Several issues in the MIG welding process can contribute to excessive spatter, including: Insufficient shielding gas. Dirty base materials, contaminated or rusty weld wire. Voltage or travel speeds that are too high.
MIG Welding
Materials: Thinner sheet metals and alloys such as mild steel, stainless steel as well as aluminum. 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).
Porosity is caused by the absorption of nitrogen, oxygen and hydrogen in the molten weld pool which is then released on solidification to become trapped in the weld metal. Nitrogen and oxygen absorption in the weld pool usually originates from poor gas shielding.
If your electrode is not completely shiny, you have some argon contamination. It could be from a faulty collet body, a leak, or.... it could be a bad bottle of argon. Look at the steel where you welded also, you should have a symmetrical shiny circle with no heat tint.
Porosity, one of the most common MIG welding defects, is the result of gas becoming trapped in the weld metal. Inadequate shielding gas coverage is among the biggest culprits, and this can be addressed in several ways. First, check the regulator or flow meter for adequate gas flow, increasing it as necessary.
Appearance: Welds should have a consistent, smooth, and uniform appearance. Profile: Depending on the application, welds need to be flat, concave, or convex. Coloration: A good weld will have a color-free appearance that indicates no oxidation has occurred.
Bubble Gum: A poor quality weld that looks like chewed bubble gum. Busted Out: Failed a weld test.
Pushing usually produces lower penetration and a wider, flatter bead because the arc force is directed away from the weld puddle. In addition, pushing usually offers a better view and enables you to better direct wire into the joint.
For primary welding training, programs typically take six months to a year. Functional welding training programs may take longer, and all welding programs will vary moderately depending on the school. A Welding course will not need as long as other, more traditional areas of studies need.
In most cases, the gun should be angled slightly in the direction of motion. This is called the travel angle, and 15 degrees is a good place to start. Looking at the gun from the end of a seam, the angle of the gun to the work is called the work angle. For a butt joint, 90 degrees is ideal.
Typical weld defects found in MIG welding are lack of fusion and penetration, craters and cracks, undercut, burn-through, and porosity in the weld metal.
You will have undercut on the toes of the weld and the weld puddle will be too hot to control and will usually be crowned up in the middle. Another clue is if you burn a rod down to about 3 inches long and your stick welding rod is glowing red, you are too hot.
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.
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.
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.
A caterpillar weld is usually incorrect settings (cold) or moving too fast, or both.
Some argue that stick welding is stronger than MIG welding, since it offers better penetration for thicker materials. However, MIG welding can provide good welds despite not being as effective on thicker metals, and is better for joining thinner metals with a good finish and less risk of burn-through.
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.”
A: Ropey welds — welds that are too convex and high— typically occur when welding with too high of wire feed speed and too low of voltage. This is particularly true in the flat and horizontal position. Increase the welding voltage and/or decrease wire feed speed to remedy the problem.
Horizontal Welding Position
It is more challenging to perform than vertical and overhead positions and requires higher skill. In the horizontal position, the weld axis is roughly horizontal. The position is executed based on the type of weld. For a groove weld, the weld face is along a vertical line.