Posts Tagged ‘oxy-fuel’

Good oxy-fuel operators know that safety depends on proper and responsible use of oxy-fuel equipment. Safety has been a central principal at Victor for 100 years. In fact, one of its early innovations was a safer regulator because founder L.W. Stettner had lost an eye in an industrial accident and wanted to prevent that from happening to others. In that spirit, here are a few oxy-fuel safety tips that may prevent accidents from occurring in the first place:

Cylinder-Safetycropped

Fire triangle:

The foundation for all oxy-fuel processes is the “Triangle of Combustion” or “Fire Triangle”. Combustion requires three elements: fuel, oxygen and heat. Operators must control each of these elements, which is why safety starts with a clean work area, free from combustibles.

Oxy-fuel processes produce flames, sparks and a small amount of infrared rays. Eye protection options include a face shield, goggles or safety glasses, all with the appropriate shade lens. If operators use a face shield, they must also wear safety glasses underneath.

For operators that work in street clothes, choose tightly woven fabrics made from natural fibers. Wool is naturally flame retardant, and blue jeans, denim and cotton duck are also good choices. Wearing a lab coat or welding jacket (or at least sleeves) is a good idea; heavy-duty applications often require leather chaps and spats. Button shirt collars and sleeves, and don’t cuff pant legs, as they provide a perfect area to catch sparks and slag.

 

Cylinder identification and handling:

Operators commonly assume cylinder colour indicates a specific gas. Unfortunately, distributors and gas suppliers can paint their cylinders any colour they want. To identify a T cylinder’s contents, read the label. If a cylinder doesn’t have a label, don’t use it.

All cylinders have a United Nations (UN) gas identification marking on their label. Common ID numbers include UN 1072 for oxygen, UN 1001 for acetylene, UN 1978 for propane and UN 1077 for propylene.

When moving cylinders, secure them with a strap or chain and install cylinder caps. Victor engineers understand that an improperly secured cylinder creates a hazardous situation. EDGE regulators feature SLAM (Shock Limitation and Absorp- tion Mechanism) technology. This three-stage “crumple zone” is built into the adjusting knob to help protect against serious cylinder damage in the event of a fall.

 

Gases in the work area:

Oxygen is the source for many gas-related accidents, and a primary culprit is using oxygen in place of compressed air, such as to blow dust off clothing or work areas.

The most widely used fuel gas is acetylene. Other fuels are commonly referred to as “alternate fuels.” These include LP gases (propane, propylene and butane) and compressed gases such as natural gas and methane.

Acetylene cylinders contain a porous mass saturated with liquid acetone. The acetylene gas is then pumped into the cylinder, absorbed into the acetone and released as it is used. Because of its nature, always use and store the acetylene cylinder in an upright position, and never use acetylene above 15 lbs. pressure. Acetylene has a tendency to disassociate above 15 PSI, which can cause a chemical reaction.

Acetylene withdraw rate is critical: never withdraw more than 1/7th of the cylinder volume per hour. For example, if a particular cylinder held 280 cubic feet, dividing that by 7 yields 40 usable cubic feet per hour of gas.

 

Equipment set-up – regulators:

Because different gases have different volume and pressure requirements, manufacturers engineer regulators for specific gases. Victor regulators are colour-coded and labeled for easy identification, such as green for oxygen and red for acetylene.

Pure oxygen can reduce the kindling temperature of petroleum-based lubricants to room temperature, leading to violent combustion. As such, the first safety check is to inspect regulator valves, threads and seats and ensure they are free of oil. Parts contaminated with oil or grease should be inspected and cleaned by qualified service personnel.

 

Equipment set-up – hoses:

There are three grades of hose. Use R and RM grade for acetylene. T grade hose may be used with any fuel gas and is the only grade allowable for alternate fuels. The acetylene hose, which is typically red, has a groove across one nut, which indicates a left-hand thread. The oxygen hose, which is typically green, will not have a groove, indicating that it’s a right-hand thread. Before attaching the hose, inspect it for oil, grease and cracks.

After attaching, remove potential contaminants by purging the hose. To purge a hose, adjust the regulator knob to about 5 PSI and allow gas to flow for a few seconds. Depending on the length of hose, that time may vary. Back out the adjusting knob after allowing adequate flow and repeat the process for the other hose.

