Method for producing high strength tinplate and tinplate produced thereby

Abstract

The present invention relates to a method for producing high strength three-piece steel can bodies and the cans produced thereby.

Description

[Technical field]

[0001] The present invention relates to a method for producing high strength tinplate and the tinplate produced thereby. [Background technology]

[0002] Most cans produced today are one of two types: three-piece cans, consisting of three components: a bottom lid, a body that is usually more or less cylindrical, and a top; and two-piece cans, consisting of two components: a bottom lid, an integral body, and a top.

[0003] A technique called double seaming is usually used to attach the can body to the can lid (top and bottom), after which the can contents are protected from outside contamination. The three-piece can body is formed from a rectangular sheet that is rolled into a (cylindrical) body, and the ends are joined by soldering or welding. Welded cans hold a large portion of the market, while soldered cans are almost entirely disappearing from the market.

[0004] Tinplate is a sheet or strip of light gauge cold-rolled low carbon steel coated on both sides with industrially pure tin to protect the steel from corrosion, primarily for use in the packaging industry. The tin layer is usually deposited by electrolysis, usually in a continuous production line.

[0005] Steel substrate for tinplate is manufactured as single reduced (SR) strip and double reduced (DR) strip (see Figure 1). SR strip is cold rolled directly to final gauge, then annealed and tinned. The DR product is given a first cold roll reduction to reach an intermediate gauge, then annealed and then a second cold roll reduction to the final gauge. The resulting DR product is usually stiffer, harder and stronger than the SR product which may allow for the use of light gauge steel for certain applications.

[0006] Tinplate combines in one material the strength and formability of steel and the corrosion resistance, solderability and good appearance of tin. In this broad description, today there is a very wide range of products that are tailor-made to meet end-use requirements. The production of the steel substrate and the subsequent coating with tin are independent of each other, and any set of properties of steel can theoretically be combined with any tin coating. The composition of the steel used in tinplate is closely controlled, and different types with different formability ("tempers") can be produced according to the grade selected and its processing technique. Tinplate is sold in steel thicknesses from about 0.10 mm to about 0.49 mm. The steel can be coated with tin in various thicknesses. Different thicknesses (different coatings) on the two sides can be formed on the inner and outer surfaces of the container to meet various conditions. Also, different surface finishes can be produced for various applications.

[0007] The tin is deposited as a whitish coating with a slight metallic luster. When required, the tin is flow-melted by induction or resistance heating (or a combination) to produce a shiny, mirror-like finish. This flow-melting process enhances the corrosion resistance of the product through the formation of an inert tin-iron alloy layer.

[0008] When producing blanks for three-piece can bodies from strips of tinplate, there are two basic options: the so-called C-grain blanks and the H-grain blanks.

[0009] C-grain blanks are cut from the strip so that the ends of the blanks to be welded are parallel to the width of the coil. H-grain blanks are cut from the strip so that the ends of the blanks to be welded are perpendicular to the width of the coil (see Figure 2). A C-grain can body is therefore a three-piece welded can body in which the welds (or weld direction) are perpendicular to the rolling direction of the body sheets. C stands for circumferential and the rolling direction is circumferential of the can body (see Figure 2). An H-grain can body is a three-piece welded can body in which the welds (or weld direction) are parallel to the rolling direction of the body sheets (see Figure 2). H stands for height and the rolling direction is height of the can body.

[0010] For many years, in ingot cast steel, dirt particles were rolled-in into the material. These dirt particles were aligned along the rolling direction, and therefore can bodies produced with the rolling direction parallel to the weld (H-grain cans) suffered more risk of cracked flanges due to dirt particles in the material. For this historical reason, most of the 3-piece cans were (and still are) produced as C-grain cans. Today, there is another reason for retaining the C-grain format. Most of the 3-piece (food) cans are produced from DR material quality because the second rolling of the recrystallized annealed cold rolled steel strip provides additional strength rocking steel. The difference in mechanical properties with respect to the rolling direction (anisotropy) is inherent to DR material and favors C-grain cans. The smaller risk of flange cracking and the greater weld coverage for C-grain cans are the main reasons for continuing to use C-grain can bodies. Welding range (also called welding latitude) is expressed in amperes of current required to form weld nuggets with a weld that is neither too cold nor too hot, which reduces weld strength, and which is too hot, which increases the risk of molten metal splashing. Summary of the Invention [Problem to be solved by the invention]

[0011] It is an object of the present invention to provide a method for producing high strength tinplate having a tensile strength of 435 MPa to 700 MPa and improved H-grain weldability, i.e. maximum weld coverage for three-piece can bodies.

