LR Grade EH40 is a high-tensile-strength steel plate for shipbuilding and marine applications, certified by Lloyd's Register of Shipping (LR). In the grade designation, E indicates a high level of toughness verified by impact testing at -40°C, H signifies high strength, and 40 corresponds to a minimum yield strength of 390 MPa. The steel is known for its durability, weldability, and corrosion resistance, and it is suitable for hulls of ships, offshore platforms, and other marine structures.
Specification and Delivery Conditions
LR Grade EH40 shipbuilding steel plate is supplied in thicknesses of 3-250 mm, widths of 1200-4200 mm, and lengths of 3000-18000 mm. The standard delivery condition is TMCP (thermomechanical control processing) or normalized. Optional supplementary requirements include ultrasonic examination (UT), as-rolled condition (AR, for reference only), quenching and tempering (Q+T), Z-direction testing (Z15, Z25, Z35), Charpy V-notch impact testing, third-party inspection (for example SGS), and coated or shot-blasted and painted surfaces.
Chemical Composition
The heat-analysis composition limits for LR/EH40 are approximately: carbon 0.18% max, manganese 0.9-1.6%, phosphorus 0.035% max, sulfur 0.035% max, acid-soluble aluminum 0.015% min, niobium 0.02-0.05%, vanadium 0.03-0.10%, titanium 0.02% max, copper 0.35% max, chromium 0.20% max, nickel 0.40% max, and molybdenum 0.08% max. These limits control weldability and toughness; the exact values should always be confirmed against the current LR rules for materials and welding, because the silicon limit is commonly 0.50% max rather than the figure shown in some supplier tables.
Mechanical Properties
For plate thickness up to 100 mm, LR/EH40 requires a minimum yield strength of 390 MPa and a tensile strength of 510-650 MPa, with a minimum elongation of 20%. Charpy V-notch impact testing is carried out at -40°C. For thickness up to 50 mm the required impact energy is 26 J (single value) / 39 J (average); for 50-70 mm it is 31 J / 46 J; and for 70-100 mm it is 37 J / 55 J. Because the impact requirement tightens with thickness, thicker plates are usually supplied in the TMCP condition to guarantee the required low-temperature toughness.
Equivalent Grades in Other Classification Rules
Equivalent high-strength E40 grades are available under other classification society rules: NV E40 (DNV), GL-E40 (Germanischer Lloyd), AB/EH40 (ABS), BV/EH40 (Bureau Veritas), CCS/E40 (China Classification Society), K E40 (Korean Register), R E40 (RINA), and RI/E40 (Registro Italiano Navale). The corresponding ASTM designations are covered by ASTM A131 Grade EH40. When a project is classed by a different society, the equivalent grade should be selected from that society's rules and verified by the class surveyor.
Typical Applications
LR Grade EH40 marine steel plates are primarily used in hull construction of bulk carriers, oil tankers, container ships, and general cargo vessels. The steel's high tensile strength and impact resistance ensure structural integrity under heavy loads, strong waves, and dynamic marine conditions. It is also applied in decks, superstructures, and bulkheads, where stability and load-bearing capacity must be maintained while resisting deformation, and in offshore platforms, drilling rigs, and floating production storage and offloading (FPSO) units, where low-temperature impact toughness and resistance to harsh sea conditions are critical. Additional uses include keels, ribs, frames, and brackets in critical vessel parts.
Frequently Asked Questions
Q1: What does EH40 mean in shipbuilding steel?
A1: E denotes impact testing at -40°C, H denotes high strength, and 40 denotes a minimum yield strength of 390 MPa.
Q2: What is the difference between LR EH40 and ASTM A131 EH40?
A2: They are essentially the same strength and toughness class; LR grades are specified in Lloyd's Register rules, while ASTM A131 Grade EH40 is the equivalent designation used in ASTM specifications.
Q3: Which delivery condition is preferred for EH40?
A3: TMCP or normalized. TMCP is preferred for thicker plates because it provides fine grain structure and reliable toughness at -40°C.
Q4: Can EH40 be welded without preheat?
A4: EH40 has good weldability, but preheat may be required depending on plate thickness, heat input, and ambient temperature. Follow the approved welding procedure specification and the class rules.
Q5: What supplementary tests are commonly specified for EH40?
A5: Ultrasonic examination, Z-direction testing (Z15/Z25/Z35), additional Charpy testing, and third-party inspection such as SGS are common options.
