When it comes to welding, there is a variety of material that you work with and you will want to know the best methods for each material. Welding is a very old occupation that dates back hundreds of years and, as expected, it has changed significantly over time.
A brief history of welding
Welding in a nutshell is a very old process of joining metallic materials through melting. The material is usually steel which, after it has been melted, is put through a cooling process and the joints are fastened. Joining metals goes back as far as the bronze and iron ages in the near east and Europe. In later generations welding was used in India and iron was the prime material. In the 1800’s welding was starting to use advanced methods that were developed by Sir Humphrey Davy of electrical arc. In the 1880’s Nikolai Slavyanov continued to use advanced methods in a process which he developed called metal electrodes. The 19th century would see the developments of techniques such as resistance welding, thermite welding, oxyfuel welding, and arc welding. Welding would continue to advance through the influence of the military in both world wars.
20th century advanced methods
After the war, methods such as stud welding, submerged arc welding. In the industry of shipbuilding and automotive there are a number of different methods that were used, some of those methods would be:
- MIG (Metal inert gas), or gas metal arc welding, this is a popular welding method; it has great versatility and the welding time is very fast. The popular metals used would be aluminum, stainless steel, and mild steel.
- TIG (Tungsten inert gas), or gas tungsten arc welding, this is a process,which uses a tungsten electrode, inert gas, and other materials to act like a filler. The combination of all these different materials helps to join everything together. It is important, that experience welders use this method, since it will bring about such a high quality.
- SMAW (Shielded metal arc welding), this is also referred to as stick arc welding. A very basic process, and easy one to master; very popular in home projects.
- Gas Welding, also referred to as Oxy Acetylene Welding is a very old method and is used for repair work in things such as pipes, and tubing. The costs are reasonable and if you have a good welder, it can do the job.
- Resistance Welding is a process that involves generating heat resistance from a number of metals. It is very energy efficient, a high production rate; there is no need for filler. The only problem with this method is that it produces very low weld strength, so it is not used for just any application. Do your research if you decide to use this method.
- Energy beam welding is a process that makes use of high laser beams and has a very high energy density, which will help reduce the size of the weld area. This method is quite reliable, but it may not be the most cost efficient method and you must be aware of potential thermal cracking.
- Solid state welding is a process which does not involve melting pieces of material. This method uses procedures such as ultrasonic, explosion, friction, magnetic pulse, co-instruction, cold exothermic, diffusion, hot pressure, high frequency, roll and induction welding.
These are some of the most common methods; some of them are more advanced than others and some require very sophisticated equipment. But more than likely, you will be able to find what you need to for your project.
What other methods to consider
If you do not have the equipment, or if you’re on a tight budget, you may want to look at other options. One thing to look into is parts, which may have specific joint designs. Many joint designs can cater to specific welding methods. Some of the joint designs used are:
- Butt joint
- Edge joint
- Corner Joint
- Lap Joint
Lap joints are a great joint to use if using laser beam, resistance and electron beam welding. If you are trying to start your own business, and looking to invest, TIG and MIG welding are very common methods and pretty cost efficient. If you decide to use these methods the benefits are:
- The effectiveness of the method
- Pretty easy to learn
- Very low hydrogen
- High rate of deposition
- Less amount of cleaning
- The welding time is much quicker
- There is not much skill involved (MIG)
- Very efficient
- The results are pretty consistent
- Can be used on a variety of metals (TIG)
There are some faults:
- High Maintenance (MIG)
- Start up is costly (MIG)
How to test for quality
When you want to test the quality of your weld method; there are two ways:
- Destructive, when using this method you will want to utilize a stress gauge, a high-speed camera, and a sound detector. This equipment will capture any flaws, so you can make the proper adjustments.
- Non-destructive uses a number of techniques that will not risk causing damage to your material.
These methods check for things such as:
- HAZ (heat affected zone)
- Deficient wire delivery
- Lack of fusion
- Lamellar tearing
- Gas inclusions
There are also alternate methods to consider such as:
- Visual inspection
- Ultrasonic testing
- Magnetic particle inspection
- Dye penetrant inspection
- Industrial computed tomography
If you decide you want to have a profession as a welder or as an inspector, know that you will be exposed to high levels of heat, which may cause potential health problems. It is important to take proper steps to avoid any health risks:
- Wear protective equipment
- Have the areas equipped with plenty of equipment for ventilation
- Have fire extinguishers near by in case of a fire
- Do not use galvanized steel due to levels of zinc
When you take these precautions, and know the various methods welding can be enjoyable and highly effective. This will help you in knowing what method works for you in regards to welding.
What is the best method
If you’re new to welding I would say the best method SMAW (Shield Metal Arc Welding); the reason being is, as I mentioned it is a very basic method, and it is easy to adapt to, and it is good for home projects. When you can master this method, it will be easy to adapt to other forms of welding. SMAC, can be used on basic materials, which can be easily obtained, and it will overall have you become familiar with the process. When you become comfortable, you can move to other methods, I would encourage MIG (Metal Inert Gas), this method is very popular, so you could find someone to help walk you through the process, and it is easy to obtain stainless steel. Both of these methods, are also the most cost efficient, and the most reliable. Some of the other methods may not yield the results you need, or finding the right material may be difficult. If you want to work with lasers, that could be a very interesting method, but that will be a major investment, and you will need to have experience before beginning a method such as that.