Difference between ABS FH47 and ABS FH51 steel plate

ABS FH47 is an extra-high-strength marine steel plate certified by the American Bureau of Shipping (ABS) for demanding shipbuilding and offshore applications. The "F" grade signifies it is impact tested at the extremely low temperature of -60°C, ensuring exceptional toughness for vessels operating in polar and Arctic environments . It has a minimum yield strength of 460 MPa (67 ksi) and a tensile strength ranging from 570 to 720 MPa (83-104 ksi), with a minimum elongation of 17% . This grade is specifically designed for critical structural components in ultra-large container vessels, including upper deck areas, hatch coamings, and longitudinal structures where high strength and fracture resistance are paramount .

ABS FH51 is an ultra-high-strength marine steel plate also certified by ABS, manufactured through advanced quenching and tempering processes. Like FH47, it is impact tested at -60°C, with minimum impact energy requirements typically around 50J (longitudinal) for standard thicknesses . The "51" denotes a minimum yield strength of 500 MPa (73 ksi) and a tensile strength ranging from 610 to 770 MPa (88-112 ksi), with a minimum elongation of 16% . This grade is designed for the most demanding load-bearing applications, including self-elevating drilling platforms, jack-up rig legs, and critical marine structures requiring maximum strength-to-weight ratio .

Both ABS FH47 and ABS FH51 are ABS-certified ultra-high-strength marine steels with exceptional low-temperature toughness tested at -60°C, ensuring reliable performance in the most extreme Arctic and harsh marine environments . Their primary difference lies in strength level: FH47 offers a minimum yield strength of 460 MPa with tensile strength of 570-720 MPa, making it suitable for high-strength hull structures and heavy-duty offshore platforms, while FH51 provides a higher minimum yield strength of 500 MPa with tensile strength reaching 610-770 MPa, designed for more demanding applications requiring superior strength-to-weight ratio. Both grades feature strictly controlled chemical composition (carbon ≤0.16%) and maintain good weldability for critical marine service . The selection between them depends on whether the project requires the balanced strength of FH47 or the enhanced performance of FH51 for more extreme structural demands.

Chemical Composition

Mechanical Property