to repeatedly exposing at high temperature.If there occurs described sagging, be then difficult to the shape keeping moulded product.In addition, if thermal stresses is applied on a particular location thick and fast, then high-temperature yield strength may reduce, and distortion or the destruction of shape of product occur.Therefore, in order to ensure the steadiness of shape, it is 55MPa or higher that product should meet yield strength when about 700 DEG C of high temperature, in addition, to be oxidized under the high temperature conditions to prevent steel plate and in order to obtain adhesivity to coating material when coating, possible demand schedule surface properties, i.e. fade resistance.
Although stainless steel plate is mainly used in heat-resisting object, its production cost is very high, such as, because add a large amount of expensive alloying element, Cr, Ni etc.In addition, when at high temperature heating, can chromium carbide be precipitated at grain boundaries in the combination of the Cr via C and crystal boundary thus in the Cr-depleted region formed, produce intergranular corrosion, thus cause erosion resistance to reduce.
In order to ensure the oxidation-resistance under high temperature, Aludip can be used.When this Aludip being heated to 400 DEG C or higher high temperature, Fe and Al may spread mutually and grow alloy interface layer, thus loses surface gloss at short notice and cause fading, and thermotolerance is deteriorated.The application of this steel plate is adversely limited.
In addition, the product manufacturing such as such as locomotive exhaust system, baking oven, house chimney and boiler are for being contained in the finite space, and therefore steel plate is formed by multiple method thus gives complicated shape, then need procedure of processings such as extending or bend.Like this, except above-mentioned high temperature properties, also need room temperature processibility.
Therefore, Japanese Unexamined Patent Application publication Unexamined Patent No.9-176816 disclose in a kind of steel Al amount and solid solution N amount through adjust steel plate, described steel plate is aluminized, postheat treatment to strengthen thermotolerance and processibility.But described steel plate is difficult to being in application in the product component of 550 DEG C or higher temperature, and also not easily adjusts the amount of the steel constituent of interpolation, cause the deterioration of processibility and due to aging and produce manufacturing deficiency.
In addition, Japanese Unexamined Patent Application publication Unexamined Patent No.8-319548 discloses a kind of Aludip, and it is formed with coating from the teeth outwards, thus shows superior hot strength.But, provide the method for improvement coating condition due to this patent instead of strengthen the method for steel plate character, being difficult to the component adjusting coating, required thermotolerance can not be obtained.
Summary of the invention
Technical problem
Therefore, the present inventor has carried out much research and has tested to solve problems of the prior art, and propose the present invention based on test result, one object of the present invention is, a kind of high heat resistance processing cold-rolled steel sheet and its manufacture method are provided, wherein, in order to use it for the purposes needing high temperature properties and room temperature processibility simultaneously, as being used in locomotive exhaust system, baking oven, in house chimney and boiler, can reduce and add expensive alloying element, and steel constituent and processing conditions can be optimised, therefore described processibility can be manufactured at low cost, the steel plate of thermotolerance and fade resistance excellence.
Technical scheme
In order to realize above-mentioned target, one aspect of the present invention provides a kind of high heat resistance processing cold-rolled steel sheet, it comprises the N, 0.015% or the iron of less S and surplus and other inevitable impurity of P, 0.002-0.006% of Al, 0.003-0.020% of Mn, 0.02-0.08% of Co, 0.10-0.35% of Nb, 0.02-0.20% of C, 0.02-0.06% of 0.002-0.005%, in % by weight.
Another aspect of the present invention provides a kind of high heat resistance processing cold-rolled steel sheet, it comprises the N, 0.015% or the iron of less S and surplus and other inevitable impurity of P, 0.002-0.006% of Al, 0.003-0.020% of Mn, 0.02-0.08% of Sn, 0.10-0.35% of Co, 0.05-0.25% of Nb, 0.02-0.20% of C, 0.02-0.06% of 0.002-0.005%, in % by weight.
In addition, in the present invention, described Nb and Co is 0.6-3.0 relative to the value of effective interpolation ratio ((Nb × Co)/C) of C, and in addition, (Nb, Co) C base carbide composite precipitation is formed on cold-rolled steel sheet.In addition, described cold-rolled steel sheet is made up of polygonal ferrite and acicular ferrite.
