CN1890389A - Steel sheet for containers, and manufacturing method therefor - Google Patents

Abstract

Steel sheet and manufacturing method for manufacturing steel sheet for containers are provided. For example, the steel sheet (or at least a portion thereof) can include approximately, in terms of mass%, C: 0.0800% or less, N: 0.600% or less, Si: 2.0% or less, Mn: 2.0% or less, P: 0.10% or less, S: 0.05% or less, Al: 2.0% or less, and the remainder Fe. The sheet (or portion thereof) can be cold-rolled, and then the atmosphere, temperature, time, etc. of recrystallization annealing or subsequent heat treatment may be adjusted to control the change in N content in the steel, for example controlling the N content and hardness of the surface layer and mid-thickness layer to bring them within an appropriate range. The surface roughness can be 0.90 m or less in terms of Ra, and PPI, which is the number of concavo-convex peaks per one inch of length, may be 250 or more.

Description

The steel plate and the manufacture method thereof that are used for container

Technical field

The present invention relates to steel plate, comprise that surface-treated is used for the steel plate of metal vessel such as beverages can, and manufacture method.

It requires the right of priority of the Japanese patent application submitted on December 9th, 2003 2003-409918 number, and its content is incorporated this paper into as a reference.

Background technology

With beverages can, food cans etc. is the steel plate that is used for container of representative, is made more and more frivolous so that reduce the production cost of these class different vessels, has used the following material of 0.2mm now.When using this ultra-thin materials to make container, the adhesive power of attenuating that many problems comprise tone for example, top coat can appear and owing to being difficult to the weldability that the control surface state causes.

As everyone knows, described at for example Japanese Patent Application Publication H11-197704, H8-3781 and H6-57488, the condition of surface of steel plate greatly affects tone, top coat adhesive power and weldability.In addition, a kind of method that is used for the control surface roughness has been described among the Japanese Patent Application Publication H7-9005.In the publication of quoting in the above, must accurately create conditions, but the degeneration of productivity aspect obviously is inevitable with the control surface state.In addition, the conventional control method described in these publications always is not enough to improve tone, top coat adhesive power and the weldability of the container made from ultra-thin materials, and this is an one object of the present invention.

An object of the present invention is by providing a kind of special steel plate and manufacture method thereof to solve the problem of the tone that depends on the surface of steel plate state about container, top coat adhesive power and weldability in the container that uses the ultra-thin sheet material manufacturing.Another object of the present invention is to carry out certain mode control improvement is provided by apply nitrogenize at the surface of material and interior thickness layer, thus can make not only may command surface of steel plate state but also can avoid increasing the special processing of any obstruction productivity.

Summary of the invention

The technology of having described in post-weld annealed process nitrogenize steel plate for Japanese patent application 2003-119381 and 2003-100720 number and suitably having controlled nitridation conditions at the thickness direction of plate.This technology does not provide in order for example excessively to reduce steel plate flexible purpose when greatly improving the container resistance capacity to deformation.In the process of the weldability of estimating these materials etc., confirmable is to have such a case, and promptly the condition of surface of steel plate becomes more favourable, thereby makes it possible to improve greatly tone, top coat adhesive power and the weldability of container.These characteristics depend on the state of surface of steel plate, even and proposed one not as usual to this class material carried out applies catholyte, use tensio-active agent, meticulous control Cr oxide compound, use that the roll-in precision of meticulous control carries out also existing under the situation of special roll-in etc. about make the problem aspect the container by ultrafine steel plate materials.

For example, carry out nitrogenize after cold rolling when increasing the nitrogen content in the steel, produce tone, top coat adhesive power or weldability that different surface hardnesses not necessarily can be improved jar usually simply.Yet, exemplary of the present invention by suitable control composition of steel, nitridation conditions and nitrogenize after the state of steel plate make it possible to improve tone, top coat adhesive power and the weldability of the jar of making by ultra-thin materials.In addition, according to the exemplary brief description of steel plate of the present invention and correlation method reach the optimum condition of these exemplary advantage.

According to one of the present invention exemplary that is used for the steel plate of container is to have the 0.400mm or the steel plate that is used for container of plate thickness still less, it is characterized in that it comprises, by percentage to the quality, C:0.0800% or still less, N:0.600% or still less, Si:2.0% or still less, Mn:2.0% or still less, P:0.10% or still less, S:0.05% or still less and Al:2.0% or still less; (the N content of 1/8 thickness surface layer)-(the N content of 1/4 thickness interior thickness layer) is 10ppm or more, (the N content of 1/8 thickness surface layer) is 20000ppm or still less, surfaceness is counted 0.90 μ m or lower with Ra, and PPI is that the concavo-convex peak number of each inchage is 250 or more.

According to the exemplary that another is used for the steel plate of container of the present invention is to have the 0.400mm or the steel plate that is used for container of plate thickness still less, it is characterized in that it comprises, by percentage to the quality, C:0.0800% or still less, N:0.600% or still less, Si:2.0% or still less, Mn:2.0% or still less, P:0.10% or still less, S:0.05% or still less and Al:2.0% or still less; (the average Vickers' hardness of steel plate cross section of 1/8 thickness surface layer)-(the average Vickers' hardness of steel plate cross section of 1/4 thickness interior thickness layer)＞10 points, perhaps (the average Vickers' hardness of steel plate cross section of 1/8 thickness surface layer)-(the average Vickers' hardness of steel plate cross section of 1/4 thickness interior thickness layer)＞20 points, surfaceness is counted 0.90 μ m or lower with Ra, and PPI is that the concavo-convex peak number of each inchage is 250 or more.

In addition, also can comprise following by percentage to the quality a kind of, two or more compositions according to the exemplary of steel plate of the present invention: titanium: 0.05% or still less, Nb:0.05% or still less and B:0.015% or still less.By the average assay of 1/4 plate thickness interior thickness layer, steel plate can comprise following a kind of, two or more compositions: titanium: 4 * C+1.5 * S+3.4 * N or more, Nb:7.8 * C+6.6 * N or more and B:0.8 * N or more.And, steel plate can comprise by percentage to the quality following a kind of, two or more compositions: Cr:20% or still less, Ni:10% or still less and Cu:5% or still less.In addition, also to comprise by percentage to the quality total amount be 0.1% or Sn still less, Sb, Mo, Ta, V and W to steel plate.

The exemplary of method that is used for the steel plate of container according to a manufacturing of the present invention is the 0.400mm or the manufacture method of the steel plate of plate thickness still less, it is characterized in that and to comprise, by percentage to the quality, C:0.0800% or still less, N:0.0300% or still less, Si:2.0% or still less, Mn:2.0% or still less, P:0.10% or still less, S:0.05% or still less, Al:2.0% or still less and the cold-rolling of steel plate of the Fe of surplus and unavoidable impurities, then simultaneously or after recrystallization annealing, carry out nitrogenize, wherein (the average increasing amount of N content (mass percent) on whole plate thickness directions) is no more than 6000ppm, and (increasing amount of the N concentration of 1/8 thickness surface layer) is controlled at 20000ppm or lower, the absolute value of (increasing amount of the N content (mass percent) of 1/8 thickness surface layer)/(increasing amount of the N content (mass percent) of 1/4 thickness interior thickness layer) is controlled at 2.0 or higher, surfaceness is controlled at 0.90 μ m or lower in Ra, and PPI is that the concavo-convex peak number of each inchage is controlled at 250 or more.

The exemplary of method that is used for the steel plate of container according to another manufacturing of the present invention is the 0.400mm or the manufacture method of the steel plate that is used for container of plate thickness still less, it is characterized in that to comprise by percentage to the quality: C:0.0800% or still less, N:0.0300% or still less, Si:2.0% or still less, Mn:2.0% or still less, P:0.10% or still less, S:0.05% or still less, Al:2.0% or still less and the steel plate of the Fe of surplus and unavoidable impurities carry out cold rolling, then, simultaneously or after recrystallization annealing, carry out the manufacture method of nitrogenize, wherein average across the direction of plate thickness on the increasing amount of N content be no more than 6000ppm, control (the average Vickers' hardness of steel plate cross section of 1/8 thickness surface layer)-(the average Vickers' hardness of steel plate cross section of 1/4 thickness interior thickness layer)＞10 points, perhaps (the average Vickers' hardness of steel plate cross section of 1/8 thickness surface layer)-(the average Vickers' hardness of steel plate cross section of 1/4 thickness interior thickness layer)＞20 points, surfaceness is controlled at 0.90 μ m or lower in Ra, and PPI is that the concavo-convex peak number of each inchage is controlled at 250 or more.

In addition, exemplary steel plate composition can also be by percentage to the quality be grouped into by following a kind of, two or more one-tenth: titanium: 0.05% or still less, Nb:0.05% or still less and B:0.015% or still less.By the average assay of 1/4 plate thickness interior thickness layer, also can comprise following a kind of, two or more compositions: titanium: 4 * C+1.5 * S+3.4 * N or more, Nb:7.8 * C+6.6 * N or more and B:0.8 * N or more.

Another exemplary steel plate composition can be by percentage to the quality be grouped into by following a kind of, two or more one-tenth: Cr:20% or still less, Ni:10% or still less and Cu:5% or still less.The steel plate composition also can be by total amount by percentage to the quality 0.1% or still less Sn, Sb, Mo, Ta, V and W form.For simultaneously or after recrystallization annealing, carry out nitrogenize, the plate temperature can be in 550～800 ℃ steel plate comprise 0.02% or the atmosphere of more ammonias in place and be no less than 1 second but be no more than 360 seconds time, make be in after the nitrogenize temperature in the thermal history in 550 ℃ or the higher temperature scope (℃) and the product of time (second) be 48000 or lower, the average rate of cooling that perhaps makes 550 ℃～300 ℃ is 10 ℃/second or faster.After the recrystallization annealing and before the nitrogenize or the ratio of cold-rolled compression again after the nitrogenize can be 20% or littler.

According to can be after the avoiding nitrogenize complicated processing of the steel plate that is used for container of illustrative embodiments of the invention and manufacture method thereof and because the productivity that this complex process caused is improved tone, top coat adhesive power and the weldability of container when hindering.Therefore, it can keep with traditional sheet material and comprise the same high productivity of method of the complex process that is used for ultra-thin tank plate and a kind of industrial useful effect is provided.

