KR E43 steel plate, also written as RE43, R E43, KR Grade E43 or market names such as EH42 / EQ43, is the extra-high-strength hull structural steel of Korean Register (KR) Rules for the Classification of Steel Ships (IACS UR W16 extra-high-strength family) with 420 MPa minimum yield, 530-680 MPa tensile strength and Charpy V-notch toughness at -40°C [-40°F]. In the grade name, "E" is the toughness class, and "43" is the site strength label for about 420 MPa yield (ABS EQ43 family). Gangsteel, a steel plate exporter, supplies KR E43 / RE43 plates cut to size for shipbuilding, offshore platforms and marine structures.

Data source: Per IACS UR W16 (extra-high-strength hull structural steel) as adopted in KR Class hull structural steel rules, cross-checked with LR EH42 / ABS EQ43 sibling pages on gangsteel.net. Official mill/certificate grade is typically RE43 (R E43); KR E43 names the same class on this site. Verify the current KR Class edition before ordering.

KR E43 / RE43 Chemical Composition (Heat Analysis)

 

ElementCMnSiPSAl (acid sol.)
KR E43, %0.20 max1.70 max0.10-0.550.030 max0.030 max0.015 min
ElementNNbVTiBNotes
KR E43, %0.020 max0.02-0.050.04-0.100.02 max0.005 maxNi/Cu/Cr/Mo per delivery condition (N/TM/QT) in UR W16

Per IACS UR W16 / KR Class extra-high-strength rules. Exact maxima for Ni, Cu, Cr and Mo depend on delivery condition (N/NR, TM or QT). Carbon equivalent / CET / Pcm limits apply by thickness and condition; confirm on the mill certificate and current rule edition.

Product Analysis (Check Analysis)

 

When product analysis is required, apply ASTM A6/A6M Table A permitted variations to the heat limits unless the element is min-only or not listed in Table A.

ElementHeat analysis limitProduct analysis (heat ± A6)
C0.20 max0.24 max
Mn1.70 maxsee A6 Table A vs heat upper limit
Si0.10-0.550.05–0.61 (approx. A6)
P0.030 max0.040 max
S0.030 max0.040 max
Al (acid sol.)0.015 minno A6 Table A tolerance; product value not tabulated
N0.020 max0.025 max (typical A6 +0.005)
Nb0.02-0.050.010–0.060
V0.04-0.100.030–0.110
Ti0.02 max0.03 max
B0.005 maxproduct analysis often not applicable

Product analysis applies only when specified; for a range, results may not vary both above and below it.

KR E43 / RE43 Mechanical Properties

 

GradeYield strength, minTensile strengthElongation, min
KR E43 / RE43420 MPa [61 ksi]530-680 MPa [77-99 ksi]18%

Per IACS UR W16 / KR Class rules (common t≤50 mm values). Yield may step down for thicker plates per UR W16; confirm thickness-dependent values on the order.

Charpy V-Notch Impact Requirements (-40°C [-40°F])

 

ThicknessTest temperatureLongitudinal, avg minTransverse, avg min
t≤50 mm-40°C [-40°F]42 J28 J
50<t≤70 mm-40°C [-40°F]42 J28 J
70<t≤100 mm-40°C [-40°F]42 J28 J

Per IACS UR W16 / KR Class extra-high-strength practice. Average of three full-size specimens; transverse values apply when required. Thicker plates by agreement.

Delivery Condition and Deoxidation

Deoxidation: Killed, fine-grain practice. Delivery condition: typically TMCP or QT for extra-high-strength plates; N/NR may apply at lower extra-high levels per rules. E-class (R E43 / EQ43) grades are supplied normalized or TMCP; as-rolled delivery is not permitted for the E toughness class. Optional extras: UT, Z15/Z25/Z35, KR survey.

Thickness Coverage

Extra-high-strength KR A/D/E/F 43/47/51/56/63/70 plates (about 420-690 MPa family) are commonly supplied from about 6 mm to 100 mm thick (thicker by agreement under UR W16). Width 1500-4000 mm and length 6000-18000 mm are typical.

