Understanding Gas Metal Arc Welding

Gas metal arc welding (GMAW) is a metal joining process that plays a critical role in the manufacturing sector. The welding process uses a consumable wire electrode that feeds continuously through the contact tip and a power supply that creates an electrical arc between the metal electrode and workpiece. The arc heats the metals, allowing them to join, while shielding gas protects the weld from environmental contamination during the process.

GMAW operations use two types of gases—inert or active—each of which characterizes one of the process’s two forms: MIG and MAG. Metal inert gas (MIG) welding uses inert gas during the welding process, while metal active gas (MAG) welding uses active gas. In addition to being categorized based on the assist gas employed, GMAW operations can also be classified based on their modes of transfer.

Although GMAW typically uses a constant voltage and direct current power system, the process also employs alternating current systems with a range of different amps and voltages and varying electrode diameters. Additionally, depending on the requirements and restriction of the welding application, GMAW can be configured to be semi-automatic—i.e., require some human operator involvement—or fully automatic with mechanized control. These options make the process a viable solution for a wide range of fastening applications.

Transfer Modes of GMAW

As noted above, GMAW uses different metal transfer modes. Each mode offers distinct characteristics and best use cases and is largely dependent on the specific welding process, power supply, and consumable employed. A variety of factors influence which transfer mode should be used for a GMAW application, including the amount and type of current, electrode chemistry, surface, and diameter, type and delivery of shielding gas, and contact-to-workpiece distance. The choice of transfer mode affects which filler metal is ideal.

The four modes of GMAW transfer include:

  • Globular. This mode uses CO2 shielding gas, which is less expensive than other shielding gases such as argon. Although it offers a higher deposition rate that allows for faster welding speeds, it generates more heat than other modes, resulting in uneven weld surfaces and greater spatter production. To combat these disadvantages, welding operations that use the globular metal transfer mode require thicker materials and entirely flat positioning.
  • Short-Circuiting. Welding operations that use the short-circuiting metal transfer mode are also referred to as short arc GMAW or SCT. In this transfer mode, short-circuiting occurs as the electrode contacts the workpiece, providing transfer rates of between 20 and 200 times per second. It uses a mixture of 75% argon and 25% CO2 or three-part gas mixtures as its shielding gas and can be used for thin (less than ¼ inch) stock of ferrous metals and pipes without backing.
  • Spray. In the spray transfer mode, molten droplets of material—usually smaller than the diameter of the electrode—spray across the workpiece. This mode uses a variety of mixtures from 80% to 98% argon with 2% to 20% CO2 and requires higher voltage or amperage, faster wire feed rates, thicker materials, and horizontal or flat positioning.
  • Pulse-Spray. The main characteristic of this mode is an alternation between a high voltage spray current and a low background current. This quality enhances the spray transfer process by supercooling the weld pool during the low current cycle and reduces heat generation and distortion.

Advantages of GMAW

Each of the transfer modes provides its own advantages in specific applications. However, there are some general advantages associated with using gas metal arc welding, including:

  • Ability to be configured for semi-automatic or fully automated operation
  • Versatility regarding material and joint thickness
  • Ease of cleanup and lack of chipping
  • Welding position flexibility
  • Cost-effectiveness
  • Process speed
  • Environmental friendliness (minimal waste is produced as electrodes are fully consumed)

Applications of GMAW

GMAW arose as a solution for welding aluminum and other non-ferrous materials. However, due to its capacity to speed up the welding process, its use has spread to steel and stainless steel applications. Its versatility allows for its use in any industry and with a wide range of materials. Some of the most common applications for GMAW include:

  • Automotive production and maintenance operations
  • Robotic assembly lines
  • Pipe fitting
  • Track construction and maintenance operations in the railway industry

Contact G.E. Mathis for Your GMAW Needs

At G.E. Mathis, we offer precision arc and MIG welding services to customers across a broad range of industries, including agriculture, mining, aerospace, military, and construction. Armed with a state-of-the-art facility and years of industry experience, our team of highly skilled welders has the tools and expertise necessary to offer a variety of welding services. In addition to GMAW, we provide:

  • Dual wire submerged arc/MIG Welding
  • Flux core arc welding (FCAW)
  • Gas tungsten arc welding (GTAW)
  • Seam welding
  • Shielded metal arc welding (SMAW)
  • Submerged arc welding (SAW)

Located in Chicago, Illinois, our 135,000 square foot facility—equipped with fully automated, CNC-controlled welding equipment—allows us to meet virtually any customer specifications on high precision, large volume projects. Our capabilities include:

  • Production capacities for large weldments up to 12 feet wide or 80 feet long with the tightest tolerances available in the industry
  • Material capabilities for a wide range of metals, such as carbon steel, stainless steel, Hardox® wear plate, Strenx®, and other alloys

To ensure the quality of our products, both our personnel and facilities maintain compliance with the highest certification standards, such as AWS D1.1, D1.6, D9.1, and D10.9.

