When you oxy acetylene weld metals, you must use a filler rod that are of the same thickness as the metal being welded. If the metal of the filler rod is too thin, the resulting weld will be weakly and will not be able to remain strong. If the metal of the filler rod is too thick, the metal will add too much heats to the metal being welded which can potentially warp the metal.
It is essential to use a filler rod of the appropriate size for the thickness of the metal being welded, the size of the welding tip being used, and the types of flame that will be used during the oxy acetylene welding process. The size of the metal filler rods must be chosen according to the thickness of the metal being welded. If the metal being welded is thin metal, such as 1/16 inch thick metal, it is best to use a 1/16 inch thick metal filler rod and welding tip so that the heat will not damage the thin metal.
Choosing the Right Filler Rod for Oxy-Acetylene Welding
However, if you use thin metal filler rods on heavy metal, such as 1/4 inch thick metal, there will not be enough metal to create a good weld. For heavier metals and metal plates, it is best to use 1/8 inch or 1/16 inch thick metal filler rods so that the metal will fuse proper with the metal being welded. The type of flame to be used when oxy acetylene welding metal determine the type of metal filler rod that should be used.
Neutral flames are used with most steel work because the flame does not add carbon to the metal and does not remove carbon from the metal. Carburizing flames are used with aluminum because the flame will lower the surface tension of the metal allowing it to flow. Oxidizing flames are used when brazing bronze metal because it will cut the zinc fumes allowing it to flow into the metal joint.
There are different types of steel metal filler rods that is used to weld metal. RG45 filler rods are used in applications where the metal will experience little stress because they flow easy and do not create much spatter on thin metal. RG60 metal rods are used in welds with metal pipes because they have a tensile strength of 60,000 PSI.
Finally, RG65 metal rods are used for repairs to heavy metal because they offer the maximum amount of strength to metal. However, workers use RG65 metal rods with slow passes on the metal being welded and stress relief used after the welding process. Specialty metals will require certain specialty metal filler rods and flames to properly weld those metals.
Metals like aluminum will require metal filler rods that contains flux along with a carburizing flame to prevent the formation of oxide on the metal being welded. Metals like bronze are used to weld cast iron metal or metals of different metals, but it requires an oxidizing flame and flux to keep the metal weld being formed is free of oxide. Metals like stainless steel will require the use of ER308 metal filler rods along with a neutral flame to prevent the loss of chromium from the weld and to keep the metal from distorting during the welding process.
However, if welding metal like cast iron, it will require that the metal be preheated and allowed to cool slow after welding. The acetylene pressure should never go beyond 15 PSI as using beyond this level of pressure can create a flashback in the weld flame. Low levels of acetylene pressure should be used with small welding tips and higher levels of acetylene pressure should be used with larger welding tips.
The metal will also require adjustments to the amount of oxygen used during the welding process. Other safety requirements for the oxy acetylene welding process include purging the welding hoses of any moisture, using an oxygen hose arrestor and a flashback arrestor, and lighting the acetylene gas flame before lighting the oxygen gas flame. Understand the difference between brazing and fusion welding.
Brazing is the welding process where two metals are joined without melting the metal. This process requires flux to help the metal weld properly with the metal being welded. Fusion welding is the process of melting the metal being welded along with the metal filler rods.
Fusion welding requires the use of metals of similar composition to the metal being welded and does not require flux. Welding processes include brazing metal with bronze to steel metal with a preheat of 400 to 500 degrees Fahrenheit or fusion welding with a preheat of 900 degrees Fahrenheit or higher. As with all metal welding processes, it is essential that the requirements for the specific metal being welded are understood.
For instance, if welding mild steel it is essential to use a neutral flame along with RG45 and RG60 metal filler rods. For welding thin metal components of automobiles it is essential to use small tips and metal filler rods of small sizes. For welding metal that is covered in zinc it is essential to use a metal filler rod of bronze to weld the zinc layer and vents the fumes created from the welding process.
For welding heavy metal plates it is essential to use RG65 metal rods along with using passes to allow for even welding of heavy metal plates. Finally, metal welding processes can use metal rod comparison grids to ensure the metal filler rods is correct for the metal being welded along with the flame and flux that will be used during the welding process.
