CN Standards for Stainless Steel Bar

The old BS970 Parts 1 & 3:1991 standards have been replaced by a number of EN Standards, the most important of which are shown below.

CN10088-3 Replaces BS970 Part 1: 1991 & BS970 Part 3: 1991 covering chemical composition & mechanical properties.
CN10058 Tolerances for Hot Rolled Flat Bars CN10059 Tolerances for Hot Rolled Square Bars EN10060 Tolerances for Hot Rolled Round Bars CN10061 Tolerances for Hot Rolled Hexagonal Bars.
CN10278 Tolerances for Bright Bars (Drawn, Turned or Ground).
ISO186 Parts 1 & 2 Tolerance Classifications.

Diameter Tolerances

Smooth Turned

-                                        Diameter (mm)
+                                        Tolerance (mm)
-to 30
+                                        +0/-0.084
-to 50
+                                        +0/-0.100
-to 79
+                                        +0/-0.120

(These are H10 tolerances, which are ‘all minus’ tolerances)

Rough Turned

-                                        Diameter (mm)
+                                        Tolerance (mm)
-to 150
+                                        -0/+1.50
-to 225
+                                        -0/+2.00
-to 410
+                                        -0/+3.00

(These are ‘all plus’ tolerances)

Bright Drawn

-                                        Diameter (mm)
+                                        Tolerance (mm)
-to 10
+                                        +0/-0.036
-to 18
+                                        +0/-0.043
-to 30
+                                        +0/-0.052

These are H9 Tolerances

H9 Tolerances are ‘all minus’ tolerances: +0mm/- Figure in table

Width & Thickness Tolerances

Hot Rolled Square - Width & Thickness

-                                        Size (mm)
+                                        Tolerance (mm) +/-
-to 150
+.50
-to 225
+.00
-to 410
+.00

Hot Rolled Flat - Thickness

-                                        Size (mm)
+                                        Tolerance (mm) +/-
-                                        Up to 20
+.50
-to 40
+.00
-to 80
+.50

Hot Rolled Flat - Width

-                                        Size (mm)
+                                        Tolerance (mm) +/-
-to 40
+.75
-to 80
+.00
-to 100
+.50
-to 120
+.00
-to 150
+.50

Angle Bars

Leg Length

Leg (mm)	Leg Length Tolerance (mm) +/-	Thickness (mm) +/-
20	1.50	0.40
25	1.50	0.50
30	2.00	0.50
40，50	2.00	0.60
60，70，80，90，100	3.00	0.75

Internal Radius

-                                        Leg (mm)
+                                        Maximum Internal Radius (mm)
-，25，30
-，60
-，70，75，80
-，100

ISO 286 Tolerances (in mm)

EXAMPLES:

H8 = Precision Ground

H9 = Bright Drawn

H10 = Smooth Turned

Tolerance (mm) for Given Tolerance Number

Diameter (mm)	6	7	8	9	10	11	12	13
>1 ≤ 3	0.007	0.009	0.014	0.025	0.040	0.040	0.090	0.140
>3 ≤ 6	0.008	0.012	0.018	0.030	0.048	0.048	0.120	0.180
>6 ≤ 10	0.009	0.015	0.022	0.036	0.058	0.090	0.150	0.220
>10 ≤ 18	0.011	0.018	0.027	0.043	0.070	1.110	0.180	0.270
>18 ≤ 30	0.013	0.021	0.033	0.052	0.084	0.130	0.210	0.330
>30 ≤ 50	0.016	0.025	0.039	0.062	0.100	0.160	0.250	0.390
>50 ≤ 80	0.019		0.046	0.074	0.120	0.190	0.300	0.460
>80 ≤ 120	0.022			0.087	0.140	0.220	0.350	0.540
>120 ≤ 180	0.025			0.100	0.160	0.250	0.400	0.630
>180 ≤ 250				0.115	0.185	0.290	0.460	0.720
>250 ≤ 315						0.320	0.520	0.810
>315 ≤ 400						0.360	0.570	0.890
>400 ≤ 500						0.400	0.630	0.970
>500						0.440	0.700	1.100

Straightness Tolerances for Bright Bars

Taken from BS EN 10278:1999, applicable to Bright Bars only.

Method of measuring deviation - Preferred Method B.1 from BS EN 10278:

The bar shall be supported on a suitable surface so as to eliminate or minimise sagging.
A 1 metre long straight edge shall be placed on the surface of the bar at any position along it’s length. No part of the straight edge shall be within 150mm of the ends of the bar.
Straightness shall be determined by measuring the gap between the bar and the straight edge by suitable means such as a feeler gauge.

Deviation from Straightness

Product	Dimension	Maximum Deviation (mm) Within a 1m Length Measured at Least 150mm from Either End of Bar
Round		1.0mm
Square & Hexagon	≤75mm	1.0mm
Square & Hexagon	>75mm	1.5mm
Flat	Width <120mm	On Width: 1.5mm
Flat	Width <120mm	On Thickness: 2.0mm
Flat	Width ≥120mm	On Width: 2.0mm
Flat	Width/Thickness <10.1	On Thickness: 2.5mm
Flat	Width ≥120mm	On Width: 2.500

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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.