LR FH40 Steel Plate | FH40 Shipbuilding Steel Plate

LR FH40 steel plate, also written as LR/FH40, LR Grade FH40, Lloyd's Register FH40 or simply FH40 ship steel plate, is the higher-strength hull structural steel of Lloyd's Register Rules for Ships (IACS UR W11 higher-strength family) with 390 MPa minimum yield, 510-650 MPa tensile strength and Charpy V-notch toughness at -60°C [-76°F]. In the grade name, "F" is the toughness class, "H" means higher strength and "40" refers to the strength level (historically about 40 kgf/mm²). Gangsteel, a steel plate exporter, supplies LR FH40 plates cut to size for shipbuilding, offshore platforms and marine structures.

Data source: Per IACS UR W11 (ordinary/higher-strength hull structural steel) as adopted in Lloyd's Register Rules for Ships. Verify the current LR edition before ordering.

LR/FH40 Chemical Composition (Heat Analysis)

Per IACS UR W11 / LR Rules for Ships (higher-strength hull structural steel). Nb, V and Al grain-refining elements may be used singly or in combination; when used in combination the individual minima do not apply. Where acid-soluble Al is not less than 0.015%, the Si minimum does not apply. Carbon equivalent: Ceq = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15 (%). 依据 IACS UR W11 / LR Rules for Ships.

Product Analysis (Check Analysis)

IACS UR W11 / LR Rules for Ships do not separately tabulate product (check) analysis limits for higher-strength grades. When product analysis is required, the finished plate shall meet the heat limits subject to ASTM A6/A6M Table A permitted variations (same practice as ABS MW Pt2).

依据 IACS UR W11 / LR Rules for Ships. Product analysis applies only when specified; for a range, results may not vary both above and below it.

LR/FH40 Mechanical Properties

Per IACS UR W11 / LR Rules for Ships. Yield and tensile values apply for the full thickness range covered by the grade (typically up to 100 mm for these ship plates).

Charpy V-Notch Impact Requirements (-60°C [-76°F])

Per IACS UR W11 / LR Rules for Ships. Average of three full-size Charpy V-notch specimens; not more than one value below the average and none below 70% of it. Longitudinal values shown; transverse values apply when required by the rules or purchase order.

Delivery Condition and Deoxidation

Deoxidation: Killed, fine-grain practice. Delivery condition: FH grades are supplied normalized or TMCP for -60°C toughness, with tighter P/S and N chemistry. Optional extras by agreement include ultrasonic testing, Z-direction (Z15/Z25/Z35) through-thickness testing and third-party LR survey.

Thickness Coverage

Higher-strength LR AH/DH/EH/FH 32/36/40 plates are commonly supplied from about 6 mm to 100 mm thick (up to 150 mm by agreement). Width 1500-4000 mm and length 6000-18000 mm are typical.

Equivalent Steel Grades of LR/FH40

IACS member societies harmonize ordinary and higher-strength hull grades under UR W11; dual certification (for example LR + ABS, or LR + ASTM A131) is common when ordered that way.

FAQ about LR FH40 Steel Plate

What is LR FH40 steel plate?

It is a higher-strength hull structural steel under Lloyd's Register Rules for Ships (IACS UR W11), with 390 MPa minimum yield, 510-650 MPa tensile strength and Charpy toughness at -60°C [-76°F].

What does FH40 stand for?

The letter F is the toughness class (Charpy at -60°C), H means higher strength, and 40 is the strength level (historically about 40 kgf/mm², now 390 MPa min yield).

What is the yield strength of LR FH40?

Minimum 390 MPa (57 ksi), tensile 510-650 MPa (74-94 ksi), elongation about 20% min.

What is the impact test temperature for LR FH40?

Charpy V-notch at -60°C [-76°F]. Longitudinal average minima are 39 J up to 50 mm, 46 J for 50-70 mm and 55 J for 70-100 mm.

What is the difference between LR FH40 and LR EH40?

FH40 is tested at -60°C; EH40 at -40°C. FH has tighter P/S/N chemistry.

Is LR FH40 the same as ABS FH40 or ASTM A131 FH40?

Requirements are essentially harmonized under IACS UR W11. ABS FH40 and ASTM A131 FH40 are counterparts; dual certification is common when ordered with the required surveys.

Is LR FH40 weldable?

Yes. Controlled carbon and Ceq give good weldability; preheat may be required for thick sections depending on Ceq and restraint.

What heat treatment is required for LR FH40?

FH40 is supplied normalized or TMCP for -60°C toughness with tighter chemistry.

What thickness is available for LR FH40?

Typical supply is about 6-100 mm thick (up to 150 mm by agreement), 1500-4000 mm wide and 6000-18000 mm long.

Other LR Steel Plate Grades

LR Grade A steel plate | LR Grade B steel plate | LR Grade D steel plate | LR Grade E steel plate | LR AH32 steel plate | LR AH36 steel plate | LR AH40 steel plate | LR DH32 steel plate | LR DH36 steel plate | LR DH40 steel plate | LR EH32 steel plate | LR EH36 steel plate | LR EH40 steel plate | LR FH32 steel plate | LR FH36 steel plate

Equivalent Class Society Grades

LR FH40 corresponds to the same grade under the other IACS member classification societies and ASTM A131: CCS FH40 steel plate, ABS FH40 steel plate, ASTM A131 FH40 steel plate, GL FH40 steel plate, DNV F40 steel plate, BV FH40 steel plate, NK F40 steel plate, KR F40 steel plate, RINA FH40 steel plate.