Among the commonly known welding defects, incomplete penetration and fusion, porosity and slag inclusions are the most common to affect welding strength.
Weld from the bottom up.
Like building a house, you cannot start the bricks at the top. Weld metal is a liquid. When it goes in it needs support, that is why we need to always start at the bottom.
Bubble Gum: A poor quality weld that looks like chewed bubble gum. Busted Out: Failed a weld test.
Electric shock is the most serious hazard posed by welding and can result in serious injuries and fatalities, either through a direct shock or from a fall from height after a shock.
The major cause of a crack is when internal stresses exceed the strength of the weld metal, the base metal, or both. And once a focal point for these stresses—that is, a stress riser—develops and accumulates, a crack can propagate.
Signs of a bad weld include: Lack of uniformity, cracks down the middle of the bead, too thin, and/or a lack of discoloration of the parent metal (which should be about 1/8 of an inch).
Where cracking occurs in or adjacent to welded joints, a satisfactory repair may be made by welding. It is important that the cracked material is gouged or machined away sufficiently to permit a full penetration repair weld to be made, with no traces of crack left behind and no new significant defects introduced.
Three of the most common are Arc, MIG (Metal, Inert Gas) or GMAW (Gas, Metal Arc Welding), and TIG (Tungsten Inert Gas) welding. In order to know which process is best for the particular job you're working on, here's what you should know about each of them. Arc welding is the oldest of these three welding processes.
The three most common welding types are – Arc, MIG and TIG welding.
Weld defects are often caused by improper technique or parameters, such as poor shielding gas coverage or incorrect travel speeds.
Prolonged exposure to welding fume may cause lung damage and various types of cancer, including lung, larynx and urinary tract. . Health effects from certain fumes may include metal fume fever, stomach ulcers, kidney damage and nervous system damage.
Protect your entire body with fire retardant clothing, shoes, and gloves. Wear eye protection at all times. Weld only in a firesafe area. Never do any welding, cutting, or hot work on used drums, barrels, tanks, or other containers.
A: You can receive a shock from the primary (input) voltage if you: touch a lead or other electrically "hot" component inside the welder while you have your body or hand on the welder case or other grounded metal with the power to the welder "on."
TIG welding is the hardest form of welding to learn for a variety of reasons. The process of TIG welding is slow and takes time to get used to as a beginner. A TIG welder requires a foot pedal to feed the electrode and control the variable amperage while maintaining a steady hand at the welding torch.
An edge joint is the weakest type of weld join, so isn't suitable for load-bearing jobs.
Welding in the overhead position—with the workpiece directly above the welder—is widely thought to be the most difficult welding position. Pipe welding is also well known to be particularly challenging welding work.
It should be remembered that welding over weld metal is actually a very common occurrence. Multi-pass welds after all are manufactured by welding over weld metal! There are also many accepted procedures in which welds overlap.
Porosity is caused by the absorption of Hydrogen, Oxygen, Nitrogen, or Contaminants, trapped in the weld pool. One reason this could be caused is due to a lack of gas coverage since the contaminants from the atmosphere can enter the molten pool, creating pinholes in the solidified weld.