In addition, in the present invention, the volume fraction of described acicular ferrite is 5-15%, and Sn-base oxide layer is formed on the surface of cold-rolled steel sheet, and described Sn-base oxide layer can be Sn
2o
3layer.
In addition, another aspect of the present invention provides a kind of manufacture method of high heat resistance processing cold-rolled steel sheet, comprise this heating steel billet, hot rolling, batch (winding) and cold rolling, thus obtained cold-rolled steel sheet, described steel billet comprises the C of 0.002-0.005%, the Nb of 0.02-0.06%, the Co of 0.02-0.20%, the Mn of 0.10-0.35%, the Al of 0.02-0.08%, the P of 0.003-0.020%, the N of 0.002-0.006%, 0.015% or less S, and the iron of surplus and other inevitable impurity, in % by weight, by described cold-rolled steel sheet 800 DEG C or higher temperature annealing, and by this annealed sheet steel with 30 DEG C/sec or the cooling of higher rate of cooling.
In addition, another aspect of the present invention provides a kind of method manufacturing high heat resistance processing cold-rolled steel sheet, comprise this heating steel billet, hot rolling, to batch and cold rolling, thus obtained cold-rolled steel sheet, described steel billet comprises the C of 0.002-0.005%, the Nb of 0.02-0.06%, the Co of 0.02-0.20%, the Sn of 0.05-0.25%, the Mn of 0.10-0.35%, the Al of 0.02-0.08%, the P of 0.003-0.020%, the N of 0.002-0.006%, 0.015% or less S, and the iron of surplus and other inevitable impurity, in % by weight, by described cold-rolled steel sheet 800 DEG C or higher temperature annealing, and by this annealed sheet steel with 30 DEG C/sec or the cooling of higher rate of cooling.
In addition, in the present invention, in steel billet, Nb and Co is 0.6-3.0 relative to the value of effective interpolation ratio ((Nb × Co)/C) of C.Described hot rolling is included in 900-950 DEG C and carries out finish rolling, and described hot rolling may further include the step cooled with the rate of cooling of 20-80 DEG C/sec by hot-rolled steel sheet.
In addition, described in batch and can carry out at 560-680 DEG C, described annealing can be carried out at 800-900 DEG C.
Invention effect
According to the present invention, cold-rolled steel sheet can with cost manufacture low compared with traditional stainless steel plate, and multiple processing characteristics can be endowed, such as stretch flangeability (stretch flangeability), bendability and deep drawing quality (deep drawability), thus show superior room temperature processibility.In addition, due to the precipitation of the alloying element of solid solution, anti-aging character can increase, thus elongation at yield (yield elongation) does not occur, and thus obtains high formability.Further, hot strength is very high, thus guarantees the shape steadiness of the product used under the high temperature conditions, the thus work-ing life of extension device, and fade resistance excellence at high temperature.
Accompanying drawing explanation
Fig. 1 is the photo compared the invention plate 3 of embodiment 1 and the microtexture of contrast plate 10.
Fig. 2 is the photo compared the invention plate 3 of embodiment 2 and the microtexture of contrast plate 6.
Embodiment
Hereinafter, cold-rolled steel sheet of the present invention will be described in detail.
The present inventor is repeated and repeatedly studies and test, the present invention finally not only meets multiple processing characteristics, such as stretch flangeability, bendability and deep drawing quality etc., and anti-aging character and erosion resistance, but also ensure that yield strength is 55MPa or larger 700 DEG C time, and at high temperature fade resistance may be added.
Like this, one embodiment of the invention (hereinafter referred to " the first invention ") disclose the production of high heat resistance processing cold-rolled steel sheet, wherein in steel plate component, carbon containing minute quantity, and control amount and the ratio of Nb and Co added, thus form meticulous (Nb, Co) C-base carbide composite precipitation, optimize annealing and cooling conditions, to guarantee the volume fraction of predetermined acicular ferrite, thus the steel plate obtained not only at high temperature has excellent thermotolerance and erosion resistance, and in room temperature, there is fabulous resistance to deterioration and processibility, therefore such as locomotive exhaust system is applicable to, baking oven, the product component of house chimney and boiler etc.
