EN S355JR steel

Identity, edition and product form

ArcelorMittal's S355JR hot-rolled flat product gives 355 MPa minimum yield at 1.5–16 mm and 345 MPa above 16 through 20 mm. At 18 mm, its longitudinal Charpy entry is 27 J minimum at +20°C. The catalogue cites EN 10025-2:2004 in its grade cross-reference. Confirm the governing edition for the actual order. Treat the impact temperature as a test condition and assess the component's service temperature separately. ArcelorMittal S355JR mechanical table

S355JR, material number 1.0045, is a non-alloy structural steel grade associated with EN 10025-2. DIN's current publisher record identifies EN 10025-2:2019, adopted as DIN EN 10025-2:2019-10. That part concerns technical delivery conditions for hot-rolled non-alloy structural steels. Salzgitter grade table; DIN edition record

Record the JR suffix, delivery condition, dimensions, required tests and inspection document.

Separate the material standard from a producer's declaration of performance. For example, thyssenkrupp's hot-rolled-strip S355JR declaration identifies EN 10025-1:2004 as its harmonized standard and EN 10051 for dimensional tolerances. This does not make EN 10025-1 a competing grade designation or date the current Part 2 edition. thyssenkrupp declaration, pp. 3–4

Strength: 355 MPa is thickness-dependent

A useful producer-specific hot-rolled flat-product example is ArcelorMittal's catalogue:

The catalogue's comparison section still references EN 10025-2:2004. Treat these as its published product values, not a reproduction of every thickness band in the 2019 standard. Check the ordered edition and current producer confirmation, particularly outside this range. ArcelorMittal A30, S355JR mechanical table

The independent thyssenkrupp strip declaration gives 355 MPa minimum yield through 16 mm and 345 MPa above 16 through 25.4 mm, with 470–630 MPa tensile strength over its declared range. These values illustrate why a grade number alone cannot settle the strength of a thicker product. thyssenkrupp declaration, p. 4

JR: impact test, not service-temperature approval

Salzgitter lists 27 J at +20°C for S355JR, versus 27 J at 0°C for S355J0 and at −20°C for S355J2. Its impact footnote treats the requirement as an average of three specimens, permits one individual result up to 30% below the required value, and specifies proportional energy reduction for subsize specimens used at 6–10 mm product thickness. Salzgitter mechanical properties and footnote 3

Do not translate “JR” into a claim that every piece has been individually impact-tested, or that a component is safe at all temperatures above +20°C. Confirm the actual inspection and certification requirements. Where low temperature, high restraint, fatigue or fracture consequences matter, obtain a toughness selection appropriate to thickness, stress state, fabrication and the design rules. A Charpy energy is not a fracture-toughness value and cannot be inserted directly into a crack-tolerance calculation.

Read elongation with equal care. A result using an 80 mm gauge length cannot be compared directly with a proportional specimen result as though the percentages were the same material constant. Retain test orientation and gauge definition when comparing certificates or supplier tables.

Delivery condition, welding and forming

ArcelorMittal distinguishes +AR, without special rolling or heat-treatment requirements, from +N, a rolling condition equivalent to normalization. It also distinguishes its S355JR AM FCE chemistry from the catalogue's EN grade entry. Do not carry a producer's tighter chemical limits over to all generic S355JR stock. ArcelorMittal delivery conditions and chemistry

Salzgitter describes the JR/J0/J2/K2 families as generally weldable, while requiring an application-appropriate welding technique. It says suitability for cold forming can be ordered separately. These are useful selection statements, not a universal preheat exemption or bend-radius guarantee. Salzgitter application and welding guidance

For a welded assembly, use the actual heat chemistry, section thickness, restraint, consumables and hydrogen controls when establishing the procedure. A quoted maximum carbon equivalent is not a complete welding instruction. For a bent part, agree forming suitability before buying and qualify the intended radius, orientation, edge condition and tooling. Do not assume thermal cutting, welding or subsequent heat treatment leaves every original acceptance property unchanged.

Specify the required corrosion-protection system separately. The grade name does not define paint preparation, galvanizing behavior, coating thickness or service life. Agree surface requirements with the fabricator and coating supplier before processes make the relevant surfaces inaccessible.

Bounded calculation example

Assume an unperforated 50 mm-wide strip at 20 mm thickness, loaded by 100 kN in uniform tension. Gross area is 50 × 20 = 1000 mm²; nominal stress is 100000 / 1000 = 100 MPa. Against the cited 345 MPa minimum yield for this thickness, the simple yield-force product is 345 × 1000 = 345 kN. Using 355 MPa would give 355 kN, 10 kN higher.

Neither product is an allowable load. The example omits partial factors, holes, eccentricity, connections, fatigue and fracture. Its purpose is to show the thickness selection explicitly, not to qualify a structural detail.

Source versions and procurement

The DIN publisher record establishes the 2019 Part 2 edition. The thyssenkrupp declaration explicitly prints Duisburg, November 19, 2019; its URL's June 2021 directory is not its issue date. Salzgitter and ArcelorMittal are live catalogue pages without a declared issue date used here. Retain the ordered specification, delivery condition and material records with part traceability rather than treating this summary as an acceptance certificate.

See also grades, tempers and conditions.