1. Scope 1.1 This specification covers zinc-nickel alloy coatings applied by the electrolytic process to hot-rolled and cold-rolled steel sheet. The coating has a smooth, spangle-free surface. The zinc-nickel-coated sheet covered in this specification is produced in a range of coating masses to provide coatings that are compatible with the service life required. The coating mass varies, from very thin coatings that are usually painted to provide good service, to relatively heavy masses that provide good corrosion resistance in the bare (unpainted) condition. The composition range is 9 to 16% nickel by weight, with the balance being zinc. 1.2 The product shall be coated on one or both surfaces and may have equal or differential coating masses on the two surfaces. Sheet coated with equal coating masses on each surface would have similar levels of corrosion protection on each surface. Often, however, a higher level of corrosion protection is required on one surface than is required on the other. Thus one surface may have a heavier coating mass than the other. The light coated (or uncoated) surface is typically painted to provide additional corrosion protection. 1.3 This coating process has essentially no effect on the base metal mechanical properties and can be used on any grade or quality of hot or cold rolled steel sheet. The coated sheet is available as commercial quality, drawing quality, drawing quality special killed, structural (physical) quality, or high-strength low-alloy steel. 1.4 The values stated in SI units are to be regarded as the standard.