[0012] It is also an object of the present invention to provide a method for producing a welded three-piece can body having a tensile strength of 435 MPa to 700 MPa.

[0013] It is also an object of the present invention to provide a method for producing a welded three-piece can body having a tensile strength of 435 MPa to 700 MPa and with reduced or no second cold rolling reduction. [Means for solving the problem]

[0014] The object of the present invention is to provide a material with a lower yield stress (R eL A method for producing high strength tinplate having improved H-grain weldability for three-piece can bodies, comprising the steps of: Percent by weight: C: 0.045~0.095; Mn: 0.250~0.475; Si: 0 to 0.030 Al_sol: 0.005~0.025; N: 0.0070~0.0140; S: 0~0.020; P: 0~0.020 Optionally, Cr:0~0.100; Cu: 0~0.100; Ni: 0~0.100; Ti: 0~0.010; Nb: 0~0.010; V: 0~0.010; one or more of; Remainder: Inevitable impurities resulting from iron and steel making processes producing a hot rolled strip by hot rolling of the steel slab produced by the BOF-steelmaking process, wherein the hot rolled strip preferably has a crown value C40 of maximum 0.045 mm; thereafter, subjecting the hot rolled strip to a first cold rolling to an intermediate thickness, the reduction of the first cold rolling being between 85% and 91%, and then subjecting the cold rolled strip to a recrystallization annealing by continuous annealing or batch annealing to produce a fully recrystallized annealed strip; Thereafter, the fully recrystallized annealed strip is subjected to a second cold rolling to a final thickness, the reduction of the second cold rolling being between 2% and 17%; The annealed strip is then electrolytically tinned on one or both sides to produce tinplate. This is achieved by a method comprising:

[0015] The invention will now be described with the aid of the following non-limiting figures. [Brief description of the drawings]

[0016] [Figure 1] Figure 1 shows a schematic diagram of the cold rolling process according to the present invention. If the reduction ratio (DR) of the second cold rolling is 0, the lower diagram changes to the upper diagram. The coating includes a tin plating and optionally an additional coating such as a polymer coating. [Diagram 2] FIG. 2 illustrates the major differences between C-grain and H-grain can bodies. [Diagram 3] FIG. 3 shows a strip produced according to the invention, on which blanks for three-piece can bodies are projected, which, after cutting, can be used to produce H-grain can bodies in the upper figure and C-grain can bodies in the lower figure. [Figure 4] FIG. 4 is a cross-section of a weld in a three-piece can body showing the heat affected zone and a side stripe of bare steel and a powder coating or lacquer or the like to protect the weld. [Diagram 5] Figure 5 shows a schematic diagram of the film lamination process used to cover a tin-plated steel substrate with a polymeric film. The drawing shows double-sided coating, but this may also be performed on a single side. [Figure 6] Figure 6 shows a schematic of the direct extrusion process used to coat a tin-plated steel substrate with a polymer film. Although the drawing shows double-sided coating, this may also be performed on a single side. [Figure 7] 7 is a top view of a portion of a polymer-coated tin-plated steel substrate showing a strip showing bare edges and zones without polymer coating. The lines drawn in the zones without coating reflect the vertical cutting lines, the horizontally drawn lines reflect the horizontal cutting lines, and the distance between the horizontal lines is the blank height of the resulting three-piece can. [Figure 8] FIG. 8 shows the results of a good weld, a cold weld where the metal did not melt, and a hot weld where splatter occurred. [Figure 9] FIG. 9 is a diagram showing the definition of the crown C40. [Figure 10] FIG. 10 shows the geometry of the cone test. [Figure 11] FIG. 11 shows a schematic cross-section (not to scale) of a laminate comprising a steel substrate provided with a tin layer on each side (steel substrate + tin layer = tinplate) and with a thermoplastic polymer laminate layer on each side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The inventors have found that a tailored chemical composition of the steel strip is necessary to give the desired strength to the three-piece can. The process starts with producing a thick or thin steel slab, for which molten steel is produced in a BOF-steelmaking process based on pig iron from a blast furnace or direct reduction process, or in an EAF-steelmaking process. The EAF-steelmaking process generally produces a higher amount of unavoidable impurities / residual elements in the steel produced in the EAF-steelmaking process, mainly as a result of the process being based on molten scrap and / or direct reduced iron, and due to the more limited options for refining steel in the EAF-steelmaking process compared to the BOF-steelmaking process. Therefore, the BOF-steelmaking process is the preferred, but not the only, steelmaking process for producing the steel according to the present invention.