Contact us today for more information about our gas metal arc welding capabilities or request a quote from one of our experts for your next project.

Our Experience at FABTECH

It’s always a great experience for us to interact with other manufacturers and see what new technologies are trending in the industry. Trade shows and conferences provide us the chance to do just that. This year, G.E. Mathis Company sent a team to attend the FABTECH trade show, which took place in Chicago in November.

At this year’s event, we exhibited, presenting ourselves as a job shop able to fabricate component parts for potential customers. We showcased our various capabilities, which allowed us to show the breadth of work we can handle. It was an exciting show for us, we saw a lot of traffic, and we were able to connect with current customers as well as meet new customers and generate some good leads for future business. We had two of our reps manning the booth at all times, enabling them to answer any questions regarding our capabilities as well as keep a pulse on the industry.

As the show features equipment vendors, fabricators, and businesses that sell services, it is the perfect opportunity for a company like ours to share our capabilities and see what else is happening throughout the industry. For us, it was nice to gain exposure to new people, and we hope to be able to build on the leads we generated. Overall, we thought this year’s show was a success, and we look forward to the industry’s future events. We hope to see you there!

Choosing the Right Material for Your Fabrication Needs

During the initial planning phase of fabrication, there are many things to consider. One of the most important of these considerations is material selection—what’s the absolute best choice for your part?

In industries and applications where the metal will be coming into contact with other hard materials that can wear it out due to abrasion, a good choice is an abrasion resistant (AR) plate. AR plates are designed for use in harsh environments.

Of course, there’s more than one type of AR plate, and we would recommend using Hardox®. Hardox® is chemically engineered to provide abrasion resistance throughout the entire thickness of the material, not just the surface. Many other AR plates only offer the abrasion resistance on the surfaces of the material, becoming softer towards the center of the material. Specific benefits of Hardox® include:

  • 1/4" Hardox-450 cone weldmentHardox® is generally more formable.
  • Readily weldable without pre- or post- heating (whereas pre- and post-heat may be necessary to prevent stress fractures in the material and the weld itself when using regular AR plates, no heat treatment is needed for Hardox® up to 2 inches).
  • Longer part life as a result of even abrasion resistance throughout the thickness of the plate.
  • Hardox® is blasted and primed at the mill, which results in material that better resists rusting and scaling.

While different machining processes and specific environments can affect material choice, as a general rule, when an AR plate is right for the job, Hardox® can be highly advantageous. In mining, construction, and other industries, it’s been known to save time, money, and worry. As an official Hardox® Wear-Parts member, (one of only a handful in the country audited and authorized by SSAB, the maker of Hardox®), G.E. Mathis has a great deal of experience using it, and therefore is well aware of its benefits. When selecting abrasion-resistant material, put your confidence in a fabricator with a proven track record.

Constructing your Stainless Steel Needs

You’re a customer in the architectural field, and you’re in need of precision laser cut stainless steel panels for your next project. In order for your project to go off without a hitch, these ¼” thick stainless steel panels must measure 63” in width and 143” in length. Not only do you need a quantity of 91 pieces, but you also need the large metal panels to be laser cut to a tolerance of ±0.015 in. To top it off, your project schedule is under a time crunch, and it is necessary that you receive these parts within the next few weeks. It’s pertinent, then, that you find a metal working company who can meet all of your needs in a quick turnaround time. Where do you go?

For one firm in particular, they came to GE Mathis Company. This customer came to us with an engineered drawing of these exact needs. So how did we fulfill their requirements? We took A240-T304 stainless steel and used our 6,000 watt laser to cut the stainless steel plates precisely to the customer’s specifications. Once the panels were cut, we then ground and de-burred the laser cut edges to ensure that the panels were precise and ready to use. Even better – we were able to do all of this in three weeks! It is important to our entire staff to meet the needs of every customer – whether in the architectural field or other industrial fields.

GE Mathis Comapny: Growing Up in 2013

What do we want to achieve in 2013? As the new year gets off to a good start, all of us here at G.E. Mathis Company have reflected on the year that was and are setting future goals. So what do we have in mind?

2012 was a positive year of growth, not just for us, but for manufacturing as a whole. This past year, we have seen an upward growth and we would certainly like to build on that in 2013. Currently, as we are trending upwards, we are slowly returning to a more comfortable manufacturing level—close to a place we held prior to the recession. Our customers have said they are cautiously optimistic about the growth, and we attribute our current success to our wide range of capabilities.

How do we hope to grow ourselves and contribute to the industry? Currently, we are expanding our capabilities, so that we continuously meet the requirements of our customers. As we continue to see positive signs of improvement in the economy, we hope that our capabilities can contribute to this progress. Recently, we invested in new machinery that provides us with unique welding capabilities. After putting this machine into operation, we hope to service a wide range of applications and industries.

