RU2381293C2 - Soft black sheet iron for tinning and method of its manufacturing - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy field, particularly to manufacturing of soft black sheet irons with hardness HR30T 49±3 or HR30T 53±3, provided for tinning. It is molten steel, containing following components, wt %: carbon ≤ 0.006, manganese 0.10 - 0.20, aluminium 0.025 - 0.075, silicon ≤ 0.03, titanium 0.04 - 0.08, phosphorus ≤ 0.015, sulphur ≤ 0.015, nitrogen ≤ 0.003, oxygen ≤ 0.004, iron and unavoidable admixtures are the rest and it is implemented its pouring at temperature of discharge 1190 - 1250° C with receiving of slab. It is implemented hot rolling of slab into strip at final temperature of rolling 880 - 920° C. It is winded strip into roll at temperature 550 - 630° C. It is implemented etching, cold rolling with reduction ratio at level 82 - 92%, continuous annealing at temperature 720 - 770° C during 25 - 50 seconds and training with extension of strip for 0.8 - 3.0%.

EFFECT: there is provided required hardness of sheet metal.

12 cl, 9 tbl, 6 ex

Description

FIELD OF THE INVENTION

The present invention relates to soft tinplate for tinning and a method for its manufacture, in particular, it relates to soft tinplate for tinning having a hardness of HR 30T (Super Rockwell hardness, measured using a diamond table), component 49 ± 3 (in hereinafter referred to as T-1CA) and 53 ± 3 (hereinafter referred to as T-2CA), respectively, and the method for their manufacture. This soft black tinplate for tinning is obtained using the method of continuous annealing of titanium-containing steel, free of interstitial atoms, (IF-steel), used mainly in the manufacture of a bucket of flower baskets with an expanding diameter, a can lid with a difficultly deformed shape and cans produced by deformation when stamping.

State of the art

In accordance with Japanese industry standard JIS G 3303, Table 1 shows the hardness range HR 30T of tin-plated steel sheet for various tempering classes, with tempering classes T-1 to T-3 designed for soft black tin for tinning, while classes from T-4 to T-6 are designed for solid gestures.

Table 1 Hardness range of different tinplate classes the class hardness range HR 30T T-1 46 ~ 52 T-2 50 ~ 56 T-2.5 52 ~ 58 T-3 54 ~ 60 T-4 58 ~ 64 T-5 62 ~ 68 T-6 67 ~ 73

In the prior art, tin-plated steel sheet is produced mainly using low-carbon aluminum-deoxidized steel. Japanese Patent Number 8073943, issued to Japan Steel Pipe Co., Ltd on March 19, 1996, uses low-carbon aluminum-grained steel to produce soft tin black for tinning with a hardness of HR 30T less than or equal to 54-60, which is a hardness of HR 30T grade T-3. The content of chemical components in it is as follows: 0.050% ≤C≤0.085%, preferably 0.060% ≤C≤0.080%; 0.05≤Mn≤0.60%; Si≤0.02%; P≤0.02%; Al≤0.10%, and the ratio of the number of Al atoms to N is greater than or equal to 15. The temperature of the strip winding into a roll during hot rolling is maintained at 550-620 ° C, and the heating temperature during annealing is controlled so as to be higher than 650 ° C, and lower than the phase transition temperature Al. After that, the tin is cooled to a temperature of 350-450 ° C with a cooling rate of ≥30 ° C / second and undergoes aging for more than 30 seconds.

Significant aging occurs in the production of tinplate using low-carbon deoxidized aluminum. After aging, the hardness of the product will increase, while the machining characteristics will become poor, and in conditions of deep stamping, large expanding diameter, large deformation, such as significant bending, defects such as cracking, slip line, cross-hatching, distortion will easily appear , edging on the surface. In addition, the inevitable problem of aging of low-carbon steel leads to the fact that tinplate subjected to tinning tends to form wrinkles and edging during bending and generates slip lines after deformation during stamping or stretching, which makes it difficult to satisfy the user's requirement. In addition, mild aluminum-mild steel is not suitable for the production of very soft tin-plated tin.

With the development of IF steel production technology, developed countries first began to use IF steel, including Nb, in the large-scale production of tinned steel sheet. Due to its inherent properties of good formability and aging resistance, tinned IF steel products have been highly competitive in the market.

