What is the difference between S235 and S355?
The main difference between S235 and S355 structural steel lies in their yield strength. S355 has a higher minimum yield strength (355 MPa) than S235 (235 MPa), making it a stronger and more rigid material. While their chemical compositions are nearly identical, the difference in strength is achieved through different rolling and cooling techniques during manufacturing.
At S235, the column body reaches 5% plastic strain, while at S355, the welds on the head plate reach the maximum allowable stress, leading to a less ductile failure mechanism. To obtain the same moment resistance at S355 as at S235, the joint can be optimized for material savings.
S235 vs S355
S235:
Yield Strength: 235 MPa
Tensile Strength: 360-510 MPa
Commonly used for: Low-stressed parts in steel and mechanical engineering, where high strength is not a primary requirement, according to Murray Steel Products and thyssenkrupp Materials Processing.
S355:
Yield Strength: 355 MPa
Tensile Strength: 470-630 MPa
Commonly used for: Applications requiring higher strength and load-bearing capacity, such as in construction, shipbuilding, and machinery.
What is equivalent to S235 steel grade?
S235JR equivalent grade is GB Q235B, IS2062 grade B.
What is the ASTM grade equivalent of S355?
ASTM A572-50
The chemical composition and mechanical properties of S355 are governed by EN Standards However, some projects may require materials that meet ASTM standards. ASTM has identified A572-50 as an acceptable substitution for S355.
What is the Chinese equivalent of S235JR steel?
Q235B
The closest Chinese equivalent to S235JR (EN 10025-2) is Q235B (GB/T 700-2006). While these grades share similar mechanical properties, subtle differences in composition and performance must be carefully evaluated for compliance and safety.
