This article originally appeared in Connector Magazine, Fall 2020 Edition
Erectors can save cost and time by taking this welding technique in-house
Large steel erection projects commonly require heat treatment for welding because of the thick materials used in structural steel construction. Proper implementation is critical; so often this work is outsourced. The perceived level of expertise to perform this work can make the prospect of using in-house personnel daunting. However, most welding contractors are actually fully capable of performing on-site heat treatment operations.
The two primary methods for heat treating metal are preheating and post-weld heat treatment (PWHT). Preheating is the process of heating the base metal to a specific temperature prior to welding to minimize the temperature difference between the welding arc and the base metal. This process helps to reduce internal stresses that occur as substantial temperature differences between the weld and the base metal normalize, which can cause cracking and distortion. Slowing the cooling rate also allows hydrogen to escape from the weld, which minimizes the potential for cracking.
Dear Valued Red-D-Arc Customer:
As we all continue to adjust to the global COVID-19 pandemic, we would like to take a moment to reach out to you to inform you that Red-D-Arc is continuing to vigilantly monitor the evolving developments and adjusting as necessary in order to safeguard our workforce and limit any potential impacts or disruptions to our commercial relationships.
At this time, Red-D-Arc operations are currently proceeding as usual, to the extent permitted by relevant governmental and federal authorities. While we are aware that various government-imposed shutdowns have been implemented for various industries in certain geographic locations, Red-D-Arc – like its parent company, Airgas – identifies itself as a business which provides essential services, including the supply of necessary equipment to various power plants, oil refineries, the petrochemical industry, government-led construction projects, and so forth.
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.
Welder working with a wirefeeder under a ship in drydock
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.
View our selection of semi-automatic wirefeeders and MIG wire feed welders.
When MIG welding was first invented, it used a constant voltage source of electricity for the arc. While this method is still used today, the invention of pulsed MIG welding has allowed welders to realize several advantages over conventional MIG welding, several are listed below:
- Pulsed MIG can be used to weld thin materials. Conventional MIG welding runs at a constant amperage whereas pulsed MIG welding runs a peak and background amperage. The constant switching between these two amperages enables pulsed MIG welding to put out a lower overall heat input into the material. This helps prevent blowouts on thin materials.
- Pulsed MIG has less spatter than conventional MIG welding. Pulsed MIG welding uses a peak electrical currents to cleanly burn the wire off at a high amperage. Pulsed MIG welding also employs a lower background welding amperage immediately after the peak electrical current to prevent the interaction of the electrical arc and the wire from becoming unstable. This ultimately results in a reduced amount of spatter.
- Pulsed MIG welding is excellent for out of position welding. At the same voltage and wire feed settings, conventional MIG tends to have a weld puddle that is larger and more fluid than that of pulsed MIG. Pulsed MIG has more controllable puddle that prevents it from falling out when gravity is a concern during out of position welding. Furthermore, the reduced amount of spatter than can be achieved with pulsed MIG makes it safer for the welder to perform the out of position operation.
One of our customers was trying to heat 42” diameter pipe using pear burners so that welders could weld out the joints. Our team saw an opportunity to create a solution that would help our customer get the job done much more quickly. To make this in-the-field heating job go faster, we put together a package including a Miller ProHeat 35 induction heating system, a 60kVA generator and a DP25 power distribution panel.
With this setup we were able to get the pipe up to 250 degrees in about 5 minutes. Our customer was able to beat the competition’s target time by over 19 hours and has been asked to quote on other pipeline work for their client. Needless to say they were pleased with the solution and the opportunity for extra work it created.
This portable induction turnkey package is a great way to heat pipes in remote locations. There is less risk to the welders from the hot pipe and the process is much, much faster.
Custom turnkey packages like the one described here are Red-D-Arc’s specialty. Our team of experts has created turnkey solutions to solve challenges in diverse industries including, mining, oilfield, offshore, nuclear and manufacturing. We enjoy helping our clients find new ways to grow their businesses, by combining the latest technology, depth of experience and flexible leasing options that fit their needs.
Remote worksites pose no obstacle. We’ll bring portable generators with enough power for your portable welders, induction heaters, lighting and anything else that needs power.