[0018] Of course, it is possible to refine the EAF-melt in a BOF-steelmaking process. In the present invention, the combination of EAF and BOF is also considered to be a BOF steelmaking process.

[0019] After the steelmaking process, the slabs are processed into hot rolled strip in a conventional hot strip mill or in a thin slab casting and direct rolling mill.

[0020] It should be noted that the chemical composition of the steel slab may be varied independently within the ranges set forth in the claims, so long as each individual element is within the range set forth in the claims.

[0021] Sulfur and phosphorus are residual elements and are not considered to be beneficial elements. They are considered unavoidable impurities and therefore their presence is preferably limited. The content of sulfur and phosphorus is preferably not more than 0.015%, more preferably not more than 0.010%, respectively. Aluminum is used as a deoxidizer to remove oxygen from the molten steel. Some aluminum still exists in the steel as alumina, the rest is called Al_sol, which may exist as aluminum in solid solution, for example precipitated as AIN.

[0022] The maximum amount of optional elements Cr, Ni and Cu is preferably 0.075% each, more preferably 0.060% each. The amount of Sn, Mo and B as unavoidable impurities is preferably 0-0.030%, 0-0.020% and 0-0.005%, respectively.

[0023] In a preferred embodiment, the steel slab produced by the BOF-steelmaking process comprises, in weight percent: C: 0.045~0.095; Mn: 0.250~0.475; Si: 0 to 0.030 Al_sol: 0.005~0.025; N: 0.0070~0.0140; S: 0~0.020; P: 0~0.020; Cr:0~0.030; Cu: 0~0.040; Ni: 0~0.060; Ti: 0~0.004; Nb: 0~0.004; V: 0~0.004; Ni+Cu+Cr+Mo+Sn+Nb+Ti+V:0~0.100; Remainder: unavoidable impurities resulting from the iron and steel making process; Includes.

[0024] Copper, nickel and chromium are also unavoidable impurities because they are difficult to remove from the melt and, in small amounts, their presence does not adversely affect the performance of the steel. Tin and molybdenum are also unavoidable impurities and their levels must be carefully controlled because their presence can adversely affect the performance of the steel. The sum of the most important residual elements (Ni+Cu+Cr+Mo+Sn+Nb+Ti+V) is preferably kept below 0.100%.

[0025] It is very important that the hot rolled strip is as flat as possible to be able to provide the required H-grain weldability in the final tinplate. Thickness variations over width lead to thickness variations in the materials to be welded together, which concerns the welding efficiency and the weld quality of the can body. If the welding window is large, the weld quality and efficiency are maximized over a wide range of thicknesses of the ends to be welded together, which is particularly important for producing H-grain bodies because of the thickness variations over the width of the strip, but is also valuable for producing C-grain can bodies.

[0026] When a strip is hot rolled, a crown is formed across its width. Crown is the difference in thickness with maximum thickness at the center and minimum thickness near the ends. It is a well-known fact that subsequent cold rolling cannot change the crown created in the hot rolling process without causing flatness defects in the resulting cold rolled strip. The relative crown and wedge are measured at a certain distance from the ends due to edge drop. For C40 and W40, this distance is 40mm from the ends and the crown and wedge are calculated as follows:

[0027]

number

[0028] The inventors have found that a C40 crown value of the hot rolled strip of up to 0.045 mm is preferred. More preferably, C40 is equal to or less than 0.040 mm, even more preferably equal to or less than 0.035, and most preferably equal to or less than 0.030 mm. This low level of crown in the hot rolled strip allows the cold rolling process to produce strip with very small thickness differences across the width, which is of great benefit to the H-grain welding process for producing three-piece can bodies from cold rolled strip, since the thickness differences between the ends that will be welded together are correspondingly small. Combined with the steel chemistry, this provides a welding process with a larger weld window without the need to change the welding parameters to produce a complete weld. A larger weld window allows a complete weld to be produced regardless of whether the blank is cut from the end of the strip or from the center of the strip. If the crown is greater than 0.045 mm or if the chemistry is not within the ranges set forth herein above, the weld window or flanging ability may be insufficient to handle the thickness difference, resulting in weld nugget formation with either too cold or too hot a weld.