 

Torch inspection:

Most torches come in two sections, the torch handle and various attachments for heating, cutting and welding. Before using an attachment, check its cone end and be sure the two O-rings are neither missing nor damaged. Repair them or replace them if necessary. On a cutting attachment, check the seating end for the tip. Dents or scratches here could lead to a leak and promote an accident.

Before connecting any attachment to the torch, inspect the seating area of the torch handle and the thread assembly. When attaching them, hand-tighten only. Using a wrench will damage the O-rings.

Next, inspect the cutting or heating tip to ensure the holes are free of debris. On a cutting tip, check the seating end for scratches or dents. To properly secure a cutting tip, which is a metal-to-metal seal, tighten it with a wrench. Before cutting, make sure the cutting oxygen lever moves freely.

 

Leak test:

After connecting the attachments and tips, operators need to check the entire system for leaks. The steps to perform a leak test are as follows:

Completely back out the regulator adjusting mechanism. Open the cylinder gas valve slowly until the high pressure gauge reading stabilizes, then shut off the cylinder valve. Monitor the gauge for any pressure drop, which would indicate a leak of the high pressure side of the system. If no leak is evident, open the cylinder valve and adjust the oxygen regulator to deliver 20 PSI.

Repeat the process with the fuel gas valve and regulator, but be sure to adjust the fuel gas regulator to deliver about 10 PSI. Close both the oxygen and fuel cylinder valves. Turn the adjusting screw or knob counterclockwise one-half turn. Observe the gauges on both regulators for a few minutes. If the gauge readings do not change, then the system is leak tight.

Open the cylinder valves again. Any movement of the needles indicates a possible leak. If a leak is observed, stop. Do not use leaking equipment. Check all the connections. If the leak can’t be found, have the equipment inspected by a qualified technician.

Purging the torch:

Torches also need to be purged to eliminate the possibility of gases mixing prematurely, which could lead to a flashback, or worse. To start, open the oxygen valve on the torch handle all the way. With a cutting attachment, also open the preheat oxygen valve. Depress the cutting lever for three to five seconds. Shut the oxygen valves and repeat the process for the fuel side. This is also a good time to recheck the regulators to make sure they maintained set pressure.

 

Shut down:

Regardless of fuel gas used, always shut down the oxygen first and the fuel last. This technique leak checks both valves every time the torch is shut down. A snap or a pop indicates a leaking oxygen valve, while a small flame at the end of the tip indicates a fuel gas leak.

To shut down the entire system, start by closing both cylinder valves. Next, release the pressure inside the system by opening the oxygen valve on the torch until pressure decays; do the same with the fuel gas valve. Next, release the tension on the regulator by turning the knob or screws counterclockwise until they move freely. Check the regulators to be sure they indicate zero pressure in the system.

Always follow the proper shutdown procedures when finished cutting, even if it’s just for a lunch break. Never leave oxy-fuel systems pressurized while unattended. A leaking torch or hose could cause a pool of gas to build up (such as inside a barrel), creating a serious hazard.

 

Leader, participant guidelines:

By following these guidelines, operators minimize the possibility of an accident and make the environment safe for those around them. To support training efforts, Victor offers a DVD featuring a 36-minute Oxy-Fuel Safety Video in English or Spanish and extensive supplemental documents. These documents include checklists for many of the best practices discussed in this article, a 65-page Leader’s Guide on how to conduct a successful seminar and a Participant’s Guide with training materials and quizzes to assess knowledge absorption.

Advertisements

By Nakhleh Hussary, Ph.D., David Pryor

When purchasing a new automated cutting table or retrofitting an existing one, which process is best–oxyfuel or plasma? The nature of the application and cutting process both play a role.

Plasma or oxyfuel? - TheFabricator.com

Which process will ultimately yield the lowest cost per cut—oxyfuel or plasma—after all variables are considered? The basic nature of each process immediately dictates some choices when you are purchasing a new automated cutting table or retrofitting an existing one.

