The main difference between E250 and E350 grade steel plates is their yield strength. E250 has a minimum yield strength of 250 MPa while E350 has a minimum yield strength of 350 MPa. This means that E350 grade steel plates are stronger and more durable than E250 grade steel plates, making them suitable for applications that require high strength & load bearing capacity. However, E250 grade steel plates are more ductile & easier to weld, making them ideal for applications where formability is essential.