ISO 15208:2012 pdf – Continuous hot-dip zinc-coated twin-roll cast steel sheet of commercial quality.
1 Scope This International Standard specifes the characteristics of continuous hot-dip zinc-coated twin-roll cast steel sheet of commercial quality manufactured using the twin-roll cast steel-making process. The product is intended for applications where resistance to corrosion is of prime importance. The steel sheet is produced in a number of coating mass, surface treatments and ordering conditions. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 1460, Metallic coatings — Hot dip galvanized coatings on ferrous materials — Gravimetric determination of the mass per unit area ISO 2178, Non-magnetic coatings on magnetic substrates — Measurement of coating thickness — Magnetic method ISO 3497, Metallic coatings — Measurement of coating thickness — X-ray spectrometric methods ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature ISO 7438, Metallic materials — Bend test ISO 16160, Hot-rolled steel sheet products — Dimensional and shape tolerances ISO 16162, Cold-rolled steel sheet products — Dimensional and shape tolerances ISO 16163, Continuously hot-dipped coated steel sheet products — Dimensional and shape tolerances 3?Terms?and?defnitions For the purposes of this document, the following terms and defnitions apply 3.1 continuous hot-dip zinc-coated steel sheet product obtained by hot-dip coating of cold-reduced sheet coils or hot-rolled sheet coils on a continuous zinc-coating line
3.4 smooth?fnish surface produced by skin-passing the coated material in order to achieve an improved smooth surface condition as compared with the normal as-coated product 3.5 differential coating layer having a specifed coating-mass designation on one surface and a different coating-mass designation on the other surface 3.6 skin pass light cold rolling of the zinc-coated steel sheet NOTE The purpose of the skin pass is to produce a higher degree of surface smoothness and, thereby, improve the surface appearance. The skin pass also temporarily minimizes the occurrence of a surface condition known as stretcher strain (Luder’s Lines) or futing during the fabrication of fnished parts. The skin pass also controls and improves fatness. Some increase in hardness and loss of ductility can result from skin passing. 3.7 twin-roll cast steel sheet steel sheet produced by casting to near fnal thickness directly from the liquid metal with minimal hot rolling to achieve the fnal thickness 4 Thickness 4.1 Zinc-coated commercial quality twin-roll cast sheet is produced in thicknesses up to 2,0 mm, inclusive, after zinc coating, and in widths up to 2 000 mm in coils and cut lengths. 4.2 Zinc-coated twin-roll cast sheets less than 600 mm wide may be slit from wide sheets and may be considered sheets. 4.3 The thickness of zinc-coated twin-roll cast sheet steel may be specifed as a combination of the base metal and metallic coating or base metal alone. The purchaser shall indicate on the order which method of specifying thickness is required. In the event that the purchaser does not indicate any preference, the thickness as a combination of the base metal and coating shall be provided. Annex A describes the requirements for specifying the thickness as base metal alone.
5.6 Surface treatment 5.6.1 Mill passivation A chemical treatment is normally applied to zinc coatings to minimize the hazard of wet storage stain (white rust) during shipment and storage. However, the inhibiting characteristics of the treatment are limited and if a shipment is received wet, the material shall be used immediately or dried. 5.6.2 Mill phosphating Zinc-coated steel sheet may be processed chemically at the manufacturer’s works to prepare all types of coatings for painting without further treatment, except normal cleaning. 5.6.3 Oiling The zinc-coated steel sheet as produced may be oiled to prevent marring and scratching of the soft surface during handling or shipping and to minimize wet storage stain. If the zinc-coated sheet receives a passivating treatment, oiling further minimizes the hazard of wet storage stain. 5.7 Coated coil joining Continuous coil coating lines use various methods to join coil ends. These methods include lap welding, butt welding and stitching. The shipment of coils containing the joined ends shall be permitted, if agreed upon between the manufacturer and the purchaser. 5.8 Dimensional and shape tolerances 5.8.1 Dimensional tolerances applicable to zinc-coated steel sheet shall be as given in ISO 16163. The tolerances for thickness apply to products whose thickness is a combination of base-metal and coating thickness. 5.8.2 Where the base metal thickness is specifed, the thickness tolerances of Tables 6, 7 and 8 of ISO 16163:2010, shall apply to the average product thickness, as calculated in accordance with Annex A. The tolerances for thickness of the base metal shall be as given in ISO 16160 for hot-rolled steel and ISO 16162 for cold-rolled steel.