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How is Electrolytic Tinplate Coil Processed?
Electrolytic tinplate coil is one of the available environmentally friendly packaging materials. Electrolytic tinplate coil is a steel sheet in coil with tin coated on both sides. This combines the strength of steel with the corrosion resistance and soldering properties of tin.
Productions of Electrolytic Tinplate Coil
Electrolytic tinplate coil steel used to make tinplate is lightweight, low-carbon steel. There are many important steps involved in its production that affect tinplate’s properties.
Basic tinplate production steps:
- Hot rolling steel sheet in coil with pickling
- Cold rolling
- Slitting
- Degreasing
- Annealing
- Temper rolling
- Smoothing
- Tin Coating
- Cutting or shearing
- Packaged
Hot rolling steel sheet in coil with pickling
Pickling: Hot rolled coils must be pickled before cold rolling. The pickling has the following functions:
- Remove the iron oxide scale generated during hot rolling;
- Cut the sides of the steel strip neatly;
- Coat with rolling lubricating oil to prevent rust and lubricate;
- Check and remove various surface defects harmful to subsequent cold rolling and other processes;
Cold rolling
After pickling, the hot-rolled strip enters the cold-rolling process. The strip undergoes plastic deformation when passing through the work rolls, and the thickness is reduced from about 2mm to about 0.2mm. During cold rolling, in order to reduce the friction between the strip and the work rolls and take away a large amount of heat energy generated due to plastic deformation, cold rolling lubricating oil and coolant should be sprayed on the strip. A single-stand reversible mill is used. In order to effectively maintain the shape of the roll, it is important to control the temperature of the coolant. Available production range: 0.12mm-0.55mm.
Slitting
Cut the cold-rolled material into the required specified width. Available production range: 600mm-1000mm
Degreasing
In the cold rolling process, grease and other foreign matter are adhered to the surface of the tin-plated original plate after the rolling oil is cooled. If the annealing oil is not washed off and directly annealed, the oil will not be completely burned and carbonaceous stains will remain on the strip. The production of tin plate cannot meet the quality requirements. Therefore, the tin-plated original plate must be electrolytically cleaned to remove these greases before annealing. The commonly used cleaning method for tin-plated original boards is to perform chemical degreasing and electrolytic degreasing in a degreasing solution.
Annealing
This step makes the steel soft and achieves the desired grain structure. Batch annealing produces deep-draw to hard and stiff steel that can withstand vacuum and pressures, so is best for making cans and bottles. Continuous annealing is a shorter process that gives smaller grained steel.
Temper rolling
The ferrite crystals of hot-rolled strip steel are subjected to about 80 to 95% of cold working during the cold rolling process. The grains are elongated into fibrous structures. Due to the high dislocation density, cold work hardening increases the strength and the processing performance is basically basic almost loss. In order to restore the processability of the tin-plated original plate, the original plate in the work-hardened state is heated to a high temperature, maintained for a certain period of time and then slowly cooled.
Principle of the annealing cycle: rapidly heat to about 680°C, hold for 20 to 25 seconds, then cool to 480°C at a controlled speed, and rapidly cool to close to room temperature.
Smoothing
The annealed strip is in a relatively soft state and needs to be subjected to a slight cold rolling treatment, that is, flattening, or “quenching and tempering rolling”. The flattening reduction rate is relatively small, 0.5 to 4%.
The function of leveling:
(1) Stress relief platform;
(2) Partially improve the plate shape and give the tin plate surface condition;
(3) Make the strip steel have appropriate hardness.
Tin Coating
The electroplating tin plating unit consists of three main process sections: pre-processing, electroplating and post-processing.
The pre-treatment of tin plating consists of pickling, alkali washing, water washing and brushing. The purpose is to ensure the quality of electroplating, and the surface of the original strip steel plate must be clean.
The purpose of alkali washing: the strip steel passes through the hot alkali solution in the alkali washing tank and is electrolytically cleaned under the action of the energized electrode. The oil and dust on the surface of the strip steel are mechanically removed through the chemical action of the alkali cleaning solution and the hydrogen and oxygen generated by electrolysis. The scour is removed.
The purpose of pickling: to remove the oxide film and oil stains attached to the surface of the original plate to obtain a clean surface suitable for tinplate
Cutting or shearing
According to the customer’s order requirements, the tinplate master roll is slit into tinplate steel strips or cut into Electrolytic tinplate coil to meet the needs of different customers. In addition, some customers will require that the tinplate be printed with the required size and pattern for use in the packaging of different products.
Packaged
According to the different requirements of customers, the Electrolytic Tinplate Coil is packaged to ensure that the product is not damaged during transportation as much as possible. Professional suppliers can provide high-quality products and guarantees
The specific production process of Electrolytic Tinplate Coil is explained above. I hope it can help you understand tinplate. Witop Tinplate is a professional tinplate manufacturer in China. If you are looking for tinplate suppliers and have any questions about tinplate, we are happy to help you.
