Cold Rolled
Cold rolled steel is made using hot rolled steel through pickling, cold rolling and heat treatment. It is relatively thin with a thickness of 0.2 mm to 2.0 mm. Cold rolled steel is highly aesthetic and easily machinable, thus widely used for premium applications in modern society. We are increasingly focused on offering value-added products as demand for highly functional, cold rolled products is rising.
Manufacturing Process
Powered by state-of-the-art facility and technology, POSCO operates a totally computerized, end-to-end full automatic production system. This allows us to deliver high-quality and high-performance products fit to the needs of customers.
- 1. Pickling
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Hot rolled coils pass through a pickling line, where scale breaker machines and hydrochloric acid solutions are used to remove any surface scale and/or oxide film that which causes surface flaws during the final stage of cold rolled steel processing.
- 2. Cold Rolling
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Pickled coils are cold rolled in tandem mills to a specified thickness, typically 40 to 90%, of original material dimensions. Fully automated shape adjustment is ensured through state of the art process machinery.
- 3. Electrolytic Cleaning
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The purpose of electrolytic cleaning is to remove lubricant oil and contaminants on the cold rolled steel prior to the annealing process.
- 4. Annealing (Heat Treatment)
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This is a highly productive manufacturing method whereby steel products with extra deep drawing qualities and high tensile strength can be produced. Two annealing methods are commonly used: batch annealing and continuous annealing.
- 5. Skin Pass
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This final rolling process is performed in order to remove minor surface defects such as stretch marks and to produce a smooth, lustrous surface. Skin Pass results in a further thickness reduction of about 1%.
