Flux Cored Arc Welding (FCAW)

Flux Cored Arc Welding is an automatic or semi-automatic arc welding process using a wire that contains flux in its core. FCAW is mainly two types i.e. FCAW-S and FCAW-G. And after burning, it creates shielding gases and produces welds. Flux-cored arc welding is an internal shielding process and produces some spatter as well. After the welding, it leaves a slag and needs to be removed later.

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Post Highlights:

• Brief History of Flux Cored Arc Welding
• Principle of FCAW
• Flux Cored Arc Welding Equipment
• Type of Electrodes used for FCAW
• Features of Flux Cored Arc Welding
• Fabrication Codes of FCAW Process
• Variables of FCAW
• How to Master in FCAW Process?
• Applications of FCAW
• Benefits of FCAW
• Drawbacks of FCAW Process
• Employment Area for FCAW Type
• Job Types for FCAW Process
• Salary of FCAW Welders

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Flux Cored Arc Welding Brief History

FCAW Historic View

The first-time FCAW-G process (gas-shielded flux-cored arc welding) was developed in the 1950s. Years after year, the manufacturing units made so many improvements in the shape of its equipment and products. During that time, the FCAW process was limited to the line of low alloy steel electrodes and carbon steel. So, it was offering this either for all-position welding or flat and horizontal only.

Multi-purpose Single Electrode

At the time, there were relatively few variations in the formulations of electrodes. Mostly, one available electrode was intended to be employed in different applications and welding processes. Normally, either 100% carbon dioxide (CO₂) shielding gas or mixed argon (Ar)/ CO₂ shielding gas was to be applied.

There was a general manufacturing philosophy of developing an electrode with multi-purposes during the 1960s. And the same electrode was intended to be used for all products. Further, it was successful to some extent in meeting the demands of welding markets and industries.

FCAW in Modern Times

Time and trends have been changed in the 21st century. Nowadays, the structural engineers and industrial designers emphasizing of specifying higher-strength, lower-weight steels for cost savings and productivity. That’s why many industries have made these base materials their first choice due to this consideration.

Principle of FCAW

FCAW process works on direct currents. It can be connected either by electrode positive (reverse polarity) or electrode negative (straight polarity). In addition, the flux-cored wire is designed in the way that it can work with both DCEP or DCEN.

FCA welding process is a bit difficult due to its internal shielding, not external like others. The shielding is very positive, and after welds, it produces some spatter. As the process goes on, it lays a slag that covers the weld. Normally, the slag is removed after some time when it became cool. As a result, slag protects the weld in molten form and imparts it some time for being cold. Most of the mild steel applications outdoor use the FCAW welding type.

Equipment of Flux Cored Arc Welding

The basic FCAW welding kit consists of the following equipment:

• Power source – it provides an uninterrupted power supply to the welding arc.
• Welding cables
• A wire feeder and controls
• Welding gun – it is a holder of an electrode.
• A spool magazine, water cooling and pressure regulator, etc.

FCAW Electrode Types

There are two categories of FCA electrodes i.e. gas-shielded, flux-cored electrodes (FCAW-G) and self-shielded, flux-cored electrodes (FCAW-S). They are steel tubes with flux inside them. Electrodes can be wrapped in a coil or spool. They are as follows:

• ‘HD’ type FCAW-G electrodes – they are designed for high-deposition, out-of-position capability. (i.e., UltraCore® HD-M, UltraCore® HD-C).
• ‘SR’ type FCAW-G electrodes – they are used for stress-relieved applications. (i.e., UltraCore® SR-12).
• FCAW-G electrodes – they are applied on chromium-molybdenum (Cr-Mo) steels. (i.e., Cormet 1, Cormet 2).
• FCAW-G electrodes – they are designed for pipe welding applications. (i.e., Pipeliner® 81M, Pipeliner® 101M, Pipeliner® 111M).
• FCAW-G electrodes, they are designed to be used with a specific type of shielding gas. (i.e., UltraCore® 71C, UltraCore® 71A85).
• FCAW-G electrodes – they are employed in exceptionally high deposition rates in the flat and horizontal positions. (i.e., UltraCore® 70C, UltraCore® 75C).
• FCAW-G electrodes – they are for improved low-temperature toughness properties. (i.e., UltraCore® 712A80, UltraCore® 81Ni2A75-H).
• FCAW-G electrodes – they can be used on higher-strength steels (i.e. 80 ksi, 90 ksi, and 100 ksi minimum tensile strength). (i.e., UltraCore® 81Ni1A75-H, Outershield® 91K2-H, Outershield® 690-H).

Flux Cored Arc Welding Features

• FCA is a weather-friendly process. It can perform even in windy conditions and considers good for outdoor welding activities.
• It does not require a shielding gas.
• FCAW imparts a higher production rate as it does not require changing electrodes periodically.
• The process generally uses direct current constant voltage types.
• Flux Cored Arc Welding results in very low chances of porosity after laying welds.
• The welding type is generally portable and has good penetration into the base metal.
• In this process, an electrode positive provides better penetration and electrode negative gives lighter penetration.
• Metals like high nickel alloys, mild and low alloy steels, and stainless steels use the FCAW process.

Fabrication Codes of FCAW Process

The provisions and fabrication codes of FCAW are as follows.

AWS D1.1

• First, the codes state that the FCAW process is deemed as qualified processes as per Section 3.0 – Prequalification of WPS.
• Second, it states with respect to welder qualification, a 3G qualification qualifies for all other positions except the Overhead position.