JP 719192 (Japan Steel Pipe Co. Ltd), published August 1, 1995, discloses the production of soft tinplate for tinning having the following composition:

C≤0.004%, Mn≤0.6%, Al: 0.03-0.10%, N≤0.004%, Nb: 0.021-0.050%, and the ratio of the number of atoms Nb and C is more than 10. This patent uses niobium-containing IF steel and has a special requirement for Nb content. Since niobium-containing IF steel is very sensitive to processing parameters, especially to hot rolling parameters, the product properties are unstable and heterogeneous. In addition, its recrystallization temperature is high, so that the heating temperature during annealing is also required to be high. The production of this product requires a greater number of transitional turns of the roll and a longer duration of the transition process. In particular, inside the continuous annealing furnace, curvature and even breakage of the strip easily occurs. As a result, the continuous strip discharge performance is poor. In addition, due to the high consumption of thermal energy and the high price of niobium as an alloying element, production costs are relatively high. In addition, niobium-containing IF steel has poor ductility. Although its anisotropy is small, its general mechanical properties are worse than that of titanium-containing IF steel. Finally, during mining and smelting, Nb exhibits a certain degree of radioactivity, so there is a debate as to whether it is harmful or not for the human body that tinplate, including Nb, is mainly used in the food industry.

Moreover, the aforementioned patent discloses that the coiling of a hot-rolled strip is carried out at 600-800 ° C. This temperature of winding the strip into a roll, especially its upper limit (800 ° C), is too high for practical implementation. The temperature range of the strip winding of the strip claimed in this patent is obviously unjustified, because when the winding is performed at a temperature of about 800 ° C, the steel sheet is substantially oxidized. Even above 630 ° C, the scale thickens visibly, which not only affects the etching rate in subsequent operations, but also affects the surface quality of the final product. In addition, the aforementioned patent discloses that annealing is performed at a temperature of 670-800 ° C. However, since the mentioned patent uses niobium-containing IF steel for the production of soft black tin for tinning, while annealing is carried out at a temperature of about 670 ° C within the range of the heating temperature during annealing described in the mentioned patent (for example, 670-740 ° C), it is difficult for steel sheet to achieve recrystallization at the usual speed of the production line. That is, it is impossible to produce an acceptable soft black sheet for tinning. Thus, the annealing heating temperature range claimed in the aforementioned patent is obviously unreasonable.

Disclosure of invention

The objective of the present invention is to create a soft tin class T-1CA and T-2CA for tinning, produced by continuous annealing of titanium-containing IF steel.

For the mentioned purpose, the present invention provides soft tin grade T-1CA and T-2CA for tinning, containing the following chemical components in weight percent:

C≤0.006%, preferably C≤0.004%,

Man: 0.10-0.20%,

Al: 0.025-0.075%, preferably Al: 0.030-0.060%,

Si≤S 0.03%,

Ti: 0.03-0.08%, preferably Ti: 0.05-0.07%,

P≤0.015%,

S≤0.015%,

N≤0.003%,

O≤0.004%,

the rest is iron and some inevitable impurity elements.

The following is the purpose and description of the main elements of the present invention.

Content C≤0.006%

With increasing C content, the hardness of soft black tin for tinning increases, on the other hand, along with this, its ductility decreases. In order to stably maintain the hardness of HR 30T at a level lower than 56 and to ensure the formability of the material, it is necessary that the C content be ≤0.006%, so as to obtain the proper hardness and excellent formability. On the other hand, in the case of increasing the content of C, in order to provide resistance to aging of soft black sheet for tinning, the amount of Ti used should be increased accordingly. As a result, production costs also increase. Therefore, it is recommended that the C content is not too high. The preferred content of C is ≤0.004%.

Mn content: 0.10-0.20%

Mn is the main reinforcing element for soft black tin for tinning. The higher its content, the higher the hardness of the product. But the price of Mn is relatively high. In order to reduce the cost while maintaining satisfactory properties, the lower its quantity, the more economical and affordable it is. When its content is maintained at a level lower than 0.20%, for soft black tin grade T-2CA for tinning, which requires higher hardness, this requirement can be met by convenient and economical increase in elongation during training. But when its content is lower than 0.10%, the material becomes too soft. On the other hand, in the steel itself there is a certain amount of Mn. Thus, if a Mn content of less than 0.10% is required, then it is necessary to reduce the Mn content in steel, which leads to a large increase in cost. For this reason, the present invention limits the Mn content to a range of 0.10-0.20%.

