Tolerances to BS EN 10058 for hot rolled flat stainless steel bars

Introduction

Tolerances for hot rolled stainless steel bars are included with the general standards for hot rolled steel bars. The various sections are covered by:-
BS EN 10058 - Flat bars
BS EN 10059 - Square bars
BS EN 10060 - Round bars
BS EN 10061 - Hexagon bars

All of these can be used in conjunction with bars specified to BS EN 10088-3. This article covers flat bar tolerances to BS EN 10058, and cover thickness, width, length, straightness and 'out-of-section'.
The data given is not intended to replace that shown in individual standards to which reference should always be made.
Dimensions and tolerances for stainless steel long products are covered in more detail in the BSSA special report 'A Specifiers Guide to the New EN Standards for Stainless Steel Long Products' available in the publications area of the web site.

Width, thickness , straightness and 'out-of-section'

The table below, based on Table 2 of the standard, summarizes width, thickness, straightness and 'out-of-section' deviations.

Width (b) Nominal width Limit deviation
- between 10 and 40 +/- 0.75
- over 40 up to 80 +/- 1
- over 80 up to 100 +/- 1.5
- over 100 up to 120 +/- 2
- over 120 up to 150 +/- 2.5
Thickness (t) Nominal thickness Limit deviation
- up to 20 +/- 0.5
- over 20 up to 40 +/- 1
- over 40 up to 80 +/- 1.5
Straightness (q) Nominal cross-section Tolerance in the plane
- below 1000 mm2 below 0.4% of measuring length
- 1000 mm2 and above below 0.25% of measuring length
Out-of-section (u) Nominal thickness Tolerance
- between 10 and 25 0.5
- over 25 up to 40 1
- over 40 up to 80 1.5

Notes
All dimensions are in mm.
If agreed at the enquiry and order stage, limit deviations (ranges) can be all plus, minus zero, rather than equal plus / minus.

Length tolerances

The standard states 'Depending on the type of length, flat bars shall be cut to lengths within tolerances given in Table 3'. Table 3 categorises the type of length and notes that it is the purchaser's responsibility to indicate at enquiry and order stages the type of length required and the length range or length required. No further explanation of the terms used in the standard is given. The table below, is based on Table 3 of the standard.

Type of length Range Limit deviation
Manufacturing length (M) 3000 to 13000 with a range of 2000 per order item 10% of bars may be below the minimum for the ordered range, but not less than 75% of the minimum of the range
Fixed length (F) 3000 to 13000 +/- 100
Exact length (E) below 6000 +/- 25
- between 6000 and 13000 +/- 50

Notes
All dimensions are in mm.
If agreed at the enquiry and order stage, limit deviations (ranges) can be all plus, minus zero, rather than equal plus / minus.

Methods of measurement

BS EN 10058 specifies methods of measurement for the dimensional tolerances given. These are summarised below.

Width and thickness

 

 

Width and thickness must be measured at least 100mm from the end of the bar.

Straightness

 

 

Straightness is measured as the maximum distance from a flat bed on which the bar rests to the underside of the "hogs back" shape of the bar. Straightness must be measured over the total length of the bar.

Out-of-section

 

 

Out-of-section tolerance, u, applies to both nominal width, b and nominal thickness, t.

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