What is S235JR steel grade?

Gangsteel, a leading manufacturer and exporter of structural steel plates, supplies premium EN 10025-2 S235JR steel plates for construction, bridges, and heavy machinery applications. S235JR is a non-alloy structural steel grade from EN 10025-2, offering moderate strength, good weldability, and impact resistance at +20°C. This article provides a comprehensive overview of what S235JR steel grade is, including its designation breakdown, chemical composition, mechanical properties, applications, and benefits, offering valuable insights for engineers, fabricators, and procurement specialists.

s235jr steel grade Introduction to S235JR Steel Grade

S235JR steel grade is part of the EN 10025-2 standard for hot-rolled non-alloy structural steels, specifying technical delivery conditions for products like plates, bars, and sections. It ensures consistent quality and performance for welded, bolted, and riveted structures. S235JR is one of the most common entry-level grades, known for its cost-effectiveness and versatility in general construction.

The grade designation "S235JR" is a coded system:

• S: Stands for "Structural steel," indicating the steel is intended for structural purposes, such as load-bearing components in buildings or bridges.
• 235: Refers to the minimum yield strength in MPa for plates up to 16 mm thick. For thicker plates, the yield strength decreases slightly (e.g., 225 MPa for 16–40 mm).
• JR: Indicates the impact toughness, requiring a minimum Charpy V-notch impact energy of 27 J at +20°C (room temperature). This ensures the steel resists brittle fracture in standard conditions.

This designation allows quick assessment of the steel's capabilities. For example, compared to EN 10025-2 S355JR steel (yield 355 MPa), S235JR is more affordable for low-load applications. Gangsteel produces S235JR plates in compliance with EN 10025-2, ensuring traceability and quality certification for global projects. For related grades, explore EN 10025-2 S275JR or EN 10025-2 S275J0 steel.

s235jr steel grade Chemical Composition

The chemical composition of s235jr steel grade is optimized for strength, weldability, and toughness, with low carbon content to prevent brittleness. The table below shows the chemical composition limits (% by weight) as per EN 10025-2 for S235JR (maximum values unless specified):

Key Notes on Chemical Composition:

• Carbon (C): Capped at 0.17% to ensure good weldability and ductility, reducing the risk of hardness in the heat-affected zone during welding.
• Manganese (Mn): Up to 1.40% enhances strength and toughness, crucial for load-bearing applications.
• Phosphorus (P) and Sulfur (S): Both limited to 0.035% to improve impact resistance and reduce brittleness, especially important for the JR toughness rating.
• Silicon (Si) and Copper (Cu): Provide moderate corrosion resistance, allowing the steel to form a protective patina in atmospheric exposure.
• Nitrogen (N): Controlled at 0.012% max to promote fine grain structure, improving mechanical performance.

This composition makes S235JR a low-alloy steel with excellent formability. Gangsteel’s S235JR plates are produced with precise chemical control, often with lower impurities for enhanced performance. For higher strength, consider EN 10025-2 S355J2 steel.

s235jr steel grade Mechanical Properties

S235JR steel grade exhibits robust mechanical properties, suitable for structural engineering. The table below summarizes its key properties for plates up to 16 mm thick, as per EN 10025-2 (values decrease for thicker plates):

Key Notes on Mechanical Properties:

• Yield Strength: 235 MPa min allows for low to moderate-load applications, with values for thicker plates (e.g., 225 MPa for 16–40 mm).
• Tensile Strength: 360–510 MPa provides good resistance to breaking under tension.
• Elongation: 26% ensures excellent ductility for forming and welding.
• Impact Toughness: 27 J at +20°C guarantees resistance to brittle failure in standard conditions.
• Hardness: 120–170 HB indicates low hardness, easy to machine while durable.

These properties make S235JR reliable for welded structures. For higher toughness, consider EN 10025-2 S235J2 steel from Gangsteel.

s235jr steel grade Weldability and Fabrication

S235JR steel grade has excellent weldability due to its low carbon equivalent (CEV max 0.35 for thicknesses up to 30 mm), allowing for welding without preheating in many cases. It is compatible with common welding methods like SMAW (using low-hydrogen electrodes such as E7018), GTAW, and SAW. For thicker plates (>40 mm), preheating to 100–150°C is recommended to avoid cracking in the heat-affected zone (HAZ).

