The basic alloying elements in super-bainitic steels are C-Mn-Si and the structure of ultra-fine bainite

martensite and residual austenite is obtained by low temperature phase transformation at 300 〜500 ℃. In order to decrease critical cooling velocity

promote bainite transformation

partial super-bainitic steels are added Cr

Ni

Mo etc. alloy elements with decreasing C

Mn content to improve weldability of steel products. The super-bainitic steel has ultra-high strength and better plasticity

and its yield and tensile strength are respectively 〜1 200 MPa and 1 600 ~ 1 700 MPa with elongation ~ 15%. The yield strength of new generation super-bainitic steel is more than 1 300 MPa

and its tensile strength is more than 1 700 MPa.