Elijah Han.CMO of zpcnsteel.com which is a mature and professional steel product manufacturer, focusing on the steel industry for nearly ten years, with an annual export volume of 1 million tons, mainly producing carbon steel, stainless steel, aluminum, copper and their derivatives.
Like hot rolled coil, hot rolled coil is also manufactured by continuous casting process. It is based on cold rolled and coated coils, but can also be used directly in industrial applications such as steel pipes, construction, shipbuilding, gas containers, presses and power lines. It is supplied to the market in the form of coil or custom flat products. For pickled and oiled coils, acid is used to remove oxides from the metal surface, which is then cleaned and oiled to reduce rust.
The main processes of hot rolling pickling include laser welding, tension straightening, turbulent pickling, in-line straightening, shearing, online oiling, etc. In the actual use process of the hot-rolled pickled sheet, the use cost is greatly reduced. , Replacing cold-rolled sheets with pickled sheets can save business costs. Compared with ordinary hot-rolled sheets, hot-rolled pickled sheets remove iron oxide scale on the surface, improve the surface quality of steel, and facilitate welding, oiling and painting. At the same time, after sinking, leveling and shearing, the dimensional accuracy is high, and the platform can be changed to a certain extent to make it more flat and practical. In addition, the hot rolled pickled sheet improves the surface finish of the original hot rolled coil and improves the appearance.
Compared with the ordinary hot-rolled sheet, the hot-rolled pickled sheet removes the iron oxide scale on the surface and improves the surface quality of the steel. The pickling line is also equipped with a straightener. After leveling, the deflection of the roughness of the steel plate is reduced, the surface finish is improved, and the appearance is improved. Stained boards are easy to weld, oil and paint. By replacing cold-rolled sheets with pickled sheets, companies can effectively save costs.
Steel for cold forming can be divided into ordinary steel, stamping steel, deep-drawing steel and ultra-deep-drawing steel according to the application. Cold-formed steel is designed with low-carbon and ultra-low-carbon components, and has good stampability, weldability and high dimensional accuracy. Oil treatment prevents coils from rusting during shipping. Cold-formed steel is mainly used in the home appliance industry.
Sewing beam steel has good strength and formability and excellent surface quality. For the manufacture of automobile beams and beams. Has good flexural strength, good flatness and long-cut flatness, excellent durability and fatigue resistance.
Car wheel steel
Automobile wheel steel has good cold forming properties and is used to manufacture rolled automobile rims and spokes with good weldability, fatigue resistance and low temperature effect.
Automotive Structural Steel
Baotou automobile structural steel has high strength, good formability and weldability, high dimensional accuracy and surface quality, and is widely used by various automobile and parts manufacturers to produce various auto parts, such as pillars, gaskets, reinforcement plates, wheels etc.
Hot rolled pickled and oiled steel sheet can be used in a variety of industries:
Automotive industry: The main uses of hot-rolled pickling in the automotive industry are as follows: vehicle chassis systems, including beams, sub-beams, etc.; wheels, including rims, spokes, etc.; interior trim panels. The carriage board is mainly the bottom plate of various trucks. Other seals include bumpers, brake covers and other small interior parts.
Machinery industry: (excluding automobiles) mainly includes textile machinery, mining machinery, fans and some general machinery.
Light industrial household appliances: mainly used for the manufacture of compressor shells, clamps, water heaters and other household appliances. Chemical oil barrels.
Others: road guardrails, bicycle parts, various welded pipes, supermarket shelves, store shelves, control cabinets, fences, iron ladders, stamping parts of various shapes.
Hot-rolled steel strip is rolled and coiled at high temperature, and under these conditions, the iron oxide scale formed on the surface of the strip can tightly cover the surface of the strip and cover the surface defects of the strip. If these iron oxide strips are directly fed into the cold rolling mill, it will affect the surface quality and performance of the cold rolled sheet, and even damage the circulation equipment and the cold rolled steel coil. Therefore, residual iron oxide must be removed from the strip before cold rolling. Descaling is usually done with the help of vegetable preservatives. Therefore, etching is the process of removing iron oxide residues from the metal surface by chemical means, so it is also called chemical etching. Acid method, acid-base method, hydride method, electrolysis method, etc. are usually distinguished by production methods. However, most continuous plants use etching methods using sulfuric or hydrochloric acid.
Currently, about 3/4 of the world’s hot-rolled strip produced strip is processed on continuous strip etching lines, and 98% of the strip – horizontal (horizontal) continuous etching. washing machine.
Once a thorough understanding of the pickling process is obtained, it is easy to understand that the main functions of pickling are:
1) Remove dirt and grime on the surface of hot rolled strip;
2) Remove the corners of the hot-rolled strip according to the width of the product;
3) Check and eliminate surface defects of steel plates that are not suitable for cold rolling;
4) Smear antiseptic (oil) on the surface of the steel plate;
5) Adjust the roll weight. After understanding the basic function and function of digestion, it is possible to carry out targeted research on the quality of digestion and the defects of hot-rolled etched steel plates.
At present, there are three kinds of strip etching equipment in metallurgical plants, namely: semi-continuous etching device, horizontal continuous etching device and continuous tower etching device.
Semi-continuous etching cells are also called pressure etching cells (or pressure extraction cells). Operation process: cutting – straightening – etching (removing the oxide layer on the inner surface of the pickling tank) – cleaning (drying) – trimming (cutting head, tail, tongue) – dressing.
Horizontal continuous etching installations are called continuous etching installations because the end of the next coil of steel is welded to the end of the previous coil of steel, and the strip is then continuously passed through the etching tank until it reaches a. a certain height. Weigh, cut the strip and lower the folded strip. The process is divided into three stages.
1) Raw material preparation part: supply-dissolution-decomposition of iron oxide scale on the surface of strip steel-straightening-cutting head and tail-welding-straightening.
2) Part of the pickling process: straightening – trimming – rinsing – drying.
3) Finished product area: trimming-lubricating-file-file.
Continuous etching on the tower: It is a method of spraying hot hydrochloric acid solution on the surface of the strip to remove the iron oxide residues on the surface of the strip when the strip runs continuously in the vertical tower. The tape is moved up and down the tower in one or more turns, forming a process known as a single- or multi-column continuous etch. Main and tail equipment, the composition and parameters of the unit are generally no different from horizontal units. In the center of the equipment there is a pickling section, a cleaning section and a drying section.