Plasma cutters are capable of cutting metals in simple and complex shapes including producing holes, bevel edges, gouging, and markings. Plasma is a cost effective and practical alternative to oxy-fuel, laser and water jet cutting processes and is used in industrial, trade and DIY applications. Plasma cutters are used in all types of industries including manufacturing, pharmaceutical, oil/gas and arms industries.
When gas is heated to extremely high temperatures, the electrons in the gas molecules break free from the nucleus, turning the gas into plasma. Plasma cutting is carried out by directing the plasma jet through the metal.
The advantages and disadvantages of plasma cutting as compared to the other cutting processes are as follows:
- Ability to cut all electrically conductive materials including stainless steels and non-ferrous alloys (aluminium, brass, copper etc.). Note: Stainless steel and non-ferrous alloys cannot be cut using oxy-acetylene cutting
- Good quality cuts
- Can be used on a work site for manual cutting as the equipment is portable and light weight.
- Automation is readily achievable as with other cutting processes. CNC plasma cutting machines are able to cut complex shapes at high speeds.
Effective in cutting metals up to 6” thick.
- Not good for cutting non-conductive materials. Note: Water jet and laser cutting processes are a better alternative for these types of materials.
The following content is for general information only and should not be understood to be a complete guide to plasma cutting safety. Be sure to follow the manufacturers’recommendations and all standard safety practices employed when working with electrical equipment.
Electrocution: The high power output and voltage (110 to 150VDC) required for the plasma cutting poses potentially fatal risks of electric shock. Some of the precautions to avoid electrocution include: Electrical grounding of the plasma cutter, appropriate personal protective equipment (PPE – e.g. rubber gloves in addition to welding gloves) needs to be worn, check all cables before starting work, ensure work area is dry etc.
Eye and Skin Protection:
The plasma cutting process emits severe infrared and ultraviolet rays which are harmful to the eyes and skin. A face shield or safety glasses fitted with the correct lens shade must be worn. To protect the skin against molten metal and fumes, PPE (protective clothing, safety shoes, welding gloves, welding apron when appropriate etc.) covering the whole body is required.
Toxic Fumes and Gases:
The plasma cutting process emits smoke and potentially harmful gases (as is the case with laser and oxy-acetylene cutting). Appropriate ventilation is required to direct the fumes away from the operator. This may be achieved by fume extraction systems. A welding helmet with fume protection may also be required in certain situations.
Ensure there are no flammable materials near the work place.
Noise: Noise levels of up to 120 decibels, the operator and personnel near the plasma cutter require hearing protection.
Risks due to Pressurised Gases: Secure cylinders, secure/check hoses and connections.
Variations of plasma cutting
Gases: Different gases are used to suit the metal being cut. Compressed air or oxygen are generally used for cutting carbon steels, whereas inert gases like argon or nitrogen are used for cutting stainless steels. Dual gas system (plasma and shielding gas) allows you to run on separate plasma and shielding gases to optimize the performance e.g. Air/Air, O2/Air, N2/Air, N2/CO2, Ar-H2/N2 or other combinations. Shielding gas also assist with torch cooling. Additionally, liquid cooled torches are available for high power applications which provide maximum cooling and long consumable life.
On board compressors:
Plasma cutters are available with integrated air compressor for portable units and are suitable for lighter cutting applications.
CNC machines with water bed:
As an alternative to fume extraction systems, plasma cutting on CNC machines is carried out with the water under or fully covering the work piece. This provides for a more cost effective fume removal option. The water bed also suppresses the noise caused by the plasma cutting process. Under water cutting, additionally minimizes distortion which is particularly useful when cutting thin materials.
There are two types of arc starts available –pilot arc or touch. In touch arc start, the nozzle has to contact the work piece to start the arc, whereas in a pilot arc, an arc is present in the plasma nozzle and there is no contact required between the nozzle and the work piece.
High frequency start relies on high frequency and voltage power to ionize the gas. If can be used with a pilot arc torch or touch start to initiate the plasma. The disadvantage of high frequency start is that it can interfere with the electronic circuitry in the vicinity.
In back blow plasma initiation, the flame is started in the inside of the torch by the movement of a piston, initiating an arc and ionising the gas. This arc forms the pilot arc and stays on whether the nozzle is in touch with the work piece or not.
