16 Oct 2019
Top 3 Welding Defects And Their Remedies
Defects are very common in every manufacturing industry such as welding industry, fabricating industry. They can be occurred due to improper technique. If you consider the welding process then you will get a list of welding defects. Among them, three defects are most identified. They are weld crack, porosity and undercut. However, they can be easily avoided.
This is one of the most common types of welding defects and also considered as a serious defect. Based on the temperature, welding crack is classified into 3 different categories. They are hot cracks, cold cracks and crater cracks.
Hot cracks: These cracks are common. They generally occur during the crystallization method of any welding joint.
Cold cracks: Cold cracks are also very common. They occur when the solidification starts at 200 degrees Celsius.
- Crater cracks: Crater cracks generally appear when the arc is prematurely terminated in the weld crater. These are shallow cracks.
- There are many ways to avoid this welding defect. Some common ways are:
- Metal preheat
- Use the right joint design.
- Remove impurities.
- Use proper metal.
- Use only the appropriate welding speed
- Fill the crater properly.
Porosity generally occurs due to the absorption of different trapped gases such as hydrogen, oxygen and nitrogen in the weld pool. This is another common welding defect. There are several reasons for this defect. It can be generally caused by insufficient electrode deoxidant, moisture presence, poor gas shield, improper surface treatment, huge gas flow, contaminated surface, presence of grease, paint, rust or oil.
Porosity can be easily removed by cleaning materials. Dry electrodes should be used and the arc distance should be properly maintained. Other common ways are:
- Identify the gas flow.
- Check the pressure and current settings
- Minimise the arc speed that allows the gases to reduce.
- Usage of right electrodes.
- Advanced welding techniques is highly essential.
The undercut is a welding imperfection. The undercut can be occurred due to many reasons. They are an excessive flow of welding current, improper welding speed, use of a large electrode, poor welding technique, improper usage of shielding gas and filler metal.
the undercut can be easily avoided by using the right electrode angle. The arc length must be reduced. Travel speed of the electrode must be maintained. Proper welding technique must be essential.
Porosity undercut and weld cracks can be easily identified by a welding inspector. During the inspection, he or she properly check every portion of the welding joint and if the defects are identified then necessary steps can be taken.