Description of drawings

Fig. 1 is according to the 1/4 thickness surface layer of the steel plate that is used for container of illustrative embodiments of the invention and the typical side-view of 1/8 thickness surface layer.

Fig. 2 be marked with for its light plate the Vickers' hardness measuring position Fig. 1 the layer explanation.

Embodiment

The steel product ingredient that is used for illustrative embodiments of the invention is described below.Steel product ingredient is represented by mass percentage.

Be defined as C:0.0800% on C content concrete before the annealing, this is favourable for the degeneration aspect of being avoided processibility.For example, the upper limit can be decided to be 0.0600% or lower, perhaps more preferably is 0.0400% or lower.

According to the steel of illustrative embodiments of the invention, wherein have with the C similar characteristics, can have the low levels of similar C by the content of the nitrogenize N that increase after the annealing, this is favourable from the viewpoint of guaranteeing intensity etc.Even C:0.0050% or still less, intensity also can guarantee, 0.0020% or C content still less also allow.At C content is 0.0015% or still less the time, can produce the ultra-soft material that belongs to outside the common container material standard, and this depends on the balance with the amount of nitrogenize.

Similar with C, annealing before N content on be defined as N:0.0300% or lower, this is favourable for the degeneration aspect of being avoided processibility.N:0.0200% or lower be preferred, N:0.0150% or lower be preferred, N:0.0100% is further preferred, N:0.0050% or lower be further preferred, N:0.0030% is and is further preferred.It should be noted that as will be described below, provide favourable effect a kind of tone, top coat adhesive power and the weldability for jar by the N that introduces of nitrogenize after the annealing, this with annealing before effect of N of existence be different.

Can add the intensity that Si regulates container.Too many Si can reduce processibility and coating characteristic, so the content of Si is preferably 2.0% or lower.In according to steel of the present invention, Si can form nitride with the N that penetrates into owing to nitrogenize in the steel at grain boundary, thereby causes embrittlement and retarding effect of the present invention, and therefore should preferably limit Si content is 1.5% or lower, and even 1.0% or lower.

Can add Mn and regulate intensity.Too many Mn can reduce processibility, so the content of Mn is set at 2.0% or lower.

Can add P and regulate intensity.Too many P not only can reduce processibility, but also can hinder the nitrogenize of steel plate, and the content that therefore preferably sets P is 0.10% or lower.

S can reduce hot ductility, and can hinder casting and hot rolling, and the content of therefore setting S is 0.05% or lower.

Al is used for the element of deoxidation a kind of can the adding.Too high-load Al makes that casting is more difficult and causes damage as the surface imperfection of increase, so the content of Al is set at 2.0% or lower.

To describe below except the above-mentioned effect and the control thereof of the element the fundamental element that the steel plate that is used for container is considered usually.

Ti can improve the recrystallization temperature of steel plate, and reduces the annealing transmission of ultra-thin steel sheet, and this is one of the object of the invention.Thereby Ti can be set at 0.050% or lower.In the common application of the high r value of special requirement not, do not need to add Ti, and be preferably set to 0.03% or lower, 0.02% or lower be more preferred.

Nb has with Ti and similarly acts on, and improves the recrystallization temperature of steel plate and obviously reduces the annealing transmission of ultra-thin steel sheet, and this is one of the object of the invention.Thereby the content of Nb is preferably 0.050% or lower.In the common application of the high r value of special requirement not, need not add too many Nb, be preferably 0.03% or lower, 0.01% or lower be more preferred.

When in according to the steel plate of comprising of illustrative embodiments of the invention about 0.01% or more Ti and Nb, adding B, can improve the recrystallization temperature of steel plate, obviously reduce annealing transmission simultaneously as the ultra-thin steel sheet of one of the object of the invention.On the other hand, if the content of Ti and Nb is low, so just exist little disadvantageous effect on this point, in fact recrystallization temperature is lowered, and making like this can recrystallization annealing under lower temperature.In addition, because B has the effect that the annealing of improving is transmitted, so it can even initiatively add.But,, the tangible sheet material cracking of (comprising bloom, billet etc.) in casting cycle, will occur, so the upper limit is preferably set to 0.015% along with excessive interpolation.In order to reduce recrystallization temperature and to improve annealing and transmit, the relation of N content should satisfy B/N=0.6～1.5 before B content and the nitrogenize.

In addition, as one of the object of the invention, for the Ti by before nitrogenize, keeping solid solution and make since in nitridation process, penetrate into from the surface titanium nitride that the N the steel plate forms especially the formation in the surface of steel plate layer increase effect, preferably by the average assay adding titanium of 1/4 thickness interior thickness layer: 4 * C+1.5 * S+3.4 * N or more, Nb:7.8 * C+6.6 * N or more and B:0.8 * N or more in one or more compositions.Because the N content of upper layer of the present invention can change a lot, and above-mentioned value also can correspondingly change, therefore can so represent the average assay of 1/4 thickness interior thickness layer before and after nitrogenize.

According to exemplary of the present invention, can be by using wherein represent the value in the final sheet material after the nitrogenize because the average assay of 1/4 thickness interior thickness layer of very little variation takes place in nitrogenize.In addition, in order to give the erosion resistance of characteristic as increasing that exemplary of the present invention does not have explanation, Cr:20% or lower, Ni:10% or lower and Cu:5% or lower adding will not reduce effect of the present invention.Especially, the Cr of solid solution preferentially combines with the N nitrogenize that is seeped into owing to nitrogenize in the steel plate in the steel, and has the effect that forms meticulous Cr nitride in steel, particularly at surface of steel plate, can utilize these nitride to increase effect of the present invention like this.For this purpose, preferably add 0.01% or higher Cr.But Cr also can increase the recrystallization temperature of steel plate, and excessive adding can reduce the annealing transmission as the ultra-thin steel sheet of one of the object of the invention significantly.The reduction that the annealing that causes for fear of raising owing to recrystallization temperature is transmitted, the add-on that preferably limits Cr is 2.0% or lower.The content of Cr is 0.6% or when lower, the rising of recrystallization temperature can be suppressed to the degree that practical problems might not occur.

In addition, can add total amount be 0.1% or Sn still less, Sb, Mo, Ta, V and W with when in no case can reducing effect of the present invention, give illustrative embodiments of the invention do not had the explanation characteristic.

In the above-mentioned element, under given conditions, P, B, Sn and Sb can reduce the nitrogenize efficient as an important requirement of the present invention, thereby the preferred maximum level of considering to limit them is to balance each other with nitridation conditions.

Division on the steel plate thickness direction be used to describe illustrative embodiments of the invention is described below with reference to Fig. 1.

For example, corresponding zone in " 1/8 thickness surface layer " representative graph 1.In addition, corresponding zone in " 1/4 thickness interior thickness layer " representative graph 1.Be present in two surfaces of steel plate corresponding to the zone of " 1/8 thickness surface layer ", and go for any material according to exemplary of the present invention, at least one such surface belongs within the scope of the present invention at this point.Nitrogen between top and the bottom distributes or Hardness Distribution can change by surface treatment before nitriding method and the nitrogenize and the different treatment mode after the nitrogenize.Exemplary of the present invention also is applicable to this steel plate with different end faces and bottom surface layer.This is because can reach purposes more of the present invention, i.e. tone, surface adhesion and weldability, for example, only on a surface.

" the N content of 1/8 thickness surface layer " can be determined by analyzing after the polishing steel plate only stays interesting areas.Equally, for " the N content of 1/4 thickness interior thickness layer ", use by grinding off the resulting analytical value of analysis of two surfaces after only staying interesting areas.

For " the average Vickers' hardness of steel plate cross section of 1/8 thickness surface layer " and " the average Vickers' hardness of steel plate cross section of 1/4 thickness surface layer ", can use in the position on the thickness direction and can produce enough little impression in order to the Hardness Distribution on the steel plate cross sectional thickness direction is done vickers hardness number measured under the load of suitable evaluation.Can set the measuring position on the thickness direction so as to obtain at least two be within 1/8 thickness and be the measuring position of spaced at equal intervals on thickness direction.The mean number of each area measure value is considered as corresponding cross section average hardness.Require the distance between the attention impression, but measure for Vickers' hardness usually, can provide from the suitable distance of nearest impression according to the size of impression.For this reason, as shown in Figure 2,, just can keep distance suitable between the impression when keep moving of suitable distance along the plate surface direction.In addition, near the zone plate surface, the influence of plate surface also can become a problem; For this situation, will use at the observed value that has resulting transverse section hardness on of equal value stacked and the steel plate that connects.

The steel plate cross section of the 1/8 thickness surface layer " maximum Vickers' hardness " and " the steel plate cross section maximum Vickers' hardness of 1/4 thickness interior thickness layer " is meant the highest hardness of each the regional Hardness Distribution that obtains from above-mentioned " the average Vickers' hardness of steel plate cross section of 1/8 thickness surface layer " and " the average Vickers' hardness of steel plate cross section of 1/4 thickness surface layer ".

Because the spot segregation of composition element and the ununiformity of structure, analytical value and Hardness Distribution show some sum of errors variation usually, and this can remove outlier and measure by the experimental of suitable q.s.

The nitrogenize state is described below, and this also is an important condition for exemplary of the present invention, comprises because the content of N increment that nitrogenize causes and annealing back N.

Provided the difference on the N content that is produced between the surface layer part of steel plate and the interior thickness layer segment according to exemplary of the present invention.This difference is represented with (the N content of 1/8 thickness surface layer)-(the N content of 1/4 thickness interior thickness layer).This value can be set in 100ppm, is preferably 200ppm, more preferably 300ppm, more preferably 500ppm, further be preferably 1000ppm, 2000ppm more preferably again, 3000ppm more preferably more also.If difference is worth less than this, not only can not reach as tone, top coat adhesive power and the weldability of some purposes of the present invention, and also some sizable variations can arranged owing to the difference on nitrogenize content on the quality of material, thereby cause sizable dispersion on the material quality between the coiled material inside and coiled material in actual production.In addition, the upper limit of (the N content of 1/8 thickness surface layer) can be set in 20000ppm.Can represent 1/8 thickness surface layer with the mean value of 20000ppm, because in illustrative embodiments of the invention generally, outermost N content will be 20000ppm or higher, and this will cause at an easy rate that cosmetic issue is as electroplating defective.In view of the situation, the upper limit of (the N content of 1/8 thickness surface layer) preferably is decided to be 6000ppm, more preferably 3000ppm.