[0029] When low crown C40 values ​​in the hot rolled strip are realized, problems arise for the hot strip mill, since a high crown would help the hot strip mill. It should be noted that the desired crown value in the hot rolled strip may be realized by cutting off the ends until the crown reaches the desired minimum value of 0.045 mm. This cut hot rolled strip may then be processed into the cold rolled strip according to the invention. Economically, this is not attractive, since it results in loss of material that has already undergone some processing. It should also be noted that the cold rolled strip is already produced with a certain amount of over-width. By aiming for some over-width, the process ensures that at least the desired amount of blank can be cut from the width of the final cold rolled strip. It is clear that it is important that the amount of cutting loss is minimized in order to minimize losses in material and costs. This can be achieved by ensuring a low hot strip mill crown.

[0030] The hot rolled strip is cold rolled in a first reduction with a first cold roll reduction of 85%-91%, then recrystallization annealed, then cold rolled in a second cold roll reduction of 2-17% depending on the desired final tensile strength level and thickness. Finally, the DR strip is provided with a tin layer on one or both sides using known continuous electrolytic tinning lines. In a preferred embodiment, the annealing is performed in a continuous annealing line (CA-line). Higher heating and cooling rates can be realized in a CA-line compared to batch annealing, which allows very fast process cycles and produces a more homogenous product over the length and width of the strip, which is beneficial for the manufacture of three-piece cans. Also, higher heating, and especially higher cooling rates, can result in smaller grain sizes and therefore higher strength of the material.

[0031] One important advantage of the H-grain body is its commercial nature: the height of the can body is determined by the blank size. It is easier to change the can height for a given diameter of the H-grain can body, because the blanks are cut from the strip in the rolling direction and the width of the strip is adjusted to the number of blanks obtained from the width of the strip. The number of specifications is reduced, thereby providing cost savings to the can manufacturer.

[0032] There may be an additional advantage to facilitating H-grain welding: H-grain cans can only be practically manufactured in large quantities when welding pre-coated materials such as side striped polymer coated steel substrates, such as Tata Steel's proprietary Protect® material.

[0033] In one embodiment, the minimum carbon content is 0.050% and preferably the maximum carbon content is 0.090%. Carbon is the primary hardening element in steel, and hardness increases as carbon content increases. However, ductility and weldability decrease with increasing carbon.

[0034] In one embodiment, the manganese content is at least 0.300%, preferably at least 0.325%. A suitable maximum manganese content is 0.450%, preferably a maximum of 0.425%.

[0035] In one embodiment, the steel slab according to the invention comprises max. 0.020% Si, preferably max. 0.015% Si, more preferably max. 0.010% Si. Silicon is a residual element and is not considered to be a beneficial element for tinplate, and therefore its presence is preferably limited. It is known that silicon may also have a negative effect on the corrosion resistance of tinplate. Ti and Nb are residual elements and affect the properties of steel when already present in trace amounts. Therefore, Nb and Ti contents are further preferably limited to max. 0.002% and max. 0.002%, respectively.

[0036] The amount of tin, and therefore the thickness of the tin layer deposited on the surface of the DR substrate, affects the weldability, therefore the amount of tin on the tinplate is preferably up to 5.0 g / m 2 , more preferably up to 4.5 g / m 2 , and even more preferably up to 4.0 g / m 2 It is.

[0037] In order to retain sufficient corrosion resistance after welding, the amount of tin on the tinplate is preferably at least 1.5 g / m 2 , more preferably at least 2.0 g / m 2 , and even more preferably at least 2.5 g / m 2 or at least 2.8 g / m 2 It is.

[0038] The method according to the invention can be used to manufacture blanks for three-piece cans in C-grain or H-grain orientation. However, the method according to the invention is very well suited to include a lamination step in which a thermoplastic polymer laminate layer is formed on one or both sides of the tinplate to form a laminate. The laminate of the steel substrate is thus provided with a tin layer on one or both sides, thereby producing a tinplate which is further provided with a thermoplastic polymer laminate layer on one or both sides. The thermoplastic polymer laminate layer may be formed on one or both sides of the tinplate using direct extrusion and in-line lamination, or by film lamination using an adhesive layer to bond the thermoplastic polymer laminate layer(s) to the tinplate, or by film lamination using a thermal bond to bond the thermoplastic polymer laminate layer(s) to the tinplate. The polymer laminate layer may be the same on both sides of the tinplate.

