Amperage are a measurement of the electrical current and controls the amount of heat that will be produced during the welding processes. Heat is one of the critical factors in the welding process, as the heat determine the depth to which the weld will penetrate the metal. Using too low of an amperage setting will result in insufficient penetration of the metal, which will result in the weld crack under load.
Conversely, using to high of an amperage will cause the metal to distort or even develop holes in the metal, especially if the metal are thin. The amperage setting should match the thickness of the metal that is being welded and the type of consumables that is being used. Stick welding use a coated metal rod, and the diameters of that metal rod determines the amperage that should be used.
Set the Right Amperage for Welding
If the metal rod that is being used for stick welding are thinner, the amperage should be lower to avoid boiling the flux coating of the metal rod. For thicker metal rods, the amperage should be higher to allow for the deposition of more metal. The manufacturer of the metal rod will provide informations on the amperage settings for the metal rod.
MIG welding use a wire feed speed to set the amperage for the welding process. Using the wrong wire gauge for the metal will result in problem during the welding process such as spatter. Thin wire can be used for thick metal, but using thin wire will require make multiple passes over the area being welded.
Using thicker wire on thick metal will allow the metal to heat up faster during the welding process. Thick wire is used to weld at high speeds to complete the production runs. TIG welding require high levels of control over the amount of heat that is used during the welding process.
The tungsten electrode will not melt during the welding process but will shape the arc that are created. Selecting the wrong size for the tungsten electrode will cause the tungsten electrode to ball up during the welding process. If welding aluminum, a foot pedal may be used to adjust the amperage since aluminum welding require alternating current.
For welding steel, direct current should be used since the welding of steel produce a focused heat that allow for narrow and deep welds. The thickness of the metal can help to establish the baseline for the amperage settings. For every thousandth of an inch of metal thickness, one amp of amperage should be used.
For quarter inch mild steel, weld settings can start at 250 amps. Aluminum will absorb the heat quick during welding, so the amperage should be increased for welding aluminum. For stainless steel, the metal will hold heat longer than other metals; hence, the amperage should be decreased by ten or fifteen percent.
For welding in an overhead position, the amperage should be decreased to allow the molten metal to remain on the metal piece without drip. Heat input in welding is calculated by dividing the product of the amperage and voltage settings by the travel speed of the welding machine. Heat input is one of the critical factors in welding since the heat input will determine the amount of distortion in the metal structure.
For thin metal parts, it is necessary to use lower heat input so that the parts will remain flat. For thick metal parts, high heat input are used for the root passes. The duty cycle of the welding machine determine the amount of time that it will operate at a specific amperage before it require a cooling period.
If this value is ignored, the welding machine will undergo a thermal shutdown. If the metal burns through the metal, increasing the travel speed will solve the problem. High travel speeds will allow for the heat to be distributed across the metal piece.
Using a heat sink for the metal or welding shorter welds will also reduce the amount of heat that is directed at the metal. Before welding the metal piece, it is essential to make test bead on a sample of metal. Test beads will allow the welder to ensure that the amperage and other settings are correct before welding the metal piece.
By following the charts and rules for welding machines and metals for amperage settings, welders can avoid burn-through in the metal and create lasting and stable welds.