Last resulting at steel upper layer and the interior thickness layer between difference on the hardness that produces be another distinguishing characteristics of illustrative embodiments of the invention.This difference can represent that its value is 10 or bigger with the average Vickers' hardness of steel plate cross section of the steel plate cross section average Vickers' hardness-1/4 thickness surface layer of 1/8 thickness surface layer, is preferably 30 or bigger, at more preferably 90 or bigger.If difference is worth less than this, just can not obtain tone, top coat adhesive power and weldability as some purposes of the present invention.In addition, the difference on the hardness between the upper layer of steel and the interior thickness layer also can be represented according to (the maximum Vickers' hardness of the steel plate cross section of 1/8 thickness surface layer)-(the maximum Vickers' hardness of the steel plate cross section of 1/4 thickness interior thickness layer).In this case, value can be 20 or bigger, is preferably 60 or bigger, more preferably 120 or bigger.

In order to control the N content and the hardness of the upper layer of comparing with hardness with the N content of aforesaid interior thickness layer, also should provide the preceding state of a suitable nitrogenize.For example, as mentioned above, the N content of nitrogenize front spring is preferably 0.0300% or lower.If before nitrogenize, comprised a big N content, be difficult to so to produce effect of the present invention.In addition, in order to increase the content of N by nitrogenize when avoiding reducing processibility, need the upper limit of N content after the nitrogenize, it is set at N:0.600% or lower.N content is preferably N:0.300% or lower, N:0.150% or lower more preferably, and more preferably N:0.100% or lower further is preferably N:0.050% or lower, and more more preferably 0.030% or lower.Yet a higher N content is preferred, and this is not only in order further to harden by nitrogenize institute hardened zone and to be in order stably to obtain the effect of nitrogenize.

In addition, according to exemplary of the present invention, the increase of N must not spread all over whole sheet metal thickness.For example, effectively increase surface layer part N content so that the absolute value of (the N increasing amount of 1/8 thickness surface layer)/(the N increasing amount of 1/4 thickness interior thickness layer) be 2.0 or higher be preferred.Here the reason of regulation absolute value is that wherein the N analysis on Content value of the almost immovable interior thickness layer of composition can become sometimes less than the value of whole sheet metal thickness owing to various types of sum of errors variation of measuring occasion that depend on.This coefficient is preferably 3.0, and more preferably 5.0 or higher, more preferably 10 or higher.

Next the control of description list surface state, this is the effect of maximum of the present invention.With regard to the description list surface state, various possibilities are arranged, but in the scope of illustrative embodiments of the invention, will and represent that the PPI of the concavo-convex peak number amount of each inchage describes according to surface roughness Ra.Its measuring method does not have special restriction, can use usual method such as tracer agent and laser method, two and three dimensions measurement etc.

Illustrative embodiments of the invention are characterised in that Ra is that 0.90 μ m or lower and PPI are 250 or higher.If Ra is too high or PPI is too low, will reduce owing to the concavity and convexity on surface as characteristics such as the tone of the object of the invention, top coat adhesive power, weldabilities.Ra is preferably 0.80 μ m or lower, 0.70 μ m or lower more preferably, and more preferably 0.60 μ m or lower further is preferably 0.50 μ m or lower.In addition, PPI is preferably 300 or higher, and more preferably 350 or higher, more preferably 400 or higher, further be preferably 450 or higher, more more preferably 500 or higher.On qualitative, the concavity and convexity of the even height that exists with high-density is preferred.Do not have special lower limit requirement for Ra, it can control to the value that is fit to purposes based on nitridation conditions, the cold rolling condition of sclerosis etc.But the lower limit of Ra does not preferably comprise 0, in fact can be 0.02 μ m or higher.The upper limit of PPI is not specified yet, and can control based on nitridation conditions, the cold rolling condition of sclerosis etc., and this depends on purposes.In general, become high more to such an extent as to many more N are approached the N concentration on surface by emanating, so resulting Ra is low more, and PPI is high more.Is to contain the nitrogenize of carrying out the relative short period of time in the air of ammonia with N towards the isolating illustrative methods in surface.Condition of surface also is subjected to composition and compression ratio, rolling pass and the roll roughness in crystal grain diameter, annealing temperature and cold rolling condition and the nitrogenize post-hardening cold-rolled process of steel of preexist and the plating condition effect when electroplating.Therefore, when being difficult to that condition of surface controlled to specific scope, basic controlling is identical with the common control of carrying out, and those skilled in the art can reach this basic controlling after the test several times without a doubt.

By convention, in order so to control roughness, shift the concavity and convexity of roll in can the sclerosis cold-rolled process after annealing, perhaps carry out morphology Control such as special electrolysis treatment or metal or other material coating based on top coat, and the morphology Control of accurately carrying out coating etc., this is because roughness also depends on the adherence state to surface of steel plate such as coating to a great extent.Yet exemplary of the present invention is subjected to the influence of this situation hardly, thereby makes in manufacturing processed it is favourable.For example, mention the concavity and convexity of roll, by convention since the concavity and convexity of roll be rolled wear and tear, for the concavity and convexity that keeps surface of steel plate is within the desirable scope, therefore be necessary often to carry out the replacement of roll or the mechanical workout of concavity and convexity, caused the excessive burden aspect productivity and labor force like this, must stop producing as maintenance for roll.In contrast, according to the present invention, the influence of cold rolling process of being hardened hardly of the condition of surface of steel plate, and do not have the too many necessary wearing and tearing of handling the roll concavity and convexity, so just can carry out piece and process.In addition, for the form of metal plating, just can electroplate the very fine Metal plating coating that homodisperse under the conditioned disjunction conditions of similarity has uniform shapes need not meticulous especially control.Though the roughness of surface of steel plate is produced the technology of the sort of roughness so hardly and the reason of condition effect is unclear, think that all the reason that produces roughness is steel plate itself.The mechanism of this technology is discussed below.

For example, according to exemplary of the present invention, between the surface of steel and interior thickness layer, can form big N concentration difference and the nonhomogeneous hardness that obtains thus.Particularly the N concentration of steel plate outmost surface layer is considered to comprise the N of high density, can't obtain usually dissolving in the resulting steel by tradition.On the other hand, steel plate interior thickness layer is the same with conventional steel plates soft.When this sheet material is rolled processing, can form many meticulous crackles at upper layer, it has poor ductility, and this is considered to understand directly and the concavity and convexity of remote effect surface of steel plate, this can illustrate with another exemplary of the present invention, and is necessary for the steel plate that is used for container.Like this, can suppose, steel plate of the present invention do not depend on treatment condition but the institute of steel plate inherent own forms the ability of the concavity and convexity that produces by optical processing, be owing to the difference on the ductility between surface of steel plate layer segment and the interior thickness layer segment, and indirectly because the difference on the hardness.Thereby preferably adopt according to the steel plate of illustrative embodiments of the invention and suitably control the hardness of steel plate on thickness direction.

Ratios in the upper layer between the material quality of the thickness of hardened layer, surface layer part, particularly ductility, upper layer and the interior thickness layer segment etc. can influence the concavity and convexity according to preferred surface layer of the present invention.Therefore, if there is no depart from extreme condition of the present invention, as the extreme increase of evenly nitrogenize, upper layer nitride concentration on whole sheet metal thickness or because the formation of the excessive titanium nitride that the high titanium content of steel plate causes, if and steel plate is to make under according to condition of the present invention, the roughness of surface of steel plate will be in the desirable scope so.

Usually, because most of sclerosis is cold rolling generally to be to carry out after annealing, therefore can in steel plate, obtain desirable condition of surface and need not to control especially according to illustrative embodiments of the invention, but since when with sheet material during through common successive annealing line the bending of furnace bottom roll caused forming meticulous crackle at surface of steel plate, so harden and cold rollingly be considered to unessential.

When steel plate itself has when so forming the ability of meticulous uniform concavity and convexity on the surface, both made the meticulous control of in coating procedure, not carrying out coating conditioned disjunction conditions of similarity, coating also can be adhered to meticulous and equably, and presents desirable form and distribution according to the concavity and convexity of steel plate.

Next, discuss nitridation conditions in more detail.From the viewpoint of productivity, according to the nitridation process of illustrative embodiments of the invention can be preferably simultaneously with or the recrystallization annealing after cold rolling, carried out subsequently after continuously carry out with recrystallization annealing, still be not limited to this.Mention method for annealing, can use with continuous annealing in batches.But from the productivity of nitridation process and the inhomogeneity viewpoint of material quality in the nitride material volume, continuous annealing is preferred.In addition, in order to obtain big advantage as the illustrated plate surface of illustrative embodiments of the invention and the material quality of interior thickness layer by control, nitridation time and thermal history subsequently are oversize to be disadvantageous, and in this, preferably adopt continuous annealing apparatus to carry out nitriding treatment at least.Do not having to use the sheet material of continuous annealing under the situation of cause specific.Carry out the successive anneal and especially have many advantages by dividing several parts control furnace atmospheres to carry out first half term recrystallize and the second half nitrogenize, as the homogeneity of productivity, material quality, the simplification of control nitrogenize state etc.

In addition,, can suppress recrystallize so and keep the state of non-recrystallize plate, can cause the obvious degeneration of processibility like this, therefore should merit attention if before recrystallize is finished, carry out nitrogenize.This boundary still is easy to find to keep the condition of non-recrystallize material for a person skilled in the art by comprehensive decision such as composition of steel, nitridation conditions, recrystallization annealing condition after suitable test.Definite N content of steel plate that not only should be taken into account of nitridation process is because the increase of nitrogenize, but also to consider steel plate composition and recrystallization annealing condition, and the thermal history after the nitrogenize etc., and to see N from the surface of steel plate to the interior region diffusion and hardness along the variation on the plate cross-sectional direction.If simply use by Rockwell (Rockwell) hardness as the determined material quality of index, just can't obtain tone, top coat adhesive power and weldability as the object of the invention.In fact, need here to determine condition, but basic idea is as described below, thereby and exemplary of the present invention can be described according to the proper amt of test.