How to select a plasma cutter?
The following needs consideration when selecting a plasma cutter:
Manual or mechanised ?
Are you looking to cut by hand or use a CNC machine? – consider the availability of CNC interface signals and voltage divider (to provide safe voltage levels from the torch to control the height of the torch automatically).
Required Cut thicknesses and quality
Material thickness needs to be matched with the capabilities of the plasma cutter. The cutting capabilities are specified as thickness limits by the manufacturers as follows:
Sever cut – just capable of cutting this thickness with dross and slag left behind
Rated cut – this is the rated cut thickness specified by the manufacturer of the plasma cutter
Quality cut – a quality cut is achieved for materials up to this thickness
Kerf (cut width) – higher quality plasma cutting systems can make narrower cuts
Consumables cost and life considerations – consumable life is specified as the number of cuts or starts
Red-d-Arc has a wide selection of plasma cutting equipment from the market leading manufacturer Hypertherm covering the following:
Amperage range: 15A to 200A
Cutting range: 5/16” to 2” thickness
Single and 3 phase
Single and dual gas systems
Packages of plasma cutter with generators are available.
Also, mobile compressors run on diesel up to 450 CFM are also available for rental.
Have a look at our complete range of plasma cutting products.
Are you looking for the best rates on portable welder rentals? We can fulfill your welding equipment needs. At Red-d-Arc, we offer you a wide variety of welding equipment for almost every purpose. We provide customized recommendations on each piece of equipment that we rent out.
Get in touch with us today to learn more about our welding equipment rental and long term welder leasing programs. We make it our goal to offer you state-of-the-art welding tools at the most competitive rental rates.
The Best in Welding Equipment Rentals
If you are looking for a great deal on a mig welder rental, check out our selection. Metal inert gas (MIG) welder models are great for welding indoors or in enclosed spaces. These machines use flux core wire that makes them the perfect option when welding tears or breaks on farm equipment.
However, MIG welders have plenty of other uses that make them perfect for a wide variety of other types of equipment. Keep in mind, however, that you do need a particular set of controlled conditions in order to obtain the best possible results.
We carry a variety of models, including the following:
Pre-weld and post-weld heat treating is critical for many welding operations. Without proper thermal manipulation, welds and heat affected zones can have mechanical properties that are undesirable. Worse yet, inadequate heat treatment can result in cracks and devastating weld failures. While temperature and time are the primary concerns when heat treating a weld, the heating method should also be considered diligently when selecting a process. Induction heating is one of the most popular types of heat treating methods, and rightfully so. The benefits of induction heating are many, and Red-D-Arc has the equipment you need to successfully implement an induction heat treating operation for your projects.
What is Induction Heating?
Induction heating is a heat treating process that, when used properly, can alter the mechanical properties of a weld and its adjacent base metal in a way that meets the demands of the application in which the weld is being used. Induction heating relies on the science of electromagnetism to heat the part. Induction coils are placed around the material being heat treated, and alternating current is fed through them. This alternating current going through the induction coils creates a rapidly alternating magnetic field.
The eddy currents that occur as a result of this heat the material surrounded by the coils. Magnetic materials are even more easily heated by the alternating magnetic fields.
Induction Heating Equipment
Setups for weld induction heat treating can vary somewhat from application to application, but Red-D-Arc has the equipment needed for most common scenarios. Every induction heating system requires a power source. The power source converts electricity from a power grid into an electrical current that can be used to energize another critical piece of equipment in an induction heating setup: the induction coils. Induction coils are typically made out of copper and are not required to be in contact the workpiece. The power source and the induction coils are the two main components of an induction system, although other pieces of equipment such as blankets can be used to shield the induction coils and aid the heating process.
Why Use Induction Heating Over Other Heating Processes?
Induction heating has many benefits over other processes. Torch heating operations do not have the accuracy of induction heating methods. The flame heats the workpiece in an extremely varied way. Also, a torch heating operation must start with its heating on the outside and let the temperature “soak” its way into the part. Induction heating can use a variety of electrical frequencies to adjust the initial heating position within the depth of the material to some extent. Additionally, the width and length of the heated material can be adjusted precisely with induction heating, unlike torch heating.
