Overview
LR AH46 is an extra-high-strength marine steel plate certified by Lloyd's Register for shipbuilding and offshore applications, typically supplied in normalized, TMCP, or quenched and tempered conditions. LR AH55 is an ultra-high-strength marine steel plate also certified by LR, requiring advanced processing and typically supplied in TM or QT conditions.
Mechanical Properties
LR AH46 has a minimum yield strength of 460 MPa, tensile strength of 570 to 720 MPa, and minimum elongation of 19 percent, with impact energy of 31 J transverse and 46 J longitudinal at 0 degrees C. LR AH55 has a minimum yield strength of 550 MPa, tensile strength of 670 to 830 MPa, and minimum elongation of 18 percent, with impact energy of 37 J transverse and 55 J longitudinal at 0 degrees C. The maximum thickness for TM or QT supply is 150 mm.
Chemical Composition
Both grades limit carbon to 0.21 percent, silicon to 0.55 percent, manganese to 1.70 percent, phosphorus and sulfur to 0.035 percent, with microalloying niobium, vanadium, and titanium.
Applications
AH46 is suitable for high-strength hull construction and offshore structures. AH55 is designed for more demanding load-bearing applications requiring a superior strength-to-weight ratio.
Selection Guidance
Choose AH46 where the balanced strength of 460 MPa serves general high-strength marine construction. Choose AH55 where maximum strength per unit weight is required, accepting the more complex alloying and advanced processing.
Frequently Asked Questions
Q: What is the yield strength of LR AH46?
A: 460 MPa minimum, with tensile strength of 570 to 720 MPa and 19 percent elongation.
Q: What is the yield strength of LR AH55?
A: 550 MPa minimum, with tensile strength of 670 to 830 MPa and 18 percent elongation.
Q: What impact temperature applies?
A: 0 degrees C for both grades.
Q: What delivery conditions are available?
A: Normalized, TMCP, or quenched and tempered, with TM or QT for AH55.
Q: What is the maximum thickness?
A: 150 mm for TM or QT supply.
Q: Where is AH55 used?
A: In demanding load-bearing applications requiring superior strength-to-weight ratio.
For LR AH46 and AH55 certified marine steel plate quotations, contact our sales team.
