A good weld should be visually appealing, with a smooth and uniform weld bead that shows proper fusion and penetration. Bad welds, on the other hand, may contain defects like porosity, pinholes, or slag on the weld surface, which can compromise the strength and reliability of the weld.
The sign of a quality and secure weld is that you will not see the weld at all. If there is any visible evidence of a weld, it will be in the form of a bead that has no holes or cracks and is uniform overall. A high-quality weld is made using high-quality materials.
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).
The goal of a weld bead is to create a strong bond with the base material that has sufficient penetration or fusion. A good-looking weld is clean and is the same color as the base metal, both inside and out-. The width of the bead should be consistent and have an attractive face surface profile.
Gas Tungsten Arc Welding (TIG) is probably the highest quality and most expensive of the arc welding processes. It is generally performed manually; however, there are some automatic applications.
A good weld is easy to distinguish. It will be straight and uniform with no slag, cracking, or holes. There will be no breaks in the weld. It shouldn't be too thin and there should be no dips or craters in the bead.
Stick or Arc welding
Stick welding is a manual arc welding process that uses a consumable electrode covered with a flux to lay the weld. It produces strong welds and works well with thicker materials. It is a versatile welding process, is simple to set up the equipment, and is generally easy to learn.
Common causes of weld undercut include excessive voltage with too fast of travel speeds and improper gun angle. When the voltage is too high, the arc tends to push the molten weld pool out of the joint. To prevent the problem, lower your voltage and reduce your travel speeds.
Among the commonly known welding defects, incomplete penetration and fusion, porosity and slag inclusions are the most common to affect welding strength.
A weld that is too small or too short for the application can fail from tension, compression, bending or torsional loads. If a weld is made to be in an application where a cyclical load is going to be applied, it will be beneficial to consider a filler metal option with increased impact toughness and ductility.
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.
Bubble Gum: A poor quality weld that looks like chewed bubble gum. Busted Out: Failed a weld test.
The four main types of welding are: Gas Metal Arc Welding (GMAW/MIG), Gas Tungsten Arc Welding (GTAW/TIG), Shielded Metal Arc Welding (SMAW), and Flux Cored Arc Welding (FCAW). Earn your degree in Welding Engineering Technology from NEIT and begin your new career path today!
The torch will sizzle, with the occasional pop. This usually means that your welder is set up properly and you are laying a quality bead. Popcorn Popping: If your welding sounds more like popcorn than bacon, with lots of snapping and popping, this may signify that your wire speed is too fast.
Aluminum. The first impression of aluminum is that since it is pliable and easily manipulated, it should be easy to weld. In reality, it is considered to be the most difficult metal to weld since it is an alloy and therefore mixed with other metals. Some have even called welding with aluminum a “nightmare.”
Weld metal is usually always tougher than mild steel.
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.
Avoid Clutter
Sparks from the welding arc can fly up to 35 feet in distance, so it's important to keep your workspace clear, especially of any flammable materials. As a general rule, always stay organized and keep everything in its place.
The weld quality of a joint is highly dependent on factors like material properties, spatial distribution, e.g., location of heat sinks along the weld path and geometry of joint, temporal history of the material temperature of the welding process and cooling rate [329].