5 Must-Have Features in a cold rolled stainless steel coils

Cold rolled sheet products have been available for many years and are used for a multitude of applications such as appliances – refrigerators, washers, dryers, and other small appliances, automobiles – exposed as well as unexposed parts, electric motors, and bathtubs. Today’s cold rolled sheet products are much improved over those used in the past. They offer better control of thickness, shape, width, surface finish, and other special quality features that compliment the emerging need for highly engineered end use applications. To meet the various end use requirements, cold-rolled sheet products are metallurgically designed to provide specific attributes such as high formability, deep drawability, high strength, high dent resistance, good magnetic properties, enamelability, and paintability.

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The first step in manufacturing Cold Rolled Sheet Products involves cold reducing coils of hot-rolled, pickled product to a thinner thickness. The primary feature of cold reduction is to reduce the thickness of hot-rolled coils into thinner thicknesses that are not generally attainable in the hot rolled state. The cold reduction operation induces very high strains (work hardening) into the sheet; thus, the sheet not only becomes thinner, but also becomes much harder, less ductile, and very difficult to form. However, after the cold-reduced product is annealed (heated to high temperatures), it becomes very soft and formable. In fact, the combination of cold reduction and annealing lead to a refinement of the steel that provides very desirable and unique forming properties for subsequent use by the customer.

The hot-rolled, pickled coils incoming to the cold reduction mill have to have excellent quality attributes. The pickling operation must be well-controlled to assure that all the oxides formed during hot rolling are removed. The thickness of the hot-rolled strip is important in that the properties of the final cold rolled and annealed product is influenced by the percent of cold reduction. This means that the thickness of each hot-rolled coil is carefully controlled to provide the mill with a specific thickness to achieve the proper percent cold reduction. Among other things, the percent of cold reduction affects the forming behavior of the product after annealing.

The cold-rolled coil product is appreciated for its diverse applications and outstanding advantages. So how is cold rolled steel manufactured and what are its current popular applications, all questions will be answered in the article below!

What is the cold rolled coil?

Cold-rolled steel (trademarked CRC) is generated at the final stage of making steel from billet. Cold rolled coils are produced based on steel billets at low temperatures, more specifically, CRC has origin from hot rolled steel, then it will be processed through a cool process to make the surface become smooth and improve eye-catching brightness.

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Features of cold rolled coils 

Cold rolled coil often possesses a glossy surface by an oil layer treated in the rolling process. Besides the smooth surface, the product also offers outstanding durability advantages 20% higher than hot rolled coil. Along with that, cold rolled coil also has good impact resistance and ductile properties, so it is easy to bend and cut on requests.

However, because it is still a metal, the cold rolled coil is easy to oxidize if it is not well preserved. Specifically, when the product exists in highly acidic or alkaline environments as well as it has to suffer from harsh weather environments, it will easily cause the steel surface to rust. To overcome this situation, the manufacturer usually has to periodically maintain it by applying a layer of oil to create a protective film for the steel core.

Process production of cold rolled coils

The steel production process will have to go through many separate stages that require strict control to ensure the hardness of the steel and avoid the case that the compositional elements are changed during the period of production.

• Stage 1 - Preparation of input materials and removing rust surface: the main input material of cold rolled coil is hot rolled coil. Hot rolled coil often brings low aesthetics through the rough appearance, so the manufacturer will proceed to spray a specialized acid directly on the surface to clean it.
• Stage 2 - Cold rolling stage: the manufacturer will use mechanical force with oil to roll the steel at a low temperature which is equal to room temperature at that time. This cold rolling process has the effect of making the steel structure stronger as well as changing the surface of the steel. However, in principle, the cold rolling process only changes the steel structure and it will keep the original steel's compositions. Because of those technical standards, cold rolling stages will require strict control in order to avoid surface cracking due to excessive force.
• Stage 3 - Soft annealing: steels that have undergone the cold rolling process will often be in hard condition, so they will be treated with a next step, which is soft annealing. The steel will now be annealed in an electric furnace containing 100% hydrogen gas to help remove the hardness after rolling, enhancing the ductility of the steel to make use of construction applications.

Application in specific fields

Depending on outstanding advantages such as shiny appearance, good loading resistance, cold rolled coil is widely used in the construction, manufacturing and mechanical industries. It also shows some benefits to human daily life. Specifically, some popular areas include:

• Construction works: taking advantage of the sturdy structure thanks to the low carbon content, people often use CRC for many construction purposes. Some practical applications in popular construction include making structural frames, purlins, ...
• Machine parts, spare parts for automobile and aircraft equipment
• Household and consumer appliances: refrigerators, air conditioners, stoves,...

Looking for cold rolled coil suppliers directly from Vietnamese factories

Since the company was established and entered the market until now, MRS Steel has always maintained our mission of being a pioneer in the field of providing comprehensive steel solutions for international importers. Recognizing the important role of cold rolled steel, MRS Steel has been present and accompanies you in finding reputable sources.

If you want to learn more, please visit our website Hot Dipped Galvanized Steel Coils.