BS ISO 14788-2017 pdf free download.Steel sheet, zinc-5 % aluminium alloy- coated by the continuous hot-dip process, of commercial, drawing and structural qualities
4 Dimensions
4.1 Zinc-5 % aluminium alloy-coated steel sheet is produced in thicknesses from 0,25 mm to 5 mm inclusive after coating, and in widths of 600 mm and over in coils and cut lengths. Zinc-5 % aluminium alloy-coated steel sheet less than 600 mm wide may be slit from wide sheet and will be considered as sheet.
4.2 The thickness of zinc-5 % aluminium alloy-coated sheet steel may be specified as a combination of the base metal and metallic coating, or as the 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 of the base metal alone.
5 Conditions of manufacture
5.1 Steelmaking
Unless otherwise agreed by the interested parties, the processes used in making the steel and in manufacturing zinc-5 % aluminium alloy-coated sheet are left to the discretion of the manufacturer. On request, the purchaser shall be informed of the steelmaking process being used.
5.2 Chemical composition
The chemical composition (heat analysis) shall conform to the requirements given in Tables 1 and 2.
5.3 Chemical analysis
5.3.1 Heat analysis
An analysis of each heat shall be made by the manufacturer in order to determine compliance with the requirements given in Tables 1 and 2. On request, a report of the heat analysis shall be made available to the purchaser or the purchaser’s representative. Each of the elements listed in Tables 1 and 2 shall be included in the report of the heat analysis. When the amount of copper, nickel, chromium or molybdenum present is less than 0,02 %, the analysis may be reported as “< 0,02%”.
5.3.2 Product analysis
A product analysis may be made by the purchaser in order to verify the specified analysis of the product and shall take into consideration any normal heterogeneity. The product analysis shall be in accordance with Tables 2 and 3.
5.4 Mechanical properties
5.4.1 Commercial and drawing quality
5.4.1.1 Ordering conditions
Zinc-5 % aluminium alloy-coated steel sheet of designations 01, 02, 03, 04 and 05 is supplied under the following two ordering conditions.
a) Ordering condition A: steel when ordered to mechanical properties shall, at the time the steel is made available for shipment, satisfy the applicable requirements of Table 4, when they are determined on test pieces obtained in accordance with the requirements in Clause 7. The values specified in Table 4 are applicable for the periods indicated in Table 5 from the time that the steel is available for shipment.
b) Ordering condition B: steel when ordered to make an identified part shall be supplied with a commitment to satisfactory manufacturing performance within a properly established breakage allowance, which shall be previously agreed upon between the interested parties. In these cases,the part name, the details of fabrication, and special requirements (such as freedom from stretcher strain or fluting) shall be specified.
In the case of ordering condition B, mechanical properties of the steel sheet may also be agreed upon by the interested parties and such properties may not necessarily satisfy the requirements of Table 4.
5.4.1.2 Fabrication qualities
Zinc-5 % aluminium alloy-coated steel sheet is available in several fabrication qualities as given in 3.1 to 3.5.
5.4.1.3 Interstitial-free steel
Stabilized interstitial-free (IF) steel is applicable to orders for designations 03, 04 and 05, provided that the purchaser is informed of the substitution and that related shipping documents reflect the actual material shipped.
5.5 Coating
5.5.1 Coating mass
The coating mass limits shall conform to the limits for the designations shown in Table 7. The coating mass is the total amount of coating on both sides of the sheet, expressed in grams per square metre. The interested parties shall agree upon the coating mass of differentially coated products. If a maximum coating mass is required, the manufacturer shall be notified at the time of ordering.
5.5.2 Coating adherence
Zinc-5 % aluminium alloy-coated steel sheet shall be capable of being bent in any direction, in accordance with the mandrel diameter requirements of Table 8, without flaking of the coating on the outside of the bend. Flaking of the coating within 7 mm from the edge of the test piece shall not be a cause for rejection.BS ISO 14788 pdf download.