ASME SEC VIII

• UHT-82 clause explains the welding requirements as per the welding process
• The code says regarding the FCAW process, the consumable should consist of SFA 5.29 and SFA 5.36

ASME SEC IX

• The provision of QW-255 defines the welding variables for procedure qualification for GMAW and FCAW.
• QW-355 states the welding variables for welder qualification for FCAW and GMAW processes

API RP 582 (Welding Guidelines for the Oil, Gas and Chemical Industries)

• Section 5.1 defines the FCAW is an acceptable welding process.
• FCAW-G (Gas shielded) may be used for either fillet or groove welds for pressure boundary or structural welding.
• Table 5-1 (H4 or H8) states the use of FCAW consumables in pressure containing equipment. Further, it emphasizes that the diffusible hydrogen limit should be met.

API 1104 (Welding of Pipelines and Related Facilities)

As per the provisions of the American Petroleum Institute-

• Section 12 reveals that FCAW Automatic Welding is an acceptable process.
• And its subsection 12.5 reveals the detail of each process of an essential variable.

M-601: NORSOK (Standard for Welding and Inspection of Piping)

• Section 4.4 explains the details and essential variables with respect to the FCAW process variable, e.g. an increase in filler wire diameter.

ASME B31.1, B31.3, and B31.8

• Normally, these codes do not have a reference for any welding process. In this case, the client gives acceptance to fabricators that comply with design requirements.
• Some of the clients, Flour Canada, L&T, Alstom, ISGEC, NTPC, GE, Thermax, etc. accept the FCAW process for welding of piping spools in the Oil and Gas sector.

FCAW Variables and Parameters

• Arc Voltage
• Electrode Extension
• Angle and Travel Speed
• Electrode Angles
• Shielding Gas Composition (if required)
• Electrode Wire Type
• Speed of Wire Feed
• Application of straight polarity for FCAW self-shielded and reverse polarity for FCAW gas-shielded wire.

How to Master in FCAW Process?

Required Skills for Welder

A welder needs to perform some of the skills for obtaining the maximum results from the welding process.

• There should be advances in equipment/systems. It helps welder in self-correction while welding.
• CV against CC power source characteristics leads to a nearly constant arc gap.
• Less welder fatigue ensures consistent performance over long working hours.
• Use of modern equipment (programmable). It helps welder in replicating the performance.
• A much wider parameter window within the same diameter of wire leads to a lot of flexibility.
• Use of semi-automatic process.

Industries Using FCAW Process

• Automotive Products Industry
• Chemical Plants and Refinery
• Heavy Equipment Manufacturing Industry
• Industrial Piping System
• Maintenance/Repair Industry
• Nuclear Power Plants
• Power Plants
• Pressure Vessels Industry
• Railroads and Track
• Road/Construction Equipment Industry
• Ship Building Industries
• Underwater Welding Industry
• Waterfront Structures
• Wind Tower Industry

Advantages of FCAW

• FCAW is capable of overcoming atmospheric contamination.
• It can lay welds even in bad weather conditions. Therefore, it has become a better choice for outdoor welding activities.
• Besides this, Flux Cored Arc Welding is suitable for outdoor applications of mild steel.
• FCA process is a good choice for thicker materials as there is no risk of cold lapping.

Disadvantages of Flux Cored Arc Welding

• Comparatively, FCAW equipment is more costly than other welding processes.
• It cannot weld all types of metals.
• FCAW equipment is not portable the same as of SMAW or GTAW processes.
• Flux Cored Arc Welding emits a high level of harmful noxious fumes and it must be ventilated.
• In the FCA process, there is a possibility of mechanical problems like irregular wire feed, melted contact tips, and porosity of the weld.
• Welders need to remove slag covering the weld frequently.
• The electrode wire of the FCAW process has a higher cost vis-a-vis a solid electrode wire.

Employment Area for FCAW Type

The following are some of the companies offering jobs to applicants with the FCAW process.

• ALL Crane, Brook Park, OH
• APTIM, Westwego, LA
• BA Fabrication, Tucson, AZ
• Brown & Root Industrial Services, Freeport, TX
• Comfort Systems Mid-South, Montgomery, AL
• Edwards Moving & Rigging, USA
• FTS International, Aledo, TX
• Phillips 66, Sweeny, TX
• Pohlad Companies, Brunswick, GA
• McDermott, Willis, TX

Job Types for FCAW Process

• Combination Welder
• Shop Pipe Welder
• Combo Welder
• Entry Welder (Welder Trainee)
• Fitter
• Welder II
• Pipe Welder/Fitter
• Structural Welder (Entry Level)
• Welders (FCAW)
• Truck Assembler
• Welder Fitter

Salary of FCAW Welders

The salary figure for welders in the United States of America is not the same. It differs from place to place and company to company depending on various local factors. On average, the salary of a welder is US$ 52,000. But the figure varies from company to company.

Company Names	Salary (US$)
Great Dane Trailers LLC	38,000
Freight Car America	40,000
BAE Systems Inc.	40,000
Huntington Ingalls Industries	48,000
General Electric Co (GE)	48,000
General Dynamics Electric Boat	51,000

Thus, the above-mentioned information on Flux Cored Arc Welding explains various aspects with great details. It is so much important for aspiring students, welders, professionals and general users in many ways.

Related: Other Welding Types