Oxy-Acetylene Welding

Oxy-Acetylene Welding is the welding process of heating two pieces of metal to melting point, bringing the parts together and while still in a molten stage hammered together to form a joint. Learning how to weld using this process will give a complete overview of welding.

The Oxy-Acetylene Welding process requires the use of a special welding torch that mixes oxygen and acetylene gasses that can produce a small intense flame heat of up to 6300 degrees. This temperature is more than twice the melting point of most metals.

This process has been widely used in the past for the manufacture of wrought iron projects such as iron gates and fences. These methods have widely been superseded by the introduction of electric arc welding.

Today Oxy acetylene welding is generally restricted to industries that work with copper pipe and the joining of copper and brass. Other specialized applications include such as building up of brass wear plates and the welding of cast iron housings that may be cracked using brass or bronze rods as a filler.

Gas Cutting Using Oxy-Acetylene.

Most gas torches include a function for gas cutting. This is in the form of a lever style valve that allows an extra burst of oxygen through the cutting torch to the work that has been heated to melting point.
This injection of oxygen to the work causes the parent metal to burn away with great force and speed, producing a small narrow cut in the metal.

Using this method has allowed metals to be cut easily either manually or by machines called profile cutters. Gas cutting manually can easily cut metals of 1/16 of an inch and up to two inches where as profile cutting can cut steels up to four inches thick.

Many profile cutting machines now use LPG gas instead of acetylene as the flame and cut produced is cleaner. Propane torches for auto and manual cutting are constructed differently to acetylene torches and also require different cutting tips

Welding Rods

When choosing welding rods try to avoid buying inferior quality as the better your grade of material in the welding rod the better the end result will be.

Your welding rod is used to lay over additional metal to the weld therefore it needs to match the parent metal. If the metals are dissimilar then best efforts to locate a filler rod comprising of a composition of the two metals. For example if welding manganese, or nickel specific welding rods of specific alloys are recommended.

Welding wire and Oxy-Acetylene Welding rods are most always of Norway steel. This grade is most pure and gives a sound soft weld especially suited to machining if required. When welding aluminium the proper rod is most important as aluminium is difficult to weld and requires alloyed rods to ensure even flowing.

Gas Welding – How It Works

gas weldingGas welding or oxygen-acetylene welding is made possible because there are some gasses that burn at extremely high temperatures. With this process, oxygen as well as acetylene are fed from holding tanks to a torch and then when needed ignited. This combination makes a gas that burns at an incredible 5500 degrees Fahrenheit. This process was first put into use during the early part of the 1900s. The individual doing the welding holds a filler metal rod in one hand and the torch in the other, and using the intense heat at the end of the torch melts the filler metal into a joint which fuses two pieces of metal together.

This process can be used to fuse pipe together or to repair splits. It is particularly useful with pipe that is less than 2 inches diameter. It can also be used to work with sheet metal, as well as just about any metal that is used in industry. Gas welding is a bit slower than when using arc welding but it is also seen to give the welder much more control over the work they are trying to do.

There are some things to remember when working with gas welding that must be kept in mind for the sake of safety.

  • For the sake of safe storage, keep cylinders of oxygen and other gases stored separately with at least 20 feet between them, or they can be divided by a proper firewall.
  • Cylinders can burn easily so it is recommended that they be kept away from any combustible and flammable materials.
  • Maintain cylinders in storage areas where others cannot get to them to tamper with them, away from heat and to prevent damage to them.
  • Cylinders should always be maintained in an upright position, and when possible, chained to retain this position even when jostling takes place.
  • Always check the valves to assure they are closed prior to moving the cylinders.
  • Always have regulators and defending caps in place.
  • Never pull cylinders. Instead roll them on their bottom edges when moving is necessary.
  • During transport, reduce the cylinder movement by placing chains around them to prevent falling and extreme movement.

Oxy-acetylene is the typical combination used in gas welding and is generally chosen for general cutting and welding work including work to repair rips and tears in metal. Each gas is contained in its own cylinder and combined through the use of separate hoses leading from regulators attached to the top of the cylinders. These hoses then lead to the torch where they are attached to create the mixture needed to create the intense heated to work with metals.

The regulators are necessary to control the flow of gases, and a non-return valve is also needed to prevent the possibility of detonation of the acetylene tank. This valve is all part of the checks needed for proper and safe use of oxy-acetylene gas welding.

Other equipment required to work with oxy-acetylene gas welding would be a check valve, welding torch, cutting torch, rose-but torch, and injector torch. All of this equipment do different types of gas welding and allow the user to make the right cuts or joints that are required for the work they are completing.

 


Arc Welding Cast Iron

With no two pieces of cast iron being the same there are obvious challenges to arc welding cast iron. Most cast iron welding is due to maintenance and cracked casting repairs. The main two methods of welding cast iron is by using oxy acetylene welding processes or using stick / arc welders.

welding cast ironCast iron may be welded using a covered steel electrode, however this technique ought to be applied as an emergency solution solely. Whenever using any steel electrode, a contraction with the steel weld material, any carbon acquired in the cast iron from the weld metal, and also the hardness in the weld metal due to quick cooling down has to be considered. Steel shrinks a lot more than cast iron if ceded from the molten into a solid condition.

Each time a steel electrode is employed, that unequal shrinking can cause stresses in the joint following welding. Whenever a great quantity of filler metal is used on the joints, the actual cast iron may possibly fracture just back from the line of fusion unless of course precautionary measures are undertaken. To beat a lot of these complications, the prepared joints ought to be welded by way of depositing any weld metal in small stringed beads, 0.70 to 1.0 in. long (20.0 to 25.5 millimeters).

These are typically made sporadically and, in some instances, with the back-step and skip method. To help prevent hard spots, your arc ought to be struck in the V, rather than on the surface area on the base metal. Every brief length of weld metal employed on any joints ought to be carefully peened whilst hot using a modest ball peen hammer, plus permitted to cool prior to further weld metal being applied. This peening activity forges the actual metal and also minimizes any cooling down strains.

Cooling can also be assisted by covering the casting with a specialized cooling blanket or by covering the casting with sand. Arc welding cast iron is a slow process relying on diligent peening and cooling processes.