Aluminum is a light weight metal. It has great mechanical properties so that it can be formed into right shape as per your needs. Welding, machining, forging and casting can be performed very easily with aluminum. In order to use aluminum for high temperature applications, it should be mixed with other metals. There will be improvement in strength, appearance and cost factor when you go for alloy. There are different processes which can be implemented as per the pros and cons.
Welding aluminum and alloys
Aluminum and alloys can be welded in a very satisfactory manner by using arc welding process. If you go through ‘how to weld aluminum’ information, you will understand various metal-arc and carbon-arc welding procedures. When pure aluminum is mixed with various kinds of metals, there will be improvement in mechanical and thermal properties. Based on the composition of the alloy some can go through heat treatment and some cannot go through heat treatment.
When you implement arc welding process, highly concentrated heat zone will be created. The metal should be distorted beyond certain limit. The aluminum welding is different from stainless steel welding. Aluminum has high thermal conductivity. There will not be any color change even though it reaches the melting point. It has low melting temperature and very high thermal expansion coefficient. Hard and thin aluminum oxide surface will be formed when aluminum reacts with the oxygen present in the air.
If the moisture in air is absorbed during welding, it leads to porosity issues. If there is rapid cooling, hydrogen will be retained during the solidification of the weld. The presence of hydrogen leads to porosity. The welding strength and ductility will also decrease in this process.
How to weld aluminum? In order to accomplish welding in the best possible way, quality welding rods should be used. In order to repair pipes and tanks welding sticks are used. Even though there is wind, the welding will be done in the best possible way. However, it will not lead to precision work. Aluminum welding rods are used by skilled welders so that the welding will be strong and deliver the performance without any issues.
The flux formed during the welding process should be removed in a successful way. Instead of using aluminum welding rods, you can use wire feed welding so that there will be great quality enhancement. As there are different kinds of aluminum alloys, you should be aware of the information about different kinds of alloys.
1xxx series alloy group is widely used in electrical and chemical industries. These alloys are made with 99% of aluminum or higher purity. In case of 2xxx purity, copper is the principal alloy. After accomplishing the heat treatment very high strength will be obtained. In case of 3xxx series, manganese is the main alloy. However, it will not allow you heat treatment operations. The melting point is reduced by using 4xxx series alloys in which silicon is the major component. In order to perform cold working and obtain good corrosion resistance, 5xxx series is used. 6xxx series is used to accomplish heat treatment in the best possible way. Silicon and manganese is present in 6xxx series. Zinc is the major component in 7xxx series. Aircraft frames are prepared with aluminum alloy compromising of zinc and magnesium.
Cleaning during welding
If you go through ‘how to weld aluminum and enhance its strength’ topic, you will also learn about the cleaning process. Because of the great affinity with oxygen, aluminum oxide will be formed on the surface. Before performing welding, brazing or soldering operation, the film should be removed. Before preparing the surface, the film should be scrapped off. The scrapping can be done by using a sharp tool. Sand paper, wire brush and similar kind of items can also be used to perform the scraping in the best possible way. The formation of flux can also be prevented by using inert gas.
Aluminum welds should not be cleaned with caustic soda. Solutions whose pH value is above 10 should not be used in this process as they are prone to react chemically. if the cleaning is not done properly un-melted oxides will be trapped in the weld pool. It will have impact on physical properties such as ductility and weld cracks.
How to weld aluminum plates whose thickness is less than 1/8 inch? If the plate thickness is less than 1/8 inch, it is difficult to control the arc with butt and fillet welds. Metal arc welding is suitable for heavy material and it can be used for plates up to 2.5 inch thickness.
During the arc welding process, the current and polarity settings should also be checked. The settings should be changed as per the manufacturer of electrodes. There are different types of welding techniques. You should choose right technique based on the type of joint, alloy composition and functionality.