BS ISO 14788:2017 pdf free
BS ISO 14788:2017 pdf free.Steel sheet, zinc-5 % aluminium alloy-coated by the continuous hot-dip process, of commercial, drawing and structural qualities
The product is normally suitable for welding, such as spot welding, roller-seam welding and fusion welding, if appropriate welding conditions are selected with special attention to the heavier coatings.
When the carbon content increases above 0,15 %, spot welding becomes increasingly difficult. Because the heat of welding might have a significant effect on lowering the strength of grade 550, this grade is not recommended for welding.
Zinc-5 % aluminium alloy-coated steel sheet is a suitable base for paint, but the first treatment may be different from those used on uncoated steel. Pre-treatment primers, chemical conversion coatings (chromate, phosphate or oxide type), and some paints specially formulated for direct application to zinc surfaces, are all appropriate first treatments for zinc-5 % aluminium alloy-coated sheet. In drawing up a painting schedule, consideration shall be given to whether the zinc-5 % aluminium alloy-coated sheet shall be ordered in the passivated or not passivated state.
NOTE Surfaces with certain passivation treatments (e.g. chromated) are not suitable for phosphating or the application of a pre-treatment (etch) primer.
The coating finish of zinc-5 % aluminium alloy-coated steel sheet is either a normal, as-coated surface with unrestricted spangle growth (see 3.11), or a skin passed, surface that has improved smoothness compared to an as-coated surface (see 3.12 and 3.13).
A chemical treatment is normally applied to zinc-5 % aluminium alloy-coated steel sheet to minimize the hazard of wet storage staining (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.
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 coil ends shall be permitted if agreed upon between the purchaser and the manufacturer.
Dimensional and shape tolerances applicable to zinc-5 % aluminium alloy-coated steel sheet shall be as specified in ISO 16163. The tolerances for thickness apply to products whose thickness is a combination of base metal and coating thickness.BS ISO 14788 pdf download.
