S355J2 steel is one of the popular structural steels used in various industries, especially construction and machine parts. The designation S indicates structural steel, the value 355 indicates the minimum yield strength given in MPa, and the symbol at the end J2 indicates fracture toughness at -20℃.
You can read more about the S355J2 steel grade on this page.
S355J2 steel with the additional symbol +N specifies the delivery condition of products. The +N symbol indicates products after normalizing, which can be hot-formed after delivery. Normalizing is a heat treatment process that involves heating steel to a certain temperature (30-50℃ higher than Ac3), annealing at this temperature, and then slowly cooling it in air. Thanks to the normalizing process, the steel gains a homogeneous fine-grained structure, which in turn improves the mechanical properties of finished products.
S2355J2+N steel chemical composition
A very important factor determining the mechanical properties of a given steel is its chemical composition. According to melt analysis, the chemical composition of S2355J2+N steel should be in accordance with the values given in the table below.
| Designation | C in % max. for a product with nominal thickness in mm | Mn % max. | P % max. | S % max. | Si % max. | Cu % max. | ||
|---|---|---|---|---|---|---|---|---|
| Steel mark | No. of steel | ≤ 40 | >40 | |||||
| S355J2 | 1.0577 | 0,20 | 0,22 | 1,6 | 0,025 | 0,025 | 0,55 | 0,55 |
Steel S355J2+N mechanical properties
| Steel | Mechanical properties | ||||
|---|---|---|---|---|---|
| Steel mark | Rp0,2 [MPa] | Rm [MPa] | HB | Elongation [%] | Impact strength |
| S355J2 | 355 | 470 - 630 | 146 - 187 | ≥25 | 27 J (20°C) |
S355J2+N steel application
S355J2+N steel is widely used in construction and heavy industry where higher strength and resistance to dynamic loads are required. Thanks to its high strength and good weldability, it is often chosen for engineering projects where safety and reliability are crucial.
It is most often used for the construction of:
- bridge structures, i.e. welded and welded structures
- industrial machinery and its parts
- structural elements in civil engineering i.e. for the construction of buildings, halls, towers, concrete reinforcement bars, etc.
- support structures for industrial equipment, e.g. frames, brackets and towers
- support structures for overhead lines, e.g. telecommunication and power towers.
| EU EN | Steel number | Germany DIN | USA AISI | Poland PN |
| S355J2+N | 1.0577 | St52-3N | 1020 | 18G2A |
S355J2+N vs S235JR comparison
Comparing S355J2+N steel with S235JR steel, the main difference is the value of yield strength and tensile strength. S355J2+N steel has a higher yield strength (355 MPa) compared to S235JR steel (235 MPa), making it suitable for applications requiring higher strength.
In addition, S355J2+N steel exhibits higher impact strength at lower temperatures
(-20℃), which is important in conditions where dynamic loads and low temperatures are present. The table below shows a comparison of the two steels:
| Steel | Mechanical properties | |||
|---|---|---|---|---|
| Steel mark | Rp0.2 [MPa] | Rm [MPa] | HB | Impact strength |
| S235JR | 235 | 360 - 510 | 100 - 154 | 27 J (20°C) |
| S355J2+N | 355 | 470 - 630 | 146 - 187 | 60J (-20°C) |
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