Principles of Coating Technology
Principles of Coating Technology
Principles of Coating Technology
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GFE Schmalkalden e.V. Build-up welding<br />
arc welding – control <strong>of</strong> current voltage characterisitics<br />
External current control - DU control<br />
• Power generator with dropping characteristics<br />
• Voltage will be used for wire feeding<br />
• Shortening the arc length reduces voltage drop<br />
reduced wire feed rate<br />
increased arc length<br />
Internal current control - DI control<br />
• Nearly constant voltage<br />
• Shortening the arc length<br />
increase welding current<br />
increased melt <strong>of</strong> electrode<br />
increased arc length<br />
control<br />
<strong>Principles</strong> <strong>of</strong> <strong>Coating</strong> <strong>Technology</strong> II<br />
arc<br />
Weld dirction<br />
electrode Current contact<br />
welded<br />
layer<br />
substrate<br />
power<br />
supply<br />
GFE Schmalkalden e.V. Build-up welding<br />
Manual arc welding<br />
• Using manual guided rod electrodes<br />
• Arc ignition by a shortcut <strong>of</strong> the electrode with the component surface<br />
• Only power generators with dropping characteristics (due short cut ignition)<br />
• Arc is firing between component end electrode<br />
• Dilution <strong>of</strong> droplets with molten component surface<br />
Transfer<br />
from metal<br />
to slag<br />
arc<br />
<strong>Principles</strong> <strong>of</strong> <strong>Coating</strong> <strong>Technology</strong> II<br />
Covered electrode<br />
Electrode cover<br />
Core wire<br />
Shielding gas<br />
Melt bath<br />
slag<br />
Molten<br />
zone<br />
Substrate<br />
material<br />
39<br />
40<br />
20
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