In automated oxyfuel cutting, a fuel gas (typically natural gas) heats the metal to its kindling temperature, where a high-pressure stream of pure oxygen rapidly oxidizes and blows away the metal. This process works with carbon steel because iron oxide melts at a lower temperature than steel. Oxyfuel does not work with aluminum because aluminum oxide melts at a higher temperature, and it won’t work with stainless steel because it doesn’t oxidize.

Conversely, the high-precision plasma process works with any electrically conductive material, making it suitable for cutting steel, stainless steel, and aluminum. It heats a gas (usually oxygen, nitrogen, or hydrogen) to an extremely high temperature and ionizes it so that it becomes electrically conductive, allowing the electric arc to transfer to the workpiece. The arc’s heat melts the workpiece, and the force of the plasma and shielding gases blows away the molten metal to cut the workpiece.

Understanding Cost Factors

Assuming costs for the cutting table, controller, and gantry are similar for both processes, the key factors influencing the acquisition and operation of a cutting table are summarized in Figure 1. At first glance, you might think that many factors seem to favor the oxyfuel process, which is why it has been the preferred cutting process of many fabricators for decades. But thanks to the extremely fast piercing and cutting speeds of modern high-precision plasma systems, the choice has become much less clear-cut (so to speak), especially on material less than 1.5 in. thick.

Plasma or oxyfuel? - TheFabricator.com

Figure 3When multiple oxyfuel torches can cut in parallel, cut costs per foot decrease significantly. Photo courtesy of C&G Systems Corp.

Low-cost Oxyfuel

Oxyfuel cutting requires very little capital to implement and operate. A machine torch setup (including hoses, manifolds, and required accessories) costs about $3,000, and a multiple-torch setup can still cost less than $10,000. A cutting tip costs approximately $25 and will last for about 100 hours of cutting. Most automated systems use natural gas because, at least in North America, the cost is nearly free at $0.0001 per cubic foot. Oxygen, the single largest operating cost for the oxyfuel process, runs at about $0.010 per cubic foot. A high-precision automated system also uses oxygen for the plasma gas when cutting mild steel, but at lower volumes.

Once installed, an oxyfuel system operates almost maintenance-free. Other than changing consumables, the torch, gas distribution, and manifold system are extremely robust.

Oxyfuel’s primary limitation is its relatively slow piercing and cutting speeds. As Figure 2 shows, the torch may cut up to 30 inches per minute (IPM) on thin material, but the speed levels out around 15 IPM on material 2 in. and thicker.

In metal 0.25 to 1.5 in. thick, slow cutting speeds drive up the cut cost per foot. However, at thicknesses of 2 in. and greater, the plasma process no longer has a speed advantage.

Oxyfuel also provides an advantage when the same pattern can be cut in parallel, which enables using multiple oxyfuel torches (see Figure 3). In fact, up to eight torches on the same gantry is relatively common. Note that if the part requires multiple pierces, or if a limited part run can’t justify adding more torches, the advantage may tip back to plasma.

Plasma or oxyfuel? - TheFabricator.comFigure 5With a few turns, this cartridge with 100-amp consumables can be replaced with a cartridge for cutting at 400 amps.

High-speed Plasma

An automated high-precision plasma system costs an average of 10 times more than an oxyfuel system. Its torch consumables cost more too—about $45 for an electrode tip and shield cap—and the electrode may last for only two shifts, depending on the application.

However, the speed of plasma cutting gives it a pronounced economic advantage. Equipment manufacturers have developed 400-amp plasma systems that increase travel speed on medium-thickness material and remain competitive with oxyfuel on steel up to 2 in. thick (see Figure 4). For example, they can cut 1-in.-thick mild steel at more than 80 IPM, while oxyfuel cuts at less than 20 IPM. On thinner materials, the speed advantage is even more significant, with plasma cutting 0.5-in.-thick steel at 150 IPM. The cost per foot is about $0.045 for plasma and $0.210 for oxyfuel.

Applications involving part nests and workpieces requiring multiple pierces also are more suitable for the plasma process because the plate does not require preheating, as it does with oxyfuel. Plasma can pierce 1.25-in.-thick steel in about 1.5 seconds, whereas oxyfuel takes about 20 seconds.

In places with high labor rates, including the U.S., Canada, and Europe, obtaining fast cutting speeds and cycle times is critical for profitable plasma operation. As a result of higher-capacity and higher-speed systems, plasma now is commonly found in heavy equipment, pressure vessel, ship, rail, and other fabrication operations that previously were the domain of oxyfuel cutting.

