Structural steel I-beam

01

Read the rolling tolerances for your section

ArcelorMittal's sections sales programme lists IPE parallel-flange beams with dimensions to EN 10365:2017 and tolerances to EN 10034:1993, and IPN taper-flange beams (flange slope 14%) with dimensions to EN 10365:2017 and tolerances to EN 10024:1995. [1] [2] Its beam tolerance table under EN 10034 sets limits by size: depth +3/−2 mm up to 180 mm, +4/−2 mm above 180 to 400 mm, +5/−3 mm above 400 to 700 mm and ±5 mm above 700 mm; flange width +4/−1 mm up to 110 mm, +4/−2 mm above 110 to 210 mm, +4/−4 mm above 210 to 325 mm and +6/−5 mm above 325 mm. [1]

Thickness limits follow the same pattern. Web thickness is ±0.7 mm below 7 mm, ±1 mm from 7 to 10 mm, ±1.5 mm from 10 to 20 mm and wider above; flange thickness is +1.5/−0.5 mm below 6.5 mm, +2/−1 mm from 6.5 to 10 mm and +2.5/−1.5 mm from 10 to 20 mm. Straightness is 0.0030L for depths above 80 to 180 mm, 0.0015L above 180 to 360 mm and 0.0010L above 360 mm; length is −0/+100 mm and mass ±4%. The table adds that other tolerances are by agreement. [1]

Editorial calculation: an IPE 400 is listed at 66.3 kg/m with h = 400 mm, b = 180 mm, tw = 8.6 mm and tf = 13.5 mm. [1] Under the table above that gives depth +4/−2 mm, flange width +4/−2 mm, web ±1 mm and flange +2.5/−1.5 mm. A 12 m length weighs a nominal 795.6 kg (66.3 × 12), with ±4% allowing about ±32 kg, and a straightness limit of 0.0010 × 12,000 = 12 mm.

Editorial note: a mill certificate shows the grade, not the tolerance class. If your fabrication relies on tighter fit-up than the standard, write the limits into the order, since ArcelorMittal states that its usual rolling tolerances can be reduced only by agreement. [1]

Give the supplier the section series and designation, dimension and tolerance standards, steel grade and quality, lengths and length tolerance, quantity per size, surface condition and any coating, inspection document type, and any ultrasonic or other testing.

02

Set the steel grade and check yield by thickness

ArcelorMittal's table for non-alloy structural steels to EN 10025-2:2019 gives minimum yield strength by nominal thickness: S235 at 235 MPa up to 16 mm and 225 MPa above 16 to 40 mm; S275 at 275 and 265 MPa; S355 at 355 and 345 MPa; and S460 at 460 and 440 MPa. Tensile strength for S355 is 470–630 MPa up to 100 mm, and the JR, J0 and J2 qualities are impact-tested at +20, 0 and −20 °C (27 J). [1]

The same programme offers HISTAR steels at 355 and 460 MPa yield and FRITENAR at 355 MPa; HISTAR uses in-line quenching and self-tempering (QST), is delivered thermo-mechanically rolled under ETA 10/0156 and meets EN 10025-4:2019. It says both can be welded without preheating for heat inputs of 10–60 kJ/cm above 0 °C with low-hydrogen consumables. [1]

Editorial calculation: the IPE 400 flange is 13.5 mm thick, so S355 gives 355 MPa; an IPE 600 has a 19 mm flange, which falls in the above-16-mm band and gives 345 MPa. [1] Use the band that matches the thickest part your design relies on.

A linked supplier page lists I-beam material grades Q235B and Q345B (China), S235JR to S460 (EN) and A36 and A572 Gr.50 (ASTM), referring to GB/T 706-2008, GB/T 1591-2018, EN 10025, EN 10034 and ASTM A6. [3] Name one grade and standard per order rather than an equivalence list.

SteelConstruction.info extends the BS EN 10025-2 yield table to thicker material: S275 has a minimum yield of 275, 265, 255 and 245 N/mm² for t ≤ 16, 16–40, 40–63 and 63–80 mm, and S355 has 355, 345, 335 and 325 N/mm²; minimum tensile strength is 410 and 470 N/mm² for 3–100 mm and 400 and 450 N/mm² for 100–150 mm. It explains that the number in the grade name is the yield for material up to 16 mm thick and that the UK National Annex to BS EN 1993-1-1 allows the minimum yield for the actual thickness to be used as the characteristic value. For design it gives a modulus of elasticity E = 210,000 N/mm², Poisson's ratio 0.3, shear modulus G = E/[2(1 + ν)] (81,000 N/mm²) and a coefficient of thermal expansion of 12 × 10⁻⁶/°C at ambient temperatures, and notes that BS EN 10025 sets mandatory limits on carbon equivalent value (CEV) for weldability. [4]

Editorial calculation: G = 210,000 / (2 × 1.3) ≈ 80,800 N/mm², which the reference rounds to 81,000. With α = 12 × 10⁻⁶/°C, a 12 m beam that warms by 30 °C lengthens by 12 × 10⁻⁶ × 30 × 12,000 ≈ 4.3 mm, about 4 % of the +100 mm length tolerance in the EN 10034 table; the 30 °C change is an assumed example. [4] [1]

03

Section heights, lengths and coatings in the supplier listing

The listing reviewed gives I-beam heights of 100–900 mm and standard lengths of 6–18 m, with galvanizing and painting options; ask which mill rolls the section and for the mill certificate.

04

Web, flanges and root radius: what each part of an I-section carries

05

Section dimensions and rolling tolerances per beam designation

The dimension rows use the IPE 400 from ArcelorMittal's programme as the worked example; for any other designation take h, b, tw and tf from the section table and the tolerance band that matches its depth.

06

Send the section, grade and delivery data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Section: [series; designation, e.g. IPE 400]
Standards: [dimensions; tolerances]
Steel: [grade and quality; standard]
Length: [lengths; tolerance]
Quantity: [per size]
Surface: [as rolled; blasted; galvanized; painted]
Documents: [inspection certificate type]
Testing: [UT or other, if required]

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