ASTM A918-2019 pdf free download

ASTM A918-2019 pdf free download.Standard Specification for Steel Sheet, Zinc-Nickel Alloy Coated by the Electrolytic Process for Applications Requiring Designation of the Coating Mass on Each Surface
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 pro- duced in a range of coating masses to provide coatings that are compatible with the anticipated 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 from 9 to 16 % nickel, by weight, with the balance being zinc. 1.2 The product shall be coated on one or both surfaces with equal or differential coating masses on the two surfaces. Sheet coated with equal coating masses on each surface has similar levels of corrosion protection on each surface. Often, however, a higher level ofcorrosion protection is required on one surface than is required on the other. In these situations, one surface shall be specified with a heavier coating mass than the other. Either surface, when specified to be painted, will provide additional corrosion protection as compared to an unpainted surface. 1.3 This coating process has essentially no effect on the base metal mechanical properties, and use is permitted on any grade of hot- or cold-rolled steel sheet. The coated sheet is available as Commercial Steel (CS), Drawing Steel (DS), Deep Drawing Steel (DDS), Extra-Deep Drawing Steel (EDDS), Structural Steel (SS), High-Strength Low-Alloy Steel (HSLAS), High- Strength Low-Alloy Steel with Improved Formability (HSLAS-F), Solution-Hardened Steel (SHS), or Bake- Hardenable Steel (BHS). 1.4 The values stated in SI units are to be regarded as the standard.1.5 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Ordering Information
4.1 Orders for products to this specification shall include the following information, as necessary to adequately describe the desired product: 4.1.1 Name of product (electrolytic zinc-nickel alloy-coated steel sheet). 4.1.2 ASTM designation and year of issue. 4.1.3 Base metal type (hot rolled or cold rolled). 4.1.4 Base metal designation {Commercial Steel (CS), Drawing Steel (DS), Deep Drawing Steel (DDS), Extra-Deep Drawing Steel (EDDS), High-Strength Low-Alloy Steel (HSLAS), High-Strength Low-Alloy with Improved Formabil- ity (HSLAS-F), Solution-Hardened Steel (SHS), or Bake- Hardenable Steel (BHS)}.4.1.5 Formability type, strength, grade, or class, or combi- nation thereof, as required for structural or high-strength low-alloy steels. 4.1.6 Coating designation (see 3.1). 4.1.7 Surface treatments required (see Note 1). N OTE 1—Steel sheet is available without surface treatment (dry) or with surface treatments designated as chemical treatment, oiled, or phos- phatized. Unless otherwise specified sheet is furnished oiled. 4.1.8 Dimensions (show thickness (minimum or nominal), width, and length, if cut lengths). 4.1.9 Coil size (must include inside diameter, outside diameter, and maximum coil weight). 4.1.10 Application (part name and description). 4.1.11 Special requirements, if applicable. 4.1.12 Certification, if required, heat analysis and mechani- cal property report.
5. Coating Mass
5.1 Coating mass shall conform to the requirements for coating designation (mass and type) as given in Specification A917 and in Table 1 for the specific coating designation. The mass of the coating is the single spot value on each surface of the sheet in grams per square metre. 5.2 Coating Mass Tests: 5.2.1 Test Methods E1659 describes the weigh-strip-weigh method is a destructive test that determines coating mass by measuring the difference in weight between a coated and a stripped (uncoated) sample. If one surface is protected suitably during the initial stripping, coating mass can be determined for each surface independently. Conversion of the coating mass to coating thickness is possible only if the density of the coating is known precisely.