Fabrication properties include good machinability and formability, with the as-rolled or normalized condition reducing distortion during heat treatment. Post-weld heat treatment (PWHT) at 600–650°C is advised for stress relief in ASME-coded applications. Gangsteel’s S235JR plates are supplied with optimized bonding, ensuring reliable welding, similar to EN 10025-2 S275J2 steel but with lower strength.

s235jr steel grade Physical Properties

Physical properties of S235JR steel grade contribute to its usability in various environments:

• Density: 7.85 g/cm³, typical for carbon steels, ensuring predictable weight calculations in design.
• Thermal Conductivity: 50 W/m·K at room temperature, suitable for heat transfer in structural components.
• Coefficient of Thermal Expansion: 11–13 × 10^-6 /K, allowing for stable performance in temperature-varying conditions.
• Modulus of Elasticity: 210 GPa, providing stiffness for load-bearing structures.
• Poisson's Ratio: 0.3, indicating typical elastic behavior under stress.

These properties make S235JR versatile for both static and dynamic loads, with good resistance to thermal expansion in construction. For offshore use, consider EN 10025-2 S355K2 steel.

s235jr steel grade Corrosion Resistance and Durability

S235JR steel grade has moderate corrosion resistance in non-aggressive environments, enhanced by silicon and copper additions that form a protective patina in atmospheric exposure. For corrosive conditions, it can be painted or galvanized. Its durability is evident in its fatigue resistance and toughness, with a fatigue limit around 150–200 MPa for cycles up to 10^7. In low-temperature applications, its +20°C impact toughness prevents brittle failure, extending service life in mild cold climates.

Gangsteel offers clad or coated S235JR plates for enhanced durability in harsh environments, such as EN 10025-2 S235J2 steel for lower strength needs.

Comparison with Other EN 10025-2 Grades

S235JR steel grade is an entry-level grade in the S235 family, offering lower strength than S275 or S355 but excellent cost-effectiveness. The table below compares S235JR with other EN 10025-2 grades:

S235JR's +20°C toughness makes it ideal for standard conditions, while S235J2 is better for cold applications. For higher strength, consider EN 10025-2 S450J0 steel.

Applications of S235JR Steel Grade

S235JR steel grade is versatile and widely used in applications requiring moderate strength and good toughness:

1. Construction: For buildings, bridges, and stadiums, where its strength and ductility are essential.
2. Offshore Engineering: In platforms and wind turbines, leveraging its corrosion resistance and impact toughness.
3. Heavy Machinery: For cranes, excavators, and mining equipment, where durability under dynamic loads is critical.
4. Shipbuilding: In hulls and superstructures, benefiting from its weldability and strength.
5. Energy Sector: For pipelines and storage tanks, offering reliability in varying temperatures.

Gangsteel’s S235JR plates are available in thicknesses from 6–300 mm, with options for cut-to-size and cladding for specialized applications like EN 10025-2 S355K2 steel.

Why Choose Gangsteel for S235JR Steel Grade?

Gangsteel is a trusted supplier of S235JR and equivalent plates, offering:

• Certified Quality: Plates undergo ultrasonic testing, Charpy impact tests at +20°C, and chemical analysis to meet EN 10025-2 standards.
• Customization: Available in thicknesses from 6–300 mm, with options for normalization, cut-to-size, and beveling.
• Global Supply: Competitive pricing and reliable delivery from China to worldwide markets.
• Technical Support: Guidance on selecting S235JR versus other grades like EN 10025-2 S355J0 or EN 10025-2 S355K2 steel.

Gangsteel Solution

S235JR is a non-alloy structural steel grade with 235 MPa yield strength, 360–510 MPa tensile, and 27 J impact at +20°C, ideal for general construction. Gangsteel’s high-quality S235JR plates ensure compliance and reliability for your projects. For equivalent standards, explore our BS EN 10025-2 material grade guide.

Gangsteel

Gangsteel explains S235JR steel grade, detailing its designation, chemical composition, mechanical properties, and applications. Keywords: S235JR steel grade, S235JR properties, S235JR chemical composition, S235JR applications