To begin with, they have different colored bands that are used to identify them. However, there are several other important differences to consider when selecting a tungsten. Here some of the various types with the respective characteristics:
EWTh-2: 2% thoriated tungsten. EWTh-2 is color-coded with a red band. It is known for its durability, ability to withstand high currents, and excellent arc starts. It is primarily welded using a negative polarity and direct current. It does not have great characteristics when welding with AC.
EWLa-2: 2% lanthanated tungsten. EWLa-2 is color-coded with a blue band. It is known for its excellent arc starting ability, excellent current carrying ability, and can withstand many arc cycles. It can be welded as the negative electrode using direct current or with alternating current.EWP: Pure tungsten electrode. EWP is color-coded with a green band. It has excellent arc stability. It is almost exclusively used with alternating current. Tungsten emission is more likely with a pure tungsten electrode when compared with other alloyed tungsten electrodes.
EWCe-2: 2% ceriated tungsten. EWCe-2 is currently color-coded with a gray band, although in the past it was color-coded with an orange band. It is quite similar to EWLa-2 in that it has excellent current carrying ability, excellent arc starting ability, and can last through many different arc start and arc termination cycles.
How do I prevent wire feeding issues when using the MIG welding (GMAW) or flux-cored arc welding (FCAW) process?
Wire feeding issues can be caused by a variety of circumstances. Some of the most common reasons for wire feeding issues include:
- Drive roll tension: The drive rolls that push or pull the wire through the system have a tension that is either too great or too little. Adjust the spring pressure until tension is appropriate.
- Drive roll size: The drive rolls may be the wrong size. For instance, if 1.3 mm drive rolls are being used to move 0.9 mm wire, slipping will most likely occur.
- Drive roll type: Some wire require specific kinds of grooves for optimal feeding. Flux-cored and metal-cored arc welding wires typically require V-groove drive rolls that are knurled. Aluminum wires require a smooth U-shaped groove.
- Drive roll condition: Worn drive rolls will be ineffective at moving wire through the system.
- Liner size: If a liner is too small for the wire it will not feed. If the liner is too big, the wire may have too much freedom to twist inside of it, causing an unpredictable feed.
- Liner type: For most wires, steel liners work excellent. However, some wires, such as aluminum, require a nylon liner to help ensure proper feeding.
- Liner condition: A worn liner will be detrimental to wire feeding. Replace the liner if it is worn or damaged.
- Contact tip size: A proper contact tip size should be used. If the tip is too small, the wire will not feed; if the tip is too large, wire feeding and electrical conductivity may be negatively affected.
- Wire condition: Not all wire manufacturers put out the same quality product. Some wires may have thin and thick spots as well as lubricants that can cause poor wire feeding.
By guest blogger David H.
Some years back I was working in a shipyard in San Francisco. The yard had several small repair jobs going, plus a fairly large project building six ocean-going barges. The supervisor who was in charge of the barge-building project was looking for volunteers to operate semi-automatic wire feeders, using flux-cored wire, to weld stiffeners to the skin of the barges. I had never used a wire feeder before, so I volunteered out of curiosity.
After a very short training period, possibly all of 30 minutes but I think a bit less, I was off and running. I was impressed by the quality of the welds and the speed at which they were deposited. Without question I was outpacing anything that could be done by stick welding, and I felt it was easier to maintain a uniform weld size too. The machine itself was light enough and small enough to move without difficulty, and the spools of wire lasted long and were quick and easy to replace when the spool of welding wire was finished.
Red-D-Arc has nearly a dozen semi-automatic wire feeders available for almost any application. We also carry fully automatic wire feeders, which are faster still and appropriate in certain circumstances – like building storage tanks – especially for large-deposition welds.