Most people who have been in a technical profession know the constant need for a variety of tools. One minute you may need a pliers, then a knife, then a file, then a screwdriver, and once the day is all done, a bottle opener. This is the reason why multi-tools have become so popular; they combine all of these tools into one. In the world of welding, there is something similar to a multi-tool. It is known as a multi-process welder. Red-D-Arc carries multi-process welders because we know that one minute you might be self-shielded flux core welding some dirty, ½” thick steel and then the next minute be fitting up 18 gauge aluminum that you need to gas tungsten arc weld.
Red-D-Arc provides a wide variety of multi-process power sources to suit many customer needs. The Miller XMT is a type of multi-process welder that Red-D-Arc carries. All XMT variations provide the capability to MIG, TIG, flux core, and stick weld. The Field Pro series also possesses Miller’s proprietary pulse waveform known as Regulated Metal Deposition (RMD).
This is a pulsed short arc MIG welding process that is excellent at bridging wide gaps that can result from poor fit-up.
Red-D-Arc is aware that multi-process welders aren’t always operated in ideal conditions. Extreme heat and environments with high amounts of dust can destroy welding power sources. That is why Red-D-Arc provides the EX360. The “EX” is for extreme, because this power source can handle extreme conditions. If protection from dust and heat are a concern while using multiple welding processes, the EX360 may be your solution. The EX360, as well as several other multi-process welders offered by Red-D-Arc, are available in four-pack and six-pack configurations to enable increased productivity.
Submerged arc welding is an excellent process to achieve high deposition rates, and Red-D-Arc has them. However, some applications require additional welding processes besides just submerged arc welding. When this is the case, Red-D-Arc also has multi-process submerged arc welding machines. The DC1000, for instance, provides end users with the ability to not only submerged arc weld, but also provides stick, MIG, and flux cored arc welding capabilities.
For additional information on Red-D-Arc’s multi-process welding product offerings, visit our multi-process welder page.
Some of the most difficult welds to make are those that require the welding of a small diameter to a plate. Gas tungsten arc welding or gas metal arc welding joints such as these require a high degree of operator skill, take a great deal of time, and can be a quality nightmare. These factors become even more troublesome when the material with the small radius being welded is in the vertical or overhead position. Fortunately, Red-D-Arc provides stud welding equipment that increases productivity, decreases the required operator skill immensely relative to other welding processes, and allows for consistent, repeatable weld quality on materials with small radii.
What is Stud Welding?
Stud welding is a fusion welding process that is commonly used for the joining of small round stock to plate. The process requires a power source, a stud welding gun, a ground clamp, and the materials that are to be welded. To carry out the stud welding process, a solid, round piece of metal, also known as a stud, is placed into the stud welding gun.
Depending on the type of stud welding process, a ferrule may be placed around the stud to shield the weld and protect the adjacent base material. The trigger on the gun is pulled, and a weld is quickly made across the entire faying surface of the stud to the plate on which it is being welded.
Capacitor Discharge Stud Welding
Capacitor discharge stud welding is a very useful type of stud welding. It uses capacitors to unload a high amount of electrical energy into the weld joint via the stud in an extremely short amount of time (far less than one second). It is a very clean welding process that requires minimal post-weld attention. It can also weld very thin materials, down to 0.015” thick. Capacitor discharge stud welding is well-suited to weld aluminum, steel, and stainless steel. ¼ inch diameter studs is usually around the upper limits of most capacitor discharge stud welders. Red-D-Arc provides the Proweld CD-312 stud welder to give you world-class capacitor discharge stud welding capability.
Drawn Arc Stud Welding
Drawn arc stud welding is another very popular type of stud welding. During this process, an electrical arc is created between the base material and the stud. Drawn arc stud welding also creates a weld joint that joins the entire faying surface of the stud to the plate on which it is being welded. Although drawn arc stud welds do take longer than capacitor discharge welds, they typically take less than two seconds of arc time per weld. Drawn arc stud welding also typically requires the use of ferrules. These ferrules are ceramic rings that go around the stud in the gun prior to welding. One advantage of drawn arc stud welding over capacitor discharge welding is that it is capable of welding studs with diameters over 1 inch. The Proweld AC-1850 and the Proweld AC-3000 are two drawn arc stud welding solutions carried by Red-D-Arc to provide customers with extremely fast, high quality stud welds.
