The requirements for cold-rolled steel strip primarily encompass the following aspects:
① Surface Condition and Surface Roughness. Cold-rolled steel strip features excellent processability and an aesthetically pleasing surface finish; it is frequently utilized for exposed panels and deep-drawing applications, and thus, surface defects must be strictly avoided.
② Dimensional and Shape Accuracy. The dimensional accuracy of cold-rolled steel strip covers precision in thickness, width, and length, with permissible deviations explicitly stipulated in relevant standards. Shape accuracy is typically characterized by flatness, lateral camber, and squareness, the allowable limits for which are also defined within these standards.
③ Processability. Cold-rolled products serve a wide array of purposes and undergo numerous processing methods-ranging from simple bending to deep drawing. In terms of processability, they can be broadly categorized into two types: formability (encompassing extensibility and deep-drawability) and shape retention. Formability refers to the material's capacity to be processed into a specific shape. Shape retention refers to the dimensions and geometry of the material after the processing load has been removed; the inherent characteristic of maintaining this processed shape is termed "shape stability."
④ Aging Characteristics. The phenomenon of "aging" refers to the changes that occur in a metal or alloy over the passage of time. Cold-rolled steel sheets are susceptible to both quench aging and strain aging. Quench aging occurs when the material is rapidly cooled from within a specific temperature range; strain aging, conversely, occurs during subsequent cold working (such as temper rolling) following annealing-notably, the yield point elongation (or "yield plateau") that was eliminated during temper rolling may reappear after a certain period.
⑤ Special Properties. This category primarily encompasses specific attributes such as enamelability, corrosion resistance, electromagnetic properties, and blanking performance.