Another embodiment of the invention (hereinafter referred to " the second invention ") discloses the production of high heat resistance processing cold-rolled steel sheet, wherein in steel plate component, carbon containing minute quantity, and control amount and the ratio of Nb and Co added, thus form meticulous (Nb, Co) C-base carbide composite precipitation, optimize annealing and cooling conditions, to guarantee the volume fraction of predetermined acicular ferrite, and add Sn to form Sn-base oxide layer at surface of steel plate, thus the steel plate obtained not only at high temperature has superior thermotolerance, erosion resistance and fade resistance, and in room temperature, there is superior resistance to deterioration and processibility, therefore such as locomotive exhaust system is applicable to, baking oven, the product component of house chimney and boiler etc.
First, the reason of component in restriction first invention is described (in whole specification sheets, % by weight is expressed as % simply).
In the present invention, add carbon (C) to strengthen the intensity of steel plate, and mainly generate Nb carbide base and precipitate because reacting with Nb and consume.Along with the amount of the C added increases, tension force and yield strength can increase, but the excessive membership that adds reduces processibility.Therefore, the upper limit of adding this component is preferably set to 0.005%.But if the amount of C is less than 0.002%, cannot obtain the strengthening effect of (Nb, Co) C-base composite precipitation, particle size can increase, thus causes the great variety in steel.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 intensity and the hot workability of steel, but formation MnS can deteriorated ductility and processibility.If add excessive Mn, ductility can decline, and to add a large amount of alloying elements be unhelpful, and can cause center segregation.Therefore, the upper limit adding this component is preferably set to 0.35%.If the amount of Mn is less than 0.10%, although processibility increases, be difficult to guarantee required intensity.Therefore, the amount of Mn is restricted to 0.10-0.35%.
Add aluminium (Al) with deoxygenation in molten steel is combined with the alloying element of solid solution in steel, thus improves ageing property.Therefore, its consumption is preferably set to 0.02% or more.If the amount that this component adds is more than 0.08%, in steel, the amount of inclusion increases and produces surface imperfection, reduces processibility.Therefore, the amount of Al is restricted to 0.02-0.08%.
Add phosphorus (P) to increase intensity and the erosion resistance of steel.For guaranteeing described character, the amount containing P is preferably 0.003% or more.But, if described amount is more than 0.020%, center segregation may be produced when casting, and processibility reduces.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 is less than 0.002%, cannot obtain enough hardness, the position forming precipitation tails off.On the contrary, if its consumption is more than 0.006%, because excessive solid solution alloy element may occur aging, cause sclerosis, thus become the major cause of deteriorated plasticity.Therefore, the amount of N is restricted to 0.002-0.006%.
Sulphur (S) is combined with Mn in steel, thus forms non-metallic inclusions, and it has the effect of initiation corrosion and can cause red brittleness, and the amount therefore contained is preferably the least possible.The amount of S is restricted to 0.015% or less.For guaranteeing above effect, the amount of preferred S controls 0.010% or less.
Niobium (Nb) to the raising of the intensity of steel plate and grain refining effective.In the present invention, its C of solid solution in steel is combined and forms (Nb, Co) C-base carbide composite precipitation, thus improves ageing property and formability.By the formation of described (Nb, Co) C-base carbide composite precipitation, intensity can increase and suppress ferrite crystal grain growth at high temperature, thus obtains the thinning effect to ferrite particles.Therefore, the amount that Nb preferably adds is 0.02% or more.If its consumption is more than 0.06%, steel may harden, and in the anneal continued, processibility can reduce, and the surface properties of steel plate also may deterioration.Therefore, the amount of Nb is restricted to 0.02-0.06%.
Cobalt (Co) promotes the formation precipitated in steel, thus gains in strength and erosion resistance.For reaching above effect, the amount containing Co is preferably 0.02% or more.If its consumption is more than 0.20%, then the elongation of steel declines, and can increase manufacturing cost owing to adding a large amount of expensive alloying element, but not helps lend some impetus to precipitation.Therefore, the amount of Co is restricted to 0.02-0.20%.
