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1 Translated English of Chinese Standard: GB/T ICS NATIONAL STANDARD OF THE PEOPLE S REPUBLIC OF CHINA GB H 61 Replacing GB/T Wrought aluminium and aluminium alloy plates, sheets and strips for general engineering Part 3: Tolerances on forms and dimensions 一般工业用铝及铝合金板 带材第 3 部分 : 尺寸偏差 Issued on: December 31, 2012 Implemented on: October 1, 2013 Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the People s Republic of China; Standardization Administration of the People s Republic of China. Page 1 of 19

2 Table of Contents Foreword Scope Classification and grading Requirements Inspection methods for tolerances on dimensions Others Page 2 of 19

3 Foreword GB/T 3880 Wrought aluminium and aluminium alloy plates, sheets and strips for general engineering is divided into three parts: Part 1: Technical conditions of delivery; Part 2: Mechanical properties; Part 3: Tolerances on forms and dimensions. This Part is part 3 of GB/T This Part is drafted according to the rules given in GB/T This Part replaces GB/T Wrought aluminium and aluminium alloy plates, sheets and strips for general engineering Part 3: Tolerances on forms and dimensions. Compared with GB/T , the major technical changes in this Part are as follows: EXPAND the maximum thickness from mm to mm ; EXPAND the maximum width from 2,500.0mm to 3,500.0mm ; MODIFY the maximum thickness of cold-rolled plates, sheets and strips to 6.00mm. MODIFY the requirements for the tolerances on thicknesses, widths, lengths and diagonals as well as the side curvature of part of the high precision grade of plates, sheets and strips. This Part, using redrafting method, was formulated by making reference to EN Aluminium and aluminium alloys Sheet, strip and plate Part 3: Tolerances on dimensions and form for hot-rolled products and EN Aluminium and aluminium alloys Sheet, strip and plate Part 4: Tolerances on shape and dimensions for cold-rolled products. The consistent degree BETWEEN this Part AND EN and EN is not equivalent. This Part shall be under the jurisdiction of the National Technical Committee for Standardization of Non-ferrous Metals (SAC/TC 243). Drafting organizations of this Standard: Southwest Aluminum (Group) Co., Ltd., China Non-ferrous Metals Standards Metrology and Quality Institute, CHALCO Ruimin Aluminum Strips Co., Ltd., Northeast Light Alloys Co., Ltd., Xiamen Page 3 of 19

4 Wrought aluminium and aluminium alloy plates, sheets and strips for general engineering Part 3: Tolerances on forms and dimensions 1 Scope This Part of GB/T 3880 specifies the tolerances on forms and dimensions of the wrought aluminium and aluminium alloy plates, sheets and strips for general engineering. This Part is applicable to the wrought aluminium and aluminium alloy rolled plates, sheets and strips for general engineering. 2 Classification and grading 2.1 Classification of aluminium or aluminium alloys Aluminium and aluminium alloys are divided into Type A and Type B. SEE Table 1. Designation series Table 1 Alloy Classification Classification of aluminium or aluminium alloys A 1 All All The maximum content of Mn shall not be greater than 1.8%. The maximum content of Mg shall not be greater than 1.8%. The sum of the maximum content of Mn and the maximum content of Mg shall not be greater than 2.3%. For instance, 3003, 3103, 3005, 3105, 3102 and 3A21. The maximum content of Si shall not be greater than 2%, such as 4006 and The maximum content of Mg shall not be greater than 1.8%. The maximum content of Mn shall not be greater than 1.8%. The sum of the maximum content of Mg and the maximum content of Mn shall not be greater than 2.3%. For instance, 5005, 5005A and B Other alloys except the Type A, such as 3004 and 3104 Other alloys except the Type A, such as 4015 Other alloys except the Type A, such as 5A02, 5A03, 5A05, 5A06, 5040, 5049, 5449, 5251, 5052, 5154A, 5454, 5754, 5082, 5182, 5083, 5383 and Page 5 of 19

