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The old BS970 Parts 1 & 3:1991 standards have been replaced by a number of EN Standards, the most important of which are shown below.

Diameter Tolerances

Smooth Turned

Diameter (mm) Tolerance (mm)

18 to 30

+0/-0.084

31 to 50

+0/-0.100

51 to 79

+0/-0.120

(These are H10 tolerances, which are 'all minus' tolerances)

Rough Turned

Diameter (mm) Tolerance (mm)

75 to 150

-0/+1.50

151 to 225

-0/+2.00

226 to 410

-0/+3.00

(These are 'all plus' tolerances)

Bright Drawn

Diameter (mm) Tolerance (mm)

6 to 10

+0/-0.036

11 to 18

+0/-0.043

19 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) +/-

75 to 150

1.50

151 to 225

2.00

226 to 410

3.00

Hot Rolled Flat - Thickness

Size (mm) Tolerance (mm) +/-

Up to 20

0.50

20 to 40

1.00

40 to 80

1.50

Hot Rolled Flat - Width

Size (mm) Tolerance (mm) +/-

10 to 40

0.75

40 to 80

1.00

80 to 100

1.50

100 to 120

2.00

120 to 150

2.50

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, 75, 80, 90, 100

3.00

0.75

Internal Radius

Leg (mm) Maximum Internal Radius (mm)

20, 25, 30

4

40

5

50, 60

7

65, 70, 75, 80

9

90, 100

10

ISO 286 Tolerances (in mm)

EXAMPLES:

  • H = All Minus Tolerance e.g. 45mm dia. H9 = +0 / -0.062
  • J = Tolerance Divided e.g. 45mm dia. J9 = +/- 0.031
  • K = All Plus Tolerance e.g. 45mm dia. K9 = +0.062/ -0 (The K tolerance is usually only applied to larger diameter bars - over 75mm)

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

0.060

0.090

0.140

>3 ≤ 6

0.008

0.012

0.018

0.030

0.048

0.075

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:

  1. The bar shall be supported on a suitable surface so as to eliminate or minimise sagging.
  2. 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.
  3. 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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