Westermans – Specialist Dealers in new and pre-used Sub-Arc Welding Equipment at affordable prices
Sell – Buy – Hire
Equipment for submerged arc welding
The submerged-arc welding (SAW) process is similar to MIG where the arc is formed between a continuously-fed wire electrode and the work piece, and the weld is formed by the arc melting the work piece and the wire. However, in SAW a shielding gas is not required as the layer of flux generates the gases and slag to protect the weld pool and hot weld metal from contamination. Flux plays an additional role in adding alloying elements to the weld pool.
Essential equipment components for SAW are:
As SAW is a high current welding process, the equipment is designed to produce high deposition rates.
Compliments of Welding Specialists Arc Energy Resources of England
ESAB, Lincoln Electric, Miller Welding, Fronius, Gullco and SAF
What we do:
We buy and sell all associated equipment to sub-arc welding including, Power sources, Column and Boom Manipulators, Rotators, Tractors, Positioners, Flux hoppers and accessories. All of our equipment is prepared to order.
SAW can be operated using either a DC or an AC power source. DC is supplied by a transformer-rectifier and AC is supplied by a transformer. Current for a single wire ranges from as low as 200A (1.6mm diameter wire) to as high as 1000A (6.0mm diameter wire). In practice, most welding is carried out on thick plate where a single wire (4.0mm diameter) is normally used over a more limited range of 600 to 900A, with a twin wire system operating between 800 and 1200A.
In DC operation, the electrode is normally connected to the positive terminal. Electrode negative (DCEN) polarity can be used to increase deposition rate but depth of penetration is reduced by between 20 and 25%. For this reason, DCEN is used for surfacing applications where parent metal dilution is important. The DC power source has a ‘constant voltage’ output characteristic which produces a self-regulating arc. For a given diameter of wire, welding current is controlled by wire feed speed and arc length is determined by voltage setting.
AC power sources usually have a constant-current output characteristic and are therefore not self-regulating. The arc with this type of power source is controlled by sensing the arc voltage and using the signal to control wire feed speed. In practice, for a given welding current level, arc length is determined by wire burnoff rate, i.e. the balance between the welding current setting and wire feed speed which is under feedback control.
Square wave AC square wave power sources have a constant voltage output current characteristic. Advantages are easier arc ignition and constant wire feed speed control.
SAW can be carried out using both manual and mechanised techniques. Mechanised welding, which can exploit the potential for extremely high deposition rates, accounts for the majority of applications.
For manual welding, the welding gun is similar to a MIG gun, with the flux which is fed concentrically around the electrode, replacing the shielding gas. Flux is fed by air pressure through the handle of the gun or from a small hopper mounted on the gun. The equipment is relatively portable and, as the operator guides the gun along the joint, little manipulative skill is required. However, because the operator has limited control over the welding operation (apart from adjusting travel speed to maintain the bead profile) it is best used for short runs and simple filling operations.
Mechanised welding – single wire
As SAW is often used for welding large components, the gun, wire feeder and flux delivery feed can be mounted on a rail, tractor or boom manipulator. Single wire welding is mostly practised using DCEP even though AC will produce a higher deposition rate for the same welding current. AC is used to overcome problems with arc blow, caused by residual magnetism in the workpiece, jigging or welding machine.
Wire stickout, or electrode extension – the distance the wire protrudes from the end of the contact tip – is an important control parameter in SAW. As the current flowing between the contact tip and the arc will preheat the wire, wire burnoff rate will increase with increase in wire stickout. For example, the deposition rate for a 4mm diameter wire at a welding current of 700A can be increased from approximately 9 kg/hr at the normal 32mm stickout, to 14 kg/hr at a stickout length of 178mm. In practice, because of the reduction in penetration and greater risk of arc wander, a long stickout is normally only used in cladding and surfacing applications where there is greater emphasis on deposition rate and control of penetration, rather than accurate positioning of the wire.
SAW can be operated with more than one wire. Although up to five wires are used for high deposition rates, e.g. in pipe mills, the most common multi-wire systems have two wires in a tandem arrangement. The leading wire is run on DCEP to produce deep penetration. The trailing wire is operated on AC which spreads the weld pool, which is ideal for filling the joint. AC also minimises: interaction between the arcs, and the risk of lack of fusion defects and porosity through the deflection of the arcs (arc blow). The wires are normally spaced 20mm apart so that the second wire feeds into the rear of the weld pool.
