What is S235 grade steel?
S235 is a common European non-alloy structural steel defined in standard EN 10025-2.
- S = Structural steel
- 235 = Minimum yield strength of 235 MPa for thickness ≤16 mm
S235 is not a single material. it is split into three main sub-grades (JR, J0, J2) that differ in impact toughness (Charpy V-notch test).
| Grade | Charpy V-Notch Impact Test Temperature | Best Used For |
| S235JR | Tested at +20°C (Room temp) | General indoor applications, warm climates, or non-critical structures. |
| S235J0 | Tested at 0°C | Moderate climates with occasional freezing temperatures. |
| S235J2 | Tested at -20°C | Outdoor structures in cold climates, bridges, and critical infrastructure. |
| The "R" in JR means "Room temperature", "0" means 0°C, and "J" indicates Impact Toughness of 27 Joules. | ||
Mechanical properties (S235JR, ≤16 mm)
- Minimum yield strength: 235 MPa
- Tensile strength: 360–510 MPa
- Elongation: ~24%
Typical applications include:
- Steel building structures
- Structural frames
- Columns and beams
- Steel platforms
- Supports and brackets
- General fabrication
- Machinery structures
- Structural hollow sections
- Square and rectangular hollow sections
- Welded structural components
What is S275 grade steel?
S275 is a non-alloy structural steel grade defined by the European standard EN 10025-2. It sits directly above S235 in the strength hierarchy and is the second-most commonly used structural steel in Europe.
- S = Structural steel.
- 275 = The minimum yield strength in megapascals (MPa) for the smallest thickness range (≤ 16 mm). This means it takes at least 275 N/mm² of stress to permanently deform it-about 17% stronger than S235's 235 MPa.
In short: It is the "medium-strength" cousin of S235-offering higher load-bearing capacity while still maintaining excellent weldability and formability.
The Sub-Grades (JR, J0, J2) – Exactly the same as S235
Just like S235, S275 is split into three toughness grades based on impact testing temperature:
| Grade | Impact Test Temp | Best Used For |
| S275JR | +20°C (Room temp) | Indoor, warm climates, or non-critical structural parts. |
| S275J0 | 0°C | General outdoor use in temperate regions. |
| S275J2 | -20°C | Bridges, cranes, and cold-environment infrastructure. |
Typical applications include:
Building Structures
Used for beams, columns, frames, supports and other load-bearing components.
Structural Hollow Sections
S275 can be used for square, rectangular and circular structural hollow sections.
Bridges and Infrastructure
Suitable grades may be used in structural components where the project specification permits S275.
Steel Platforms and Supports
Common in industrial structures, access platforms, equipment supports and frames.
Machinery and General Fabrication
Its combination of strength, ductility and weldability makes it useful for fabricated structures and machinery components.
What is the difference between S275 and S235 steel?
S235 and S275 are both European mild structural steels;
S275 has higher yield strength, while S235 offers better ductility and easier welding / cold forming.
1.Mechanical Properties
| Property | S235 | S275 | The Practical Impact |
| Yield Strength (≤16mm) | 235 MPa | 275 MPa | S275 is 17% stronger. It takes more force to permanently bend or deform it. |
| Tensile Strength | 360–510 MPa | 410–560 MPa | S275 has a higher ultimate breaking point. |
| Elongation | ~24% | ~21% | S235 is more flexible-it can bend further before cracking. S275 is slightly stiffer and more brittle. |
2.Chemical Composition: S235 vs S275
| Chemical Element | S235JR | S275JR |
| C (Carbon) | ≤ 0.17% | ≤ 0.21% |
| Si (Silicon) | ≤ 0.035% | ≤ 0.035% |
| Mn (Manganese) | ≤ 1.40% | ≤ 1.50% |
| P (Phosphorus) | ≤ 0.035% | ≤ 0.035% |
| S (Sulfur) | ≤ 0.035% | ≤ 0.035% |
| Cu (Copper) | ≤ 0.55% | ≤ 0.55% |
| N (Nitrogen) | ≤0.012% | ≤ 0.012% |
| The most noticeable difference is that S275 can have slightly higher carbon and manganese limits than S235, depending on the specific subgrade. | ||
Why Does Carbon Matter?
Carbon increases steel strength and hardness, but excessive carbon can reduce:
Weldability
Ductility
Toughness
Why Does Manganese Matter?
Manganese contributes to:
Higher strength
Improved hardenability
Better resistance to some forms of embrittlement
It also combines with sulfur, helping improve the steel's overall quality.
3. Toughness suffixes (JR / J0 / J2)
The suffix defines impact resistance and works for both grades:
- JR: 27 J Charpy impact at +20°C
- J0: 27 J at 0°C
- J2: 27 J at −20°C
Example: S235JR and S275JR have the same impact requirement; only strength differs.
4.Which one should you choose?
| Scenario | Recommended Grade | Reason |
| Light frames, brackets, floor plates, consumer products | S235 | Cheaper and easier to bend. Strength isn't critical. |
| Heavy machinery, bridge girders, crane booms, high-rise columns | S275 | You need the extra 17% yield strength to save weight and material. |
| Your design is limited by bending deflection | Either (S235) | Since both have the same stiffness, S275 won't fix the bend. Save money with S235 and increase the beam depth instead. |
| You are cold-bending tight radii | S235 | Its higher ductility (26% elongation) makes it less likely to crack during sharp bending. |
| You are welding outside in winter (-5°C) | S235JR or S275J2 | For S275 in the cold, you might need special electrodes; S235 is more forgiving. |
Youfa Steel Pipe Group supplied steel structure products for the construction project of Kuwait International Airport in 2025, with a total supply of 1500 tons.
The supplied products are SHS (Square Hollow Section) and RHS (Rectangular Hollow Section) structural steel tubes.
SHS and RHS hollow sections feature uniform wall thickness, excellent torsional rigidity and neat geometric profiles. These characteristics make them highly suitable for airport large-span building frameworks, roof trusses, support columns and load-bearing bracing members. Their smooth outer surface simplifies surface treatment, painting and anti-corrosion protection, which is critical for long-term service in Kuwait's hot, arid high-temperature climate.
As core components of airport steel structures, SHS and RHS deliver reliable static and dynamic load performance, meeting strict European structural design requirements for public transportation infrastructure. Hollow tubular steel also optimizes weight-to-strength ratio, reducing overall dead load of the building while maintaining structural stability for this large-scale airport terminal.
Contact us for more information regarding EN10219 steel structural tubing specifications and product options, or request a quote for further pricing details today.
Youfa steel pipe is your trusted source for premium EN10219 carbon steel tubing products.
