TWI522480B - A method for producing a film for tin plating and a film for tin plating - Google Patents

Description

Tin plating negative film and tin plating negative film manufacturing method

The present invention relates to a method for producing a tin-plated backsheet and a tin-plated backsheet, and more particularly to a tin-plated film which can be subjected to batch annealing and has a hardness of up to T4 (Rockwell surface hardness HR30T is between 56 and 66). And its manufacturing method.

Tin-plated backsheets are widely used in various tin can products after tinning on the surface. For example, common iron canned food or beverage cans are made of tin-plated steel sheets made by tin plating on the surface of tin-plated backsheets. s material. The annealing treatment of the traditional tin-plated film can be roughly divided into continuous annealing and batch annealing, wherein the continuous annealing is simultaneously annealed in the process (about 20 minutes to 30 minutes), and the continuous annealing can make the traditional tin plating The film has a maximum surface hardness of HR30T of 60 to 70 (T5 grade), but it is easy to form Ryder on the surface when the tin-plated steel sheet made of the conventional tin-plated film after continuous annealing is deep-drawn. The wire (Luder's Line) further affects the surface quality of the product. The batch annealing is to slowly anneal the traditional tin-plated film in the furnace (about 23~25 hours), and the traditional tin plating after batch annealing Although the tin-plated steel sheet made of the negative film is processed by deep-drawing, although the processing grain is not produced on the surface, the hardness of the traditional tin-plated film after batch annealing can only reach the surface hardness of Rockwell HR30T between 52~. 62 (T3 grade), that is to say, the conventional tin-plated film uses a batch annealing hardness lower than the continuous annealing, so the batch-annealed tin-plated film requires a higher thickness to achieve The same strength as the article made by continuous annealing of the tinned backsheet, such as This will increase manufacturing costs.

In order to solve this problem, the present invention provides a tin-plating backsheet having a hardness of HR30T of 56 to 66 and an elongation of 22% to 40%, and the composition includes: 0.10% to 0.14% by weight. Carbon, 0.03% or less, 0.6% or less manganese, 0.02% phosphorus, 0.030% or less sulfur, 0.2 or less copper, 0.02% to 0.10% chromium, and 0.15% or less nickel. 0.05% or less of molybdenum, 0.100% or less of aluminum, 0.0060% or less of nitrogen, and the balance of iron and impurities.

In addition, the present invention further provides a method for processing the original tinplate for casting, which comprises 0.10% to 0.14% carbon, 0.03% or less, 0.6% or less manganese, 0.02% phosphorus, 0.030 in weight%. % or less sulfur, 0.2 or less copper, 0.02% to 0.10% chromium, 0.15% or less nickel, 0.05% or less molybdenum, 0.100% or less aluminum, 0.0060% or less nitrogen, and the rest are iron and impurities; The steel preform for the tin-plated backsheet is heated to 1250 ° C ~ 1300 ° C for rough rolling, to obtain a rough rolled steel strip with reduced thickness, and the finishing rolling step: cooling the rough rolled steel strip after the rough rolling to 800 After finishing °C~920°C, the finishing rolling is carried out to obtain the finished rolling strip, and the laminar cooling step: cooling the finished strip after finishing rolling to 500 ° C ~ 700 ° C, hot coiling step: cooling the laminar flow After the finishing rolled steel strip is rolled into a roll, and the air cooling is reduced to room temperature to obtain a hot rolled steel coil, the pickling step: the hot rolled steel coil after the hot coiling is soaked in the pickling liquid to remove the surface oxide to obtain the pickled steel. Belt, cold rolling step: pickling the strip after pickling, cold rolling, reducing the thickness to between 0.15mm~0.60mm and then winding it into a roll A cold rolled steel coil is obtained, and an electrolytic cleaning step is performed: the cold rolled steel coil after the cold rolling step is subjected to electrolytic cleaning to wash the rolling oil remaining on the surface of the cold rolled steel coil, and then coiled into The roll is obtained after cleaning the steel coil, batch annealing step: the electrolytic cleaning step will be completed After cleaning, the steel coil is heated in the furnace to 550 ° C ~ 650 ° C and maintained for a period of time, cooled in the furnace to 60 ~ 110 ° C to obtain a batch of annealed steel coil, quenched and tempered: the batch annealing step will be completed The post-annealed steel sheet is subjected to quenching and tempering, and further obtained a tin-plated negative film having a Rockwell surface hardness of HR30T of 56 to 66 and an elongation of 22% to 40%.

