4343, UNS G43406, 4150, 4330V, 4330MOD, 4330+V, 4335+V LATROBE, 5029B, AMS6411, AMS6411D, AMS6427, AMS6427H, AMS6429, AMS6429D, AMS6430, AMS6430E, AMS6433, AMS6433D, AMS6434, AMS6434D, AMS6435, AMS6435C, ASTMA646, UNSK23080, UNSK33517, LESCALLOY 4330+V, K33517, MIL S-8699, MIL S-46128">

4343, UNS G43406 low alloy ultra high strength steel


4343, UNS G43406 is a low alloy steel with ultra high strength It also possessed good toughness and fatigue strength when heat treated, just slightly higher carbon than 4340 low alloy steel, displays excellent transverse properties even in larger cross sections and is often used in the rotorcraft aerospace

4343, UNS G43406 low alloy ultra high strength steel - Introduction and Application

4343, UNS G43406 is a low alloy steel with ultra high strength melted as VIM + VAR product.  It also possessed good toughness and fatigue strength when heat treated.  This alloy has just slightly higher carbon than 4340 low alloy steel.  This grade also displays excellent transverse properties even in larger cross sections and is often used in the rotorcraft aerospace market.


Melted process

VIM + VAR


4343, UNS G43406 low alloy ultra high strength steel - Chemical composition WT %

GradeChemical composition WT %
CSiMnPSCrMoAlNiV
43430.31 - 0.330.15 - 0.350.80 - 0.95Max 0.015Max 0.0050.8 - 1.00.45 - 0.500.015 - 0.035-0.06 - 0.10
UNS G434060.38 - 0.430.15 - 0.350.65 - 0.85Max 0.025Max 0.0250.7-0.90.2 - 0.3
1.65-2.00

Mechanical Property of 4343, UNS G43406 low alloy ultra high strength steel

PropertiesMetricImperial
Tensile strength≥ 860 MPa≥ 125000 psi
Yield strength≥ 690 MPa≥ 100000 psi
Elongation at break (In 50 mm)≥ 15.0 %≥ 15.0 %
Hardness, Brinell285285



Physical Property of 4343, UNS G43406 low alloy ultra high strength steel

PropertiesMetricImperial
Melting point1427°C2600°F

Heat Treatment of 4343, UNS G43406 low alloy ultra high strength steel

4343 alloy steel is heated to 829°C (1525°F) and then quenched in oil. 4343 alloy steel can also be heat treated to strength levels of 200 ksi or greater than 200 ksi, by first being normalized at 899°C (1650°F) before the heat treatment and then quenched to gain strength.

Forging: 1230-1070 °C 

Rolling: 1230-1070 °C 

Annealing: 820-860 °C



Welding of 4343, UNS G43406 low alloy ultra high strength steel

Conventional methods are used for welding 4343 alloy steel. 4343 alloy steel is preheated and post heated based on the welding procedure used for this alloy steel type, and the alloy can be joined by a brazing process.


Machining of 4343, UNS G43406 low alloy ultra high strength steel

4343 alloy steel has good machinability features in the annealed, tempered and normalized conditions. This alloy steel is difficult to be machined in the hardened condition.


Equivalent grades of 4343, UNS G43406 low alloy ultra high strength steel

4343, UNS G43406, 4150, 4330V, 4330MOD, 4330+V, 4335+V LATROBE, 5029B, AMS6411, AMS6411D, AMS6427, AMS6427H, AMS6429, AMS6429D, AMS6430, AMS6430E, AMS6433, AMS6433D, AMS6434, AMS6434D, AMS6435, AMS6435C, ASTMA646, UNSK23080, UNSK33517, LESCALLOY 4330+V, K33517, MIL S-8699, MIL S-46128