For example, nitrogenize should be carried out under 550～800 ℃ steel billet temperature.This can as in common annealing by nitriding atmosphere being set to this temperature, steel plate is passed this atmosphere so that plate temperature reaches this scope, carry out nitrogenize simultaneously then and reach.Perhaps, nitriding atmosphere can be set in lower temperature, be inserted into by the steel plate that will be heated to this temperature range and carry out nitrogenize in that nitriding atmosphere.When nitriding atmosphere was elevated to this temperature, sometimes owing to make steel plate nitrogenize efficiency degradation with the variation of the irrelevant atmosphere of steel plate nitrogenize and destruction, so temperature can be appointed as 550～750 ℃.It is preferred being set to 600～700 ℃, more preferably 630～680 ℃.

Nitriding atmosphere can comprise 10% or more nitrogen by volume, is preferably 20% or more, and more preferably 40% or more, more preferably 60% or more; And it can comprise 90% or hydrogen still less if necessary, is preferably 80% or still less, more preferably 60% or still less, more preferably 20% or still less; It can also comprise 0.02% or more ammonia if necessary.The surplus part can be oxygen, hydrogen, carbon dioxide, hydrogen carbide gas and various rare gas element.Aspect improving nitrogenize efficient and obtain the nitrogenize of specific quantity in short for some time, ammonia is especially efficiently, thereby stops N to be diffused into the steel plate interior thickness and to provide favourable effect to exemplary of the present invention.Even 0.02% or amount still less also be enough to reach this effect, but 0.1% or more amount be preferred, more preferably 0.2% or more, more preferably 1.0% or more, further be preferably 5% or more.10% or when more measuring, nitrogenize is less than time of 5 seconds and can obtains enough effects.In addition, ratio for gas except that ammonia, particularly when nitrogen and hydrogen are main gaseous constituent, from the volume ratio of viewpoint (nitrogen)/(hydrogen) of nitrogenize efficient be 1 or mostly be desirable, this ratio is 2 or can obtains nitrogenize more efficiently more at most.In addition, when when carrying out conventional annealing under the condition that nitrogenize does not take place usually in the atmosphere of mainly forming by nitrogen and hydrogen, those skilled in the art can be after suitable test the not only fusion by aforesaid ammonia, and the change dew points such as change of the fusion by utilizing tracer level gas, gas ratio are changed to atmosphere nitrogenize can take place.Exemplary of the present invention comprises taking place at least because thermal treatment comprises the atmosphere of the nitrogenize that annealing causes of can detecting based on the modern analysis ability.

Retention time in the nitriding atmosphere usually without limits, but in conjunction with 550 ℃ of the present invention or higher temperature condition, in view of the peaked steel plate thickness of 0.400mm, consider if because the N that nitrogenize caused infiltrates from surface of steel plate that the diffusion by N in the steel plate causes, when being retained in the nitriding atmosphere, steel plate arrives steel plate interior thickness layer, it just can not obtain distributing or the fact of Hardness Distribution as the N of the object of the invention so, will on be defined as 360 seconds.In addition, even improve nitrogenize efficient, the time that also needs 1 second is with the distribution of nitrogen and hardness on the result that obtains nitrogenize and the steel plate thickness direction of the presently claimed invention.2～120 seconds is preferred, more preferably 3～60 seconds, more preferably 4～30 seconds, further is preferably 5～15 seconds.When retention time is controlled at short time, should improve nitrogenize efficient by the concentration that increases ammonia concentration or analogue.

The nitrogen of the thermal history of steel plate on control steel plate thickness direction distributes after the nitrogenize also is important.Consider the diffusion of the thickness and the nitrogen in steel of described steel plate, it is undesirable at high temperature keeping for a long time.

Yet the effect of reaching illustrative embodiments of the invention by making nitrogen distribute suitably progressively penetration heat processing more significantly also is possible.For this reason, the thermal history in 550 ℃ or the higher temperature zone is important, and in this temperature province temperature (℃) and the product of time (second) be preferably 48000 or lower.This is equivalent to following 60 seconds of 600 ℃ of following 80 seconds or 800 ℃, but when temperature continuously changes, its effect can by write down the temperature variation in approximate 5 second time period and find out each time period temperature (℃) and the sum of products of time (second) and suitably estimation.24000 or be preferred more for a short time, more preferably 12000 or littler, and preferably set nitridation conditions usually so that in case finish the distribution that nitrogen in steel just can be directly determined in nitrogenize.

Together with described thermal history, the rate of cooling after the nitrogenize can influence effect of the present invention greatly.For example, the state that forms owing to nitride in the process of cooling can take place to change greatly, therefore, and when nitrogen distributes almost without any variation, even in the time of lower temperature and weak point, also can observe the difference that transverse section hardness distributes.10 ℃/s or bigger average rate of cooling can keep more solid solution nitrogen from 550 ℃ to 300 ℃, thereby it is relative harder to make surface layer part compare with the interior thickness layer, and have improved tone, top coat adhesive power and weldability.Preferably, rate of cooling is 20 ℃/s or bigger, more preferably 50 ℃/s or bigger.Yet for keeping excessive solid solution nitrogen, control is preferred, causes problem of aging because this can depend on application.

Make at the steel-sheet that is being used for container, after recrystallization annealing, can carry out again cold rolling for hardness adjustment and plate thickness adjustment.Compression ratio range used herein from the upper layer that approaches to carry out for shape adjustments rolling 1% to 50% or more, with cold rolling identical.According to exemplary of the present invention, can use the cold rolling again of same classification with regard to conventional steel plate.Do not needing under shape correction or the similar gauged situation, can not carry out again cold rollingly, and under needs shape correction or similar gauged situation, in about 0.5%～2.5% scope, carrying out again cold rolling.Steel plate of the present invention also can stand the rolling of this degree usually.Use high surpass 2.5% cold rolling again ratio with the situation of reaching higher intensity and thinness under, must apply special operational or control to steel plate of the present invention.For example, when the steel with hard upper layer and soft interior thickness layer of the present invention being applied again when cold rolling, what preferentially stand work hardening is soft interior thickness layer, and the preferential sclerosis that being used for of providing among the present invention increases the independent upper layer of resistance to deformation can lose, but the fact is opposite.That is to say, for steel plate according to illustrative embodiments of the invention, if cold rolling again rate is normal degree, cold rolling so again can preferentially the sclerosis on the contrary has the hard surface layer part of high N content, thereby forms more obvious nonhomogeneous hardness between the upper layer of steel plate of the present invention and interior thickness layer.This be because upper layer because the N of a large amount of solid solutions and nitride and easier work hardening, and the interior thickness layer is suppressed by upper layer, so it can't preferentially be out of shape and can't harden selectively to reach well beyond upper layer hardened degree.Yet, if cold rolling again ratio becomes quite high, steel plate itself can become enough hard so, even under the situation that the material quality that is not undertaken by technology of the present invention on the switchboard thickness direction distributes, also can obtain enough jar intensity like this, but can trend towards simultaneously reducing as the control of passing through surfaceness of one of distinguishing characteristics of the present invention and the effect of improved surface property and weldability, therefore, increase the cold rolling again ratio that exceeds common range of application and only have very little meaning.In addition, owing to the higher decline that causes processibility that becomes of cold rolling ratio again, therefore should avoid the application of the carelessness of high shrinkage.For the foregoing reasons, when steel of the present invention being applied again when cold rolling, compression ratio preferably approaches about 70%.

In order to make mechanically resistant material, if carry out again cold rolling, so higher cold rolling again than being desirable, be preferably 6% or higher, more preferably 10% or higher, more preferably 20% or higher, further be preferably 30% or higher, further be preferably 40% or higher again.On the other hand, be desirable clearly from the lower ratio of cold-rolled compression again of the viewpoint of ductility, therefore 50% or lower be preferred, more preferably 40% or lower, more preferably 30% or lower, further be preferably 20% or lower, further be preferably 10% or lower again, also further be preferably 5% or lower again.Especially in view of cold rolling initial stage again in preferential sclerosis of interim upper layer and the effect that obviously increases deformation resistance, so compression ratio is preferably set to 0.8～45%, more preferably 4～35%, more preferably 6～30%, further be preferably 8～25%.Carry out continuously therein in the process of recrystallization annealing and nitrogenize, from the viewpoint of productivity, the cold rolling again time is preferred after nitrogenize, if but recrystallization annealing and nitrogenize carry out with the process of separating, cold rollingly so more also can before nitrogenize, carry out.

In addition, marquis when considering welding region, for conventional material, material can be because welding heat and local softening, and in flange assembling or similar assembling process the mechanical workout strained can take place also and concentrate, thereby reduce plasticity-, but comprise in surface layer part of the present invention in the steel plate of a large amount of N, because the softening of welding heat is confined, also be favourable for the plasticity-of welding region therefore.

In the process that recrystallization annealing therein and nitrogenize are carried out continuously, from the viewpoint of productivity, the cold rolling again time is preferred after nitrogenize, if but recrystallization annealing and nitrogenize carry out with the process of separating, cold rollingly so more also can before nitrogenize, carry out.

Exemplary of the present invention goes for having the steel plate of 0.400mm or littler plate thickness.This is that the deformation of members of casting is unlikely to be problem because for the steel plate with higher thickness.In addition, for higher plate thickness, upper layer is not because therefore nitrogenize and hardened thickness is relatively little can be easy to occur effect of the present invention.Use is preferably 0.300mm or thinner, more preferably 0.240mm or thinner steel plate, and use 0.200mm or thinner steel plate can obtain very obvious effects.

A kind of effect of illustrative embodiments of the invention is not depend on after the composition adjustment and the thermal history before the annealing, perhaps makes historical.The bloom slab, cogged ingot or the thin slab that carry out under the hot rolling situation are not limited to any manufacture method such as injection molding or continuous casting steel machine method, because effect of the present invention does not depend on the thermal history before the annealing, therefore adopt bloom slab reheat method, directly carry out hot rolling and need not to reheat the CC-DR method of bloom slab, perhaps adopt the thin bloom slab casting of omitting breaking down etc. can obtain effect of the present invention.In addition, the effect of illustrative embodiments of the invention must not depend on hot-rolled condition yet, adopts the two phase region that has α+γ two phase region finishing temperature rolling, or employing wherein adds, and the also rolling Continuous Heat of thick bar steel is rolling can to obtain this effect.

In addition, when the steel plate of illustrative embodiments of the invention when acting on the material that has the weld metal zone container, the softening surface region layer cooling and the sclerosis rapidly that is suppressed and contains high especially N concentration of heat affected zone, it has the effect that increases welding strength.When addition element such as B and Nb, it is more obvious that this phenomenon can become, and it is generally used for controlling the softening of heat affected zone.