What’s one of our biggest goals for 2013? To help contribute to the growth of the economy and manufacturing, and to see industry reach the height it held before the recession. By advancing our capabilities and services, we have high expectations for our business and that of the manufacturing world!

Why we are Celebrating American Manufacturing

Manufacturing. It’s all the rage recently, especially during the month of October—it had been named National Manufacturing Month, in fact. According to a recent article, several national manufacturing associations and departments co-produced National Manufacturing Day (held on October 5th) in order to raise more awareness about manufacturing right here in America. Since companies have been so receptive to the idea, it was decided to extend the awareness for a whole month! Here at G.E. Mathis Company, we understand the importance and value of domestic manufacturing, especially since we are a U.S. manufacturer ourselves. Here are some key reasons why we believe American manufacturing is something to celebrate:

  • Economic benefits: The more manufacturing we can do domestically, the less we rely on others and the better state our economy is in. It is economically beneficial for us to export more than we import—the more we can manufacture ourselves, the more solid our economy will be.
  • Higher employment: Not only does manufacturing in the U.S provide more jobs and livelihoods for workers, but it creates even further demand for jobs. For example, here at G.E. Mathis, we produce components and products that our clients use for their products—therefore, our work is in turn spurring more work once ours is completed.
  • Higher quality: We are proud not only to be considered “Made in America,” but also to meet the highest quality standards. Not to mention, if you work with a domestic manufacturer, you have the option to check in on the production process and ensure that the products you are receiving meet your specifications.
  • Shorter lead times: With manufacturing being done domestically, the turn-around time is cut down dramatically.

To learn more about American manufacturing, join us in celebrating MFG Day!

GE Mathis: A Diversification of Options

Diversification. What is diversification, and why is it so pertinent to us, here at GE Mathis?

To start, diversification is defined (by Merriam Webster) as a balance in industries or classes to a portfolio, or the increase in the variety of products offered. It is a word that has often described our company, due to the fact that we have not limited ourselves to one application, one fabrication process, or the production of one fabricated part. In fact, our long history has given us extensive experience and a vast portfolio.

What are some products we are skilled in fabricating?
Intermediate bulk containers (IBCs) for chemical applications and high quality components for OEMs in the construction, mining, defense, and agricultural industries.

What materials can we work with?
Everything from a wide variety of Duplex SS to HARDOX® and Domex to common grades like A36, Gr-50, Gr-80, T1 and AR plate.

What fabrication processes are we experts in?
Everything from laser processing, forming, rolling, plate shearing, high def plasma cutting with bevel capabilities and welding.

What has enabled us to have such a diversified company?
There are many factors, including our lead times, ISO quality standards, and our HARDOX® wear parts membership. Our capabilities have expanded over the years, primarily because we continue to upgrade our equipment and focus on having the longest and most precise fabrication capabilities (for example, we can fabricate parts from 16 gauges to 2 in. thick!). We have continued to set our sights on improving our business and our capabilities. In other words, whatever it takes to get the job done right.

A Tradition of Quality Since 1905

Welcome to G.E. Mathis Company and our blog, the space where we plan to open a dialogue with you, our customers, and all those interested in the metal fabrication industry. We enjoy a rich history of quality, integrity, and craftsmanship that began with our great grandfather, a ‘tin knocker’ who opened a sheet metal fabrication shop here in Chicago at the turn of the 20th century. G.E. Mathis Company wagonDedication and hard work earned him a reputation for producing the highest quality fabrications, which, along with superior customer service, sowed the seeds for expansion. The shop went through a transition into the ventilation business, where continuously developing skills and technology led to jobs fabricating heavier steel plate components, which then further transitioned us into the multi-service contract manufacturer that we are today.

With the knowledge and skill passed through the hands of four generations, G.E. Mathis Company has become a nationwide supplier of long, intricate, and close tolerance fabrications. We operate a large, 135,000 sq. ft. facility housed in three separate buildings equipped with some of the largest and most versatile metal fabrication equipment available today, as well as 21 overhead bridge-type cranes for efficient material handling. Advanced production and control technologies allow us to deliver parts with the tightest tolerances in the industry, and our ISO 9001:2015 certified quality assurance program ensures product integrity and customer satisfaction.

Providing a full range of services including laser cutting, plasma cutting, press brake forming, CNC punching, welding and metal finishing, we are excited about furthering our capabilities: we are supplementing our current equipment list with a new large press brake and a submerged arc and MIG welding system at the end of the summer. We hope you take advantage of our expanded offerings in the fall!

Thanks for stopping by to read about G.E. Mathis Company; we hope to see you on these pages again soon. If you would like to learn more about our capabilities, please visit our website or contact us today.