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LR Grade D steel plate, also called LR/D, LR/D, Lloyd's Register Grade D or simply Grade D ship steel plate, is an ordinary-strength hull structural steel with -20°C Charpy toughness under Lloyd's Register Rules for Ships (IACS UR W11 ordinary-strength family). All four ordinary grades A, B, D and E share 235 MPa minimum yield and 400-520 MPa tensile strength; the grade letter sets the toughness requirement. Gangsteel, a steel plate exporter, supplies LR Grade D general strength steel plate for ship hulls, decks, bulkheads, barges and general 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.
| Grade | C, max | Mn | Si | P, max | S, max | Al (acid sol.) | C + Mn/6, max |
|---|---|---|---|---|---|---|---|
| LR/D | 0.21 | ≥0.60 | 0.10-0.35 | 0.035 | 0.035 | ≥0.015 (t>25 mm) | 0.40 |
Per IACS UR W11 / LR Rules for Ships (ordinary-strength hull structural steel). Ni, Cr, Mo and Cu are to be determined and reported. Carbon equivalent: Ceq = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15 (%); crack sensitivity: Pcm = C + Si/30 + Mn/20 + Cu/20 + Ni/60 + Cr/20 + Mo/15 + V/10 + 5B (%). 依据 IACS UR W11 / LR Rules for Ships.
IACS UR W11 / LR Rules for Ships do not separately tabulate product (check) analysis limits for ordinary-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 referencing ASTM A6 chemical tolerances).
| Element | Heat analysis limit | Product analysis (heat ± A6) |
|---|---|---|
| C | 0.21 max | 0.25 max (heat + A6 over-max) |
| Mn | ≥0.60 | min-only; no A6 product band keyed to upper limit |
| Si | 0.10-0.35 | 0.05–0.40 |
| P | 0.035 max | 0.045 max |
| S | 0.035 max | 0.045 max |
| Al (acid sol.) | ≥0.015 (t>25 mm) | no A6 Table A tolerance; product value not tabulated |
| C + Mn/6 | 0.40 max | calculated from heat analysis |
| Ni, Cr, Mo, Cu | to be determined and reported | - |
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.
| Grade | Yield strength, min | Tensile strength | Elongation, min |
|---|---|---|---|
| LR/D | 235 MPa [34 ksi] | 400-520 MPa [58-75 ksi] | 22% |
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).
| Thickness | Test temperature | Longitudinal, avg min | Transverse, avg min |
|---|---|---|---|
| t≤50 mm | -20°C [-4°F] | 27 J | 20 J |
| 50<t≤70 mm | -20°C [-4°F] | 34 J | 24 J |
| 70<t≤100 mm | -20°C [-4°F] | 41 J | 27 J |
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.
Deoxidation: Killed (t≤25 mm); killed and fine-grain (t>25 mm). Delivery condition: Killed steel; fine-grain practice required above 25 mm. Typically normalized or TMCP for guaranteed -20°C toughness. Optional extras by agreement include ultrasonic testing, Z-direction (Z15/Z25/Z35) through-thickness testing and third-party LR survey.
Ordinary-strength LR grades are commonly supplied from about 6 mm to 100 mm thick (wider/thicker by agreement with LR). Width 1500-4000 mm and length 6000-18000 mm are typical mill ranges.
| Society / Standard | Equivalent grade |
|---|---|
| LR (Lloyd's Register) | LR/D |
| ABS | ABS D steel plate (AB/D) |
| CCS | CCS D steel plate |
| ASTM A131/A131M | ASTM A131 Grade D steel plate |
| DNV | NV D |
| GL | GL-D |
| BV | BV/D |
| NK / KR / RINA | K D / R D / RI/D |
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.
It is an ordinary-strength hull structural steel under Lloyd's Register Rules for Ships (IACS UR W11 family), with 235 MPa minimum yield and 400-520 MPa tensile strength.
Grade D is Charpy tested at -20°C and must be fine-grain treated above 25 mm.
Minimum 235 MPa (34 ksi), with tensile strength 400-520 MPa (58-75 ksi) and elongation about 22% min.
Yes. Charpy V-notch at -20°C [-4°F] for all thicknesses in the grade, with energy rising by thickness band.
Requirements are essentially harmonized under IACS UR W11. ABS and ASTM A131 Grade D are counterparts; plates can be dual-certified when ordered with the required society survey and marking.
Yes. Low carbon and controlled carbon equivalent give good weldability with standard shipyard procedures; preheat depends on thickness, Ceq and restraint.
Typical mill supply is about 6-100 mm thick, 1500-4000 mm wide and 6000-18000 mm long; thicker or wider plates by agreement with LR.
Normalized or TMCP is typical above 25 mm to secure -20°C toughness with fine-grain practice.
LR Grade A steel plate | LR Grade B 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 | LR FH40 steel plate
LR Grade D corresponds to the same grade under the other IACS member classification societies and ASTM A131: CCS Grade D steel plate, ABS Grade D steel plate, ASTM A131 Grade D steel plate, GL Grade D steel plate, DNV Grade D steel plate, BV Grade D steel plate, NK Grade D steel plate, KR Grade D steel plate, RINA Grade D steel plate.
LR DH69 extra high strength steel plate: 690 MPa min yield, 770-940 MPa tensile, Charpy 69J L/46J T at -20C, TM
LR FH36 higher-strength ship steel plate: 355 MPa yield, 490-620 MPa tensile, Charpy at -60C, chemistry and equ
LR DH36 higher-strength ship steel plate: 355 MPa yield, 490-620 MPa tensile, Charpy at -20C, chemistry and equ
LR AH36 higher-strength ship steel plate: 355 MPa yield, 490-620 MPa tensile, Charpy at 0C, chemistry and equiv