The steel plate of illustrative embodiments of the invention comprises which class surface-treated situation of no matter carrying out.Promptly, in the steel plate that the user uses after the surface treatment, the steel plate of color harmony weldability after for surface treatment is necessary, and under the situation of making steel plate according to the method described above for these features the good order and condition of necessary surface of steel plate can not damaged by surface treatment.Certainly, the absolute value of PPI or Ra can obviously change owing to surface treatment, but it provides the surface of good state by the hardness on the control steel plate thickness direction for steel plate, promptly wherein form the effect of the state of low in a large number concavity and convexity, even also can on steel plate, detect fully after the surface treatment.This act as the surface-treated steel plate good color harmony weldability is provided.

For the adhesive power of top coat such as metallic coating, paint or organic membrane (laminate), the state on surface treatment front spring surface is important.Feature equally hereto, produce a good surface of steel plate state according to illustrative embodiments of the invention are disclosed by the hardness on the control steel plate thickness direction, for example, produce a state that wherein forms low in a large number concavity and convexity, the adhesive power that can provide.For surface treatment, under the situation of metallic coating, brush normally used tin, chromium (not stanniferous), nickel, zinc, aluminium or analogue.Color harmony weldability after the not only adhesive power of these coatings, and coating forms can be modified.Under the situation of the matrix of the laminate steel of having brought into use in recent years that scribbles organic membrane, and also can improve adhesive power by effect of the present invention under the painted situation directly or after metallic coating or similar coatings at steel plate.

According to purposes, exemplary of the present invention can be used for container usually, no matter they are Twopiece Can or Three piece Can, obviously no matter its problem that can will solve therein is used for any purposes to top the description under the similar situation of content.

[embodiment]

As exemplary enforcement of the present invention, use the most frequently used tinned steel plate that is used for one of tank plate type to carry out the evaluation of tone, top coat adhesive power and weldability.

About adhesive power, scribble 25mg/m in both sides with two ²The plate of epoxy phenol coated material, baking is also dry, then with nylon tackiness agent hot binding manufacturing the test test piece, it is moistening and carry out the T-type and peel off test with the mensuration stripping strength with town water.Clearly, higher stripping strength can be considered as showing better adhesive power in the assessment sample.Stripping strength is except depending on composition of steel and being used for obtaining of the present invention the creating conditions, also depend on state and essential depend on purposes etc. and different standards that therefore only the measurement on the absolute value basis is qualified does not meet practical application in some aspects usually.However, be lower than 1.5kg/5mm and be regarded as " must improve ", 1.5～2.5kg/5mm is regarded as " can use ", and 2.5～3.5kg/5mm is regarded as " well ", and 3.5kg/5mm is regarded as " very good ".

About tone, the L value that the use spectrocolorimeter obtains after the transparent vibrin of brushing 10 μ m is also dry is as indicator.Higher L value shows better tone, and these values are used for assess sample.The L value is except depending on composition of steel and being used for obtaining of the present invention the creating conditions, and also depends on state and essential depends on purposes etc. and different standards, and therefore only the measurement on the absolute value basis is suitable for and does not meet practical application in some aspects usually.However, be lower than and 60 be regarded as " must improve ", 60～75 are regarded as " can use ", and 75～90 are regarded as " well ", and 90 or higher being regarded as " very good ".

About weldability, for the seam weldering of on Three piece Can, using usually, under the situation that changes welding current, weld, welding range of current produces (generation of splashing) based on the splash in the welding process and measures, welding strength is based on peeling off test (Hein test), surface of steel plate that causes owing to flame current in the welding process and the damage of the face of weld between the electrode ring, and the criterion that is adopted is based on the width and the lower value of extent of damage.Desirable by a wider scope being considered as according to higher manufacturing stability, and according to being unlikely to always that material quality changes and coating is considered as the desirable judge that comes because the temperature of welding region increases peeling off of causing with a lower minimum value.In this exemplary,, estimate by ratio and employing the situation that wherein this ratio is high of measuring welding current mean value as optimum condition for the range of current that can weld.This ratio is except depending on composition of steel and being used for obtaining the creating conditions of illustrative embodiments of the invention, also depend on state and essential depend on purposes etc. and different standards that therefore only the measurement on the absolute value basis is qualified does not meet practical application in some aspects usually.However, be lower than in 1% being regarded as " must improve ", 1～3% is regarded as " can use ", and 3～6% are regarded as " well ", and 6% or bigger being regarded as " very good ".

Estimate on the basis of the productivity of productivity in the sclerosis cold-rolled process.Here " productivity " mentioned is not only represented the output of time per unit, but also is included as the personnel that keep desirable production line and the simplification of equipment control.Concentrating on the cold rolling reason of hardening and be surface control as a distinguishing characteristics of steel of the present invention, mainly is to carry out under the state of the art of the manipulation of roll roughness and rolling condition in by the sclerosis cold-rolled process.According to grade, mainly study based on rolling pass and the manipulation that relates to the roll roughness; In general, rolling situation is reasonably under low roughness, and it is preferred for a short time that the roll roughness is handled the wide and rolling pass of tolerance.Yet in the reality, the employing of judgement will be thought of as also that the lubricating condition and the sheet temperature that guarantee rolling back sheet material shape and thickness accuracy and adopt are handled, the simplification of roll speed control and tension control.The manipulation tolerance of these parameters is except depending on composition of steel and being used for obtaining of the present invention the creating conditions, and also depends on state and essential depends on purposes etc. and therefore different standards is difficult to describe absolute criterion of acceptability.

For the composition of interior thickness layer because the steel plate before the nitrogenize is by the traditional method manufacturing, so before the nitrogenize on the thickness direction change of elements very little, are insignificant scopes for the effect of illustrative embodiments of the invention.That is, suppose that the N content of 1/8 thickness surface layer in the nitrogenize front spring and the N content of 1/4 thickness interior thickness layer are identical.

Utilization contains steel just like composition shown in table 1～4 and carries out hot rolling, cold rolling and recrystallization annealing to make steel plate.N amount in table 1～4 is the preceding sheet metal thickness average N amount of nitrogenize.In the material some by under the condition sheet material is being passed nitriding furnace as shown in table 1～4, are controlled temperature, atmosphere of nitriding furnace etc. simultaneously, then pass the soak stove and carry out nitrogenize with recrystallization annealing.All nitrogenize begin to carry out from the annealed intermediate stage, under the condition that wherein recrystallize can be considered to have finished before nitrogenize takes place.

In addition, harden cold rolling to make steel plate.The rolling condition of these steel, final sheet metal thickness, analysis of nitrogen content result and performance evaluation result are as shown in table 5～8.What can confirm is, utilizes manufacture method of the present invention, by with the mode control on the sheet metal thickness direction within the scope of the present invention, can obtain good color tone, top coat adhesive power and weldability.In some cases, on the material of non-nitrogenize, attempt adjustment sheet surface roughness by means of the cold rolling condition of special sclerosis, yet owing to roll wear, rolling pass etc. has hindered effective production.In addition, have about the samely during in material that the steel plate roughness of the material that uses steel of the present invention is estimated when special rolling of this class can produce, its characteristic does not resemble those characteristics of steel of the present invention good.This reason is not clear, but can think and more or less can not be existed by the difference that the roughness concentration of exemplary the present embodiment is found in the condition of surface.

Table 1

Steel	Composition (quality %)							Nitrogenize			After the nitrogenize	550-300 ℃ of rate of cooling (℃/second)
													C	Si	Mn	P	S	Al	N	Temperature (℃)	Time (second)	NH3 (％)	Temperature * time (℃ * second)
	a1	0.001	0.03	0.3	0.011	0.01	0.02	0.0028	600	40	5													＜10000	20
a2												0.001	0.03	0.3	0.011	0.01	0.02	0.0028	-	-	-	-	20
	a3	0.001	0.03	0.3	0.011	0.01	0.02	0.0028	-	-	-													-	20
a4												0.001	0.03	0.3	0.011	0.01	0.02	0.0028	-	-	-	-	20
	a5	0.001	0.03	0.3	0.011	0.01	0.02	0.0028	-	-	-													-	20
a6												0.001	0.03	0.3	0.011	0.01	0.02	0.0028	600	1	15	＜10000	20
	a7	0.001	0.03	0.3	0.011	0.01	0.02	0.0028	600	3	15													＜10000	20
a8												0.001	0.03	0.3	0.011	0.01	0.02	0.0028	600	5	15	＜10000	20
	b1	0.025	0.02	0.5	0.014	0.013	0.04	0.0139	600	120	0.05													＜10000	60
b2												0.025	0.02	0.5	0.014	0.013	0.04	0.0139	600	120	0.05	40000	60
	b3	0.025	0.02	0.5	0.014	0.013	0.04	0.0139	600	120	0.05													56000	60
b4												0.025	0.02	0.5	0.014	0.013	0.04	0.0139	600	120	0.05	＜10000	5
	b5	0.025	0.02	0.5	0.014	0.013	0.04	0.0139	-	-	-													-	60
b6												0.025	0.02	0.5	0.014	0.013	0.04	0.0139	-	-	-	-	60
	b7	0.025	0.02	0.5	0.014	0.013	0.04	0.0139	600	5	10													＜10000	60
b8												0.025	0.02	0.5	0.014	0.013	0.04	0.0139	600	10	10	＜10000	60
	b9	0.025	0.02	0.5	0.014	0.013	0.04	0.0139	600	30	10													＜10000	60

