Metal inert gas welding – better known as MIG welding– is a welding process pioneered in 1948 by the Battelle Memorial Institute, a non-profit science, and development company based in Ohio, USA. Otherwise known as Gas Metal Arc Welding, the MIG technique was principally developed to weld aluminum, as well as other non-ferrous metals. MIG welding is an automatic or semi-automatic process, which uses electrode-based welding equipment(wire) to fuse metal together. This wire is fed through a welding torch or whip. Inert gas also passes through this welding torch/whip, acting as a shield which keeps the weld zone free of air-borne contaminants.
SHORT-CIRCUIT TRANSFER RELAY
In short circut transfer the wire short circuits right as it makes contact with the application, causing the metal to shift(transfer) over, in essence because of the short. This happens at a fast rate (between 19 and 200+ p.s.). One positive with this method is its tiny energy consumption. This transfer is used on thin material, a quarter in. or lower, and with root passing on pipe with no backing. It is suited for welding mostly any position and generally for smaller-diameter wires: 0.023, 0.030,0.035, 0.040, and 0.045 inches.
A spray of small molten drops across the arc gives the mode its name. This mode is typically narrower than the actual diameter of the wire, and also employs higher wire speed, amps and volts. the difference between spray and short-circuit is that with spray , the arc stays on at all times once it is established. Spray produces small spatter, making it optimal on thicker metals in both horizontal & flat positions.
Technological advances have made MIG welding equipment easier and more affordable to install, which have led to widespread adoption of the process in a number of manufacturing industries. MIG welding is now used to work with a wide range of different metals, including steel, nickel, and various metal alloys.
When put side by side with the old-fashioned ‘stick welding’ techniques, MIG welding is capable of fusing metal together extremely quickly. This is why the process has become so popular, as it is perfect for welding soft metals. Initially, MIG welding supplies were quite expensive to buy, which made the process impractical for welding steel in mass production manufacturing. The first MIG welding guns created a gas shield using argon, which was costly to obtain. However, MIG welding techniques have steadily improved over time, and semi-inert gases like carbon dioxide can now be used for shielding, which has made the process cost effective for mainstream use.
As well as enabling the welding of non-ferrous metals, MIG welding also has a number of other advantages compared to traditional techniques. MIG welding can produce continuous welds much faster and longer than other processes and creates much cleaner welds with far less unwanted splatter. The technique is also extremely versatile and can be used to weld a wide range of different alloys and metals.
However, operatives should be aware that the technique should not be carried out without proper training. MIG welding equipment is complicated to install, and both a constant flow of gas and a source of direct current are required to operate it.
In practice, the technique is also fundamentally different to traditional welding processes, which means that even welding veterans will need extensive retraining before they can competently operate MIG welding equipment.Because of the need for an inert gas shield, MIG welding equipment must also be installed in a secure environment, as an air current will interfere with the shielding process.
Despite these restrictions, MIG welding remains an extremely popular welding technique and is now commonly used in a variety of manufacturing operations. Due to the speed and precision of the process, MIG welding has become particularly popular in the automobile industry, but it is also used in a wide range of smaller metalworking operations as well. If you would like to know more about obtaining MIG welding supplies, contact a specialist retailer like trade-equip.co.uk, who will be able to help you find the right equipment for your business needs.
Compared to traditional welding techniques, there are a number of significant advantages to MIG welding, which have made the technique extremely popular within the world of manufacturing. The versatility of MIG welding means that it can be used with a variety of different metals, while the process can also be operated either automatically or semi-automatically.
MIG welding is capable of producing high quality, splatter-free welds, and operates much faster than other techniques, with only minor loss of alloying elements. Furthermore, the technique does not require the use of a flux, which negates the possibility of slag entrapment, improving weld quality even further.
You should be aware that MIG welding equipment is relatively complex to install and operate, and even experienced welders will need retraining before they can use it. Due to the importance of the inert gas shield, the welding environment is also very important, as an air current can interfere with the gas flow. Due to the high heat and weld puddle fluidity, MIG welding equipment cannot be used in an overhead welding position, which differentiates it from other welding techniques.
MIG Welding – 3 Easy Steps to Success
Simply following these 3 easy steps will help anyone who wants to MIG weld be successful.
- Having a clean joint is an absolute must.
- Setting up the welding machine is the most important part.
- Use the right welding technique.
For MIG welding joint preparation it is a critical part of the welding process. MIG welding requires the joint to be free of oil, dirt, paint, mill scale, rust, or anything that should not be there. The best way to get a clean joint is to use either a wire brush or a grinder to get the weld area down to bare metal. Without a clean joint, it is almost impossible to MIG weld!
The big secret that nobody ever mentions about MIG welding is machine set-up. Since MIG welding is a semi-automatic process, much of the skill required is to know how to set up the welding machine correctly.