The process respectively of Nb and Co is very important, but control Nb and Co remains in predetermined scope for the effective weight ratio ((Nb × Co)/C) of C, also very important to guarantee at room temperature not only to there is anti-aging character but also there is hot strength.
That is, when the value of (Nb × Co)/C is 0.6-3.0, formed by (Nb, Co) C-base carbide composite precipitation and the C of solid solution in fixing steel, guarantee the anti-aging character under room temperature and processibility thus.In addition, control annealing and cooling conditions suitably, thus form meticulous (Nb, Co) C-base carbide composite precipitation, under suppression high temperature, the growth of crystal grain, to control ferritic microtexture, finally guarantees fabulous high temperature properties thus.
But, if the value of (Nb × Co)/C is lower than 0.6, in steel, there is excessive solid solution element, cause the deterioration of anti-aging character under room temperature and processibility, and the amount of (Nb, Co) C-base carbide composite precipitation is not remarkable, makes to guarantee hot strength.On the other hand, if its numerical value is more than 3.0, steel may harden, and recrystallization temperature sharply increases, and surface properties may be deteriorated, thus be reduced in the processibility in aftertreatment.Therefore, the value of (Nb × Co)/C is restricted to 0.6-3.0.
Equally, for realizing the second invention of the present invention, tin (Sn) is added extraly.Sn exists with solid solution condition in steel, and it increases high temperature properties and erosion resistance, and is heated by thermal treatment and be oxidized, and therefore forms Sn-base oxide such as Sn on the surface of steel plate
2o
3, thus suppress to form alloy layer, to strengthen erosion resistance and fade resistance at surface of steel plate.For reaching this effect, the amount that this component preferably adds is 0.05% or more.If its consumption is more than 0.25%, manufacturing cost can increase, but not contributes to increasing erosion resistance or fade resistance.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 of surplus and inevitable impurity.As required, other alloying elements can also additionally be added to increase the character of cold-rolled steel sheet of the present invention.Add the alloying element do not recorded in embodiments of the present invention, be not considered to be beyond scope of the present invention.
Meanwhile, cold-rolled steel sheet of the present invention comprises polygonal ferrite (polygonal ferrite) and acicular ferrite.Thus, acicular ferrite is a kind of bainite grown via nucleation in austenite grains before conversion.Because this structure is by the meticulous non-metallic inclusions of disperseing in steel via nucleating growth, thus it forms random structure, wherein ferrite bar (lath) forms the crystal boundary of high angle at the time point transformed, and has relatively superior ductility or toughness.
According to the present invention, by controlling aptly to anneal and cooling conditions guarantees the volume fraction of the described acicular ferrite of 5-15%, the microtexture of formation high-density type like this.Therefore, at high temperature suppress the misgrowth of crystal grain, thus guarantee hot strength, strengthen thermotolerance.If the volume fraction of described acicular ferrite is lower than 5%, be then difficult to guarantee hot strength, make to be difficult to the thermotolerance required for acquisition.On the contrary, if the volume fraction of acicular ferrite is more than 15%, then the deterioration of processibility is caused due to hardened material.Therefore, the volume fraction of acicular ferrite is restricted to 5-15%.
Below, the manufacture method of high heat resistance processing cold-rolled steel sheet of the present invention is described in detail.
The steel billet reheating of above-mentioned composition will be had, hot rolling, batch, cold rolling, then at 800 DEG C or higher annealing temperature, thus make a kind of steel plate, and cool described steel plate with 30 DEG C/sec or higher rate of cooling, thus obtained a kind of high heat resistance processing cold-rolled steel sheet, it has superior processibility and thermotolerance, and may add fade resistance.
When in typical temperature, after the steel billet of said components is carried out reheating, during hot rolling, final rolling temperature is 900-950 DEG C.If final rolling temperature is lower than 900 DEG C, then hot rolling stops in relatively low temperature range, makes the final crystal grain formed be easy to mixing, causes the deterioration of processibility and rollability.On the contrary, if final rolling temperature is more than 950 DEG C, then cannot carry out hot rolling equably on whole thickness, the refinement of crystal grain is insufficient thus, crystal grain roughening, thus impelling strength reduces.Therefore, final rolling temperature is restricted to 900-950 DEG C.