Table 2

Steel	Composition (quality %)											Nitrogenize			After the nitrogenize	550-300 ℃ of rate of cooling (℃/second)
																	C	Si	Mn	P	S	Al	N	Ti	Nb	B	Other	Temperature	Time (second)	NH3 (％)	Temperature * time (℃ * second)
	c1	0.045	1.5	0.2	0.01	0.019	0.03	0.0024		0.001		V：0.03	650	600	8																	15000	50
c2																0.045	1.5	0.2	0.01	0.019	0.03	0.0024		0.001		V：0.03	650	10	8	40000	2
	c3	0.045	1.5	0.2	0.01	0.019	0.03	0.0024		0.001		V：0.03	-	-	-																	-	2
c4																0.045	1.5	0.2	0.01	0.019	0.03	0.0024		0.001		V：0.03	-	-	-	-	2
	c5	0.045	1.5	0.2	0.01	0.019	0.03	0.0024		0.001		V：0.03	700	1	20																	-	2
c6																0.045	1.5	0.2	0.01	0.019	0.03	0.0024		0.001		V：0.03	700	10	20	-	2
	c7	0.045	1.5	0.2	0.01	0.019	0.03	0.0024		0.001		V：0.03	700	60	20																	-	2
d1																0.011	0.02	0.03	0.096	0.012	0.08	0.0011	0.001		0.0032		700	40	0.2	＜10000	100
	d2	0.011	0.02	0.03	0.096	0.012	0.08	0.0011	0.001		0.0032		700	40	0.2																	＜10000	100
d3																0.011	0.02	0.03	0.096	0.012	0.08	0.0011	0.001		0.0032		700	40	0.2	＜10000	100
	d4	0.011	0.02	0.03	0.096	0.012	0.08	0.0011	0.001		0.0032		700	40	0.2																	＜10000	100
d5																0.011	0.02	0.03	0.096	0.012	0.08	0.0011	0.001		0.0032		700	40	0.2	＜10000	100
	d6	0.011	0.02	0.03	0.096	0.012	0.08	0.0011	0.001		0.0032		-	-	-																	-	100
d7																0.011	0.02	0.03	0.096	0.012	0.08	0.0011	0.001		0.0032		-	-	-	-	100
	d8	0.011	0.02	0.03	0.096	0.012	0.08	0.0011	0.001		0.0032		-	-	-																	-	100
d9																0.011	0.02	0.03	0.096	0.012	0.08	0.0011	0.001		0.0032		-	-	-	-	100
	d10	0.011	0.02	0.03	0.096	0.012	0.08	0.0011	0.001		0.0032		-	-	-																	-	100
d11																0.011	0.02	0.03	0.096	0.012	0.08	0.0011	0.001		0.0032		700	2	60	＜10000	100
	d12	0.011	0.02	0.03	0.098	0.012	0.08	0.0011	0.001		0.0032		700	8	60																	＜10000	100
d13																0.011	0.02	0.03	0.096	0.012	0.08	0.0011	0.001		0.0032		700	14	60	＜10000	100

Table 3

Steel	Composition (quality %)										Nitrogenize			After the nitrogenize	550-300 ℃ of rate of cooling (℃/second)
																C	Si	Mn	P	S	Al	N	Ti	Nb	Other	Temperature (℃)	Time (second)	NH3 (％)	Temperature * time (℃ * second)
	e1	0.079	0.007	0.1	0.008	0.011	0.06	0.0033	0.004			650	20	2.5																25000	10
e2															0.079	0.007	0.1	0.008	0.011	0.06	0.0033	0.004			600	10	25	＜10000	100
	e3	0.079	0.007	0.1	0.008	0.011	0.06	0.0033	0.004			-	-	-																-	40
e4															0.079	0.007	0.1	0.008	0.011	0.06	0.0033	0.004			-	-	-	-	40
	f1	0.002	0.02	0.2	0.008	0.003	0.19	0.0025	0.028	0.045		800	30	-																＜10000	＞200
f2															0.002	0.02	0.2	0.008	0.003	0.19	0.0025	0.028	0.045		-	-	-	-	＞200
	f3	0.002	0.02	0.2	0.008	0.003	0.19	0.0025	0.028	0.045		-	-	-																-	＞200
g1															0.002	0.6	1.4	0.011	0.001	0.07	0.0019	0.046		Cu：1.5，Sn：0.02	730	20	1.5	＜10000	40
	g2	0.002	0.6	1.4	0.011	0.001	0.07	0.0019	0.046		Cu：1.5，Sn：0.02	-	-	-																-	40
g3															0.002	0.6	1.4	0.011	0.001	0.07	0.0019	0.046		Cu：1.5，Sn：0.02	-	-	-	-	40
	h1	0.063	0.07	0.8	0.012	0.048	1.2	0.0276			Cr：6	780	60	-																＜10000	40
h2															0.063	0.07	0.8	0.012	0.048	1.2	0.0276			Cr：6	-	-	-	-	40
	h3	0.063	0.07	0.8	0.012	0.048	1.2	0.0276			Cr：6	-	-	-																-	40
i1															0.004	0.01	0.2	0.011	0.001	0.11	0.0055			Cr：18，Ni：4	650	60	4	＜10000	＞200
	i2	0.004	0.01	0.2	0.011	0.001	0.11	0.0055			Cr：18，Ni：4	650	60	4																35000	80
i3															0.004	0.01	0.2	0.011	0.001	0.11	0.0055			Cr：18，Ni：4	-	-	-	-	40
	i4	0.004	0.01	0.2	0.011	0.001	0.11	0.0055			Cr：18，Ni：4	-	-	-																-	40

Table 4

Steel	Composition (quality %)							Nitrogenize			After the nitrogenize	550-300 ℃ of rate of cooling (℃/second)
													C	Si	Mn	P	S	Al	N	Temperature (℃)	Time (second)	NH3 (％)	Temperature * time (℃ * second)
	j1	0.001	0.02	0.2	0.011	0.01	0.02	0.0036	650	180	0.05													＜10000	30
j2												0.001	0.02	0.2	0.011	0.01	0.02	0.0036	-	-	-	-	30
	j3	0.001	0.02	0.2	0.011	0.01	0.02	0.0036	-	-	-														30
j4												0.001	0.02	0.2	0.011	0.01	0.02	0.0036	-	-	-	-	30
	j5	0.001	0.02	0.2	0.011	0.01	0.02	0.0036	-	-	-													-	30
j6												0.001	0.02	0.2	0.011	0.01	0.02	0.0036	650	1	20	＜10000	30
	j7	0.001	0.02	0.2	0.011	0.01	0.02	0.0036	650	3	20													＜10000	30
j8												0.001	0.02	0.2	0.011	0.01	0.02	0.0036	650	5	20	＜10000	30
	k1	0.022	0.03	0.5	0.014	0.034	0.04	0.0151	650	240	0.02													＜10000	50
k2												0.022	0.03	0.5	0.014	0.034	0.04	0.0151	650	240	0.02	40000	50
	k3	0.022	0.03	0.5	0.014	0.034	0.04	0.0151	650	240	0.02													56000	50
k4												0.022	0.03	0.5	0.014	0.034	0.04	0.0151	650	240	0.02	＜10000	50
	k5	0.022	0.03	0.5	0.014	0.034	0.04	0.0151	-	-	-													-	50
k6												0.022	0.03	0.5	0.014	0.034	0.04	0.0151	-	-	-	-	50
	k7	0.022	0.03	0.5	0.014	0.034	0.04	0.0151	-	-	-													-	50
k8												0.022	0.03	0.5	0.014	0.034	0.04	0.0151	-	-	-	-	50
	k9	0.022	0.03	0.5	0.014	0.034	0.04	0.0151	650	5	10													＜10000	50
k10												0.022	0.03	0.5	0.014	0.034	0.04	0.0151	650	10	10	＜10000	50
	k11	0.022	0.03	0.5	0.014	0.034	0.04	0.0151	650	30	10													＜10000	50

Table 5

Steel	N total after the nitrogenize measures (quality %)	1/8 top layer N measures (quality %)	1/4 center N measures (quality %)	B (quality %)	Roll Ra (μm)	Tempering compression (%/pass)	Rolling pass	Tempering compression (always) %	The finished product plate thickness (mm)	Steel plate Ra (μ m)	PPI	Estimate				Criterion
																	Tone	Adhesive power	Welding	Productivity
												a1	0.0041	0.0051	0.0029						0.0022	0.5	1	1	1.0	0.15	0.45	350	b	b	b	Good	Inventive embodiments
a2	0.0028	0.0028	0.0028	0.0000	0.5	1	1	1.0	0.15	0.75	200					d	d	d	Good	Comparative example
												a3	0.0028	0.0028	0.0028						0.0000	0.7	1	1	1.0	0.15	0.9	150	d	d	c	Good	Comparative example
a4	0.0028	0.0028	0.0028	0.0000	0.7	1	3	3.0	0.15	0.45	400					a	b	a	Difference	Comparative example
												a5	0.0028	0.0028	0.0028						0.0000	0.9	1	1	1.0	0.15	1.1	120	b	c	c	Difference	Comparative example
a6	0.0193	0.0435	0.0027	0.0408	0.5	1	1	1.0	0.15	0.43	390					a	a	a	Good	Inventive embodiments
												a7	0.0388	0.1130	0.0029						0.1101	0.5	1	1	1.0	0.15	0.41	430	a	a	a	Good	Inventive embodiments
a8	0.1430	0.3610	0.0042	0.3568	0.5	1	1	1.0	0.15	0.4	540					b	b	b	Good	Inventive embodiments
												b1	0.0156	0.0182	0.0140						0.0042	0.5	1	1	1.0	0.22	0.55	300	a	b	a	Good	Inventive embodiments
b2	0.0157	0.0174	0.0141	0.0033	0.5	1	1	1.0	0.22	0.41	350					a	b	b	Good	Inventive embodiments
												b3	0.0157	0.0151	0.0147						0.0004	0.5	1	1	1.0	0.22	0.35	210	b	d	d	Good	Comparative example
b4	0.0156	0.0157	0.0156	0.0001	0.5	1	1	1.0	0.22	0.3	140					d	d	d	Good	Comparative example
												b5	0.0139	0.0139	0.0139						0.0000	0.5	1	1	1.0	0.22	0.55	140	d	c	d	Good	Comparative example
b6	0.0139	0.0139	0.0139	0.0000	0.9	1	2	2.0	0.22	0.45	350					b	c	b	Difference	Comparative example
												b7	0.0199	0.0209	0.0143						0.0066	0.5	1	1	1.0	0.22	0.52	350	b	a	a	Good	Inventive embodiments
b8	0.0380	0.0590	0.0202	0.0388	0.5	1	1	1.0	0.22	0.35	440					a	b	a	Good	Inventive embodiments
												b9	0.1780	0.2150	0.0930						0.1220	0.5	1	1	1.0	0.22	0.25	560	a	c	b	Good	Inventive embodiments

The N amount of B:(1/8 thickness surface layer)-(the N amount of 1/4 mid-depth layer)