Plasma or oxyfuel? - TheFabricator.comFigure 6In about 20 minutes, a technician can install an inverter block to increase this plasma unit’s capacity up to 400 amps.

Some fabricators are using plasma to bevel pipe, as new torch configurations provide better joint access. Still, for cutting heavy steel used for infrastructure, offshore oil rigs, and mining equipment applications and for cutting pipe in the field, oxyfuel continues to offer attractive cost benefits.

Thickness Flexibility

Optimizing cut performance, speed, and quality with either process requires changing consumables and process variables. With oxyfuel, it’s a matter of selecting the right tip and adjusting gas flow rates accordingly. With plasma, cutting different material thicknesses requires changing torch consumables. In this case, consider systems with consumables cartridges that offer a keyless/no-tool change function, as it will reduce change time to about 30 seconds (see Figure 5).

Traditionally, fabricators were somewhat boxed in when they purchased a plasma system. If they had a 300-amp system for cutting but wanted to cut 1- or 1.5-in.-thick steel at faster speeds, the best alternative was to purchase a new 400-amp system.

To address this, the next generation of plasma systems uses an inverter block design that enables end users to add more inverter blocks in 100-amp increments (see Figure 6). A field technician can perform the upgrade in about 20 minutes. The flexibility of adding more output power eliminates the dilemma of investing in too little or too much capacity.

Plasma or oxyfuel? - TheFabricator.comFigure 7To have the right capability, many fabricators opt to equip their gantry with both plasma and oxyfuel torches. Photo courtesy of C&G Systems Corp.

Setup Factors

With plasma, optimizing torch height during arc start and setting height after piercing greatly extends consumables life and is critical for lowering cut cost. Further, the CNCs for plasma systems have numerous capabilities (such as nesting programs that reduce the number of pierces and cutting routines that produce bolt-ready holes) to lower cutting costs.

Plasma or oxyfuel? - TheFabricator.comFigure 8This high-precision plasma system cut demonstrates a 0.5-degree bevel on 0.25-in. mild steel.

Finally, the standard configuration for modern CNCs lets them manage up to four oxyfuel torches and two plasma torches on the same gantry. Even if you plan to use the plasma process most of the time, you can choose to equip tables with at least one oxyfuel torch for those instances when you run into thicker steel (see Figure 7). Adding an oxyfuel torch to a plasma system may add less than 10 percent to the total cost, and it can provide a good payback when it’s needed.

Cut Quality

Oxyfuel cuts with a 0-degree bevel. However, the swirl of the plasma gas inherently creates a bevel on one side of the cut. High-precision plasma cuts with a 0- to 2-degree bevel (see Figure 8), and thinner material is actually harder to cut.

Note that an oxyfuel cut will have a heat-affected zone (HAZ) that is five to 10 times larger than a plasma cut. And regardless of the cutting process, weld procedure requirements often dictate mechanical removal of the HAZ. Ask for cut samples and discuss the situation with your equipment provider.

For a common point of reference, following are the widely accepted characteristics of a precision-cut surface:

  • Square face, perpendicularity (less than 3-degree bevel).
  • Smooth, with nearly vertical drag lines.
  • Little to no oxides.
  • Little to no dross; what dross is present should be easy to remove.
  • Minimal HAZ and recast layer (remelted metal deposited on cut edges).
  • Good mechanical properties in welded components.

It boils down to quality and cost. Which process you choose will depend on what technology can send the part to the next production step with the least amount of postcut cleaning and at the lowest cost per cut.

Opportunities in Plasma Marking

Plasma or oxyfuel? - TheFabricator.com

High-precision plasma systems using argon or nitrogen for the plasma gas can produce a clean, clear, easily readable line. This is called plasma marking. Fabricators increasingly use this process to distinguish similar components (such as left and right sides) and to permanently identify components.

Plasma marking uses the same power sources, controls, and consumables used in plasma cutting, enabling fast changeover between the two. Marking and cutting on the same table also eliminates the material handling time and costs associated with marking parts in a secondary operation.