Therefore, the tin-plated film after batch annealing can still obtain a tin-plated film having a hardness of T4 (Rock surface hardness HR30T56-66) and an elongation of 22% to 40%.

The first figure is a comparison of the hardness of the original tin-plated film after batch annealing through a batch annealing and a conventional tin-plating film.

The second figure is a comparison of the elongation of the original tin-plated film after batch annealing and the conventional tin-plating film through continuous annealing.

All of the following drawings are merely illustrative of the basic teachings of the present invention, and the extension of the number, position, relationship, and size of the components constituting the preferred embodiment will be explained in the drawings. Post-guided changes are implemented in industry skills. In addition, changes in the exact dimensions and size ratios associated with specific strengths, weights, strengths, and similar requirements are also within the skill of the industry after reading and understanding the teachings of this creation.

The tinplate for tin plating of the present invention is a steel sheet, and the tinplate for tin plating is made of a steel slab, and the steel embryo includes 0.10 to 0.14% by weight of carbon (C), 0.03% by weight or less of bismuth (Si), 0.6% by weight. The following manganese (Mn), 0.02% by weight or less of phosphorus (P), 0.030% by weight or less of sulfur (S), and 0.2% by weight or less of copper (Cu), 0.02 to 0.10% by weight of chromium (Cr), 0.15% by weight or less of nickel (Ni), 0.05% by weight or less of molybdenum (Mo), 0.100% by weight or less of aluminum (Al), and 0.0060% by weight or less of nitrogen (N) The rest are iron (Fe) and impurities.

Among them, in order to ensure sufficient strength of the tin-plated film after annealing, the content of carbon (C) is quite important. In addition, carbon is one of the most important elements affecting hardness. Generally, the higher the carbon content, the higher the strength, but the carbon content is too high, which is disadvantageous for forming and welding. Therefore, the carbon content is set to be 0.10 to 0.14% by weight.

Niobium (Si) has strengthening and deoxidizing functions, but it is not conducive to forming processing. Therefore, the low carbon soft steel has a low niobium content, which is used only when the tensile strength and electromagnetic properties are improved. Therefore, it should be controlled to 0.03 wt% or less.

Manganese (Mn) can strengthen the strength of steel by solid solution and increase the number of crystal grains of smaller size. The strength of the tin-plating backsheet is increased by adding manganese, but if a large amount of manganese is added, the corrosion resistance is poor. Therefore, manganese should be controlled to be 0.60% by weight or less.

Phosphorus (P) is a harmful residual element for tin-plated negative films, which is not conducive to forming processing due to phosphorus segregation. Phosphorus will reduce the low temperature toughness of steel and damage the corrosion resistance. Phosphorus and manganese are the same elements with high solid solution strengthening ability. In order to avoid the corrosion resistance of phosphorus, phosphorus should be controlled below 0.02%.

Sulfur (S) is present as inclusions in steel, and therefore, this is an element of corrosion resistance and ductility of the steel sheet, and should be reduced as much as possible. Therefore, sulfur should be controlled below 0.02%.

An increase in the aluminum (Al) content leads to an increase in the recrystallization temperature, and it is necessary to increase the annealing temperature. Then, the higher the annealing temperature, the higher the rate of formation of aluminum nitride (AlN), resulting in a decrease in the amount of solid solution nitrogen, resulting in a decrease in strength. So avoid possible due to aluminum The increase in the recrystallization temperature induced, the aluminum should be controlled below 0.100%.

Nitrogen (N) has a high solid solution strengthening ability, so the strength of the element is increased, and it is necessary to add nitrogen so as to effectively increase the strength. On the other hand, the problem arises when the addition of a large amount of nitrogen occurs. From the above, the nitrogen should be controlled to be below 0.060%.

