Steel strip and sheet are two important flat-rolled steel products, produced by hot-rolling and cold-rolling respectively. Hot Rolled Steel Strip and Sheet (HSSS) are the main elastic steel products manufactured by the hot-rolling process, which is mainly used in automotive, appliance and various engineering applications due to its good cold-forming, high strength, fatigue resistance, and superior weldability properties. Commonly used cold-rolled steel strip and sheet include cold rolled high strength low alloy (HSLA) steel and carbon steel.
HSSS are the most cost-effective and elastic steel products, and are made from carbon steel with yield strength up to 310 MPa and lower alloy steel, of which the yield strength can reach up to 700 MPa. HSSS have excellent formability, primarily due to their lower carbon equivalent value and thus good hot-forming properties.
The mechanical properties of HSSS depend largely on their chemical composition and microstructure. The chemical composition affects the hardness and strength of the steel, while the microstructure determines the formability, fatigue strength, and other mechanical properties. The most commonly used hot-rolled steel strip and sheet are low carbon steel, medium carbon steel, high carbon steel, low alloy steel, and high alloy steel.
In addition, HSSS can also be enhanced by further heat treatment, such as normalizing, quenching and tempering. The normalized steel has better weldability and durability, while the quenched and tempered steel gives higher tensile strength and ductility.
The size, shape, weight, and permissible deviation of HSSS mainly depend on the classification of steel and the specification required by the customer. The common specifications for HSSS are 1000mm-1600mm in width, 1.6mm-25.4mm in thickness, and 2000mm-12000mm in length. The allowable deviation of width and thickness should be within 0.6mm for lower thickness and within 0.02mm for higher thickness.
HSSS are mainly produced by hot rolling, which means that the steel is rolled at a high temperature, usually above 1000°C, to deform it into a desired finished product shape and achieve the desired mechanical properties. To this end, the HSSS is heated, flattened and rolled into strips or sheets with different thickness and width. Hot-rolled steel strip and sheet are typically supplied with pickled or mill finish and commercial temper.
Overall, HSSS are the most cost effective and elastic steel products, mainly used in automotive, appliance and various engineering applications. Their size, shape, weight, and permissible deviation mainly depends on the steel classification and required specifications. The mechanical properties of HSSS are largely determined by their chemistry and microstructure, which can be further improved by additional heat treatments.