Plasma marking can use 5 to 30 amps of current, depending on the particular material and depth of mark desired. To create a mark at lower amperages, the plasma arc creates surface discoloration caused by the deposited heat flux. This type of marking modifies only the top surface layer; the arc vaporizes a very small amount of material (if any), which may be desirable in applications where fabricators want to paint over or otherwise obscure the marking.

At higher amperages, the plasma arc melts or vaporizes a slightly larger amount of material to create an indelible mark. By varying process parameters, fabricators can control the depth and width of the mark. Some might, for example, want a mark to show through a heavy coat of paint or epoxy or after years of exposure in a corrosive environment. Plasma marking can also create dimples that facilitate drill starts or punching.

 

With the economy still providing mixed signals, Victor Technologies is approaching business with optimism. Our branding
effort is in full swing, and we are enthusiastic about our newest product offerings both in the U.S. and around the globe.
Beginning with the company name change in May of 2012, and following in October with the alignment of our cutting
brands under the Victor name, we have focused on optimizing the performance of our brand portfolio. This is reflected in the
introduction of new packaging and displays for Victor, along with new “Victor green” trade dress and packaging for Victor Thermal
Dynamics manual and automated product lines.
To our valued distributors, business partners and end users, we share the message that coupled with our brand changes, our
resolve in the pursuit of strong product solutions, innovation and technology remains unchanged.
For example, Victor has introduced its new line of 400 Series oxy-fuel torches that offer better ergonomics and end-user driven
features such as a new contoured handle, three-tube cutting attachment design and color-coded valves for clarity and enhanced
safety. The 400 Series boasts a contoured, high-strength alloy torch handle that, while lighter than a brass handle, balances better
in operators’ hands and better resists wear and abuse.
In Victor Thermal Dynamics Automation, the rollout of the AutoCut XT and UltraCut XT lines represent the next generation in
precision plasma cutting. Ultra-Cut XT systems provide the flexibility to increase cutting power and the assurance of superior
quality, higher productivity and lower cutting costs. And because of its expansion capabilities, there is never a concern about
choosing the right system.
In specialty welding, Tweco also boasts a new logo and refreshed packaging. In addition to the new Tweco Velocity MIG
consumables and light-duty Tweco Fusion MIG guns, Tweco has also announced its scheduled launch of the Tweco Classic Series
MIG guns, an enhancement to the original “numbered series” that is arguably one of the most popular gun designs in the world.
Tweco Classic enhancements will include interlocking joints for superior toughness, an angled trigger for a more comfortable pull
and refined, modernized lines.
In addition to these exciting announcements, we invite you to help us celebrate this year’s 100th anniversary of the Victor brand.
Please read about our 100th Anniversary contests in this issue of NewsUpdate, and we invite you to share in a special celebration
with us later this year at the 2013 Fabtech. Stay tuned for additional details, and again, thank you for your valued role in delivering
Victor Technologies cutting, gas control and specialty welding products that set the standard for versatility and performance.

joemueller_sig_rev

 

 

 

 

Regards,
Joseph F. Mueller
Sr. Vice President, GM Sales, Americas

Catch up with the latest in cutting, gas control and specialty welding with the latest edition of the Victor Technologies’ News Update.

In this issue, find out about the newest products including the Victor 400 Series of cutting torches and handles, the Victor G Series regulators, Tweco Fusion MIG guns and more.

We’ve also got some great articles on welding education, safety and best practices.  Check it out!

Q1Q2-2013-Victor-Technologies-Sales-and-Marketing-Newsletter

 

End-user-driven features include new contoured handle, three-tube cutting attachment design and color-coded and labeled valves knobs for clarity and enhanced safety. Torch kits include new G Series regulators that also offer greater visual acuity.

Victor®, a Victor Technologies brand, has launched its new 400 Series of oxy-fuel torches and G Series regulators to meet the needs of end-users globally. The 400 Series is a two-piece torch that incorporates innovative handle and cutting attachment designs that offer better ergonomics, a clearer view of the cutting path, visual cues for easier use and enhanced safety. The 400 Series is compatible with current 300 series consumables and accessories, and meets or exceeds performance and durability expectations of a Victor torch, the industry’s leading brand.