Torch heating requires the use of combustible gases, which can be dangerous. Volatile gases can explode and cause injury to workers and destruction of property. These combustible gases also release hazardous fumes that may require respiration or fume removal, especially in confined spaces. On the other hand, induction heating, when used properly, releases no harmful fumes. Since combustible gases are not used during induction heating, there is no risk of explosion.
Another common heat treating process is furnace heating using electrical resistors as heating coils. This process can take a very long time for thick parts, and, similar to torch heat treating, works by heating the exterior surfaces of a base material first and allowing the temperature to soak into the core. Conversely, induction heat treating can be performed rapidly, potentially shaving many minutes off of a resistance furnace operation. The core can be heated much quicker as well with induction heating. Induction coils used with a piece of equipment such as the Miller ProHeat 35 are much more portable than furnace operations as well, allowing for far more practical use in the field.
While there are many advantages to induction heating and induction heat treating, there are some disadvantages. One disadvantage is part geometry. Unless an induction furnace is being used, parts will simpler geometries such as pipe or plate are more readily induction heat treated than ones with more complex geometries simply because the induction coils must be placed around the part.
Another disadvantage is that the initial cost of an induction heating system is typically more expensive than a torch heating system. However, this is where Red-D-Arc has you covered. With our induction heat equipment rentals, you can see firsthand the benefits of induction heating without large capital investment so you can keep on welding!
Note: This article first appeared in BIC Magazine
In industry, a growing trend is the idea to use orbital welding as a solution to the mounting problem of welder shortages. It is a well-known fact there are just not enough pipeline welders to go around (no pun intended). By 2020, the American Welding Society expects the U.S. will face a shortage of 290,000 welders. Companies in other business sectors — from food service companies to banks — attempt to solve labor issues and increase efficiencies by utilizing automation to replace workers. Is automation, specifically orbital welding in this case, the way to improve operating factors and productivity?
The first part of improving welding operations is not to look at the welding process but instead examine its upstream aspect at material input. Material fit-up is the first key to improving quality and productivity. Poor fit-up causes overwelding and often leads to weld quality issues. A fillet weld that requires a quarter-inch weld has an unintentional root opening or misalignment of 1/16 inches. It then requires a 5/16-inch weld, which in turn increases weld joint volume by 57 percent. This result means 57-percent more wire, 57-percent more gas, 57-percent more use of consumables and — the most costly issue — 57-percent more time to weld that joint.
Let’s say that same 5/16-inch weld is then welded within tolerances, but the weld size is overwelded by 1/16 inch. That 5/16-inch weld then becomes a 3/8-inch one due to the compounding factors of material fit-up and a very common practice of overwelding. This weld that could have been done to code and adheres to a welding procedure is now 100-per-cent more costly then intended.
Are you buying double the gas and wire you need? Eighty-percent of most welding operating expenses are in labor. What are you paying to have someone weld 100-percent more than what is needed?
What is paramount is we can create precision fit-up and limit overwelding with the use of end-prep and orbital welding. Regardless of welder skill or the type of welding equipment, starting a weld with poor fit-up will result in a weld that costs more to produce. The conversation about quality, productivity and efficiency should not start at orbital welding or about your welder’s skills but should instead begin at end-prep. End-prep equipment, simple to operate and often overlooked because of its necessity, offers machine shop-like precision and fit-up while in the field. With the unfortunate skill gap widening in the trades, it is imperative to start your pipe or tube welding with precise fit-up, as those who can make passable welds become fewer and fewer.
We aren’t replacing welders with automation; we are making them more efficient. The goal is to take the welder you have and select the proper end-prep and orbital welding process for your job so you can possibly create twice as much time for him or her and improve quality along the way.
In order to meet the rising challenge of the lack of qualified welders, we need owners and management as well as welders to come together to increase quality and productivity. Management needs to provide welders with good material and proper equipment to work with, and the welder needs to realize we aren’t attempting to take his or her job but instead attempting to give him or her the best tools to get the best result.
When you look for a company to fulfill your business’ welding needs, you should search out a supplier that offers more than just equipment. Find a supplier that offers not just a few options of welders but solutions.
For more information, visit www.red-d-arc.com, call (866) 733-3272 or email Brian Imhulse at Brian.Imhulse@airgas.com.