Cold rolled products are used in a wide variety of end applications such as appliances - refrigerators, washers, dryers, and other small appliances, automobiles - exposed as well as unexposed parts, electric motors, and bathtubs. 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.
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. Clearly, controlling the sheet thickness along the entire length of the coil is very important to ensure that the product will perform consistently during the processing by the end user. In addition, there are a number of other product attributes that need to be controlled in the cold reduction process. Flatness (deviation from a flat plane) is one of the more important attributes. Very sophisticated strip-shape controlling technology is used to maintain good flatness. Surface finish is another product attribute that needs to be controlled during the cold-reduction process.
The product is typically available at thickness as low as 0.0142 inch although lighter gauges may be ordered. Specific ordering allows the user to specify the following:
Cold Rolled Sheets are produced with the following finishes, which are defined with a specific quantitative roughness values that are determined using a profilometer.
This is a special surface finish that is provided for applications where a distinctive pattern is desired after painting. During manufacture, one surface is rolled using a rough patterned roll to provide a "stamped" pattern on the surface that’s intended to be exposed after processing by the customer. The pattern depth is typically 0.0025 to 0.0035 inch deep. U. S. Steel provides Embossed Steel Sheet with three different types of patterns. The patterns give a distinctive appearance to the end product. Also, the patterns provide a "fingerprint" resistant surface, meaning that fingerprints are not very noticeable when the product is touched. The most widely used pattern is Super Seville 101.
Cold Rolled Full Hard Unprocessed Sheet is for applications that do not require any formability beyond very limited bending and/or rollforming. The steel is highly work-hardened, and exhibits a high resistance to denting, etc., and has only minimal ductility. The hardness is Rockwell B 84 minimum. The product is supplied directly after cold rolling without further processing; therefore it will have residual cold mill oils on the sheet surface.
Cold Rolled Full Hard Sheet is produced to either nominal or minimum thickness. Its surface finish is produced while on the cold reduction mill. This may be a matte finish or a smooth ground finish depending on the product thickness and the mill processing parameters on the specific cold-reduction mill used to manufacture the product.
U. S. Steel VITRENAMEL® Steel Sheet products are designed to optimize the performance during the application of a porcelain (or vitreous) enamel coating. Porcelain-enameled coated steel sheet products are ideal for applications such as stove tops and oven cavities; applications that require both hardness to prevent scratching and elevated temperature stability. Other applications include home-laundry appliances, hot-water heater tanks (glass-lined), cookware, and chemical processing containers.
Steels that are used for enameling need to have specialized properties in order to be coated successfully and obtain good adhesion between the enamel and steel surface. In addition, the steel sheet must possess good formability characteristics to allow the formation of intricate parts prior to enameling. Another important characteristic for the steel is to possess good resistance to sagging and high strength during the firing process. Firing to fuse the coating involves temperatures as high as 1600°F. Steels developed to meet all these criteria are a special class of cold rolled sheet; they are manufactured to possess the special set of properties that the specific application requires to achieve both good formability and good enamelability.
We offer three grades of steel for porcelain enameling: VITRENAMEL® 1 Steel, VITRENAMEL® 2 Steel and FLEXNAMEL® Steel.
These three grades are designed to be suitable for enameling. They have properties that
VITRENAMEL® 1Steel is a Porcelain-Enameling Sheet in which the carbon content has been reduced to a very low level by means of a decarburizing anneal during manufacture in the plant. This steel grade can be porcelain-enameled either by the one-coat process or by a multiple-coat process. The steel may exhibit some loss in strength after firing. The degree of loss in strength is influenced by the severity of the formation and the actual time/temperature cycle used during the firing process.
VITRENAMEL® 2 Steel is a Porcelain-Enameling Sheet in which a low carbon content and the addition of important alloying elements are achieved during steelmaking. The steel is not given a special decarburizing anneal following the cold rolling operation. This grade of porcelain-enameling steel is suitable for the application of either a single ground coat or multiple coats. It does not perform as well as VITRENAMEL® 1 for the application of a single, decorative cover coat.
FLEXNAMEL® Steel is an extra deep-drawing, fully stabilized steel that is made by utilizing vacuum degassing during steelmaking to reduce the carbon level to a very low amount, and then adding stabilizing elements that combine with the interstitial elements to make an "interstitial-free" product. This product is suitable for applications in which ground coat and cover coat enameling operations are used. FLEXNAMEL® Steel has good sag resistance, excellent formability, and is intended for parts that involve very severe drawing during manufacture.
Cold Rolled Motor Lamination Sheet is a special type of cold-rolled steel sheet produced to maximize the performance of the products for use as electro-magnetic core materials for electrical equipment components. These include electric motors, generators, ballasts and transformers. The steels used for these applications are designed to maximize the useful energy, i.e., minimize energy losses, obtained from the electrical energy input into motors, etc.
The differences between conventional cold-rolled sheet and lamination sheet products relate to the composition of the steel and certain processing modifications such as hot band annealing which is used in the manufacture of the more energy efficient lamination steel grades.
Typical Applications: Exterior and Interior Automobile parts / Large appliances / Furniture parts / Computer-cabinet hardware / Small Appliances / Tool boxes / Shelving / Lighting