Welding is a process where two or more metal pieces are fused together by the use of extreme heat and pressure and sometimes with the addition of the other metals or gases. Besides, different parts of thermoplastics can also be joined together by means of welding. Welding is often used for the manufacturing of various metallic structures and it happens that people’s lives can depend on the quality of the welds in such metallic structures. So don’t forget that low-quality welds or even common welding defects are not good and can be unsafe.
What Are the Main Three Types of Welding?
In fact, there are more than 50 types of welding (see more https://schweissgeraet-testsieger.de/einhell-bt-fw-100-test/), but basically, welding can be divided into three main types:
- Stick Welding (Shielded Metal Arc Welding): Being the easiest and the most popular type of welding, stick welding is featured by the low-cost equipment that works perfectly on any surface.
- TIG (Tungsten Inert Gas) Welding: It is used for a greater variety of materials. TIG welding also creates high-quality welds and it is characterized by the non-smoke fume production.
- MIG (Metal Inert Gas) Welding: This welding type is usually used for fusing mild steel, stainless steel and aluminum.
What Are the Most Common Welding Defects?
Unfortunately, your welds are not always strong, clean and sharp-looking. That’s true! Some of your welds can be really imperfect. But don’t worry about that! You should understand that any welder can make a mistake and get poor welds.
Welding can be a challenging task and most welders are faced with the same kinds of welding defects. In most cases, these defects are noticed by the welders only after they have finished their welding. However, these are the kinds of defects, which are pretty easy to identify and, luckily, correct or even prevent with relative ease.
Here is a list of the most common welding defects:
- Weld Cracking;
- Poor Fusion;
If you want to prevent common welding defects, first of all, you have to be sure that the material you’re going to use is clean and of good quality. Check that before you start welding! If you find any grease, oil or paint or if you’re in doubt about the material quality, you should suspend your work and remove any material that can contaminate your weld or even replace the material. Remember, this pre-weld inspection will keep you out of common defects related to the welding process and save your time as well.
What Are the Main Welding Problems and Solutions?
However, if there is something wrong with your welds, you have to detect the kind of problem and try to solve it. Below you’ll find the main welding problems and the instructions on how to fix them.
Weld Cracking is one of the most common and most dangerous defects that can happen with your welds. Weld cracks are not accepted by any the standards in the welding industry and must be corrected urgently because even the smallest crack will become larger over time and can lead to serious consequences. Cracks can be cold, hot and crater. They are usually caused by:
- welding without preheat preparation;
- unbalanced sizes of welding pieces;
- wrong electrode choice;
- using inappropriate metal;
- rigid joint design;
- low welding current but high speed.
Solutions. It isn’t simple to correct welding cracks because fixing a welding crack means creating a new weld! So, it would be better to prevent any cracks and for that, you should:
- heat pieces before you start welding;
- use proper amperage current and welding speed;
- use right metal;
- avoid impurities;
- adapt welds size to parts size.
Porosity is another great issue that often occurs in the welds creating bubble-filled areas in them. It is caused by:
- improper gas shielding;
- insufficient electrode deoxidant;
- incompatible base metal;
- dirty surface.
Solution. If you want to avoid this problem, it is important to:
- examine shield gas;
- use the right electrode;
- choose appropriate metal base;
- clean the materials before welding.
Poor Fusion is a type of welding problem when there’s a lack of complete fusion between the base and weld metals. This issue is often caused by:
- wrong electrode angle;
- incorrect diameter of the electrode;
- contaminated surface;
- too large weld pool that runs ahead of the arc.
Solutions. The best ways to adjust fusion are:
- clean the surface before welding;
- choose the correct electrode diameter;
- use the right electrode angle;
- try not to flood the arc by avoiding the molten pool.
Undercut means that there is a groove at the weld toe. Welding undercut always weakens the weld and needs fixation. This problem can be caused by:
- very fast speed of welding
- very high weld current;
- wrong electrode choice (too large one);
- using the wrong filler base;
- bad welding technique.
Solutions. In order to avoid undercut when you weld, you should:
- pick out the right electrode (avoid using too large one);
- use proper current when welding;
- use the moderate speed of welding;
- find the proper filler base;
- use multi-pass welding technique.
When it comes to the common welding problems, you should understand that everyone can make these mistakes, even the pro welders sometimes make them. The important thing is to find such problematic welds and do your best to correct them!