5 Table 6 Tolerances on Widths of Cold-rolled Plates and Sheets Grade Thickness Ordinary grade High precision grade Tolerances on widths of hot-rolled plates and sheets For the hot-rolled plates and sheets supplied after trimming, the tolerances on widths of plates and sheets shall conform to the provisions in Table 7. For the hot-rolled plates and sheets supplied without trimming, the tolerances on widths of plates and sheets shall be + 150mm or determined after the consultation between supply and requisitioning parties, and shall be indicated in the order forms (or contracts). When the requisitioning party has special requirements, the tolerances on widths of plates and sheets shall be agreed upon by the supply and requisitioning parties, and shall be indicated in the order forms (or contracts) (the sum of the absolute values of the positive and negative tolerances required for the requisitioning party shall be consistent with Table 7). Table 7 Tolerances on Widths of Hot-rolled Plates and Sheets after Trimming Thickness Tolerances on widths of strips Tolerances on widths of cold-rolled strips The tolerances on widths of cold-rolled strips shall conform to the provisions in Table 8. The high precision grade needs to be negotiated by the supply and requisitioning parties, and to be indicated in the order forms (or contracts) as required. When there are no clear indications, the ordinary grade applies. When Page 10 of 19

6 > 2.50~ % 0.5% 0.5% > 3.00~ % 0.4% 0.35% > 6.00~ % 0.4% 0.3% Hot-rolled Not required or plates and determined after 18mm 30mm sheets consultation > 50.00~ % 0.2% between supply and requisitioning parties Note: L refers to the lengths of plates and sheets. W refers to the widths of plates and sheets. R refers to any chord lengths of no less than 300mm. d refers to the wave heights. a The end portion refers to the entire board at the end included within the length range of 300mm on both ends along the longitudinal direction of plates and sheets. If the plates and sheets are square, the end portion refers to the board with square rings within the range of 300mm around the edges. 3.5 Side curvature Hot-rolled plates and sheets The ordinary grade does not require the side curvature. The high precision grade shall conform to the provisions in Table 14. The high precision grade needs to be negotiated by the supply and requisitioning parties, and to be indicated in the order forms (or contracts) as required. When there are no clear indications, the ordinary grade applies Cold-rolled plates and sheets The ordinary grade does not require the side curvature. The high precision grade shall conform to the provisions in Table 15. The high precision grade needs to be negotiated by the supply and requisitioning parties, and to be indicated in the order forms (or contracts) as required. When there are no clear indications, the ordinary grade applies Hot-rolled strips Do NOT require the side curvature Cold-rolled strips The ordinary grade does not require the side curvature. The high precision grade shall conform to the provisions in Table 16. The high precision grade needs to be negotiated by the supply and requisitioning parties, and to be indicated in the order forms (or contracts) as required. When there are no clear indications, the ordinary grade applies. Page 14 of 19

7 The ordinary grade does not require the tolerances on diagonals. The high precision grade shall conform to the provisions in Table 18. The high precision grade needs to be negotiated by the supply and requisitioning parties, and to be indicated in the order forms (or contracts) as required. When there are no clear indications, the ordinary grade applies. Table 17 Tolerances on Diagonals of Hot-rolled Plates and Sheets High Precision Grade Length a The tolerances on diagonals shall be agreed upon by the supply and requisitioning parties, and shall also be indicated in the order forms (or contracts). Table 18 Tolerances on Diagonals of Cold-rolled Plates and Sheets High Precision Grade Thickness Length a The tolerances on diagonals shall be agreed upon by the supply and requisitioning parties, and shall also be indicated in the order forms (or contracts). 4 Inspection methods for tolerances on dimensions 4.1 Rounding off of dimensions The dimension measurements are not allowed to be rounded off. 4.2 Thickness USE a micrometer with the accuracy of 0.01mm, or the measuring tools with the same accuracy to measure the thicknesses of plates, sheets and strips. Respectively KEEP away from the sides and the end portion for at least 10mm and 115mm. 4.3 Width and length Page 16 of 19