OK 74.78

OK 74.78 is an LMA AC/DC stick electrode designed for high‑tensile steels in low‑temperature applications, offering good notch toughness down to –40 °C and suitable for enclosed welding and rail cladding.

Key Features

• Low moisture coating allows use without pre‑heating.
• Good notch impact (90 J at –40 °C, 70 J at –50 °C).
• Suitable for rails requiring ~250 HV hardness and tensile strength 800‑900 N/mm².
• Vacuum‑sealed VacPac™ packaging provides dry, ready‑to‑use electrodes.

Specifications

• Welding Current: AC, DC+
• Min AC OCV: 65 V
• Diffusible Hydrogen: < 5.0 ml/100 g
• Alloy Type: Low alloyed (0.4 % Mo)
• Coating Type: Basic covering
• Tensile Strength (As Welded): 650 MPa, Yield Strength: 600 MPa, Elongation: 24 %
• Charpy Impact (As Welded): 90 J at –40 °C, 70 J at –50 °C
• Deposition rates (example 5.0 × 450 mm): 190‑260 A, 24 V, 68 % efficiency, 2.6 kg/h

Applications

• Enclosed welding of high‑strength steels.
• Rail cladding and butt welding.
• Situations where pre‑heating is not possible.
• General construction and structural steel fabrication.