CN Standards For Rolled Aluminium

Differences Between BS & CN Standards

For those familiar with the old BS1470 it is useful to highlight where the new CN standards differ:
Chemical Compositions – No Change.
Alloy Numbering System – No Change.
Temper Designations for Heat Treatable Alloys – A new wider range of special tempers having up to four digits after the T have been introduced for non- standard applications (e.g. T6151).
Temper Designations for Non Heat Treatable Alloys – No change to existing tempers but a more comprehensive definition of how tempers are achieved.
Mechanical Properties – Similar but not identical. Also, 0.2% Proof Stress must now be quoted on test certificates.
Thickness Tolerances – Considerably tighter for alloys
1050A & 3103. To reflect manufacturing difficulty the tolerances for alloys 5251, 5083 & 6082 are now wider than this, although still a little tighter than in BS1470.
Length and Width Tolerances – These tend to be tighter and are now all on the plus side (i.e. minus zero).
Flatness Tolerances – These are considerably tighter.

Alloy Groups

Please note that thickness tolerances for cold rolled material vary according to alloy, with the alloys falling into two groups as shown below.

Aluminium Alloy Groups

-                                        Alloy Group
-                                        Alloy Group I
-A, 1070A, 1050A, 1200
-, 3005, 3103, 3105
-, 4007
-, 5050
-A
-                                        Alloy Group II
-, 2017A, 2024
-, 5049, 8053, 5086, 5251, 5052, 5154A, 5454, 5754, 5182,
-, 6082
-, 7021, 7022, 7075

Thickness Tolerances

Please note that thickness tolerances for cold rolled material vary according to alloy, with the alloys falling into two groups as shown above.

The thickness tolerances also vary according to the width of the material as shown in the tables below.

Cold Rolled Sheet & Strip - Group I

Thickness (mm)	Tolerance (mm) +/-	Tolerance (mm) +/-	Tolerance (mm) +/-
	Group I 1000mm Wide	Group I 1250mm Wide	Group I 1500mm Wide
0.20 to 0.40	0.02	0.04	0.05
0.41 to 0.50	0.03	0.04	0.05
0.51 to 0.60	0.03	0.05	0.06
0.61 to 0.80	0.03	0.06	0.07
0.81 to 10.0	0.04	0.06	0.08
1.10 to 1.20	0.04	0.07	0.09
1.21 to 1.50	0.05	0.09	0.10
1.51 to 1.80	0.06	0.10	0.11
1.80 to 2.00	0.06	0.11	0.12
2.00 to 2.50	0.07	0.12	0.13
2.60 to 3.00	0.08	0.13	0.15
3.10 to 3.50	0.10	0.15	0.17

Cold Rolled Sheet & Strip - Group II

Thickness (mm)	Tolerance (mm) +/-	Tolerance (mm) +/-	Tolerance (mm) +/-
	Group II 1000mm Wide	Group II 1250mm Wide	Group II 1500mm Wide
0.20 to 0.40	0.03	0.05	0.06
0.41 to 0.50	0.03	0.05	0.06
0.51 to 0.60	0.04	0.06	0.07
0.61 to 0.80	0.04	0.07	0.08
0.81 to 1.00	0.05	0.08	0.09
1.10 to 1.20	0.05	0.09	0.10
1.21 to 1.50	0.07	0.11	0.12
1.51 to 1.80	0.08	0.12	0.13
1.81 to 2.00	0.09	0.13	0.14
2.10 to 2.50	0.10	0.14	0.15
2.60 to 3.00	0.11	0.15	0.17
3.10 to 3.50	0.12	0.17	0.19