[0039] To produce a three-piece can body, the tinplate or laminate is further processed by cutting a rectangular body blank for the three-piece can body from the tinplate or laminate. Such a rectangular blank has two sides, side w being the side where the welding is performed to form the can body, and side c being the side that will become the circumference of the can body after welding. Depending on the orientation of this blank relative to the rolling direction of the cold rolled strip, two types of can bodies can be produced: C-grain: w⊥RD and c / / RD H-grain: w / / RD and c⊥RD

[0040] When producing blanks from laminates, the weld zone needs to be bare metal, because otherwise the can body would not be welded. With C-grain can bodies this is complicated, because each blank needs to be treated individually, for example using mechanical (e.g. scouring), chemical (e.g. melting) or optical (e.g. laser) means. This is not favorable from a productivity point of view. For this purpose it is advantageous to use H-grain blanks, because the laminate can be formed by leaving a narrow strip of tinplate uncovered and laminating only the part outside the weld zone, or by locally removing the laminate layer before forming the blank in direction / / RD.

[0041] In one embodiment, the tinplate is provided with a thermoplastic polymer laminate layer to form a laminate. This has the advantage that the can body produced with the laminate layer is further protected from corrosion, and the laminate layer can also provide a good basis for decorative printing. However, to enable welding of the can body, the ends of the blank to be welded need to be bare (i.e., not covered by the thermoplastic polymer laminate layer, but bare tinplate), and these welding areas need to be protected from corrosion after welding (see FIG. 4). The thermoplastic polymer laminate layer may be formed on one or both sides of the tinplate using direct extrusion and in-line lamination, or by film lamination using an adhesive layer to bond one or more thermoplastic polymer laminate layers to the tinplate, or by film lamination using thermal bonding to bond one or more thermoplastic polymer laminate layers to the tinplate (see FIGS. 5 and 6).

[0042] When a laminate is used, multiple thermoplastic polymer laminate layers are preferably formed on one or both sides of the tinplate such that a narrow longitudinal strip of tinplate remains unlaminated. By dividing the laminate along the unlaminated longitudinal strip, the laminate is divided into narrow laminate strips of width c with unlaminated ends on either side in the direction parallel to the rolling direction.

[0043] The multiple thermoplastic polymer laminate layers have a width slightly less than the blanks that will be cut from the strip. The blanks are cut into unlaminated elongated strips, leaving just enough exposed tinplate to make the welds to close the can body. This is the preferred embodiment because it relieves the can body manufacturer from the task of removing laminate from the ends to allow for welding.

[0044] In a preferred embodiment, a three-piece can body can be produced from tinplate or laminate by cutting a rectangular body blank from the tinplate or laminate, the side c of the rectangular body blank which will form the periphery of the can body being perpendicular to the rolling direction of the cold rolled strip, and the side w where the weld will be made to close the can body being parallel to the rolling direction of the tinplate or laminate (H-grain).

[0045] In one embodiment, a three-piece can body can be produced from tinplate or laminate by cutting a rectangular body blank from the tinplate or laminate, the side c of the rectangular body blank which will form the periphery of the can body is parallel to the rolling direction of the cold rolled strip, and the side w where the weld will be made to close the can body is perpendicular to the rolling direction of the tinplate or laminate (C-grain).

[0046] According to a second aspect, the invention is also embodied in the tinplate or laminate produced using the method according to the invention, and in the body blanks or three-piece can bodies produced therefrom.

[0047] In one embodiment, the lower yield stress (R eL ), and having improved H-grain weldability for three-piece can bodies, comprising, by weight percent: C: 0.045~0.095; Mn: 0.250~0.475; Si: 0 to 0.030 Al_sol: 0.005~0.025; N: 0.0070~0.0140; S: 0~0.020; P: 0~0.020 Optionally, Cr:0~0.100; Cu: 0~0.100; Ni: 0~0.100; Ti: 0~0.010; Nb: 0~0.010; V: 0~0.010; one or more of; Remainder: Iron and unavoidable impurities It is a high strength tinplate containing

[0048] In a preferred embodiment, the high strength tinplate is Cr:0~0.030; Cu: 0~0.040; Ni: 0~0.060; Ti: 0~0.004; Nb: 0~0.004; V: 0~0.004; Ni+Cu+Cr+Mo+Sn+Nb+Ti+V:0~0.100 Includes.