There are three settings used for MIG welding.
- Wire feed speed.
- Shielding gas flow rate.
All three of these settings change depending on the thickness of the metal to be welded. On some MIG welders, there is a chart on the inside panel of the welder. This chart will give you the proper settings needed for each thickness of metal to be welded. For most welds you want the weld to have a fast crackling sound to it. The sound the welder makes should be like an egg hitting a hot frying pan. Finally, the shielding gas flow rate should be enough that the weld is protected from any surrounding air.
The welding techniques used for MIG welding are the same as most other processes. Some people like to use a whipping technique, which is a back and forth motion. Others use circles or a weaving technique that is a side to side motion. No matter what technique you use the wire stick-out should never be more than 3/4 of an inch, otherwise, the shielding gas won’t be able to do its job properly.
Here is a tip for those of you who have never MIG welded before. If you need to make a good looking weld or the weld is in a hard to reach area, simply keep spot welding until you complete the weld!
you have to decide if you’re going to use gas-less flux cored wire or a solid wire with a shielding gas. If you’re welding at home, your best bet is going to be to use the gas-less MIG welding wire. If you choose to use a solid MIG welding wire you will have the extra cost of the gas that comes in the bottle and the cost of renting the bottle itself. I believe that you can actually buy your gas bottle out right so you don’t have to keep paying a monthly rental fee.
When you MIG weld you have to use the right sized wire for the right size contact tip. So for example, if the welding wire is 0.9mm in diameter you’re going to need to use a contact tip that is marked 0.9mm. The exception to that rule is if you’re using flux cored wire or aluminum wire. In this case, you need to use a contact tip which is the next size larger, which in this case would be a 1.0mm size contact tip.
Also, you need to make sure that the drive rolls or feed rolls are marked with the same sized wire. There are three different types of grooves that are available for the feed rolls. The profiles available are “vee groove”, “u groove” and a “knurled groove”. Each one is designed for a specific type of wire.
Use a vee groove for solid wire, a u groove for aluminum and a knurled groove for flux cored wire. If you use the wrong roller you will have wire feeding issues which will give you bad welds.
Next, you’ll need to install the welding wire onto the machine. And the trick with the tensioning mechanism is to make sure that you do not tighten it up too much. If it is done up too tight, it will squash the wire out of shape. The copper coating will start to flake off the solid wire and the gas-less and aluminum wire will become difficult to feed through the welding torch.
Now make sure you’re wearing the appropriate safety gear such as boots, overalls, gloves and a welding helmet.
Attach your ground clamp to your work and adjust your wire feed speed and voltage settings according to the manufacturer’s guide. A lot of MIG welding machines these days will have a chart on the inside showing the parameters for welding wire feed speed etc.
If your machine does not have this because it is too old for example, start making some practice welds on some scrap metal. Once you have a good setting then you can transfer over to the job you want to work on.
When you have finished welding you may need to dress up all the welds with an angle grinder depending on how good you were.
MIG Welding Techniques – 3 Basic Patterns That Can Improve Your Skills!
Before beginning to weld you must have a clean joint and your MIG welding machine must be set properly. I cannot stress this enough! MIG welding is very easy to learn but since it is a semi-automatic process much of the skill relies on machine set-up! Once you have that down you are ready to weld.
The 3 patterns that work the best are:
* The whip, a back and forth motion.
* Circles are a circular or oval motion.
* Weaving is a side to side motion.
1| The whipping technique is commonly used on fillet welds. It allows a narrow bead and gives good penetration. When whipping, the back and forth motion also helps control travel speed when doing stringer beads. This technique works well on fillet welds in all positions. This is especially true of fillet welds in the overhead position.
2| Circles are just that! This technique works well on fillet welds and grove welds in all positions. When doing circles you can go from a very small circle that is almost a steady motion to a larger circle that can wash the weld into the sides of the joint. The weld produced can range from narrow to moderately wide bead.
3|Weaving is a side to side motion that is typically used on grove welds or wider joints. This welding technique is most commonly used in the vertical up position. The reason for using this technique when welding vertical up is, it produces a shelf of weld to work upward on. MIG welding in the vertical up position produces a very convex weld. It is very difficult to make a flat or concave weld in the vertical up position unless the weld is wide. Vertical down is a different story and produces a flat to concave weld.
The trick to welding downhill is to stay ahead of the puddle and weave quickly. If your travel speed is too slow, the puddle will roll over the joint, and not penetrate properly. Outside of weaving in the vertical position, all of the other positions work well with the weaving technique. When it comes to weaving, most welders have one thing in common. Most pause on the sides of the joint. This helps spread out the weld and if you count the time when you pause you will produce a very consistent weld.