Let’s Check out the Basic Guide on Gas Welding
Check out the Basic Guide on Gas Welding
Oxy-fuel welding, commonly known as oxy welding or gas welding is a process of joining different metals by application of heat generated by gas flame. The fuel gas commonly acetylene, when mixed with proper percentage of oxygen in a mixing chamber of welding torch, generates a very hot flame of about 5700-5800°F. With this flame it is feasible to bring any of the commercial metals, like cast copper, iron, steel, and aluminium, to a molten state and cause a combination of two pieces of like metals in such a way that the point of fusion will very closely deal with the strength of the metal fused. If more metal of like nature is added, the union is made even more stronger than the original. This method is called oxy-acetylene welding or gas- welding. The chemical action of the gas welding flame can be adjusted by altering the ratio of the volume of oxygen to acetylene. Cutting with the oxy-fuel or gas welding process is just the opposite from of welding. Oxy-fuel cutting uses acetylene and oxygen to heat up metal to red hot and then uses natural oxygen to burn away the warmed metal.
The first thing you need to do is explain yourself with the equipment used in gas welding and how it all works. Almost in all beginner gas welding torch kits contain everything you as a beginner needs to get started. You will need to fill or exchange the vacant tanks that came with your torch kit at any welding supplies store.
- Your main equipment will be your welding torch. The torch’s most important function is to regulate and control how the gases will flow while you are welding. The torch is made up of a handle, oxygen, mixing chamber and gas valves. The gas and oxygen move through the handle, mixes at the tip and explodes. There are three distinct flame settings are used, neutral, oxidising and carburising.
- The neutral flame settings have equal quantities of oxygen and acetylene. Welding is generally conducted out using the neutral flame.
- When we increase the oxygen flow rate the oxidising flame is obtained
- When we increase the acetylene flow in relation to oxygen flow the carburising flame is achieved
- The next equipment is a cylinder to hold oxygen and acetylene. It should be carefully checked for any indications of dents or punctures.
- Once the inception is completed, you can attach the regulator which will control the pressure in the cylinder to make sure it is consistent with the welding torch. After that, attach the regulator to the torch with the help of a welding hose. Make sure the hose has no flaws/gaps and is securely attached.
Once all things are checked, the next step is to remove any uncleanness which might harm or cause ignition. This is done by cracking open and closed the cylinder valve thoroughly, be sure to do this away from any supplier of ignition. Next, we attach the regulators to their individual cylinders and be sure they are tight enough to avoid any leaks. Now, attach the extra end of the hose to the blowpipe, there must be a stamp and sticker situated near the handle to specify which hose goes where. Once this is done, it is important to do another check for leaks before lighting up again. Close the blowtube valves and make sure that there are no leaks in your oxygen and fuel gas valve. We then open each valve slowly, keeping in mind that there should be only one open at the time and set the regulator to show up approximately 100kPA. If there are leaks, the gauge will change, and we need to apply leak testing solution or anything else to the valve to close the leak. Check it again and we are good to light up.
Lighting up the blowpipe:
To light the blowpipe, open the oxygen valve and alter its regulator until our required pressure is attained. After this and prior to lighting, let the gas flow for a bit so it can eliminate the system of air. Close the valve and replicate for the Acetylene cylinder, again, submit to the pressure chart to ensure we have the appropriate pressure for the job. Now it is time for the most important part for which we have all been waiting for, (safely) lighting the blowtorch. Open the fuel gas valve marginally and use a flint lighter to provoke the gas, this should not ever be done at a gauge pressure above 100kPa. Next, gradually open the blowpipe oxygen valve up until a neutral flame is generated. For most of the welding jobs, a neutral flame is all we will need.
After our job is done its time to safely shut down the blowtorch. We usually start by closing the blowpipe acetylene valve, supported by the oxygen valve. Then we repeat the same step on the cylinder valve. After all the valves are closed, we open the blowpipe oxygen valve to permit any remaining gas to drain out—when the regulator gauge has fallen to zero, we know that this process is done. At last we repeat this step for the acetylene valves.
When performing gas welding, following useful tips must be considered for safety and efficiency of operations and to avoid accidents while carrying out the operations:
- Secure Position: Compressed gas cylinders must be conducted with best care and always be secured in vertical position.
- Keep Grease and Oil Away: Control valves and fittings must be remained free of oil and grease.
- Keep Pressure maintained: When performing gas welding, ensure the pressure of oxygen and acetylene should be maintained.
- Rectify Cause of Backfire: In case of backfire, the priority should be to close the oxygen valve and then instantaneously close the acetylene valve. No operation should be executed until the cause of backfire is rectified.
- Ensure Proper Connections: The connections among the hose and blowpipe, and among hoses should be strongly fixed with fittings to comply with Regulatory Standard.
- Replace Old and Faulty Hoses: Any hose in which flashback has happened must be replaced with new one as soon as possible.
- Take Proper Steps for Maintenance: Only unique tools should be used to clean any congestion in the blow pipe and before performing any maintenance, full system to be isolated.
- Never Use Oxygen for ventilation: Oxygen should not ever be used for ventilation, cooling purpose or for blowing dust off the coat or clothes.
Last but not the least we should never forget to follow all safety procedures while carrying out such jobs in sheltered spaces. These are the few measures that we should keep in mind while doing the gas welding to prevent any harm.