Victor400The 400 Series features a contoured, high-strength alloy torch handle that fits naturally in most operators’ hands. While lighter than a brass handle, the new handle better resists abuse, and it balances well when hoses and attachments are connected.

To simplify use, Victor color-coded and labeled the oxygen and fuel valves for instant identification and easier operation by indicating directions for open and closed valve positions.

“Until now, it was very difficult for an inexperienced worker to effectively and intuitively identify gas valves,” says John Henderson, Group Brand Manager, Victor Technologies. “The 400 Series torch provides operators with the visual acuity necessary for safe and effective oxy-fuel cutting, even if English isn’t their first language.”

Henderson notes that design changes to simplify use help companies cope with the retirement of skilled operators and need to hire younger, less-skilled workers or workers who speak English as a second language. The durability of the torch handle also improves longevity in situations where tools receive rough treatment, a feature specifically requested by the supervisors interviewed during product development.

Better VisibilityVictor400_BetterView

To simplify use and increase precision, the 400 Series cutting attachment provides excellent line-of-sight visibility. Victor accomplished this by departing from its traditional tube-in-tube design to a sleeker three-tube design (oxy-fuel cutting requires three tubes, one each for fuel gas, pre-heat oxygen and cutting oxygen).

“Our new tube design optimizes cutting area visibility while providing strength and supporting gas flow rate requirements for tip sizes 000 through 6,” says Henderson. The 400 Series uses a universal mixer design and mixes the gases in the head of the torch. Like all Victor torches, it enables operators to use one torch for all fuels (acetylene, propylene, propane, etc.) simply by selecting the correct tips or attachments.

“Everyone familiar with the cutting performance of a Victor torch will recognize the superior performance of the new 400 Series cutting attachments,” notes Henderson. “They’ll also appreciate how the oxygen cutting lever is positioned relative to the torch handle for increased comfort.”

Victor400_ErgonomicG Series Regulators

When sold as part of the Medalist® 250 and 350 outfits, Victor’s new G Series regulator accompanies the 400 Series torch. G Series regulators use a combination of colors on the gauge face to provide clarity for reading needle position, while a scale and red tick mark indicate actual service pressure of the regulator.  The G Series also uses ergonomic color-coded knobs to indicate gas type and for better comfort when adjusting gas pressure.

ST. LOUIS, May 21, 2012 (GLOBE NEWSWIRE) –Thermadyne Holdings Corporation today announced that it has changed its name to Victor Technologies Group, Inc. and the name of its wholly owned subsidiary Thermadyne Industries, Inc. to Victor Technologies International, Inc.

“To re-position the company in the marketplace, we are returning to our roots,” says Martin Quinn, the company’s Chief Executive Officer. “Victor Technologies will recapture the pioneering spirit and embody the original attributes of the Victor brand: authenticity, reliability and innovation.”  Victor is the company’s strongest and most established brand, celebrating its 100th anniversary in 2013. “By leveraging the Victor name, we reinforce to the industry our focus on meeting the needs of the end user customer for our products and providing advanced cutting,welding and gas control solutions through each of our brands,” said Quinn. “Our vision for the company is ‘Innovation to shape the world.’”

About Victor Technologies
: Headquartered in St. Louis, Missouri, Victor Technologies provides superior solutions for cutting, welding and gas control equipment under brand names that include Victor®, Tweco®,Arcair®, Thermal Dynamics®, Thermal Arc®, Stoody®, TurboTorch®, Firepower® and Cigweld®. For more information about Victor Technologies, its products and services, visit the company’s web site at http://www.victortechnologies.com.

Cautionary Statement Regarding Forward-Looking Statements:
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These statements reflect management’s current expectations and involve a number of risks and uncertainties. Actual results may differ materially from such statements due to a variety of factors that could adversely affect the Company’s operating results. These risks and factors are set forth in documents the Company files with the Securities and Exchange Commission, specifically in the Company’s most recent Annual Report on Form 10-K and other reports it files from time to time.

Contact:
Bill Wehrman, Communications Manager
Victor Technologies
Phone: 636-728-3057
Email: media@victortechnologies.com

Alternate Contact:
Chuck Schroeder (PR Representative)
Office: 262-240-9790; Mobile: 414-467-3287
Email: chucks@imipr.com