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Steel/Building materials/Pipe/Synthetic wood manufacturer Seokyoung S-tech Co., Ltd.

Cold rolled steel sheets

CR

Uses and characteristics

Cold rolled steel products are produced by removing surface scales of hot-rolled coils, cold-rolling them to a thickness of 0.15 to 3mm, and then conducting annealing and temper rolling. They are one of the high-class steel materials mainly used for manufacturing automobiles, appliances, furniture, containers, and internal and external materials for construction.
They can also be used as the disc materials of the products that are manufactured by hot-dip galvanizing, electrolytically galvanizing, or coating aluminum, zinc, or chrome. Cold rolled steels are classified into general cold-roll, cold-roll for structure purposes, cold-roll for enameling, and high tensile steel sheets, depending on the level of processes and uses.

Pickled-and-oiled steel sheet

PO

Uses and characteristics

Pickled-and-oiled steel sheets indicate products manufactured by using hydrochloric acid to remove the scales that are generated on the hot coil surfaces in the course of hot rolling.
They are used just like other hot rolled steel products. PO products are widely used when ease of coating, painting, processing, and welding is required for general structures, automobiles, appliances, drawing.

Hot galvanized steel

HGI

Uses and characteristics

It is used for architectural deck plate, duct, switchboard, protection panel for packing, spiral pipe, tent pole, hinge, architectural scaffolding tent pole guard rail, and agricultural pipe. This product is manufactured by coating HR-coil after heating at around 500℃ in the furnace. The price is more reasonable than CG as the cold roll procedure of conventional CGI can be skipped and coated directly on the hot-coil. Moreover, this product has a better surface than the existing hot-coil as this undergoes skin pass mill (SPM) process after coating, and it is more resistant to corrosion and white lust as the surface is treated with a special procedure (chromic acid).

Galvanized Iron

GI

Uses

It is used for metal furniture, appliances, interior / exterior boards, color steel plate material, automobile interior plate, fuel tank, and building materials



Corrosion-resistance

Galvanized iron sheet is more resistant to corrosion because zinc in the composition of zinc carbonate protects the surface of the iron, when zinc has a higher tendency to ionize than iron. Specifically, the zinc that covers the surface of the iron has a higher tendency to ionize than iron so even if zinc surface is broken, iron does not corrode. In other words, the longevity of the steel sheet extends by sacrificing zinc.



Easiness to be processed

The galvanized iron sheet that is produced in the consecutive galvanizing process has a superior amount of attached zinc and a thinner layer of the iron-zinc alloy. Therefore, the coated layer is hardly detached even after the drawing process. Compared to the conventional horizon furnace, the galvanized iron sheet manufactured by the vertical furnace is more prone to be processed in various procedures.



Easiness to be painted

Galvanized iron sheet is mostly used after a final painting, and the corrosiveness of the painted products are largely dependent on the kind of original sheet, pre-painting procedures and the kind of paint.

Electrolytically galvanized steel sheets

EGI

Uses

It is used for producing an internal and external plate of appliances, steel material for painting, internal and external materials for construction purposes, metal furniture, and internal and external plate, hood, fender, and fuel tank for automobiles.



Corrosion-resistance

The sacrifice anode method resulting from the galvanic action of the zinc protects the iron inside and when exposed to the outer air a thin layer of alkaline zinc carbonate is formed, and it acts as a shield.



Easiness to be processed

Compared to GI or GA, coating attached lesser in this product and the influence of heat is smaller. Therefore, the material characteristic and easiness to be processed are maintain as CR, the original material.



Easiness to be painted

The surface is flat, can this enables a decent painting surface. Phosphate treatment is followed after painting to improve the corrosive-resistance of the product.