What Is S235JR Steel?
S235JR is a non-alloy structural steel defined in EN 10025-2. The designation means a minimum yield strength of 235 MPa in the S grade family, with the JR suffix denoting a minimum Charpy impact energy of 27 J at room temperature. The steel is weldable, formable and economical, which explains its dominance in general construction across Europe and worldwide.
In pipe form, S235JR is produced as ERW, LSAW and SSAW welded pipe, as well as seamless, for structural and light mechanical duty.
Key Properties
| Property | Value |
|---|---|
| Yield strength, min | 235 MPa |
| Tensile strength | 360-510 MPa |
| Charpy impact | 27 J at 20 degrees C |
| Carbon, max | 0.17% |
| Weldability | Excellent |
The low carbon content gives S235JR excellent weldability, which is essential for on-site construction connections.
Application Fields
| Field | Typical Use |
|---|---|
| Building construction | Trusses, columns, beams, purlins, staircases |
| Bridges | Pedestrian overpasses, small temporary bridges |
| Machinery | Frames, housings, conveyor structures |
| Municipal | Light poles, sign supports, barriers, bollards |
| Fluid systems | Low-pressure water, drainage and ventilation lines |
In building curtain walls, S235JR pipe serves as support framing where its weldability speeds installation. In prefabricated buildings, pipe components are produced in the factory and assembled on site, improving efficiency.
Limitations and Precautions
S235JR is not intended for corrosive media, high-temperature fluids above about 300 degrees C, or high-pressure piping. Load-bearing uses require professional structural calculation, and outdoor installations need hot-dip galvanizing or equivalent protection.
FAQ
Q1. What does S235JR mean?
S denotes structural steel, 235 is the minimum yield strength in MPa, J indicates impact test requirements and R means room temperature, so JR guarantees 27 J at 20 degrees C.
Q2. Can S235JR pipe be used for bridges?
Yes, for small pedestrian bridges and temporary structures with proper design and corrosion protection. Heavy road and rail bridges require higher-strength grades such as S355.
Q3. Is S235JR suitable for pressure piping?
Not for pressurized or high-temperature service. Low-pressure water, drainage and ventilation lines are within its capability when wall thickness is adequate.
Q4. What is the difference between S235JR and S275JR?
S275JR has a minimum yield strength of 275 MPa, providing higher load capacity for the same section size at a modest cost increase.
Q5. How is S235JR pipe protected from corrosion?
Hot-dip galvanizing is the standard protection for outdoor use, while painted or powder-coated finishes serve interior applications.
Q6. What welding methods are used for S235JR?
All conventional processes, including MMA, MIG, MAG, TIG and submerged arc welding, are suitable without preheat for typical wall thicknesses.