Ti content: 0.03-0.08%

Ti (titanium) is mainly used to bind free C in steel to form TiC, and Ti is favorable for increasing the aging resistance of a material, especially its stampability. In addition, TiC also to a certain extent performs the function of dispersion hardening, thus leading to an increase in the strength and hardness of the material. The price of Ti, however, is high (even though it is much lower than that of Nb), and thus its content directly affects production costs. For this reason, its content should be strictly controlled. In the present invention, it is sufficient that the Ti content is maintained at a level lower than 0.08%. But when its content is lower than 0.03%, it is impossible to bind all free C and a small amount of N in steel. For this reason, the present invention requires that the Ti content be within the range of 0.03-0.08%, preferably 0.05-0.07%.

Al content: 0.025-0.075%

Al is a deoxidizing element, also a strong nitride forming element, used mainly to bind the N atom, favorable to increase the resistance of the material to aging. In addition, Al is also a necessary deoxidizer during steel melting. If its content is lower than 0.025%, then the quality requirement cannot be satisfied, and if it is higher than 0.075, then not only the cost will be high, but the growth of crystalline grain during recrystallization during annealing will also be suppressed. For this reason, the present invention requires that the Al content is 0.025-0.075%, preferably 0.030-0.060%.

Si content: ≤0.03%

Although Si has a certain reinforcing function, in parallel it reduces erosion resistance, so that the lower its content, the better the effect of the present invention. Therefore, the Si content should be below 0.03%. When the Si content exceeds 0.03%, erosion resistance is significantly deteriorated.

The content of other elements: P≤0.015%, S≤30.015%, N≤0.003%, O≤0.004%.

The elements P, S, N, and O are harmful impurity elements and must be strictly controlled. The lower the content of these elements, the better the product of the present invention. Otherwise, the mechanical properties and erosion resistance of soft tinplate for tinning will be affected. Provided that their content is within the limit ranges of the present invention, soft tinplate for tinning that meets the requirements can be produced.

The soft tinplate tins of classes T-1CA and T-2CA are produced using a process containing the following stages: melting → continuous casting → hot rolling → pickling and cold rolling → continuous annealing → training → tinning. Another process may also be used, comprising the steps of: melting → continuous casting → hot rolling → pickling → continuous cold rolling → continuous annealing → training → tinning; or a process comprising the steps of: melting → continuous casting → hot rolling, pickling → multiple reverse cold rolling → continuous annealing → training → tinning.

The key points of the main operations are described below.

Steel melting

The molten steel is cleaned by the Rurshtal-Gereus method and vacuum degassing, in parallel, appropriate measures are taken to control the content of impurities. Finally, through a conventional continuous casting operation, a continuous casting slab is obtained and then hot rolling follows.

Hot rolling

In the hot rolling step of the present invention, the slab heating temperature (i.e., the molten metal discharge temperature) is 1220 ± 30 ° C, and the final hot rolling temperature is 900 ± 20 ° C. In theory and industrial practice, it is proved that when the final temperature is higher than 920 ° C, the surface of the steel strip is substantially oxidized, resulting in poor surface quality. On the other hand, if it is lower than 880 ° C, the hot rolled steel strip tends to form a double granular structure when two phases are formed inside the strip during rolling, and this leads to a non-uniform structure characteristic of the final product. When the final hot rolling temperature is maintained at 900 ± 20 ° C, the oxidation of the surface of the steel strip is weakened, and a double grain structure does not occur in the steel strip, resulting in a uniform structure characteristic of the final product. The final hot rolling temperature is preferably maintained at 885-915 ° C. to provide more uniform characteristics and better surface finish.

The cooling temperature of the hot rolling of the present invention is maintained at 590 ± 40 ° C. An increase in the temperature of winding the strip into a roll can reduce the hardness of the hot-rolled sheet metal, and therefore, reduce the hardness of the final product and increase the formability of the final product. However, when the temperature of winding the strip into a roll is more than 630 ° C, the scale on the surface of the steel strip tends to thicken easily, which leads to a difficult etching stage, and affects the surface quality of the product. When the strip winding temperature is lower than 550 ° C, the crystalline grains of the hot rolling intermediate are too small, which affects the structure and property of the final product. This also leads to a final product with small crystalline grains, increased strength and hardness, and poor ductility. So for soft tinned tin class T-1CA and T-2CA according to the present invention, produced by continuous annealing, if the temperature of winding into a roll of a hot strip is maintained at 590 ± 40 ° C, the amount of dross on the surface of the steel strip after the operation of winding into a roll is small, etching is easier, and the surface quality of the final product is good. Preferably, the temperature of the coiling of the strip of hot rolling was maintained at a level of 570-610 ° C, so as to obtain good ductility and better surface quality.