Stainless steel contains a minimum of 10.5% chromium which imparts it corrosion resistance by forming an oxide layer on the surface. The most common stainless steel is the austenitic type (300 series) which contains chromium and nickel as alloying elements. Other types include ferritic, martensitic and duplex stainless steels. Most stainless steels are considered to have good weldability characteristics. Most common processes used for welding stainless steel are TIG (GTAW) and MIG (GMAW). But, stick welding (SMAW) is also utilized.
Differences in Properties:
The properties of stainless steel differ from mild steel, and these differences need consideration when welding as below:
- Higher coefficient of expansion, 50% more for austenitic – this results in more distortion
- Lower coefficient of heat transfer – welding requires lower heat input as it is conducted away slowly
- Lower electrical conductivity – using the correct and consistent stick-out distance is more critical when using MIG/TIG, higher wire speed for the same current is required when MIG welding
Why segregated work area?
Welding of stainless steel is carried out in a work area segregated from carbon steels. Moreover, tools dedicated for use with stainless steel must not be used to work on carbon steels. These tools include brushes, hammers, clamps, grinders etc. The segregation of work area and tools safeguard the contamination from carbon steels, which may cause welding defects and corrosion (rust) on stainless steel. You must also wear gloves when working with stainless steel as this will prevent oil from the hands passed onto the stainless steel.
Preparation is key!
With stainless steel, it is important that the joint surfaces are thoroughly cleaned before welding to remove any dirt, grease, oil etc. The filler wire also needs to be completely clean.
Additionally, the joint design including the joint gap must cater to the higher expansion rate of stainless steels.
Filler Material Selection:
Filler materials used generally are the same as the base metal. Special considerations are required to select a filler material if welding dissimilar stainless steels or stainless steels where no identical filler material exists. Furthermore, filler materials are selected to reduce the risk of intergranular corrosion and hot cracking.
It is essential to protect the weld during welding using a mainly inert gas. Additionally, the weld root needs to be purged using a pure inert gas.
When welding austenitic stainless steels, it is important to restrict the heat input to a level which is just sufficient to ensure a good weld. The interpass temperature is limited to 350 F. Preheating is not carried out on austenitic stainless steels. Very low carbon grades (suffixed with L e.g. 304L, 316L) are used to prevent the formation of chromium carbides in the heat affected zones which causes intergranular corrosion.
Martensitic stainless steels are generally used as wear resistant materials in overlaying applications. To avoid cracking, accurate preheat needs to be applied and a minimum interpass temperature maintained.
Ferritic stainless steels are used mostly in automotive applications. The heat input in these steels during welding needs to be limited, and a maximum interpass temperature of 300 F is recommended. This will ensure that the grain growth in the material is controlled and the strength is maintained.
With duplex stainless steels, the heat input also needs to be restricted.
Cleaning and Passivation:
Stainless steel welds must be cleaned and passivated after completion to ensure corrosion resistance and good appearance. This is performed manually by mechanical (brushing, grinding, blasting), chemical (applying pickling agents and other chemicals) or electrochemical means.
Red-D-Arc has a wide range of equipment suitable for stainless steel welding for rent including the following:
Multi process welders capable of stick, TIG, MIG, submerged arc, air carbon arc cutting, flux core, up to 1500 A
MIG welding units up to 750 A
TIG welding units up to 750 A
Stick welding units – up to 625A
Also 4 and 6 Paks of welders available
Orbital welders – suitable for stainless steel pipe/tube welding
Various brands including Miller, Lincoln, Red-D-Arc
Have a look at our complete range of welding products.
Inspection, Surface Prep and Non-destructive Testing
Are you in the oil & gas industry? Are you involved in non-destructive testing, inspection, or surface preparation? How about maintenance of pipelines, heat exchangers, or pressure vessels? If you deal with these or similar operations, proper cleaning of surfaces might well be a process you regularly undertake.
Cleaning Delicate Equipment Safely
What is the best way to clean surfaces of such equipment? While there is no one best way for every circumstance, dry ice cleaning is a state-of-the-art method that can save time and money. It uses recycled CO2 in the form of solid dry ice particles as the cleaning media. Dry ice is soft and non-abrasive to most surfaces and can thus be used around delicate components, including electronics, that would be damaged by water or solvents. As the blasting equipment is portable it can be used in place, thus minimizing disassembly and other preparation time. Lastly, dry ice turns to a gas after contact with the surface being cleaned — cleanup time is rock bottom minimum, there is nothing to dispose of, contamination of moving parts is not an issue.
To begin, let’s establish what exactly we’re talking about when we say “biodiesel.” ASTM (American Society for Testing and Materials) has published a standard, D6751-07b, that defines what biodiesel is. We’re not talking about used cooking grease, or even commercially produced biodiesel, if it doesn’t meet this standard.