After above-mentioned hot finishing terminates, hot rolled steel above cools at runoff table (run-out table) with the speed of 20-80 DEG C/sec.If rate of cooling is lower than 20 DEG C/sec, the growth of crystal grain can be promoted and form comparatively coarse particle, thus reduces intensity and processibility.On the contrary, if rate of cooling is more than 80 DEG C/sec, due to cooling uneven on the direction of width, mechanical properties may be departed from.
On the run-out table after cooling, batch hot-rolled steel sheet at 560-680 DEG C.If coiling temperature is lower than 560 DEG C, hot rolled plate may slightly harden, increase cold rolling subsequently in load, thus be difficult to guarantee rollability.In addition, uneven rolling degree in the direction of the width increases, and the difference of the production behavior precipitated at low temperatures may 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 DEG C, the structure of the finished product becomes coarse, causes the deterioration of processibility and erosion resistance.Therefore, coiling temperature is restricted to 560-680 DEG C.
Then the steel plate batched described in completing is cold-rolled to desired thickness by pickling (pickling), carries out continuing annealing to control recrystallization and microtexture afterwards at 800 DEG C or higher temperature.Described 800 DEG C or higher annealing temperature are the temperature for fully guaranteeing needed for the motivating force that acicular ferrite transforms.If annealing temperature is lower than 800 DEG C, the required volume fraction of the acicular ferrite existed in steel plate microtexture cannot be obtained, thus be difficult to guarantee superior high temperature properties, increase the generation of the surface imperfection of steel plate when high temperature annealing, therefore, annealing temperature is preferably set to 900 DEG C or lower.
The steel plate of above-mentioned annealing can guarantee the volume fraction of the acicular ferrite needed by cooling.For this reason, rate of cooling remains on 30 DEG C/sec or higher.If rate of cooling is lower than 30 DEG C/sec, the volume fraction of required acicular ferrite can not be reached due to Slow cooling.
Below, by embodiment, more specific description is carried out to the present invention.
[embodiment 1]
Manufacture invention steel 1,2 and compared steel 1 to 5 by listed component in fusing following table 1, and process under processing conditions shown in table 2, thus the invention plate 1 to 4 obtained as cold-rolled steel sheet and contrast plate 1 to 10.To each cold-rolled steel sheet of described manufacture, carry out the evaluation of acicular ferrite volume fraction and room temperatures properties and high temperature properties, the results are shown in following table 3.
In the character of table 3, elongation at yield phenomenon is assessed as follows, and according to surveyed elongation at yield rate, the situation occurring to extend represents with " generation ", and the situation not occurring to extend represents with " generation ".Equally, resistance to bending according to the face bend degree of finished steel plate with five bending level evaluations.Particularly, the grade 1 and 2 that degree of crook is relatively low is assessed as " good ", and naked-eye observation is assessed as " poor " to bending grade 3-5.
Equally, sagging resistance is assessed as follows, by total length be the steel plate equipment for Heating Processing of 250mm and width 30mm 700 DEG C of reheating 100 hours, measure the sagging of steel plate afterwards, sag is the assessment of scenario of 5mm or larger is thus " poor ".Equally, when the yield strength at 700 DEG C is less than 55MPa, high-temperature yield strength is evaluated as " poor ", when it is 55MPa or larger, is evaluated as " good ".In addition, room temperature add produce crack man-hour time, processibility is assessed as " poor ".
Table 1
The component of invention steel and compared steel
Table 2
The manufacture 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 (%) | Property | Property | Intensity | |||
| Invention 1 | 9.6 | Do not produce | Good | Good | Good | Good |
| Invention 2 | 10.3 | Do not produce | Good | 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 | 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 | 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 meets 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, owing to producing (Nb, Co) C-base carbide composite precipitation and optimizing the volume fraction of acicular ferrite, the high-temperature yield strength thus after thermal treatment and sagging resistance are all fine.At room temperature add man-hour, do not occur defect, show superior room temperature processibility.
