How ABS Machining is Improving Deposition Rates with Sub-Arc Welding
There are several forms of arc welding but one method stands out for its ability to increase productivity and efficiency while producing consistent, high-quality welds: sub-arc welding. Sub-arc welding, or SAW, provides the highest deposition rates as well as the deepest penetration of any arc welding process. This welding technique also improves the working environment for personnel by reducing fumes and eliminating an open arc that creates splatter during operations. For these reasons, companies that utilize sub-arc welding benefit from greater productivity and a significant competitive advantage. The following explores the SAW process in more detail and explains how ABS Machining is improving deposition rates with sub-arc welding.
What is Sub-Arc Welding?
Sub-arc welding is utilized in various sectors including heavy industrial applications. This technique consists of a welding head that continuously feeds filler metal and a granular flux, such as silica or lime, into the welding zone. The filler material is often referred to as an electrode or wire. The term “sub” is short for submerged, which describes the arc that is buried under the flux during welding operations to protect the arc and the weld. When operations begin, the wire and flux are fed through a torch that is positioned along the weld joint. The arc heat melts some of the wire, flux, and metal pieces that are being joined together, forming a pool of molten material. Once melted, the flux becomes a conductor between the electrode and the metal being welded together, enabling a current path. Any excess flux is called slag and is removed once the weld is completed.
How SAW Improves Deposition Rates?
One of the key performance indicators of welding is the deposition rate, which is simply the amount of usable weld metal that is deposited into the weld joint in one hour of arc-on time, and is measured in pounds per hour. In general, the higher the deposition rate, the higher the welding productivity. As with any manufacturing process, there are several variables that impact the deposition rate of sub-arc welding. Below summarizes how several of these variables can be modified to improve the deposition rate. It should be noted that OEMs should consult with a trusted and knowledgeable fabrication partner, like ABS, to determine the best combination of the variables below for each given welding application.
- Polarity: the electrical circuit that is created during sub-arc welding has a positive and negative pole that is referred to as polarity. Wire-fed welding techniques are able to employ different polarities. Polarity is an important consideration since it impacts the characteristics of the weld. Generally speaking, welding with Direct Current Electrode Positive (DCEP) offers the deepest penetration whereas Direct Current Electrode Negative (DCEN) provides higher deposition rates. A third option is to weld with Alternating Current, AC, which delivers a balance between DCEP and DCEN. Welding with special equipment, such as a square-wave AC power source, allows the power source to be adjusted during welding operations to achieve the desired balance of deposition rate and penetration. This operational flexibility allows fabricators, like ABS, the ability to optimize the deposition rate for each weld.
- Wire Type: sub-arc welding is often performed with a solid metal wire; however, depending on the specific welding application, metal-cored wires may be utilized to increase productivity without increasing heat input. This type of wire travels faster and results in higher deposition rates. And in some welding applications, flux-cored wire provides productivity gains and higher deposition rates.
- Number of Wires: many sub-arc welding processes use a single electrode wire. However, if the deposition rate of the single wire is not enough, multiple wires may be fed into the welding zone to elevate productivity, while utilizing a single torch and single power source. The process of using more than one wire is often referred to as twin-wire welding. It should be noted that the introduction of additional wires typically increases the complexity of the welding process and should be monitored accordingly.
- Twin torch: another variable that can be adjusted to increase deposition rate is the number of torches. Most welding applications employ a single torch, but in some cases a second torch may be added. This arrangement is called tandem torch or twin torch welding. The key difference when moving from one to two torches is the need for a second power source for the tandem torch configuration. Sub-arc welding with twin torches results in higher deposition rates for many applications.
- Flux Selection: there are many options available for flux material and it is important to consider the various choices in order to achieve the desired deposition rate. The make-up of the flux impacts its ability to act as a conductor and carry current, where more current results in increased deposition rates.
ABS Welding Services
Established in 1971, ABS Machining has grown to become the recognized global leader in large machining, fabrication, and assembly for OEMs. The key to our success has been exceptional people, unparalleled facilities, and an unwavering commitment to quality. Our people are experts in their given field. Their expertise is matched only by their passion for serving our clients. We continue to invest in our people with education programs, cross training and in our internal accredited apprenticeship center.
ABS Heavy Fabrication is a full-service facility certified to CSA47.1 (AWSD1.1) and ASME Boiler Vessel B31.1 and 31.3 standards. Our welders are certified by CWB/AWS and ASME, and are fully trained on flux-core, gas metal, submerge arc, tig and stick electrode welding techniques. Individual customer requirements are followed and enforced in conjunction with our in-house certified weld inspectors. (CWI Level 2's). Below are some of our fabrication services:
- Robotic Welding
- Metal Fabrication
- Sub Arc Welding
- Flux Core Welding
- Mig Welding
- Metal Core Welding
- Forming
- Full Penetration Welding
- Laser Cutting
We offer a unique combination of medium to high volume production machining and welding services. Our team is committed to producing an un-paralleled level of quality and throughput, while also focusing on cost. We also offer secondary services such as mechanical assembly, making ABS a true single source solution for the most challenging programs of today and for the future.
Contact us today to see how we can help with your fabrication project, or give us a call at 1-844-227-6224.
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