Also, the word “biodiesel” is often used to describe what is actually a blend of biodiesel and diesel fuel. (The diesel fuel sold for on-road use in the U.S. is Ultra Low Sulfur Diesel fuel, or ULSD.) The term “BX” designates the blend ratio, where “X” stands for the percentage of biodiesel in the blend. So B100 means 100%, or pure, biodiesel, while B20 means 20% biodiesel mixed with 80% ULSD.
Additionally, this article doesn’t address OEM recommendations or warranty limitations. We’re simply looking at the question from a mechanical standpoint.
So now, with all that out of the way, what’s the bottom line?
Here are a couple of snags that can show up in any diesel engine when using biodiesel:
Fuel filters may initially clog:
This applies to engines that have burned petroleum diesel for years before switching to biodiesel. Over time, petroleum diesel leaves small carbon and tar deposits in a fuel system. B100, a mild solvent, will “clean out” the fuel system, dislodging these deposits. This is a good thing, but it’s inconvenient when a fuel filter clogs with these deposits. Once the fuel system is clean (usually after burning 1-2 tanks of B100), this issue goes away. B20 and lesser blends do not have this cleaning effect.
Biodiesel begins to gel at a higher temperature than ULSD. As a general rule of thumb, the greater the percentage of biodiesel present in a blend, the higher the temperature at which it will start to form wax crystals too large to pass through the fuel filter. In extreme cold, without a fuel preheating system, all but the most dilute biodiesel blends may be impractical.
Now, let’s discuss changes in diesel engine technology.
Pre-common rail diesel engines (mostly pre-2000)
These engines work very well with B100 (as well as with lesser blends). In fact, biodiesel is often a superior fuel for these engines. It is a far better lubricant than ULSD, sharply reducing injection pump wear. Unlike ULSD, which is made up solely of hydrocarbon chains, biodiesel molecules also contain oxygen. This oxygen contributes to better combustion. Thus, even though biodiesel has a lower energy content than ULSD, some engines may actually see a slight increase in power output, with minimal loss of fuel economy when using biodiesel.
Common rail diesel engines
Rule of thumb:
Any biodiesel blend works great.
Diesel engines with common rail injection systems started showing up in the early 2000s. These systems burn ULSD more efficiently than older systems, so biodiesel’s oxygen content no longer offers any real efficiency advantage, and its lower energy content manifests itself in a slight reduction in fuel economy and power. Further, high precision common rail injection systems are “tuned” to fuel of a given viscosity, and the viscosity of B100 differs significantly from that of ULSD. This may, for example, change the spray pattern of fuel into the combustion chamber, and the end result can be an increase in soot and carbon buildup.
Engines with diesel particulate filters
Rule of thumb:
While B100 works, these engines work best with lower blends, like B20.
In 2008, the EPA started phasing in its Tier IV diesel emissions standard, which required an immediate 90% reduction in particulate matter. Diesel particulate filters, or DPFs, are exactly what they sound like – a filter in the exhaust system that captures particulate matter, such as soot. To regenerate, or clean, the filter, atomized ULSD is injected into the exhaust. When it reaches the DPF, it ignites and burns off the particulates that have collected there. To accomplish this, many engines periodically inject ULSD into the cylinder during the exhaust stroke. This ULSD vaporizes and flows through the exhaust system with the other exhaust gases. Biodiesel, however, is less volatile than ULSD. When it is injected into the cylinder during the exhaust stroke, rather than flowing out through the exhaust valve as a vapor, some of it condenses on the cylinder walls as a liquid and runs down through the crankcase. Over time, this biodiesel accumulates and dilutes the engine oil. Thus, for engines equipped with this style of DPF regeneration, biodiesel blends generally should not exceed B20.
Some DPF systems are able to eliminate this problem by using an extra injector located in the exhaust system to handle regeneration. Such configurations don’t cause engine oil dilution and so are compatible with B100, but they are also less common.
Rule of thumb:
B20 works with DPF-equipped diesel engines. Higher blends work with some engines with specific configurations for DPF regeneration.
Complications associated with using B100 may vary from negligible to major, depending on the engine configuration and the operating environment. B20 and lower blends, on the other hand, present minimal complications when used in any modern diesel engine and in all but the coldest operating environments.
Diesel Generator Rentals
Red-D-Arc carries diesel, LPG and natural gas generators in a range of sizes.
D&D Power provides full service oilfield generator rentals including generator paralleling.
We also provide diesel air compressors for rent.