But, although the component of steel meets the scope of the invention in table 1, the processing conditions in table 2 departs from the contrast plate 1 to 5 of the scope of the invention, and the volume fraction of its acicular ferrite significantly reduces, not there is excellent high temperature properties, processibility and anti-aging character also poor.
Further, although the processing conditions in table 2 meets the scope of the invention, in the steel constituent in table 1, C, Nb, Co etc. depart from the contrast plate 6 to 10 of the scope of the invention, and the volume fraction of its acicular ferrite is low, room temperature and high temperature properties major part 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, but be equivalent to the sagging resistance of high temperature properties and hot strength poor.This is because do not add Co component, because this reducing (Nb, Co) C-base carbide composite precipitation and profitability thereof.Contrast plate 7 to 10 in, the solid solution C content in steel is many, therefore processibility and anti-aging character poor.And amount or its adding proportion of Nb and Co of interpolation are low, therefore (Nb, Co) C-base carbide composite precipitation is not remarkable, and make the volume fraction of acicular ferrite low, high temperature properties is poor, is difficult to meet processibility and high temperature properties simultaneously.
Meanwhile, Fig. 1 is the photo compared with the microtexture of contrast plate 10 invention plate 3.In the invention plate 3 of Fig. 1 (a), the ferrite close to polygonal shape is polygonal ferrite, and the ferrite be elongated is acicular ferrite.The volume fraction of the acicular ferrite that described invention plate 3 has is 7.9%, and the evaluation in room temperature and high temperature properties is all fine.But the contrast plate 10 of Fig. 1 (b) is not only made up of polygonal ferrite containing acicular ferrite, therefore confirms from table 3, anti-aging character, processibility and poor heat resistance.
Therefore, the condition (particularly annealing and cooling conditions) of steel constituent condition and manufacturing processed is carried out to optimization and formed meticulous (Nb, Co) C-base carbide composite precipitation, control the volume fraction of acicular ferrite, thus obtain the high heat resistance processing cold-rolled steel sheet simultaneously meeting high temperature properties and processibility with low cost.
Embodiment 2
These are carried out processing and the invention plate 1 to 5 that obtains as cold-rolled steel sheet and contrast plate 1 to 10 by obtained invention steel 1,2 and compared steel 1 to 5 by listed component in fusing following table 4 under the processing conditions shown in following table 5.Afterwards the acicular ferrite volume fraction of these cold-rolled steel sheets and room temperatures properties and high temperature properties are evaluated, the results are shown in following table 6.
Elongation at yield phenomenon is assessed as follows, and according to surveyed elongation at yield rate, the situation occurring to extend represents with " generation ", and the situation not occurring to extend represents with " generation ".Equally, resistance to bending according to the face bend degree of finished steel plate with five bending level evaluations.Particularly, be assessed as " good " in the grade 1 and 2 that degree of crook is relatively low, naked-eye observation is assessed as " poor " to bending grade 3-5.
Equally, sagging resistance is assessed as follows, by total length be the steel plate equipment for Heating Processing of 250mm and width 30mm 700 DEG C of reheating 100 hours, measure the sagging of steel plate afterwards, such sag is the assessment of scenario of 5mm or larger is " poor ".In addition, when the yield strength at 700 DEG C is lower than 55MPa, high-temperature yield strength is evaluated as " poor ", when it is 55MPa or larger, is evaluated as " good ".After steel plate keeps 48 hours in 500 DEG C, when surface gloss reduces by 30% or larger, high temperature fade resistance is evaluated as " poor ".
In addition, room temperature add produce crack (crack) man-hour time processibility be assessed as " poor ".
Table 4
The component of invention steel and compared steel
Table 5
The manufacture 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 meet 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.Owing to producing (Nb, Co) C-base carbide composite precipitation and optimizing the volume fraction of acicular ferrite, its high-temperature yield strength after heat treatment and sagging resistance all fine.Further, at high temperature surface gloss reduced rate is less than 30%, and therefore fade resistance is good, and at room temperature adds man-hour, does not occur crack, shows fabulous room temperature processibility.
