The surface of steel plates or strips must be free from defects detrimental to their intended use-such as inclusions, cracks, or rust-and must not exhibit "stop marks" (localized surface irregularities caused by production stoppages). However, defects that do not impair forming performance are permissible; these include minor surface abrasions that are imperceptible to the touch, a faint yellowish film resulting from pickling, slight pitting, scratches, roll marks, indentations, color variations, and minor creases that are imperceptible to the touch.
Since steel strips do not afford the opportunity to excise defects, delivery containing defects is permitted; however, the defective portion must not exceed 6% of the total length of the steel coil.
"Oiling" refers to the application of an electrostatically applied rust-inhibiting oil-possessing specific anti-corrosive properties-to the surface of the steel plate. Oiling is categorized into light, medium, and heavy applications, the specific requirement for which must be stipulated by the purchaser in the contract. For oiled products, the supplier guarantees that no rust will develop within a period of three months, provided that transportation and storage conditions remain normal.