OK 74.78 is an LMA electrode suitable for welding high tensile steels used in low-temperature applications. Good notch toughness down to -40°C. Very suitable for both the enclosed welding and cladding of rails, when a hardness of about 250 HV is required. The moisture content of the coating is very low, which makes OK 74.78 suitable when preheating cannot be applied.
Typical Charpy V-Notch Properties
|Impact Value||Testing Temperature|
|as welded iso|
|90 J (67 ft-lb)||-40 degC (-40 degF)|
|70 J (52 ft-lb)||-50 degC (-58 degF)|
Typical Tensile Properties
|Condition||Elongation||Shielding Gas||Tensile Strength||Yield Strength|
|As Welded||24 %||ISO||650 MPa (94 ksi)||600 MPa (87 ksi)|
|Current||Deposition Rate @ 90% I max||Diameter||Deposition Efficiency (%)||Number of electrodes/kg weld metal||Voltage|
|75-100 A||55 sec||0.9 kg/h (2,0 lb/h)||2.5 x 350.0 mm (0.098 x 13,8 in.)||62 %||73.0||22 V|
|105-140 A||86 sec||1.3 kg/h (2,9 lb/h)||3.2 x 450.0 mm (1/8 x 17,7 in.)||65 %||32.0||23 V|
|140-190 A||97 sec||1.8 kg/h (4,0 lb/h)||4.0 x 450.0 mm (5/32 x 17,7 in.)||65 %||20.5||23 V|
|190-260 A||100 sec||2.6 kg/h (5,7 lb/h)||5.0 x 450.0 mm (0.197 x 17,7 in.)||68 %||14.0||24 V|
|240-340 A||103 sec||3.6 kg/h (7,9 lb/h)||6.0 x 450.0 mm (0.236 x 17,7 in.)||69 %||10||24 V|
SFA/AWS A5.5 : E9018-D1
EN ISO 18275-A : E 55 4 MnMo B 3 2 H5
ABS 3YQ460 H5
CE EN 13479
DNV-GL 3 Y46H5
|Approvals are based on factory location. Please contact ESAB for more information.|
|Alloy Type||Low alloyed (0.4 % Mo)|
|Coating Type||Basic covering|
|Diffusible Hydrogen||< 5.0 ml/100g|
|Welding Current||AC, DC+|
Typical Weld Metal Analysis %
|Typical Weld Metal Analysis %|
|0.05 %||0.03 %||1.60 %||0.35 %||0.03 %||0.35 %|
How to purchase OK 74.78
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