[0049] In one embodiment, the high strength tinplate has an H-grain weld area of ​​at least 350A, preferably at least 400A.

[0050] In one embodiment, the high strength tinplate or laminate has an H-grain flangability of at least 8.0%.

[0051] When referring to the can bodies described above in this specification, it should be noted that these can bodies may have a circular cross-section, but may also have different cross-sections such as oval, square, rectangular, etc. The invention described herein is equally applicable to these less conventional can body shapes.

[0052] According to a third aspect, the invention is also embodied in a body blank for a three-piece can made from a tinplate or laminate according to the invention, and in a three-piece can body made from a rectangular body blank made according to the invention. The body blank is formed into a cylinder or any other suitable shape and welded to form a closed body having an open end, the weld seam closing the can body being parallel to the rolling direction of the laminated tinplate. EXAMPLES

[0053] To test the performance of the steel according to the invention in three-piece welded can bodies, the weld coverage on C and H-grain bodies was determined along with the flangeability of the bodies.

[0054] [Table 1]

[0055] [Table 2]

[0056] [Table 3]

[0057] The welding tests were carried out using a Soudronic AFB1000 bodywelder. The overlap in the weld is 0.5 mm. The upper limit of the weld is determined by the appearance of spattering during welding (= "hot welding"), the lower limit is when the fuselage becomes unweldable during the fuselage test (= "cold welding").

[0058] The results of the welding tests are shown in Table 4.

[0059] [Table 4]

[0060] The weld range of the material according to the invention is high, even greater than that of the reference material. The N content of the material appears to be important for the weldability: a higher N content results in a wider weld range.

[0061] The weld area for both C-grain and H-grain fuselage of N steel exceeds 300Amp, which is the commonly used minimum standard for the size of the weld area on a production line. Nb steel is not satisfactory for either C-grain or H-grain fuselage, and only LC steel works well for C-grain fuselage.

[0062] Cans welded at 2 / 3 of the weld area were subjected to a cone test. Can bodies (n=15) were tested at both ends of the body. In the cone test, a cone with an apex angle α of 40° is pressed into the body at a speed of 65 mm / min using an Instron 5567 compression / tension machine with a 30 kN load cell. After matching the body and the cone, the force-displacement curve is measured and the test is stopped once after the rupture of the body, which is characterized by a sudden drop in force. From the displacement of the cone, the diameter just before rupture can be determined. The rupture can occur in the material itself, in the weld, or in the HAZ. The displacement I of the cone until rupture is determined from the force-displacement curve, and thus the increase in diameter is 2·dR=2tan(α / 2)I. The absolute flangeability (%) is therefore 2dR×100 / D (%).

[0063] The results of the tests showed no difference in flangability between the two ends and therefore they were averaged. The results of the cone tests are shown in Table 5.

[0064] [Table 5]

[0065] These results show that the flangability of the C-grain body is higher than that of the H-grain body, and the H-grain ability of the inventive material is greater than that of the reference material. The inventors have determined that the absolute flangability to obtain a flange width of 2.5 mm on a 73 mm diameter can body should be at least 6.8%. It can therefore be concluded that the N steel offers considerable potential in this regard, since its flangability is significantly higher than the lower limit required for both C- and H-grain (see Table 5 (last two columns: flangability - 6.8) / 6.8 x 100).

Claims

1. Lower yield stress (R) of 435 MPa to 700 MPa measured according to EN10002-1-2001 E ｅＬ ) and has improved H-grain weldability for three-piece can bodies, with an H-grain weld area of ​​at least 300 A, comprising the steps of: In weight percent, C: 0.045-0.095; Mn: 0.250-0.475; Si:0~0.030 Al_sol: 0.005-0.025; N: 0.0070-0.0140; S: 0-0.020; P: 0-0.020; Optionally, Cr: 0-0.100; Cu: 0-0.100; Ni: 0-0.100; Ti: 0-0.010; Nb: 0-0.010; V: 0-0.010; one or more of: Remainder: unavoidable impurities resulting from the iron and steel making process; producing a hot rolled strip by hot rolling the steel slab produced by the BOF-steelmaking process; thereafter, subjecting the hot rolled strip to an intermediate gauge by a first cold rolling, the reduction of which is between 85% and 91%, and then subjecting the cold rolled strip to a recrystallization annealing by continuous annealing or batch annealing to produce a fully recrystallized annealed strip; Thereafter, the fully recrystallized annealed strip is subjected to a second cold rolling to final thickness, the second cold rolling having a reduction of between 2% and 17%; Thereafter, electrolytic tinning one or both sides of the annealed strip to produce tinplate. A method comprising:

