tailieunhanh - Standard Practice for Providing High-Quality Zinc Coatings (Hot-Dip)

"Standard Practice for Providing High-Quality Zinc Coatings (Hot-Dip)" covers the precautions that should be taken to obtain high-quality hot-dip galvanized coatings. Where experience on a specific product indicates a relaxing of any provision, the mutually acceptable change shall be a matter for agreement between the manufacturer and purchaser. | Designation A385 A385M 15 Standard Practice for Providing High-Quality Zinc Coatings Hot-Dip 1 This standard is issued under the fixed designation A385 A385M the number immediately following the designation indicates the year of original adoption or in the case of revision the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon indicates an editorial change since the last revision or reapproval. 1. Scope 3. Steel Selection This practice covers the precautions that should be taken The production of a galvanized coating has as its basis to obtain high-quality hot-dip galvanized coatings. the metallurgical reaction between the steel and the molten Where experience on a specific product indicates a zinc resulting in the formation of several iron-zinc compound relaxing of any provision the mutually acceptable change shall layers for example gamma not always visible be a matter for agreement between the manufacturer and microscopically delta and zeta in Fig. 1. In addition a layer purchaser. of the molten zinc adheres to the surface of the compound layers as the steel is withdrawn from the galvanizing bath. This specification is applicable to orders in either Upon solidification this adherent zinc forms the eta layer. inch-pound units as A385 or in SI units as A385M . Inch-pound units and SI units are not necessarily exact It is known that the exact structural nature of the equivalents. Within the text of this specification and where galvanized coating as typified by Fig. 1 may be modified in appropriate SI units are shown in brackets. Each system shall accordance with the exact chemical nature of the steel being be used independently of the other without combining values in galvanized. Certain elements found in steels are known to have any way. an influence on the coating structure. The elements carbon in excess of about phosphorus in excess of or 2. Referenced Documents manganese in excess .