Welding is an indispensable process of many industries in society. It has important role in evolution of economy. However, welding also is a dangerous job with many risks in working process from the risk of explosion, fire to unfortunate injuries when working. Therein, owning the best welding helmet is an indispensable thing in welding. In addition, if you are beginners there are many things which you have to know before starting the job. Below are some helpful advices in welding for beginners.
- Choosing electric source
With electric source when welding, choosing power of source depends on size of welding rod which you will use. Normally, if welding machine has intensity about 300 to 350 A and cycle about 60% is standard welding machine because this machine can use the welding rods having diameter from 1,6 to 6,3 millimeters. If your job usually use the welding robs having diameter 5 and 6,3 millimeters so you should use electric source having intensity about 400 to 450 A. In addition, if your job just require welding the thin pieces so you just need to prepare welding machine having intensity about 200 to 250 A because maximum diameter of welding rod in this case just usually is 3,15 or 4 millimeters.
You can use both direct current and alternating current for welding machine; however, normally direct current usually is suitable choice to implement welding on almost types of metal and all types of welding rod. Therein, when choosing direct current or alternating current for welding job need to depend on welding metal as well as type of welding rod, for example you can choose suitable electric current based on manual of producers of welding rod (normally, it will be written on the box of welding rod).
- The other factors
In addition, in order to choose suitable electric current for your jobs, you should consider about some following factors:
All types of welding rod can be used with direct current therein, when welding on alternating current, some types of welding rod for ferrous metals and welding rod for steel usually is not unstable. In addition, welding rod using with alternating current usually have to contain arc stable substance in cover.
When using welding rod having small diameter, direct current will have more advantages than alternating current about ability to cause and maintain arc.
With all sizes of welding rod, direct current will help users maintain short arc easier than alternating current (expecting welding rod containing iron powder).
Welding when standing and welding with thick materials with direct current will be easier than alternating current because users can maintain stable arc at low intensity.
Electrode of welding with alternating current does not have important role because welding line changes electrode continuously in welding process. With direct current, welding rod linking with suitable polarity can weld all types of steel however you can not use it with several ferrous metals. When using positive electrode, heat of arc will concern at welding rod therefore melting and welding speed will be higher than using negative electrode thereby users can weld faster as well as do not make welding materials transformed. Negative electrode usually is used to weld almost ferrous metals. It allows maximum fusion welding.
In addition, you need to attention that when arc welding with electrode made by tungsten in inert gas so role of welding electrode not like that (do not have effect of metal ion and slag in arc). When arc welding by tungsten electrode in inert gas, 2/3 amount of heat of arc is created on positive electrode and 1/3 on negative electrode. Therefore, people usually weld by positive electrode in order to avoid burning electrode as well as gaining the best result.
In addition, welding with direct current can lead to status deflection arc especially when you weld at the corners, end of welding line or at the structure having many details linked together. Intensity of welding line too large also easily cause deflection arc. Welding with alternating current will not cause deflection arc. Decreasing welding voltage when using long welding cable also is problem which you should consider when welding, welding cable too long can make electric source overload as well as decreasing intensity of welding line.