You may have noticed how much we rely on metal structures, whether it is the multi-story building, highway, flyover, etc. And it would be hard for you to believe how these monstrous metal structures can be screwed together. However, it is true that screws can’t hold such bulky systems, and their breakdown can be disastrous.
The various types of bulky metals are integrated by fusing them to take the strength of both metals. And here comes welding techniques that melt the metals and help them bond. Among these welding techniques, oxy-acetylene welding is one most popular gas welding methods. In this article, we’ll learn how to oxy-acetylene weld.
What is oxy-acetylene welding?
Oxy-acetylene welding ( generally known as oxygen-acetylene welding, oxy welding, or gas welding in the US ) is the process that involves the burning of oxygen and acetylene, which is a hydrocarbon. An ultimate 3200 degrees Celsius can be achieved when oxygen and acetylene in the hand-held torch are mixed in the right amount.
One can modify the chemical action of acetylene by altering the composition of oxygen to it. Chiefly, there are different flame settings which are oxidizing, neutral, and carburizing. A neutral flame setting which comprises 50 percent oxygen and 50 percent acetylene is ideal for welding.
Oxygen-acetylene welding is the only gas welding procedure that can weld hard and high melting point metals, including steel. Moreover, steel has a melting point of 1500 degrees Celsius which we can’t get by burning various gas, including hydrogen, propane, and carbon. However, these gases are excellent for brazing, silver soldering, and welding of nonferrous metals.
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Flame types in oxy-acetylene welding
As mentioned above, there are three types of flame settings a welder needs to do before performing a weld or cutting metals. The reason is each flame type has its applications.
This type of flame comprises a half amount of oxygen and half amount of acetylene. It is best for welding various metals because it bestows minimal chemical effects on metals. That’s why we do steel structure welding by neutral flame.
It is evident from the name that this type of flame will have a higher oxygen content in the whole composition. Moreover, the ratio of oxygen and acetylene is 3:2. Therefore, it is better for welding copper and alloys made of copper. However, the oxidizing flame is not ideal for welding steel as it tends to oxidize steel.
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It encompasses more amounts of acetylene gas than oxygen. This flame is incredible for welding those metals where less heat is preferable. Therefore, it is brilliant on nonferrous metals and high carbon steel, which requires less heat for melting.
Keep reading we have provided complete detail on how to oxy-acetylene weld.
Equipment used in Oxy-fuel welding
The equipment required for Oxy-Acetylene or oxy-fuel welding consists of oxygen and acetylene storing cylinders, economizes, weld torches, pressure controllers, hoses, and flame arrestors. Let’s explore them.
The essential part of the oxy-acetylene welding machine is two different gas cylinders; one is for oxygen, and another one is for acetylene. Moreover, make sure that the cylinder is airlocked and there should be no leakage in it in case it has, then it can be disastrous. The oxygen gas cylinder’s color is black, and the acetylene gas cylinder’s color is maroon.
Most people misunderstood pressure controllers with cylinder valves. When you open a cylinder valve, it will provide gas to start the welding process, but the pressure controller enables you to control the pressure of gas emerging out. For safety, it’s necessary to change the pressure control if you find any damage to it; otherwise, it can be hazardous.
Hoses are pipes that transfer gases from the cylinder to the torch. These hoses comprise a nonreturn valve to protect the cylinder from the come back of flame. Also, you should make sure that these hoses don’t come in contact with heat, grease, spark, slag, oil, and sharp metal. Moreover, any leakage in the hoses can invite a major accident, ensuring that the hoses haven’t any flaws.
These are special appearances that are accommodated in between the hose and pressure controller. The main function of a flame arrestor is to restrain the flame from reaching the cylinder; that’s why it is very crucial in the welder’s safety. On the other hand, the flashback of flame can cause a blast, which can be deadly.
The welding torch is the component of the oxy-acetylene welding machine; it is where the gasses, after passing through hoses from cylinders, eventually get mixed up. After that, mixed gases are burnt and then thrown out of the nozzle in the form of flame.
This device aims to reduce the wastage of gases ( oxygen and acetylene) when welding touch isn’t in use. Whenever the torch is resting, it will automatically get closed in order to save the gases. Moreover, re-restarting the torch requires you to remove the torch and move it over the pilot light.
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Lighting up process
Gas welding is very easy and cheap but significantly riskier than the rest of the welding procedures. Therefore, it is good to start the oxy-acetylene process carefully. Firstly, you need to open both gas cylinder valves slowly because opening the valves instantly can damage the pressure controller and lead to a disaster.
Now, it’s time to open the pressure controller on both hoses and keep on adjusting the controller until you get the desired pressure. In this way, you’ll blow out any air present in the hoses before starting the welding procedure. You should always lit the gas from the nozzle above the welding torch using a gas lighter because liquid lighters can be hazardous.
After that, adjust the acetylene pressure until the smoke emerging from the flame comes to an end. Once you notice that the smoke ends up, you’re now allowed to slowly increase the pressure of oxygen. You’ll see that the inner cone color of the flame is white and is sharply defined, which indicates that it is ready for operation.
Why is acetylene ideal for welding?
Acetylene is an ideal welding gas for the following reasons:
1. Safe fuel
When it comes to industrial welding, safety is paramount. As we know, the weight of acetylene is less than air which makes it ideal for use at lower levels like underground. The reason for this is it’s unusual for this gas to get accumulated
2. Money saver
The mixture of acetylene and oxygen is very versatile. A change in the ratio of these two gases will make them suitable for welding, brazing, and soldering. Moreover, the oxygen and acetylene cost less than propane and any other welding gas
3. Excellent results
When combined with oxygen in the right proportions, acetylene can generate fire with a maximum of 3200 degrees celsius. This flame is more than enough for welding steel and its alloys which usually have a higher melting point.
Dangers associated with oxy-acetylene welding
Despite being such a beneficial form of welding, oxy-fuel welding has various dangerous effects on a welder, which are as follows:
- Chance of gas leak blast
- Foolish use of welding or cutting torch
- Fire explosions
The welder can eliminate the dangers if he follows a safety regime we have written in the next segment. To read it, scroll down the display.
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Safety measure while performing oxy-acetylene weld
Oxy-acetylene is one of the riskiest gas welding techniques. That’s why doing it without following the safety precautions is like betting on your life.
- First of all, ensure that you’re wearing all the protective clothing and eye safeguarding glasses
- The placement of the gas cylinders should be upright
- There must be a spindle key on the valve of the acetylene gas cylinder
- You can check whether there is any leakage in the machine using a soapy build
- Immediately turn off the gas supply if you sense a leakage in the hoses
- Always clean the enclosed vessels entirely before working on them
- Make sure that your machines oxygen cylinder doesn’t come in contact with oil and grease all the times
- You need to ensure that the gas cylinder remain outside when you have to work on in the enclosed vessel
- It is better if you have fire fighting equipment along with you to cope up with any unwanted accident
After knowing how to oxy-acetylene welding and while following safety rules, you are ready to go.
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