A: very good, b: good, c: can use d: need to improve

Table 6

Steel	N total after the nitrogenize measures (quality %)	The average Vickers' hardness of 1/8 upper layer	The average Vickers' hardness in 1/4 center	C	The average Vickers' hardness of 1/8 upper layer	D	Roll Ra (μm)	Tempering compression (%/pass)	Rolling pass	Tempering compression (always) %	The finished product plate thickness (mm)	Steel plate Ra (μ m)	PPI	Estimate				Criterion
																			Tone	Adhesive power	Welding	Productivity
														c1	0.6110	275	174						101	326	152	0.3	3	2	5.9	0.1287	1.1	100	d	d	d	Good	Comparative example
c2	0.0064	196	190	6	203	13	0.3	3	2	5.9	0.1287	0.33	200					d	c	d	Good	Comparative example
														c3	0.0024	189	193						-4	193	0	0.3	3	2	5.9	0.1287	0.45	200	c	d	d	Good	Comparative example
c4	0.0024	189	193	-4	193	0	0.3	6	6	5.9	0.1287	0.75	340					b	c	c	Difference	Comparative example
														c5	0.0131	242	183						59	293	110	0.3	3	2	5.9	0.13	0.62	560	b	b	c	Good	Inventive embodiments
c6	0.0485	246	195	51	277	82	0.3	3	2	5.9	0.13	0.55	490					a	a	a	Good	Inventive embodiments
														c7	0.3420	279	213						66	293	80	0.3	3	2	5.9	0.13	0.44	450	b	a	a	Good	Inventive embodiments
d1	0.0027	201	160	41	219	59	0.3	3.0	2	5.9	0.2522	0.4	400					a	a	a	Good	Inventive embodiments
														d2	0.0025	230	192						38	239	47	0.3	3.0	4	11.5	0.2484	0.4	410	a	b	a	Good	Inventive embodiments
d3	0.0026	253	209	44	258	49	0.3	3.0	6	16.7	0.2465	0.42	340					b	b	b	Good	Inventive embodiments
														d4	0.0029	290	249						41	295	46	0.3	5.0	2	9.8	0.2475	0.45	350	a	a	b	Good	Inventive embodiments
d5	0.0028	395	358	37	398	40	0.3	5.0	6	26.5	0.25	0.48	320					b	b	b	Good	Inventive embodiments
														d6	0.0011	160	163						-3	162	-1	0.3	3	2	5.9	0.2475	0.45	180	c	d	d	Good	Comparative example
d7	0.0011	195	186	9	203	17	0.3	3	4	11.5	0.2475	0.3	230					c	c	c	Difference	Comparative example
														d8	0.0011	218	210						8	225	15	0.3	3	6	16.7	0.2475	0.3	350	b	c	c	Difference	Comparative example
d9	0.0011	255	254	1	258	4	0.3	5	2	9.8	0.2475	0.95	220					d	d	c	Good	Comparative example
														d10	0.0011	380	373						7	382	9	0.3	5	6	26.5	0.2475	0.35	510	b	c	d	Difference	Comparative example
d11	0.0061	253	210	43	269	59	0.3	3	2	5.9	0.2465	0.44	360					b	b	a	Good	Inventive embodiments
														d12	0.0134	296	220						76	322	102	0.3	3	2	5.9	0.2465	0.2	430	a	a	a	Good	Inventive embodiments
d13	0.0512	305	210	95	315	105	0.3	3	2	5.9	0.2465	0.13	600					a	b	a	Good	Inventive embodiments

The average Vickers' hardness of steel plate cross section of C:(1/8 thickness surface layer)-(1/4 mid-depth layer the average Vickers' hardness of steel plate cross section)

The maximum Vickers' hardness of the steel plate cross section of D:(1/8 thickness surface layer)-(1/4 mid-depth layer the average Vickers' hardness of steel plate cross section)

A: fine, b: good, c: available, d: need to improve

Table 7

Steel	N total after the nitrogenize measures (quality %)	A (quality %)	1/8 upper layer N measures (quality %)	1/4 center N measures (quality %)	1/8 upper layer N increasing amount (quality %)	1/4 center N increasing amount (quality %)	E	Roll Ra (μm)	Tempering compression (%/pass)	Rolling pass	Tempering compression (always) %	The finished product plate thickness (mm)	Steel plate Ra (μ m)	PPI	Estimate				Criterion
																				Tone	Adhesive power	Welding	Productivity
															e1	0.0121	0.0088	0.0366						0.0045	0.0333	0.0012	27.6	0.5	0.6	2	1.2	0.3366	0.77	430	a	a	a	Good	Inventive embodiments
e2	0.2300	0.2267	0.6620	0.0032	0.6787	-0.0001	＞100	0.5	0.6	2	1.2	0.3366	0.23	800					b	b	c	Good	Inventive embodiments
															e3	0.0033	0.0000	0.0033						0.0033	0.0000	0.0000	-	0.5	0.6	2	1.2	0.3366	0.45	160	d	d	d	Good	Comparative example
e4	0.0033	0.0000	0.0033	0.0033	0.0000	0.0000	-	0.5	1.2	2	2.4	0.3366	0.45	200					d	c	c	Good	Comparative example
															f1	0.0036	0.0011	0.0049						0.0028	0.0024	0.0003	8.0	0.5	0.6	2	1.2	0.2574	0.13	550	a	b	b	Good	Inventive embodiments
f2	0.0025	0.0000	0.0025	0.0025	0.0000	0.0000	-	0.5	0.6	2	1.2	0.2574	0.47	230					c	d	d	Good	Comparative example
															f3	0.0025	0.0000	0.0025						0.0025	0.0000	0.0000	-	0.5	1.2	2	2.4	0.2574	0.63	220	d	d	c	Good	Comparative example
g1	0.0058	0.0039	0.0159	0.0025	0.0140	0.0006	23.3	0.5	0.6	2	1.2	0.1683	0.16	450					b	b	a	Good	Inventive embodiments
															g2	0.0019	0.0000	0.0019						0.0019	0.0000	0.0000	-	0.5	0.6	2	1.2	0.1683	0.46	140	d	d	c	Good	Comparative example
g3	0.0019	0.0000	0.0019	0.0019	0.0000	0.0000	-	0.2	0.4	4	1.6	0.1683	0.15	290					c	c	d	Difference	Comparative example
															h1	0.0260	0.0004	0.0322						0.0275	0.0046	-0.0001	46.0	0.2	0.6	2	1.2	0.198	0.1	640	a	a	a	Good	Inventive embodiments
h2	0.0276	0.0000	0.0276	0.0276	0.0000	0.0000	-	0.2	0.6	2	1.2	0.198	0.25	200					d	c	d	Good	Comparative example
															h3	0.0276	0.0000	0.0276						0.0276	0.0000	0.0000	-	0.8	0.6	6	3.5	0.198	0.24	440	d	b	b	Difference	Comparative example
i1	0.0203	0.0148	0.0590	0.0065	0.0535	0.0010	53.5	0.2	0.6	2	1.2	0.297	0.05	500					a	a	b	Good	Inventive embodiments
															i2	0.0271	0.0216	0.0430						0.0088	0.0375	0.0033	11.4	0.2	0.6	2	1.2	0.297	0.04	320	a	a	a	Good	Inventive embodiments
i3	0.0055	0.0000	0.0055	0.0055	0.0000	0.0000	-	0.2	0.6	2	1.2	0.297	0.14	100					d	c	d	Good	Comparative example
															i4	0.0055	0.0000	0.0055						0.0055	0.0000	0.0000	-	0.8	0.3	6	1.8	0.297	0.1	300	d	c	d	Difference	Comparative example

A:(sheet metal thickness average N increasing amount)

E:(1/8 thickness surface layer N increasing amount)/(1/4 central core N increasing amount) absolute value

A: fine, b: good, c: available, d: need to improve

Table 8

Steel	N total after the nitrogenize measures (quality %)	A (quality %)	The average Vickers' hardness of 1/8 upper layer	The average Vickers' hardness in 1/4 center	C	The maximum Vickers' hardness of 1/8 upper layer	D	Roll Ra (μm)	Tempering compression (%/pass)	Rolling pass	Tempering compression (always) %	The finished product plate thickness (mm)	Steel plate Ra (μ m)	PPI	Estimate				Criterion
																				Tone	Adhesive power	Welding	Productivity
															j1	0.0038	0.0002	125						96	29	147	51	0.3	0.6	2	1.2	0.16	0.75	450	c	b	c	Good	Inventive embodiments
j2	0.0036	0.0000	97	93	4	99	6	0.3	0.6	2	1.2	0.16	0.55	180					d	c	c	Good	Comparative example
															j3	0.0036	0.0000	97						93	4	99	6	0.5	1	6	5.9	0.16	0.45	450	b	b	d	Good	Comparative example
j4	0.0036	0.0000	97	93	4	99	6	0.5	10.0	3	27.1	0.16	0.45	450					b	b	d	Good	Relatively
															j5	0.0036	0.0000	97						93	4	99	6	0.5	20.0	2	36.0	0.16	0.45	450	b	b	d	Good	Relatively
j6	0.0193	0.0157	139	103	36	173	70	0.3	0.6	2	1.2	0.16	0.6	450					a	a	b	Good	Inventive embodiments
															j7	0.0388	0.0352	160						99	61	171	72	0.3	0.6	2	1.2	0.16	0.55	490	a	a	a	Good	Inventive embodiments
j8	0.1430	0.1394	188	111	77	191	60	0.3	0.6	2	1.2	0.16	0.45	560					b	b	b	Good	Inventive embodiments
															k1	0.0156	0.0005	154						132	22	179	47	0.3	0.6	2	1.2	0.18	0.47	390	a	a	b	Good	Inventive embodiments
k2	0.0157	0.0006	152	133	19	164	31	0.3	0.6	2	1.2	0.16	0.43	380					b	b	c	Good	Inventive embodiments
															k3	0.0156	0.0005	141						135	6	144	9	0.3	0.6	2	1.2	0.18	0.46	220	d	b	d	Difference	Comparative example
k4	0.0156	0.0005	143	137	6	146	9	0.3	0.6	2	1.2	0.16	0.51	200					d	b	d	Difference	Comparative example
															k5	0.0151	0.0000	129						133	-4	130	-2	0.3	0.6	2	1.2	0.18	0.52	240	d	d	c	Difference	Comparative example
k6	0.0151	0.0000	129	133	-4	130	-2	0.5	1	6	9.2	0.16	0.48	560					b	d	d	Good	Comparative example
															k7	0.0151	0.0000	129						133	-4	130	-2	0.7	2.3	8	17.0	0.18	0.48	560	a	d	d	Good	Relatively
k8	0.0151	0.0000	129	133	-4	130	-2	0.9	3.1	8	22.3	0.18	0.46	560					c	d	d	Good	Relatively
															k9	0.0199	0.0048	188						135	53	286	153	0.3	0.6	2	1.2	0.16	0.33	560	a	a	b	Good	Inventive embodiments
k10	0.0360	0.0229	232	157	75	302	145	0.3	0.6	2	1.2	0.18	0.51	490					a	a	a	Good	Inventive embodiments
															k11	0.1760	0.1629	321						262	59	338	76	0.3	0.6	2	1.2	0.18	0.45	490	b	a	b	Good	Inventive embodiments
L1	0.0377	0.0355	300	145	155	315	170	-	-	-	0.0	0.15	0.11	150					b	b	b	Good	Inventive embodiments
															L2	0.0385	0.0363	320						166	154	335	169	0.3	3.0	2	5.9	0.15	0.13	250	a	a	a	Good	Inventive embodiments
L3	0.0344	0.0322	314	173	141	355	182	0.3	6.0	2	11.6	0.15	0.14	380					a	a	a	Good	Inventive embodiments
															L4	0.0396	0.0374	301						187	114	375	188	0.3	12.5	2	23.4	0.15	0.13	430	a	a	a	Good	Inventive embodiments
L5	0.0376	0.0354	292	195	97	385	190	0.3	17.5	2	31.9	0.15	0.19	410					a	a	b	Good	Inventive embodiments
															L6	0.0384	0.0362	281						200	81	390	190	0.3	22.5	2	39.9	0.15	0.16	510	a	b	b	Good	Inventive embodiments
L7	0.0368	0.0346	274	216	58	397	181	0.3	16.0	3	44.9	0.15	0.17	400					b	b	b	Good	Inventive embodiments
															L8	0.0362	0.0340	260						225	35	392	167	0.3	17.0	4	52.5	0.15	0.21	320	b	b	c	Good	Inventive embodiments
L8	0.0371	0.0349	265	237	28	405	168	0.3	15.0	5	55.6	0.15	0.27	200					b	c	c	Good	Inventive embodiments
															L10	0.0022	0.0000	180						175	5	194	19	0.3	5.0	2	9.6	0.15	0.25	130	d	b	d	Good	Comparative example
L11	0.0022	0.0000	205	211	-6	232	21	0.3	15.0	2	27.8	0.15	0.31	130					d	d	d	Good	Comparative example
															L12	0.0022	0.0000	225						220	5	244	24	0.3	17.0	3	42.8	0.15	0.24	110	d	d	d	Good	Comparative example