Equivalent Steel Grades of KR E43

 

Society / StandardEquivalent grade
KR (Korean Register)KR E43 / RE43 (LR EH42 / ABS EQ43)
LR (Lloyd's Register)LR EH42 steel plate
ABSABS EQ43 steel plate
CCSCCS E420 steel plate
GLGL E420 steel plate
DNVDNV E420 steel plate
BVBV E420 steel plate
NKNK E43 steel plate
RINARINA E420 steel plate

IACS societies align extra-high-strength hull grades under UR W16; naming differs (KR E43, LR EH42, ABS EQ43, DNV E420). Dual certification is common when ordered that way.

FAQ about KR E43 / RE43 Steel Plate

What is KR E43 (RE43) steel plate?

It is an extra-high-strength hull structural steel under KR Class Rules (IACS UR W16 extra-high-strength family), with 420 MPa minimum yield, 530-680 MPa tensile strength and Charpy toughness at -40°C [-40°F].

What does KR E43 / RE43 stand for?

KR is Korean Register. The R prefix (RE43 / R E43) is the KR mill designation. The letter E is the toughness class (Charpy at -40°C [-40°F]), and 43 is the yield-strength level in MPa. Market/LR naming often uses EH42; ABS often uses EQ43. This site uses ABS-like numbers (A43…A70), corresponding to about 420 MPa (ABS EQ43 / LR EH42 / DNV E420 family); there are no A420 paths under /kr/.

What is the yield strength of KR E43?

Minimum 420 MPa (61 ksi), tensile 530-680 MPa (77-99 ksi), elongation about 18% min (for the common thickness range).

What is the impact test temperature for KR E43 / RE43?

Charpy V-notch at -40°C [-40°F]. Typical longitudinal average minimum is 42 J (transverse 28 J) for the tabulated thickness range on this grade page.

What is the difference between NK A43, D43, E43 and F43?

Same 420 MPa strength class. Toughness class differs: A at 0°C, D at -20°C, E at -40°C, F at -60°C. Chemistry (C, P, S, Mn) is tightened for colder classes.

How does KR E43 differ from higher-strength KR A40?

KR A40 is UR W11 higher-strength (390 MPa). KR E43 is UR W16 extra-high-strength (420 MPa) with different chemistry and delivery practice (often TM/QT).

Is KR E43 the same as LR EH42 or ABS EQ43?

They are IACS counterparts in the extra-high-strength family; exact chemistry/delivery options differ by society edition. Dual certification is available when surveys are arranged.

Is KR E43 weldable?

Weldable with approved procedures for extra-high-strength ship steel. Preheat, heat input and consumable matching are critical; follow the mill WPS and KR Class welding requirements.

What heat treatment is required for KR E43?

Extra-high-strength grades are typically delivered TMCP or quenched and tempered (QT), sometimes normalized/normalized-rolled depending on strength level and thickness. E-class (R E43 / EQ43) grades are supplied normalized or TMCP; as-rolled delivery is not permitted for the E toughness class. Optional extras: UT, Z15/Z25/Z35, KR survey.

What thickness is available for KR E43?

Common supply is about 6-100 mm (thicker by agreement under UR W16 / KR Class rules), 1500-4000 mm wide and 6000-18000 mm long.

Other KR Steel Plate Grades

KR Grade A steel plate | KR Grade B steel plate | KR Grade D steel plate | KR Grade E steel plate | KR A32 steel plate | KR A36 steel plate | KR A40 steel plate | KR D36 steel plate | KR D40 steel plate | KR E32 steel plate | KR E36 steel plate | KR E40 steel plate | KR F32 steel plate | KR F36 steel plate | KR F40 steel plate | KR A43 steel plate | KR A47 steel plate | KR A51 steel plate | KR A56 steel plate | KR A63 steel plate | KR A70 steel plate | KR D43 steel plate | KR D47 steel plate | KR D51 steel plate | KR D56 steel plate | KR D63 steel plate | KR D70 steel plate | KR E47 steel plate | KR E51 steel plate | KR E56 steel plate | KR E63 steel plate | KR E70 steel plate | KR F43 steel plate | KR F47 steel plate | KR F51 steel plate | KR F56 steel plate | KR F63 steel plate | KR F70 steel plate

Equivalent Class Society Grades

KR E43 / RE43 corresponds to extra-high-strength counterparts under other IACS societies (LR EH42, ABS EQ43, etc.): LR EH42 steel plate, ABS EQ43 steel plate, CCS E420 steel plate, GL E420 steel plate, DNV E420 steel plate, BV E420 steel plate, NK E43 steel plate, RINA E420 steel plate.