Science, Maths & Technology
Manual metal arc welding (MMA)
...open-circuit voltages of 50–100 V. Power sources range from 30 to 500 Amps a.c. or d.c. Coated electrodes contain slag-forming ingredients (that produce a fluid coating over the weld as it cools) and gas-forming ingredients (that generate atmospheres of CO2, CO or H2 around the arc). Principal materials used in electrode coatings include: Carbonaceous material of the...