1. Stick welding
Stick Welding is the simplest form of welding. The technical term here is Shield Metal Arc Welding, abbreviated to SMAW. The coating ensures that the weld zone is not exposed to air while the rod is melting. This method is relatively cheap and compatible with most metals. SMAW is widely used in a number of applications i.e. construction sites, workshops, shipyards, pipelines, farm repairs, D.I.Y etc.
The quality of stick welding can be very good but requires skilled welders. The heat input is typically low, which gives a fine microstructure in the weld metal. This produces very good mechanical properties; however, the slag that protects the molten weld metal from the atmosphere can produce slag inclusions if not cleaned properly between passes and at the stop and start of each weld. There are many stops and starts in large welds, which quite often are where defects are found.
Shielded Metal Arc Welding (Stick) is the most popular welding process. It is the most versatile and uses the simplest equipment. The small light electrode and holder can be used in very tight places or reach several hundred feet away from the welding power supply.
For this type of welding, you will use a shielded metal art welding or more commonly known as Stick welding. You will use a consumable and protected electrode, or stick. The stick softens and combines metals by heating with an arc between a covered metal electrode and the base metal workpiece. As the stick melts, its protective cover also melts and shields the weld area from oxygen and other gases that may be in the air.
Often referred to as stick welding, it is a manual arc welding process using a consumable electrode that is covered with a flux to make the weld. The molten metal is free of nitrates and oxides in the atmosphere, making it fit for pipeline welding and construction, steel erection, and heavy equipment repair.
2. Flux-cored welding
FCAW welding also referred to as flux cored welding is a semi- automatic or automatic process. FCAW requires a continuously fed consumable, tubular electrode which contains a flux. Common applications for FCAW arc welding, construction, heavy fabrication, earthmoving, shipyards.
Flux-cored arc welding is similar to MIG welding because both use continuous wire and power supplies. You will combine a continuous electrode with a base metal. The electrode is a hollow tube filled with flux that is fed through the weld gun and into the weld pool. When welding outdoors, a flux shield offers protection against weather elements. This type of welding is used for welding thicker metals and is used in machining industries.
Flux-cored Arc welding has all the speed of MIG welding, with the efficiency of Stick welding. Like with MIG welding, workers performing Flux Cored Arc Welding have a continuously fed wire running through the gun. However, this wire (the consumable electrode) has a flux core, just like the electrodes used in stick welding. This eliminates the need for the addition of inert gas that MIG welding requires.
Flux-cored arc welding (FCAW) uses a continuous hollow wire electrode with a flux compound that protects the weld pool by forming a gas. FCAW is ideal for outdoor welding and for welding on dirty or contaminated materials, since it doesn’t require an external shielding gas to protect the weld from atmospheric elements. Much like the SMAW process, FCAW also produces slag that is chipped off after the weld to give it a clean look.
This type of welding is preferred for its speed and higher electrode efficiency. There are many different kinds of electrodes available for this kind of welding. Most of these are either self-shielded or gas-shielded and come in an array of classifications. Before starting any Flux Cored Arc Welding project, make sure you check the different types of FCAW electrodes to make sure that you have the right one for your project.
3. Arc welding
Arc welding uses an electric phenomenon called arc discharge. An arc discharge is an electric discharge phenomenon of a gas and refers to current released in air. When the voltage applied to two spatially separated electrodes is gradually increased, the air insulation finally breaks and current flows between the electrodes, emitting bright light and high heat at the same time.
The generated arc-shaped light is called an electric arc or arc. Arc welding is welding using the heat of an arc as a heat source. In arc welding, positive voltage is applied to the electrode (welding rod/wire) and negative voltage is applied to the base material. This makes an arc occur from the base material to the electrode. The output current of the arc is about 5 to 1,000 A and the output voltage is about 8 to 40 V. The temperature of the arc is about 5,000°C to 20,000°C. The melting temperature of iron is about 1,500°C. Consequently, the base material and electrode are heated to a high temperature and fuse together.
Now that you have chosen your most preferred welding technique, let’s take a look at the equipment, you will need to achieve your welding needs. If you are new to welding, we would recommend two main types of welding equipment – a MIG welder or a MIG/TIG/Stick.
multi-process welder. The last one comes handy, irrespective of the basic arc welding type you have chosen. Although the electric stick welders are cheaper, you will need to put in a lot of practice to get a hold of it. So, if you are just starting or you don’t weld regularly, you should get a wire feed welder.
It is vital that the welder must be able to weld to a level in which their work can pass a destructive type of bend test.
4. Materials handling
There are multiple types of NDE, but the most common are a visual inspection, radiographic inspection and liquid penetrant inspection. These inspections test to ensure there are no faults in the weld. This ensures longevity and quality of the product. If a weld fails an NDE, it is back to the PQR stage. Writing a WPS can sound simple at first, but once you learn the gritty details of the process, it can seem like a massive undertaking. The process is extremely strict because by creating a WPS, you are creating a standard.
Do NOT permit untrained personnel to install, operate or maintain equipment. Do NOT attempt to install or operate equipment until you have fully read and understand these instructions. If you do not fully understand these instructions, contact your supplier for further information. Be sure to read the Safety Precautions before starting any installation.
Two of the most common challenges, especially in construction sites, are burn backing and birdnesting which cause wire feed stoppages. Burnback is when the weld accumulates in the contact tip due to the incorrect wire feed speed. For instance, if the wire feed speed is slow or if the gun is too near the metal.