S275JR FN vs. S355J2N

Attribute	S275JR FN	S355J2N
Material Type	Carbon Steel	Carbon Steel
Yield Strength	275 MPa	355 MPa
Tensile Strength	410-560 MPa	470-630 MPa
Impact Energy	27 J at -20°C	27 J at -20°C

Introduction

When it comes to structural steel, two common grades that are often compared are S275JR FN and S355J2N. Both of these grades are widely used in construction and engineering projects due to their excellent mechanical properties. In this article, we will compare the attributes of these two grades to help you understand their differences and similarities.

Chemical Composition

One of the key differences between S275JR FN and S355J2N lies in their chemical composition. S275JR FN has a maximum carbon content of 0.24%, while S355J2N has a maximum carbon content of 0.22%. Additionally, S355J2N contains higher amounts of manganese, silicon, and phosphorus compared to S275JR FN. These differences in chemical composition can affect the mechanical properties of the steel, such as its strength and ductility.

Mechanical Properties

When it comes to mechanical properties, S355J2N has higher tensile strength and yield strength compared to S275JR FN. The minimum yield strength of S275JR FN is 275 MPa, while the minimum yield strength of S355J2N is 355 MPa. Similarly, the minimum tensile strength of S275JR FN is 410-560 MPa, while the minimum tensile strength of S355J2N is 470-630 MPa. This means that S355J2N is a stronger and more durable grade of steel compared to S275JR FN.

Impact Resistance

Another important attribute to consider when comparing S275JR FN and S355J2N is their impact resistance. S355J2N has a higher impact resistance compared to S275JR FN, making it more suitable for applications where the steel is subjected to dynamic loading or impact forces. This higher impact resistance of S355J2N is attributed to its higher strength and toughness properties, which allow it to absorb more energy before fracturing.

Weldability

Both S275JR FN and S355J2N are considered to be weldable grades of steel. However, S275JR FN is generally easier to weld compared to S355J2N due to its lower carbon content and lower alloying elements. Welding S275JR FN is less likely to result in weld defects such as cracking or distortion, making it a preferred choice for applications that require extensive welding. On the other hand, S355J2N may require preheating and post-weld heat treatment to prevent weld defects and ensure proper weld integrity.

Applications

Due to their different mechanical properties and attributes, S275JR FN and S355J2N are used in different applications. S275JR FN is commonly used in general construction, machinery, and equipment manufacturing where high strength is not a primary requirement. On the other hand, S355J2N is preferred for structural applications such as building frames, bridges, and offshore structures where higher strength and durability are essential. The choice between these two grades depends on the specific requirements of the project and the desired performance characteristics of the steel.

Conclusion

In conclusion, S275JR FN and S355J2N are two popular grades of structural steel that offer different attributes and mechanical properties. While S275JR FN is known for its ease of welding and versatility, S355J2N stands out for its higher strength, impact resistance, and durability. When choosing between these two grades, it is important to consider the specific requirements of the project and select the grade that best meets the desired performance criteria. Both S275JR FN and S355J2N have their own strengths and weaknesses, and the right choice will ultimately depend on the application and performance requirements.