Difference between S420G1+M and S420G2+M steel plate

S420G1+M is a thermomechanical rolled offshore structural steel certified under EN 10225 for fixed offshore structures, wind turbine foundations, and oil/gas platforms . The "+M" suffix indicates the thermomechanical controlled process (TMCP) , which refines grain structure through controlled rolling and accelerated cooling without additional heat treatment . It has a minimum yield strength of 420 MPa (for thickness ≤16mm) and tensile strength ranging from 500 to 660 MPa, with a minimum elongation of 19% . Maximum plate thickness is 100 mm . Impact toughness is tested at -40°C with a minimum energy requirement of 50 Joules .

S420G2+M is also a thermomechanical rolled offshore structural steel certified under EN 10225, sharing the same minimum yield strength of 420 MPa and tensile strength range of 500-660 MPa as G1 . However, S420G2+M offers stricter chemical composition controls, including a lower sulfur limit (≤0.007% vs. 0.010% for G1) and stricter phosphorus control (≤0.020%) . The higher "G" number (G2 vs. G1) signifies more stringent requirements for toughness and purity. Maximum plate thickness is also 100 mm .

Both S420G1+M and S420G2+M are thermomechanical rolled offshore structural steels under EN 10225 with identical mechanical properties (minimum yield 420 MPa, tensile 500-660 MPa) and impact requirements (-40°C, 50J) . Their primary difference lies in chemical purity: S420G1+M is suitable for general offshore applications, while S420G2+M features stricter limits on sulfur (≤0.007%) and phosphorus, offering enhanced low-temperature toughness and weldability for more demanding offshore structures . Both grades maintain good weldability and are available up to 100mm thickness.

Mechnical property for S420G1+M steel plate:
 

Mechnical property for S420G2+M steel plate:
 

Chemical composition for S420G1+M steel plate 

Chemical composition for S420G2+M steel plate