September 5, 2018 by Bob Wilson Mistakes can happen during a welding process. Defects often occur because of an incorrect process or technique; mistakes could also happen due to a lack of skill on the welder’s part.
We’ve been providing welding services in Edmonton for more than a decade now. We’ve refined and continue to improve our techniques to ensure that we handle stainless steel and aluminum efficiently and without defects. As a guide here are common welding defects and their preventive measures:
Getting Rid of Porosity
Porosity often happens due to weld metal contamination. As the trapped gases make a bubble-filled weld, the metal could weaken and collapse.
Here’s a list of why porosity occurs:
Using a longer arc
Improper gas shield
Contaminated surface
Using too high gas flow
The presence of moisture
Inadequate electrode deoxidant
Presence of pain, grease or oil, or rust
You can remedy the porosity of the weld by cleaning the materials before you start the process. Using the correct arc distance and a proper weld technique can also help resolve cavities. The right electrodes — dry ones, for instance — and materials, can also correct this welding imperfection.
Preventing a Weld Crack
A weld crack is the most serious type of welding defect. Almost all standards in the industry don’t accept it. This type of defect can appear in the weld metal, on the surface, or the area affected by the intense heat.
There are different types of weld cracks, as well. These include hot cracks, cold cracks, and crater cracks. This type of defect is often caused by the following:
Poor joint design
Base metal contamination
Failure to preheat before beginning welding
High welding speed matched with low current
Using hydrogen when welding ferrous materials
The metal contains a high content of sulfur and carbon
Prevent this type of weld defect by using the right metal. You’ll need to remove the impurities in your metal and preheat it as required. Additionally, use the proper joint design for the material and properly cool the welded area. Be sure to weld enough sectional areas, too. Use the right amperage current and welding speed. You need to properly fill the crater to prevent crater cracks.
Avoiding an Undercut
The groove formation at the weld toe is called an undercut. This welding imperfection lowers the base metal’s cross-sectional thickness. The undercut results in a weakened weld and material.
These are the following causes of the undercut defect:
Wrong filler metal
Excessively fast weld speed
Poor weld technique
Too high weld current
The electrode is too large
Incorrect use of gas shielding
Using an incorrect angle, directing more heat to free edges
Avoid this type of defect by picking a welding technique that doesn’t involve excessive weaving. Try to lower the arc length and the travel speed of the electrode. When welding is taking up too much time of your process, leave the task up to us. Our one-stop shop in Edmonton provides quality steel products and excellent welding services, giving your business an edge over the competition.
A Trusted Welding Company
Advantage Manufacturing Ltd works with commercial and industrial clients on a wide range of projects of any scale. With our advanced equipment and experience, we can bring your ideas to life or send technicians for on-site repairs. Whether it’s stainless steel, aluminum or custom work, we’ll provide quick, efficient services. Contact us today for your projects.