Cold Rolled Sheet & Strip - Group I/II

Thickness (mm)	Tolerance (mm) +/-	Tolerance (mm) +/-	Tolerance (mm) +/-
	Group I/II 1000mm Wide	Group I/II 1250mm Wide	Group I/II 1500mm Wide
3.60 to 4.00	0.15	0.20	0.22
4.10 to 5.00	0.18	0.22	0.24
5.10 to 6.00	0.20	0.24	0.25
6.10 to 8.00	0.24	0.30	0.31
8.10 to 10.0	0.27	0.33	0.36
10.1 to 12.0	0.32	0.38	0.40
12.1 to 15.0	0.36	0.42	0.43
15.1 to 20.0	0.38	0.44	0.46
21.0 to 25.0	0.40	0.46	0.48
26.0 to 30.0	0.45	0.50	0.53
31.0 to 40.0	0.50	0.55	0.58
41.0 to 50.0	0.55	0.60	0.63

Hot Rolled Plate

Thickness (mm)	Tolerance (mm) +/-	Tolerance (mm) +/-
	1250mm Wide	1500mm Wide
2.50 to 4.00	0.28	0.28
4.10 to 5.00	0.30	0.30
5.10 to 6.00	0.32	0.32
6.10 to 8.00	0.35	0.40
8.10 to 10.0	0.45	0.50
10.1 to 15.0	0.50	0.60
15.1 to 20.0	0.60	0.70
21.0 to 30.0	0.65	0.75
31.0 to 40.0	0.75	0.85
41.0 to 50.0	0.90	1.00
51.0 to 60.0	1.10	1.20
61.0 to 80.0	1.40	1.50
81.0 to 100	1.70	1.80
101 to 150	2.10	2.20
151 to 220	2.50	2.60
221 to 350	2.80	2.90
351 to 400	3.50	3.70

Length Tolerances

Thickness (mm)	Hot Rolled EN485-3 (-0mm) Plus:	Cold Rolled EN 485-4 (-0mm) Plus:
0.20 to 0.30	8.0mm	6.0mm
3.00 to 6.00	8.0mm	8.0mm
6.00 to 12.0	8.0mm	10.0mm
12.0 to 50.0	9.0mm	-
Over 50.0	9.0mm	-

Width Tolerances

Thickness (mm)	Hot Rolled EN485-3 (-0mm) Plus:	Cold Rolled EN 485-4 (-0mm) Plus:
0.20 to 3.00	-	3.0mm
3.10 to 6.00	7.0mm	4.0mm
6.10 to 12.0	7.0mm	5.0mm
12.1 to 50.0	8.0mm	-
51.0 to 200	8.0mm	-
201 to 400	11.0mm	-
	Applies to widths 1001mm to 2000mm	Applies to widths 501mm to 1250mm

Flatness Tolerances

Product	Thickness (mm)	Max Deviation over 2500mm Length	Max Deviation over 1250mm Width
Cold Rolled	0.50 to 3.00	10.0mm	5.00mm
	3.00 to 6.00	7.50mm	3.75mm
Hot Rolled	6.00 to 200	5.00mm	2.50mm

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DISCLAIMER

This Data is indicative only and as such is not to be relied upon in place of the full specification. In particular, mechanical property requirements vary widely with temper, product and product dimensions. All information is based on our present knowledge and is given in good faith. No liability will be accepted by the Company in respect of any action taken by any third party in reliance thereon. Please note that the ‘Datasheet Update’ date shown above is no guarantee of accuracy or whether the datasheet is up to date.

The information provided in this datasheet has been drawn from various recognised sources, including EN Standards, recognised industry references (printed S online) and manufacturers’ data. No guarantee is given that the information is from the latest issue of those sources or about the accuracy of those sources. Material supplied by the Company may vary significantly from this data but will conform to all relevant and applicable standards. As the products detailed may be used for a wide variety of purposes and as the Company has no control over their use; the Company specifically excludes all conditions or warranties expressed or implied by statute or otherwise as to dimensions, properties and/or fitness for any particular purpose, whether expressed or implied. Advice given by the Company to any third party is given for that party’s assistance only and without liability on the part of the Company. All transactions are subject to the Company’s current Conditions of Sale. The extent of the Company’s liabilities to any customer is clearly set out in those Conditions; a copy of which is available on request.