A:(sheet metal thickness average N increasing amount)

The average Vickers' hardness of steel plate cross section of C:(1/8 thickness surface layer)-(1/4 mid-depth layer the average Vickers' hardness of steel plate cross section)

The maximum Vickers' hardness of the steel plate cross section of D:(1/8 thickness surface layer)-(1/4 mid-depth layer the average Vickers' hardness of steel plate cross section)

A: fine, b: good, c: available, d: need to improve

According to the complicated processing and owing in the obstruction of the productivity that this complex process causes, improved tone, top coat adhesive power and the weldability of container after avoiding nitrogenize of the steel plate that is used for container of illustrative embodiments of the invention and manufacture method thereof.Therefore, can improve the productivity of the ultra-thin steel sheet that is used for container, thereby provide significant useful effect industrial.

Foregoing only illustrates the principle of invention.Because the instruction here, make that for a person skilled in the art various modifications and the variation to the description embodiment will be conspicuous.Thereby, can design many principles that embody invention of clearly not showing or describing here and thereby belong to the steel plate within the spirit and scope of the present invention and the variation scheme of method though be understandable that those skilled in the art.Here the various publications of having quoted, its full content is quoted here as a reference.

Industrial applicibility

According to the complicated processing and owing in the obstruction of the productivity that this complex process causes, can improve tone, top coat adhesive power and the weldability of container after avoiding nitrogenize of the steel plate that is used for container of illustrative embodiments of the invention and manufacture method thereof.Therefore, it can keep with traditional sheet material and comprise the same high productivity of method of the complex process that is used for ultra-thin tank plate and a kind of industrial useful effect is provided.

Claims (14)

1, be used for the steel plate of at least a container, it comprises:

At least one part, this part has 0.400mm plate thickness at the most, and comprise by percentage to the quality approximately C:0.0800% or still less, N:0.600% or still less, Si:2.0% or still less, Mn:2.0% or still less, P:0.10% or still less, S:0.05% or still less and Al:2.0% or still less

Wherein said at least one part comprises 1/8 thickness surface layer and 1/4 thickness surface layer, and the 2nd N content that a N content of described 1/8 thickness surface layer deducts described 1/4 thickness interior thickness layer is at least about 10ppm,

Wherein a N content is about 20000ppm at the most, and the surfaceness of described at least one part is about 0.90 μ m or still less in Ra, and

The concavo-convex peak number of each inchage (" PPI ") of wherein said at least one part is at least about 250.

2, be used for the steel plate of at least a container, it comprises:

At least one part, this part has 0.400mm plate thickness at the most, and comprise by percentage to the quality approximately C:0.0800% or still less, N:0.600% or still less, Si:2.0% or still less, Mn:2.0% or still less, P:0.10% or still less, S:0.05% or still less and Al:2.0% or still less

Wherein said at least one part comprises 1/8 thickness surface layer and 1/4 thickness interior thickness upper layer,

The value that the average Vickers' hardness of the first steel plate cross section of wherein said 1/8 thickness surface layer deducts the average Vickers' hardness of the second steel plate cross section of described 1/4 thickness interior thickness layer is a value greater than 10 and 20, the surfaceness of at least one part is counted 0.90 μ m or still less with Ra, and

The concavo-convex peak number of each inchage (" PPI ") of wherein said at least one part is at least 250.

3, claim 1 or 2 steel plate, wherein said at least one part further comprise by percentage to the quality following at least a composition: Ti:0.05% or still less, Nb:0.05% or still less and B:0.015% or still less.

4, the steel plate of claim 2, the average assay of wherein said 1/4 plate thickness interior thickness layer is grouped into by following at least a one-tenth: Ti:4 * C+1.5 * S+3.4 * N or more, Nb:7.8 * C+6.6 * N or more and B:0.8 * N or more.

5, claim 1 or 2 steel plate, wherein said at least one part further comprise by percentage to the quality following at least a composition: Cr:20% or still less, Ni:10% or still less and Cu:5% or still less.

6, claim 1 or 2 steel plate, wherein said at least one part comprise further that by percentage to the quality total amount is 0.1% or Sn still less, Sb, Mo, Ta, V and W.

7, make at least a method that is used for the steel plate of at least a container, wherein said at least a steel plate comprises having 0.400mm or at least one part of plate thickness still less, this at least one part comprise by percentage to the quality about C:0.0800% or still less, N:0.0300% or still less, Si:2.0% or still less, Mn:2.0% or still less, P:0.10% or still less, S:0.05% or still less, Al:2.0% or still less and the Fe of surplus and unavoidable impurities, described method comprises:

A) cold rolling described steel plate;

B) recrystallization annealing of described steel plate; And

C) in step (b) or after the step (b), the described steel plate of nitrogenize,

The average increasing amount of the N content of wherein said at least one part in whole plate thickness average is about 6000ppm at the most, the one N concentration increasing amount of 1/8 thickness surface layer of described at least one part is about 20000ppm at the most, the N concentration increasing amount of described 1/8 thickness surface layer is about 2.0 at the most divided by the absolute value of the 2nd N concentration increasing amount of 1/4 thickness interior thickness layer, and

Wherein surfaceness is about 0.90 μ m at the most in Ra, and the concavo-convex peak number of each inchage (" PPI ") of described at least one part is at least about 250.

8, make at least a method that is used for the steel plate of at least a container, wherein said at least a steel plate comprises having 0.400mm or at least one part of plate thickness still less, this at least one part comprise by percentage to the quality approximately C:0.0800% or still less, N:0.0300% or still less, Si:2.0% or still less, Mn:2.0% or still less, P:0.10% or still less, S:0.05% or still less, Al:2.0% or still less and the Fe of surplus and unavoidable impurities, described method comprises:

A) cold rolling described steel plate;

B) recrystallization annealing of described steel plate; And

C) in step (b) or after the step (b), the described steel plate of nitrogenize,

Wherein on average be about 6000ppm at the most across the increasing amount of the N content of described at least one segment thickness,

Wherein the average Vickers' hardness of the first steel plate cross section of the 1/8 thickness surface layer average Vickers' hardness of the second steel plate cross section that deducts 1/4 thickness interior thickness layer for approximately greater than 10 and 20 s' a value,

The surfaceness of wherein said at least one part is about 0.90 μ m at the most in Ra, and

The concavo-convex peak number of each inchage of described at least one part is at least 250.

9, claim 7 or 8 method, wherein said at least one part further comprise by percentage to the quality following one or more compositions: Ti:0.05% or still less, Nb:0.05% or still less and B:0.015% or still less.

10, the method for claim 8, wherein said at least one part comprises following one or more compositions in the average assay of described 1/4 plate thickness interior thickness layer: Ti:4 * C+1.5 * S+3.4 * N or more, Nb:7.8 * C+6.6 * N or more and B:0.8 * N or more.

11, claim 7 or 8 method, wherein said at least one part further comprise by percentage to the quality following one or more compositions: Cr:20% or still less, Ni:10% or still less and Cu:5% or still less.

12, claim 7 or 8 method, wherein said at least one part comprise by percentage to the quality total amount be 0.1% or Sn still less, Sb, Mo, Ta, V and W as composition of steel.

13, claim 7 or 8 method, wherein in order to carry out step (c) afterwards simultaneously or in step (b) with step (b), described steel carries out a kind of in the following process at least:

Comprise 0.02% or the atmosphere of more ammonias in and keep surpassing 1 second at least under 550～800 ℃ the plate temperature but be no more than 360 seconds, so that after the nitrogenize in the thermal history of 550 ℃ or higher temperature scope temperature (℃) and the product of time (second) be 48000 or littler, and to set 550 ℃～300 ℃ average rate of cooling be 10 ℃/second or bigger.

14, claim 7 or 8 method, wherein step (b) afterwards and the cold rolling again ratio before or after the step (c) be 20% or still less.