2. The steel slab Cr: 0-0.030; Cu: 0-0.040; Ni: 0-0.060; Ti: 0-0.004; Nb: 0-0.004; V: 0-0.004; Ni+Cu+Cr+Mo+Sn+Nb+Ti+V: 0 to 0.100; The method of claim 1 , comprising:

3. 3. The method according to claim 1 or 2, wherein the hot rolled strip has a crown value C40 of at most 0.045 mm, preferably at most 0.040 mm, more preferably at most 0.035 mm.

4. The steel slab Si: 0 to 0.020, and / or Ti: 0 to 0.002, and / or Nb: 0-0.002 3. The method of claim 1 or 2, comprising:

5. The amount of tin on the tinplate is up to 5.0 g / m ２ , preferably up to 4.5 g / m ２ , more preferably up to 4.0 g / m ２ The method according to claim 1 or 2, wherein

6. The amount of tin on the tinplate is at least 1.5 g / m ２ , preferably at least 2.0 g / m ２ , more preferably at least 2.5 g / m ２ , and even more preferably at least 2.8 g / m ２ The method according to claim 1 or 2, wherein

7. 3. The method of claim 1 or 2, wherein a thermoplastic polymer laminate layer is applied to one or both sides of the tinplate to form a laminate.

8. 8. The method of claim 7, wherein a thermoplastic polymer laminate layer is formed on one or both sides of the tinplate using direct extrusion and in-line lamination, or by film lamination using an adhesive layer to bond one or more thermoplastic polymer laminate layers to the tinplate, or by film lamination using thermal bonding to bond one or more thermoplastic polymer laminate layers to the tinplate, preferably multiple thermoplastic polymer laminate layers are formed on one or both sides of the tinplate so that a narrow strip of tinplate remains unlaminated.

9. 9. The method of claim 8, wherein dividing the laminate along the remaining unlaminated elongated strip divides the laminate into narrow laminate strips of width c having unlaminated edges on either side in a direction parallel to the rolling direction.

10. 3. The method of claim 1 or 2, wherein a three-piece can body can be produced from tinplate or laminate by cutting a rectangular body blank from the tinplate or laminate, the side c of the rectangular body blank that will form the periphery of the can body being perpendicular to the rolling direction of the cold-rolled strip, and the side w where welding to close the can body will be performed being parallel to the rolling direction of the tinplate or laminate (H-grain).

11. 3. The method of claim 1 or 2, wherein a three-piece can body can be produced from tinplate or laminate by cutting a rectangular body blank from the tinplate or laminate, the side c of the rectangular body blank that will form the periphery of the can body being parallel to the rolling direction of the cold-rolled strip, and the side w where welding to close the can body will be performed being perpendicular to the rolling direction of the tinplate or laminate (C-grain).

12. Lower yield stress (R ｅＬ ) and having improved H-grain weldability for three-piece can bodies, In weight percent, C: 0.045-0.095; Mn: 0.250-0.475; Si:0~0.030 Al_sol: 0.005-0.025; N: 0.0070-0.0140; S: 0-0.020; P: 0 to 0.020 Optionally, Cr: 0-0.100; Cu: 0-0.100; Ni: 0-0.100; Ti: 0-0.010; Nb: 0-0.010; V: 0-0.010; one or more of: Remainder: Iron and unavoidable impurities Including, High strength tinplate produced by the method of claim 1.

13. Cr: 0-0.030; Cu: 0-0.040; Ni: 0-0.060; Ti: 0-0.004; Nb: 0-0.004; V: 0-0.004; Ni+Cu+Cr+Mo+Sn+Nb+Ti+V: 0~0.100 The high strength tinplate of claim 12, comprising:

14. High strength tinplate according to claim 12 or 13, having an H-grain weld range of at least 350A, preferably at least 400A.

15. 14. High strength tinplate or laminate according to claim 12 or 13, having an H-grain flangability of at least 8.0%.

16. A body blank for a three-piece can made from the tinplate or laminate according to claim 12 or 13.

17. 12. A three-piece can body made from a rectangular body blank made by the method of claim 11, wherein the body blank is formed into a cylinder or any other suitable shape and welded to form a closed body having an open end, and the weld seam closing the can body is parallel to the rolling direction of the laminated tinplate.

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