But, in table 4, the component of steel meets the scope of the invention, but the processing conditions in table 5 departs from the contrast plate 1 to 5 of the scope of the invention, the volume fraction major part of its acicular ferrite is all very low, cause failing obtaining good high temperature properties (sagging resistance, hot strength, fade resistance), and processibility and anti-aging character (elongation at yield, resistance to bending) also very poor.
In addition, the processing conditions in table 5 meets 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, carries out properties evaluations after manufacture to it.As a result, the volume fraction of its acicular ferrite is zero or very low, room temperature and high temperature properties major part all very poor.Wherein, in contrast plate 7, do not produce elongation at yield, and obtain good resistance to bending and processibility, but it is poor to be equivalent to the sagging resistance of high temperature properties, hot strength and fade resistance.This is because do not add Co component, because this reducing formation and the profitability thereof of (Nb, Co) C-base carbide composite precipitation.Further, the C amount of contrast plate 8 to 10 containing solid solution in a large amount of steel, therefore represents the processibility and anti-aging character of going on business.In addition, do not add Nb or Co or its adding proportion is low, therefore precipitation capacity is not enough, makes the volume fraction of acicular ferrite low, sagging resistance and high-temperature yield strength low.In addition, fade resistance is poor, makes it be difficult to meet room temperature processibility and high temperature properties simultaneously.
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 ferrite close to polygonal shape is polygonal ferrite, and the ferrite be stretched is acicular ferrite.The volume fraction of the acicular ferrite that invention plate 3 has is 7.9%, all fine in room temperature and high temperature properties.But confirm in table 6, Fig. 2 (b) shows that contrast plate 6 only defines polygonal ferrite and do not contain acicular ferrite, and therefore room temperatures properties and high temperature properties are all poor.
In a word, the condition (particularly annealing and cooling conditions) of steel constituent and manufacturing processed is optimized, meticulous (Nb can be formed thus, Co) C-base carbide composite precipitation, and the volume fraction of acicular ferrite can be controlled, and Sn-base oxide layer can be formed at surface of steel plate, thus show fabulous fade resistance, can obtain with low cost the high heat resistance processing cold-rolled steel sheet simultaneously meeting processibility, high temperature properties and fade resistance thus.
Above-mentioned embodiment is an illustration only, and the present invention is not limited thereto.By the formation substantive identical with the technological thought recorded within the scope of the claims in the present invention, play any other technology of identical action effect, include within the scope of the technology of the present invention.
Claims (9)
1. a high heat resistance processing cold-rolled steel sheet, comprise the N of P, 0.002-0.006% of Al, 0.003-0.020% of Mn, 0.02-0.08% of Co, 0.10-0.35% of Nb, 0.02-0.20% of C, 0.02-0.06% of 0.002-0.005%, 0.015% or the iron of less S and surplus and other inevitable impurity, in % by weight
Wherein said Nb and Co is 0.6-3.0 for effective adding proportion (Nb × Co)/C of C, and in described cold-rolled steel sheet, form (Nb, Co) C-base carbide composite precipitation.
2. a high heat resistance processing cold-rolled steel sheet, comprise the N of P, 0.002-0.006% of Al, 0.003-0.020% of Mn, 0.02-0.08% of Sn, 0.10-0.35% of Co, 0.05-0.25% of Nb, 0.02-0.20% of C, 0.02-0.06% of 0.002-0.005%, 0.015% or the iron of less S and surplus and other inevitable impurity, in % by weight
Wherein said Nb and Co is 0.6-3.0 for effective adding proportion (Nb × Co)/C of C, and in described cold-rolled steel sheet, form (Nb, Co) C-base carbide composite precipitation.
3. the high heat resistance processing cold-rolled steel sheet described in claim 1 or 2, wherein said cold-rolled steel sheet contains polygonal ferrite and acicular ferrite.
4. high heat resistance processing cold-rolled steel sheet according to claim 3, the volume fraction of wherein said acicular ferrite is 5-15%.