Pickling and cold rolling

A combined pickling and cold rolling production line may be used, or pickling is performed first and then continuous cold rolling or multiple reverse cold rolling is performed. But it is preferable to use a combined pickling and cold rolling production line in order to increase production efficiency. During the etching operation, the speed of the production line must be adjusted in accordance with the etching performance in the production line to ensure a good etching result. When cold rolling is performed continuously, five stands are used. The full degree of compression during cold rolling is 82-92%. The full degree of compression during cold rolling will affect the mechanical properties of the strip material. In addition, the proper degree of compression during cold rolling is favorable to ensure the exact size of the solid material and control the profile of the cross section of the strip. Too small a reduction leads to a poor property of formability of the strip material, while too large a reduction leads to an increase in costs during the cold rolling operation and an unsatisfactory cross-sectional profile of the strip of solid material, affecting the stability of the continuous movement of the strip at high speed during subsequent continuous annealing operations.

Continuous annealing

In the present invention, for the production of tinned soft tin of class T-1CA and T-2CA, continuous annealing is used with a heating temperature during annealing of 720-770 ° C and a holding time of 25-50 seconds. The preferred heating temperature during annealing is 735-765 ° C. Although soft black tinplate for tinning can also be produced using annealing in a bell furnace, the mechanical property of the head, middle and tail portions of a large tinned tin product roll produced by annealing in a bell furnace is not uniform, and the cross-sectional profile of the strip and the surface quality of the product much worse than that of soft black tinplate for tinning produced by continuous annealing. The present invention prepares T-1CA and T-2CA soft tinplate by continuous annealing using titanium-containing IF steel, the mechanical properties of the product thus obtained are uniform, and the surface quality is good. The product can well meet the requirements of the user, so it has a high market competitiveness. When the heating temperature during annealing is higher than 770 ° C, the steel strip tends to bend and even break in the annealing furnace if the steel strip is wide and thin, which is caused by the softness of the steel strip. At the same time, energy consumption is also increasing. When the heating temperature during annealing is lower than 720 ° C, under conditions of a normal speed of the continuous annealing production line, it is difficult to ensure the recrystallization of the steel strip, and the hardness of the product increases, and the formability of the product deteriorates. According to the present invention, soft tinplate for tinning is obtained by continuous annealing of titanium-containing IF steel at a lower annealing temperature compared to continuous annealing of niobium-containing IF steel (according to the simulation results of annealing tests, no heating temperature during annealing of nickel-containing IF steel, except 750-800 ° C, insufficient to ensure recrystallization). Therefore, when organizing production, the amount of transition roll used can be reduced, and the time for raising and lowering the temperature can be reduced, so as to increase production efficiency and reduce production costs. In addition, the likelihood of curving and breaking the steel strip in the annealing furnace is significantly reduced due to lower temperatures. The holding time and the heating temperature during annealing affect each other. An increase in the heating temperature during annealing shortens the holding time. But the aging time cannot be less than 25 seconds, otherwise the grain growth during recrystallization is insufficient and the result is a material of too high hardness. At the same time, if the speed of the production line is slightly higher, the steel strip tends to go off the guide. On the other hand, the aging time cannot last too long. If it is longer than 50 seconds, then the production efficiency decreases due to the too low speed of the continuous annealing production line, and the crystalline grains become too large, which results in a soft material. In addition, the steel strip tends to bend and even break in the annealing furnace.

Training

After the recrystallization of titanium-containing IF steel, the strain of the training significantly affects the property, nature and quality of the material. With an increase in the strain, the strength and hardness obviously increase. For soft tinned tin class T-1CA obtained by continuous annealing according to the present invention, the training is performed by two stands after annealing. The elongation during training is maintained at the level of 0.8-1.8%. For soft tinned tin of class T-2CA, elongation during training is maintained at 1.8-3.0%. The training elongation range for the above T-1CA and T-2CA can be properly adjusted according to the thickness of the product. Smaller training elongation is applied to a thinner steel strip; and greater elongation during training - for a thicker steel strip.

