High-strength structural steel plate

01

Read minimum yield by thickness band

Parker Steel's declaration of performance for S355J2 plate to EN 10025-2 lists transverse minimum yield strength falling with thickness: 355 MPa up to 16 mm, 345 MPa over 16 to 40 mm, 325 MPa over 40 to 80 mm, 315 MPa to 100 mm and 295 MPa to 150 mm; tensile strength 470–630 MPa up to 100 mm and 450–600 MPa beyond; and elongation from 20% down to 18%. Thickness and flatness tolerances are to EN 10029. [1]

SSAB's S355J2+N Zero, offered from 6 to 60 mm, lists 355 MPa minimum yield to 16 mm, 345 MPa to 40 mm and 335 MPa to 60 mm, with 470–630 MPa tensile strength and 20–21% elongation. [2] SSAB compares its Strenx 700 structural steel, at 700 MPa minimum yield depending on product and thickness, with 355 MPa for S355, claiming up to 80% higher load-bearing capacity for the same cross-section and average weight savings of 20%, up to 40%. [3]

Editorial calculation: a 50 mm S355J2 plate carries a minimum yield of 325 MPa in Parker's declaration but 335 MPa in SSAB's product, 8.5% and 5.6% below the 355 MPa nominal grade name; design and order to the band for your actual thickness. 700 MPa is about 1.97 times 355 MPa. [1] [2] [3]

Give the supplier the standard and grade (e.g. EN 10025-2 S355J2+N), thickness, width and length, quantity, delivery condition, impact grade and test temperature, CEV limit, thickness and flatness tolerance class, inspection certificate type (e.g. EN 10204 3.1), surface condition and any through-thickness or ultrasonic testing.

02

Fix impact grade and carbon equivalent

Parker's declaration gives longitudinal Charpy impact energy of 27 J for each subgrade — JR at +20 °C, J0 at 0 °C and J2, which SSAB's S355J2+N Zero states as 27 J at –20 °C on longitudinal 10 × 10 mm Charpy V specimens. [1] [2]

For weldability, Parker lists maximum CEV of 0.45% up to 30 mm and 0.47% from 30 to 150 mm, with ladle limits including C 0.20% (0.22% over 30 mm), Si 0.55%, Mn 1.60% and P and S 0.025%. SSAB's S355J2+N Zero holds CEV to 0.45% maximum, with C 0.18%, Mn 1.60%, P 0.020% and S 0.010% maximum. [1] [2] SSAB also offers its 700 MPa grades with impact toughness guaranteed down to –60 °C in the F variant. [3]

Editorial note: a mill product that is tighter than the standard (lower CEV, cleaner sulphur) still carries the standard's name; ask for the actual heat analysis and impact results on the 3.1 certificate rather than relying on the grade designation.

03

Compare a thermomechanically rolled S460 plate's CEV and processing limits

Dillinger's material data sheet for DI-MC 460 (June 2023) describes a thermomechanically rolled fine-grained structural steel meeting EN 10025-4, supplied from 8 to 160 mm thick as basic quality B (S460M, impact-tested at −20 °C) or low-temperature quality T (S460ML, at −50 °C), CE-marked up to 150 mm. Ladle limits include 0.13% carbon, 1.70% manganese, 0.020% phosphorus and 0.003% sulphur. Its maximum CEV is 0.40% up to 40 mm and 0.39% from 40 to 80 mm, against 0.45–0.48% allowed by EN 10025-4 for the same bands. Minimum yield strength is 460 MPa in the thinnest band, falling to 410 MPa at 63–80 mm, 400 MPa at 80–100 mm and 385 MPa at 100–160 mm. Longitudinal Charpy minimums are 40 J at −20 °C for B and 27 J at −50 °C for T. Dillinger states the plate can be flame cut without preheat, needs filler adding no more than 5 ml hydrogen per 100 g of weld metal, may be stress relieved at 530–580 °C for no more than 4 hours, and must not be hot formed above 580 °C; tests are per heat and per 60 t, documented on an EN 10204 3.1 certificate. [4]

Editorial calculation: at 50 mm, DI-MC 460's maximum CEV of 0.39% is 0.08 points below the 0.47% EN 10025-4 limit and below the 0.47% Parker gives for S355J2 over 30 mm, despite about 30% higher yield strength; Dillinger states that with suitable welding parameters preheating can be omitted even above 50 mm. Because hot forming above 580 °C destroys the rolled-in properties, tell the supplier if any part will be hot bent or heat treated. [4] [1]

04

EN, ASTM and GB plate grades on the linked listings

Listings cover EN 10025 S235/S275/S355, ASTM A36/A572 and GB Q235/Q345 grades alongside other carbon steel plate; ask each for the producing mill and certificate.

05

Which plate property governs strength, fracture, welding and fit-up

06

Yield band, CEV and flatness class on a plate enquiry

For plate, a yield figure only means something with its thickness band attached, so the S355J2 entries below are given by band from Parker's declaration; width, length and density have no published value in these sources.

07

Send the grade, size and testing data together

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

Grade: [standard; grade; subgrade; delivery condition]
Size: [thickness; width; length; quantity]
Strength: [minimum yield at thickness]
Toughness: [J at °C]
Chemistry: [CEV max]
Tolerances: [EN 10029 class; flatness]
Testing: [3.1 certificate; UT; Z-quality]
Surface: [as rolled; blasted; primed]

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