The tin-plated film of the present invention can be processed through the following steps to obtain a tin-plated film having a Rockwell surface hardness of HR30T between 56 and 66 (T4 grade) and an elongation of 22% to 40%, mainly in Ar3. The slab including the specific element ratio is subjected to hot rolling below the abnormal point, and is rolled at 500 ° C to 700 ° C after hot rolling, followed by pickling, followed by cold rolling at a reduction rate of 80% or more, followed by batch annealing. The method is annealed at a temperature between 550 ° C and 650 ° C, and finally subjected to quenching and tempering to obtain a tinplate for tin plating. The detailed steps are as follows: hot rolling includes rough rolling step, finishing rolling step, laminar cooling step and hot coil Take the steps. The rough rolling step includes: 0.10% to 0.14% carbon, 0.03% or less, 0.6% or less manganese, 0.02% phosphorus, 0.030% or less sulfur, 0.2% or less copper, 0.02% by weight. %~0.10% chromium, 0.15% or less nickel, 0.05% or less molybdenum, 0.100% or less aluminum, 0.0060% or less nitrogen, and the others are iron and impurities; the billet used to make the tinplate for tin plating is heated to 1250 ° C ~ 1300 ° C, and then use the roller of the roughing mill to roll the heated billet, resulting in a reduction in the thickness of the billet, while rolling the side of the tin sheet for the tin strip with the roller of the side mill to level the side of the billet Obtain a rough rolled steel strip.

Finishing step: after the rough rolling and rolling of the rough rolling strip is cooled to 800 ° C ~ 920 ° C, the rolling of the finishing mill is used to reduce the thickness of the rough rolled strip to obtain hot rolled steel. band.

Laminar cooling step: The finishing rolling strip of the finishing mill is cooled to 500 ° C ~ 700 ° C by means of sprinkling water cooling method.

Hot-rolling step: a hot-rolled steel coil is obtained by rolling a refining rolled steel coil with a temperature of 500 ° C to 700 ° C after laminar cooling, and the hot-rolled steel coil after being wound into a coil is cooled to room temperature by air cooling ( About 10 ° C ~ 40 ° C).

After the hot rolling step is completed, the following steps are further carried out: a pickling step: the hot-rolled steel coil having a temperature of room temperature is immersed in the pickling liquid to remove the oxide on the surface of the hot-rolled steel coil to obtain a pickled steel strip.

Cold rolling step: after acid pickling, the steel strip is cold rolled by a cold rolling mill, and the thickness of the steel strip after pickling is reduced to a thickness between 0.15 mm and 0.60 mm, and then rolled into a roll. (Coil) shape obtained cold rolled steel coil.

Electrolytic cleaning step: the cold-rolled steel coil after the cold rolling step is subjected to electrolytic cleaning for washing the rolling oil remaining on the surface of the cold-rolled steel coil, and then winding it into a coil (Coil) to obtain a cleaned condition. Steel coil.

Batch annealing step: after the cold rolling step is completed, the steel coil is placed in the furnace and heated to 550 ° C ~ 650 ° C for a period of time and maintained for a period of time, then cooled in a furnace to cool down to 60 ~ 110 ° C to obtain batch annealing Steel coil.

Tempering and rolling: the batch annealing steel coil after the annealing step is subjected to quenching and tempering to adjust the shape of the batch annealed steel and the thickness of the plate surface, and further obtain the Rockwell surface hardness HR30T between 56 and 66. The tin-plated film with an elongation of 22% to 40%.

Referring to the first figure, the T4BA (BA indicates batch annealing) field indicates the creation. The surface hardness of the tinned backsheet is HR30T 56~66, and the T4CA (CA means continuous annealing) field is the hardness of the traditional tin-plated film after continuous annealing. The hardness value is between HR30T 56~66. T3BA indicates that the surface hardness of the traditional tin-plated film after batch annealing is between HR30T and 52~62. It can be seen that the hardness of the tin-plated film after batch annealing is quite close to that of the traditional tin-plating film. The hardness value of continuous annealing (T4CA) was used.

Referring to the second figure, the T4BA field indicates that the elongation of the tin-plated film of this creation is between 22% and 40% after batch annealing. The T4CA field indicates the elongation of the conventional tin-plated film after continuous annealing. Between 20% and 34%, it can be seen that the highest elongation after batch annealing of the tin-plated film is higher than the highest elongation after continuous annealing of the traditional tin-plated film, and the tin-plated film is completed. The overall elongation after batch annealing is slightly higher than that of the conventional tin-plated film after batch annealing.