Tinning

Soft tinned tin classes T-1CA and T-2CA, prepared by continuous annealing in accordance with the present invention, can be coated with tin using traditional tinning technology for ordinary tinned gestures.

A tinned soft steel strip containing chemical components according to the present invention, which is obtained from titanium-containing IF steel, according to the present invention does not have an aging problem and is also not sensitive to processing parameters during hot rolling. The recrystallization temperature of soft tinplate for tinning made from titanium-containing IF steel according to the present invention is lower than that of soft black tinplate for tinning made from niobium-containing IF steel, which leads to lower heat consumption of the furnace and a shorter transition time temperature in normal conditions of production, a reduced number of used transition turns or re-annealed turns and thereby reduces production costs. In addition, during continuous annealing in the furnace, the steel strip does not tend to bend, and the motion characteristics of the continuous strip are good, and the risk of breakage of the strip is small. The soft tinplate for tinning produced using titanium-containing IF steel according to the present invention has more stable mechanical properties than this tin produced using niobium-containing IF steel. In addition, in the preparation of soft tinplate for tinning according to the present invention, provided that the material is uniform, nature and quality hot rolling uses a lower final temperature and the strip winding temperature, the amount of scale from oxidation on the surface of the steel strip after hot rolling is small , subsequent etching is easy to do, which results in good surface quality of the final product.

Examples

The following is a description of soft tinplate for tinning produced according to the present invention.

Examples 1-6

Tinned mild steel sheet T-1CA class is prepared using titanium-containing IF steel. The molten steel is purified by the Rurshtal-Gereus method and vacuum degassing, taking various measures to control impurities. Finally, a continuous casting slab is prepared according to conventional continuous casting technology. The chemical composition of the molten steel is given in table 2, also other inevitable impurity elements are present in the steel, the rest is Fe.

table 2 The chemical composition of the gestures according to examples 1-6 (weight%) Example FROM Si Mn R S Al N Ti ABOUT one 0.0022 0.007 0.17 0.011 0,0100 0,045 0.0026 0,060 0.0040 2 0.0020 0.008 0.18 0.015 0.0120 0,025 0.0023 0,050 0.0030 3 0.0033 0,030 0.20 0.012 0.0150 0,055 0.0018 0,030 0.0023 four 0.0040 0.015 0.13 0.009 0.0080 0,060 0.0027 0,055 0.0018 5 0.0045 0.009 0.10 0.013 0.0060 0,030 0.0030 0,080 0.0027 6 0.0060 0.008 0.12 0.010 0.0085 0,075 0.0026 0,070 0.0020

Before hot rolling, the continuous casting slab is heated to a temperature to start rolling during hot rolling. It is subjected to rough rolling, finishing rolling and cooling in a laminar flow and then the strip is rolled up. After cooling at room temperature for 2-3 days, it is subjected to pickling and continuous cold rolling using a combined production line consisting of a CDCM production line (for pickling) and a continuous cold rolling production line for preparing cold rolled sheet. Specific processing parameters are given in table 3.

Table 3 The main parameters of the processing process according to examples 1-6 Examples molten metal discharge temperature (° C) end temperature of hot rolling (° C) reeling temperature of the strip of hot rolling in a roll (° C) cold rolling reduction ratio one 1220 903 615 82 2 1250 920 630 90 3 1190 880 550 89 four 1225 907 590 85 5 1220 915 610 90 6 1210 885 570 92

The cold-rolled steel strip undergoes continuous annealing at the production line of the continuous annealing and rolling processing line (CAPL) (for continuous annealing) and training at the training line of the train, followed by traditional tinning, thereby obtaining tinned tin. The parameters of the annealing process, elongation during training and the hardness of the final product are given in Table 4.

The mechanical properties of the final product are given in table 5.

Examples 7-12

Soft tin of grade T-2CA for tinning is prepared using titanium-containing IF steel. The molten steel is purified by the Rurshtal-Gereus method and vacuum degassing, taking various measures to control impurities. Finally, a continuous casting slab is prepared according to conventional continuous casting technology. The chemical composition of the molten steel is given in table 6. Other inevitable impurity elements are also present in the steel, the rest is Fe (iron).

