Quality	Standard	Material No.	Past names
S235J2	DIN EN 10025-2	1.0117	S235J2G3, S235J2G4

Testing direction	Yield strength ReH (MPa) ≤ 16 mm	Yield strength ReH (MPa) > 16 ≤ 40 mm	Tensile strength Rm (MPa) < 3 mm	Tensile strength Rm (MPa) ≥ 3 mm ≤ 100 mm
Transversal (≥ 600mm)	≥ 235	≥ 225	360 – 510	360 – 510

Sample direction a	Elongation A80 (in %) ≤ 1 mm	A80 (in %) > 1 ≤ 1,5 mm	A80 (in %) > 1,5 ≤ 2 mm	A80 (in %) > 2 ≤ 2,5 mm	A80 (in %) > 2,5 ≤ 3 mm	A5,65 (in %) > 3 ≤ 40 mm
l	≥ 17	≥ 18	≥ 19	≥ 20	≥ 21	≥ 26
t	≥ 15	≥ 16	≥ 17	≥ 18	≥ 19	≥ 24

The unalloyed structural steel grade S235J2, designated under material number 1.0117, represents a high-quality grade of basic structural steels within the DIN EN 10025-2 standard family. While the strength class S235 is generally considered standard in mechanical engineering and steel construction, the suffix “J2” defines specific requirements for impact strength, qualifying this material for safety-relevant structures and welded components under increased stress.

Materials engineering classification and differentiation

Compared to the widely used grade S235JR, S235J2 offers enhanced resistance to brittle fracture. The “J2” classification requires impact testing at a temperature of -20 °C, with a minimum value of 27 joules. In contrast, grade JR is only tested at room temperature. This low-temperature capability is a crucial criterion for engineers when components are used outdoors or in demanding climatic environments.

From a chemical perspective, 1.0117 is characterized by a controlled carbon content and a balanced manganese-silicon ratio. This results in excellent weldability and good ductility, which is particularly relevant for the further processing of flat steel products such as coils, slit strip, and sheets.

For commercial procurement and technical design, knowledge of the delivery conditions is essential, as these significantly influence the microstructure of the steel and thus its behavior during further processing (e.g., cold forming, galvanizing, or thermal cutting). Hot-rolled flat products in S235J2 are typically delivered in one of the following conditions:

The +AR condition refers to material delivered “as rolled.” In this case, no targeted thermal post-treatment takes place after the hot rolling process. The steel’s properties result primarily from the chemical analysis and the rolling process.

Technical relevance: The microstructure can vary within a batch because the cooling conditions after rolling are not strictly controlled. This condition is often sufficient for simple steel structures.

Commercial aspects: +AR is usually the most cost-effective option, as additional thermal process steps are eliminated.

For materials marked +N, the material was either normalized after rolling or brought to its final temperature directly through a normalizing rolling process. The aim is to create a fine-grained, uniform microstructure.

Technical relevance: Normalized material exhibits more homogeneous mechanical properties across the entire sheet or coil width. This leads to improved predictability in forming processes and optimized suitability for galvanizing. Stresses within the material are reduced, resulting in greater flatness when laser cutting sheets.

Application: Engineers often require +N for components that are subject to high safety requirements or where distortion due to thermal stresses must be minimized.

The +M condition describes a process in which the final forming takes place in a specific temperature range, resulting in material properties that cannot be achieved by heat treatment alone.

Technical relevance: Thermomechanical rolling achieves a combination of high strength and good toughness with a low carbon equivalent. This significantly improves weldability, as hardening in the heat-affected zone is minimized.

Differentiation: In contrast to the +N state, a +M microstructure can lose its properties through subsequent heat treatment (above the recrystallization temperature). Therefore, this state is ideal for cold working and welding, but less suitable for subsequent hot forming.

Der Einsatz von S235J2 (1.0117) als Flachstahl in Form von Coils, Spaltband oder Tafeln bietet eine technisch überlegene Alternative zum Standard-Baustahl, insbesondere wenn klimatische Einflüsse oder komplexe Schweißprozesse eine Rolle spielen. Während der Einkauf die Kosten-Nutzen-Relation der Lieferzustände (+AR, +N, +M) abwägen muss, profitiert die Technik von der erhöhten Sprödbruchsicherheit und der verbesserten Verarbeitungsqualität bei normalisierten oder thermomechanisch behandelten Güten. Die präzise Wahl der Lieferform – ob als Coil für die Serienfertigung oder als maßgenauer Tafelzuschnitt – ermöglicht zudem eine signifikante Optimierung der Materialeffizienz in der Produktion.