In summary, the tinned film of the present invention can obtain a hardness close to the continuous annealing tin-plated film after proper processing, which is advantageous for further processing the tin-plated film into a product. In addition, the original film for tin plating can be obtained after being subjected to continuous annealing to obtain the elongation after continuous annealing of the conventional tin-plated film, which is advantageous for tin-plating the surface of the tin-plated film into a tin-plated steel sheet. The processing further improves the yield.

Furthermore, the tin-plated backsheet of the present invention has sufficient hardness, so that the tin-plated backsheet can be made into a tin-plated steel sheet and then made into a product (for example, a beverage can), without increasing the thickness of the product material. The article is made to have sufficient strength.

The basic teachings of this creation have been described, and many extensions and variations will be apparent to those of ordinary skill in the art. For example, in which tin plating is used The carbon content of the backsheet is preferably from 0.10 to 0.14% by weight, so that a tin-plated backsheet having a relatively stable hardness value can be obtained.

The present invention disclosed in the specification is to be considered as illustrative and not restrictive. The scope of the present invention is defined by the scope of the appended claims, and is not intended to be limited by the scope of the invention.

Claims (3)

A tinplate for tin plating having a hardness of HR30T of 56 to 66 and an elongation of 22% to 40%, and the composition comprises, in weight%, 0.10% to 0.14% of carbon and 0.03% or less of ruthenium. , 0.6% or less of manganese, 0.02% of phosphorus, 0.030% or less of sulfur, 0.2 or less of copper, 0.02% to 0.10% of chromium, 0.15% or less of nickel, 0.05% or less of molybdenum, 0.100% or less of aluminum, 0.0060 Nitrogen below %, the balance being iron and impurities. A method for producing a tinplate for tin plating, wherein the slab for forming a tinplate for tin plating comprises 0.10% to 0.14% by weight of carbon, 0.03% or less of bismuth, 0.6% or less of manganese, 0.02% of phosphorus, and 0.030% by weight. % below sulfur, 0.2% or less copper, 0.02% to 0.10% chromium, 0.15% or less nickel, 0.05% or less molybdenum, 0.100% or less aluminum, 0.0060% or less nitrogen, and the rest are iron and impurities, The steel slab is subjected to hot rolling below the Ar3 transformation point, and after hot rolling, the hot rolled steel coil is obtained at 500 ° C to 700 ° C, followed by pickling to obtain a pickled steel strip, and then cold rolling is performed at a reduction rate of 80% or more. The rolled steel coil is annealed at a temperature between 550 ° C and 650 ° C by batch annealing to obtain a tin-plated negative film having a Rockwell surface hardness of HR30T 56-66 and an elongation of 22% to 40%. The method for manufacturing a tin-plating backsheet according to the second aspect of the invention, wherein the hot rolling comprises: a rough rolling step: the steel bill is heated to a temperature of 1250 ° C to 1300 ° C for rough rolling, resulting in a reduction in the thickness of the steel batch to obtain a coarse Rolling and rolling steel strip; finishing rolling step: cooling the rough rolled steel strip after rough rolling to 800 ° C ~ 920 ° C, after finishing rolling to obtain the finished rolling strip; laminar cooling step: after finishing rolling Rolling steel strip cooling to 500 ° C ~ 700 ° C; hot roll step Step: the refining and rolling steel strip after the laminar cooling is taken up, and the air cooling is reduced to room temperature to obtain a hot rolled steel coil; after the hot rolling is completed, the method further comprises: pickling step: soaking and pickling the hot rolled steel coil after hot rolling a liquid to remove the oxide of the surface to obtain a pickled steel strip; a cold rolling step: cold rolling the strip after the pickling, so that the thickness of the tin-plated backsheet is reduced to between 0.15 mm and 0.60 mm, and then The tin-plated backsheet is wound into a roll to obtain a cold-rolled steel coil; the electrolytic cleaning step: the cold-rolled steel coil after the cold-rolling step is subjected to electrolytic cleaning for rolling the residual rolling of the cold-rolled steel coil surface. After being cleaned, it is wound into a roll to obtain a cleaned steel coil; a batch annealing step: after the cleaning of the electrolytic cleaning step is completed, the steel coil is placed in the furnace and heated to 550 ° C to 650 ° C for a period of time, The batch annealing steel strip is obtained by cooling in a furnace to a temperature of 60 ° C to 110 ° C; quenching and temper rolling: the batch annealing steel strip after the annealing step is subjected to quenching and tempering.