5. high heat resistance processing cold-rolled steel sheet according to claim 2, the surface of wherein said cold-rolled steel sheet forms Sn-base oxide layer.
6. high heat resistance processing cold-rolled steel sheet according to claim 5, wherein Sn-base oxide layer is Sn
2o
3layer.
7. the manufacture method of a high heat resistance processing cold-rolled steel sheet, comprise heating steel billet, hot rolling, batch with cold rolling, thus obtain a kind of cold-rolled steel sheet, described steel billet contains the N, 0.015% or the iron of less S and surplus and other inevitable impurity of P, 0.002-0.006% of Al, 0.003-0.020% of Mn, 0.02-0.08% of Co, 0.10-0.35% of Nb, 0.02-0.20% of C, 0.02-0.06% of 0.002-0.005%, in % by weight; By described cold-rolled steel sheet at 800 DEG C or higher annealing temperature, thus obtain a kind of steel plate of annealing; And by described annealed sheet steel with 30 DEG C/sec or the cooling of higher rate of cooling,
Wherein said hot rolling is included in 900-950 DEG C and carries out finish rolling, and finish rolling also comprises the step being carried out with the rate of cooling of 20-80 DEG C/sec by hot rolled steel plate cooling, described in batch and carry out at 560-680 DEG C, described annealing is carried out at 800-900 DEG C.
8. the manufacture method of a high heat resistance processing cold-rolled steel sheet, comprise heating steel billet, hot rolling, batch with cold rolling, thus obtain a kind of cold-rolled steel sheet, described steel billet contains the N, 0.015% or the iron of less S and surplus and other inevitable impurity of P, 0.002-0.006% of Al, 0.003-0.020% of Mn, 0.02-0.08% of Sn, 0.10-0.35% of Co, 0.05-0.25% of Nb, 0.02-0.20% of C, 0.02-0.06% of 0.002-0.005%, in % by weight; By described cold-rolled steel sheet at 800 DEG C or higher annealing temperature, thus obtain a kind of annealed sheet steel; And by described annealed sheet steel with 30 DEG C/sec or the cooling of higher rate of cooling,
Wherein said hot rolling is included in 900-950 DEG C and carries out finish rolling, and finish rolling also comprises the step being carried out with the rate of cooling of 20-80 DEG C/sec by hot rolled steel plate cooling, described in batch and carry out at 560-680 DEG C, described annealing is carried out at 800-900 DEG C.
9. the manufacture method of the high heat resistance processing cold-rolled steel sheet described in claim 7 or 8, wherein in described steel billet, Nb and Co is 0.6-3.0 for effective adding proportion (Nb × Co)/C of C.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10-2009-0120143 | 2009-12-04 | ||
| 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 |
| 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 |
| KR10-2009-0120150 | 2009-12-04 | ||
| 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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| Publication Number | Publication Date |
|---|---|
| CN102791895A CN102791895A (en) | 2012-11-21 |
| CN102791895B true 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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| Country | Link |
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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 (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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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| 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 |
| JP3518515B2 (en) * | 2000-03-30 | 2004-04-12 | 住友金属工業株式会社 | Low / medium Cr heat resistant steel |
| 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 |
| KR20060061857A (en) * | 2003-11-14 | 2006-06-08 | 신닛뽄세이테쯔 카부시키카이샤 | Steel product for flue gas treatment facilities excellent in capability of being cut by gas and/or wear resistance, and flue gas duct |
| EP1807542A1 (en) * | 2004-11-03 | 2007-07-18 | ThyssenKrupp Steel AG | High-strength steel strip or sheet exhibiting twip properties and method for producing said strip by direct strip casting " |
| WO2007049915A1 (en) * | 2005-10-25 | 2007-05-03 | Posco | Corrosion resistance improved steel sheet for autmotive muffler and method of producing the steel sheet |
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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 (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2013512337A (en) | 2013-04-11 |
| JP5586704B2 (en) | 2014-09-10 |
| WO2011068328A2 (en) | 2011-06-09 |
| WO2011068328A3 (en) | 2011-11-03 |
| CN102791895A (en) | 2012-11-21 |
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