Table 6 The chemical composition of the gestures according to examples 7-12 Examples FROM Si Mn R S Al N Ti ABOUT 7 0.0021 0.0075 0.17 0.010 0.015 0,045 0.0030 0,070 0.0025 8 0.0019 0.0080 0.18 0.015 0.011 0,040 0.0022 0,055 0.0040 9 0.0015 0,0300 0.20 0.013 0.009 0,025 0.0023 0,030 0.0023 10 0.0060 0.0070 0.10 0.012 0.007 0,075 0.0025 0,080 0.0018 eleven 0.0040 0.0090 0.13 0.010 0.012 0,060 0.0018 0,040 0.0020 12 0.0035 0.0150 0.15 0.013 0.008 0,030 0.0020 0,050 0.0027

Before hot rolling, the continuous casting slab is heated to a temperature to start rolling during hot rolling. It is subjected to rough rolling, finishing rolling and cooling in a laminar flow and then the strip is rolled up. After cooling at room temperature for 2-3 days, it is subjected to pickling and continuous cold rolling using a combined production line consisting of a CDCM production line (for pickling) and a continuous cold rolling production line for preparing cold rolled sheet metal. The specific processing parameters are given in table 7.

Table 7 The main parameters of the processing process according to examples 7-12 Examples molten metal discharge temperature (° C) final temperature of hot rolling (° C) reeling temperature of the strip of hot rolling in a roll (° C) degree of compression during cold rolling (%) 7 1225 907 615 89 8 1210 890 600 82 9 1190 880 550 87 10 1250 920 630 90 eleven 1200 885 570 89 12 1220 915 610 92

The cold-rolled steel strip undergoes continuous annealing at the CAPL production line (for continuous annealing) and training at the training production line, followed by traditional tinning, thereby obtaining tinned tin. The parameters of the annealing process, elongation during training and the hardness of the final product are given in Table 8.

Table 8 Parameters of annealing, elongation during training and hardness of the product according to examples 7-12 Examples Annealing heating temperature (° C) Annealing Duration (seconds) Elongation during training (%) Hardness tinplate HR30T 7 750 28 2.6 53.0 8 740 33 2,4 52.8 9 770 25 2,8 53.6 10 720 fifty 1.8 54.5 eleven 735 40 2,3 54.6 12 765 26 3.0 55.1

The mechanical properties of the final product are given in table 9

Claims (12)

1. Soft black tin for tinning, containing the following components, wt.%:
C≤0.006
Mn 0.10-0.20
Al 0.025-0.075
Si≤0.03
Ti 0.04-0.08
P≤0.015
S≤0.015
N≤0.003
About≤0.004
Fe and unavoidable impurities - the rest,
obtained by single cold rolling. 2. Soft tinplate for tinning according to claim 1, in which the content of C is not more than 0.004%. 3. Soft tinplate for tinning according to claim 1, in which the Al content is 0.030-0.060%. 4. Soft tinplate for tinning according to claim 1, in which the Ti content is 0.05-0.07%. 5. The soft black tin for tinning according to claim 1, the steel sheet of which is obtained by continuous annealing. 6. The method of producing soft black sheet for tinning according to claim 1, including steel smelting, continuous casting of the molten slab, hot rolling of the slab into a strip at a slab discharge temperature of 1190-1250 ° C and at a final rolling temperature of 880-920 ° C, winding of the strip into a roll at a temperature of 550-630 ° C, etching, cold rolling with a compression ratio of 82-92%, continuous annealing at a temperature of 720-770 ° C for 25-50 s and training with a strip elongation of 0.8-3.0 % 7. The method according to claim 6, in which etching and cold rolling is performed on a combined production line. 8. The method according to claim 6, in which cold rolling is performed in the form of continuous cold rolling or reverse cold rolling. 9. The method according to claim 6, in which the specified annealing is carried out at a temperature of 735-765 ° C. 10. The method according to any one of claims 6 to 8, in which the training is performed using a single training camp or paired training mills. 11. The method according to claim 6, in which to obtain soft black tin for tinning having a hardness of HR30T 49 ± 3, training is performed with an elongation of the strip by 0.8-1.8%. 12. The method according to claim 6, in which to obtain soft black tin for tinning having a hardness of HR30T 53 ± 3, the training is performed with an elongation of the strip by 1.8-3.0%.