In manual welding, the gun is operated with a trailing angle, i.e. with the gun at an angle of 45 degrees (backwards) from the vertical. In single wire mechanised welding operations, the gun is perpendicular to the workpiece. However, in twin wire operations the leading gun is normal to the workpiece, with the trailing gun angled slightly forwards between an angle of 60 and 80 degrees. This reduces disturbance of the weld pool and produces a smooth weld bead profile.
Flux should be stored in unopened packages under dry conditions. Open packages should be stored in a humidity-controlled store. While flux from a newly-opened package is ready for immediate use, flux which has been opened and held in a store should first be dried according to manufacturer’s instructions. In small welding systems, flux is usually held in a small hopper above the welding gun. It is fed automatically (by gravity or mechanised feed) ahead of the arc. In larger installations the flux is stored in large hoppers and is fed with compressed air. Unused flux is collected using a vacuum hose and returned to the hopper.
Unlike other arc welding processes, SAW is a clean process which produces minimum fume and spatter when welding steels. (Some noxious emissions can be produced when welding special materials.) For normal applications, general workshop extraction should be adequate.
Protective equipment such as a head shield and a leather apron are not necessary. Normal protective equipment (goggles, heavy gloves and protective shoes) are required for ancillary operations such as slag removal by chipping or grinding. Special precautions should be taken when handling flux – a dust respirator and gloves are needed when loading the storage hoppers.
Have you surplus sub arc welding equipment to dispose of? Westermans will handle inspections, payment and collection quickly and always pay great prices for the latest models.
Please contact our Buying Team with any surplus SAW plant. We pay commission on successful leads too so it doesn’t have to be your stock.
For our full range of submerged arc welding equipment for sale today follow this link to our website. Or call our Sales department to discuss. We specialise in selling bespoke packages worldwide.
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Remember USED equipment offers quality without a high price tag and well worth considering for your next project.
The Compact Cladding Cell is designed for maximum cost-effective overlay welding on components up to a diameter of 1 m (3.94 in) and a maximum weight of 2500 kg (5511 lb). Despite its compact design,
The Compact Cladding Cell is an extremely powerful cladding system that provides simple operation, precise movements and extensive data logging capabilities.
Compact CNC Weld Overlay Cladding Cell with Fronius FPA 9000 CC Control
The power-team: TransTig 5000 Job with high-performance cooling unit FK 4000 R and TransTig 2200 Job – fully digital for the best welding quality with TIG hotwire.
1000KG Welding positioner fitted with a 900mm table fitted with 500mm Chuck. Slip ring systems transfer power when a face plate is rotating and are used to operating heating elements for pre-heating components.
Overall height 2400mm
Area required 2000 x 2700mm additional space required 600 x 650mm working area
It is a year we will remember as tough for our friends and colleagues in the Oil and Gas industry, Brexit and Trump.
However happy memories will remain of how we achieved record Sales from Overseas welding equipment sales, increases in our new equipment product range resulting in some great orders, our Octogenarian Founder and Managing Director Peter Westerman receiving his Lifetime Achievement Award at the Welding World Awards.
So what will develop during 2017?
This year we want to really work closely with a select number of Partners and Agents around the World to both buy and sell used Welding and Cutting machines.
We have employed a brilliant new service engineer who will undoubtedly help to get the orders completed, not only quickly, but to retain the high standards we all value.
We are seeking more New product ranges to complement our existing Stock categories.
The plan is to launch our own Client login area so that you can obtain all the information you need on any equipment purchased, documents and manuals.
With so many welding and machinery events around the world it is difficult to know where to go, we are aiming to attend if not exhibit at a fair few of these, hopefully we will meet you there?
Women’s sport is finally getting more recognition everywhere. This year we are proud to sponsor the newly created British Women’s Motocross Championships, the first of its kind in the UK. Visit our Blog and Facebook page for events and results throughout the year.
Can we help you?
Always new year resolutions are about giving something up, getting fitter and eating healthier. Our Team is already focusing on that with daily brisk walks to ensure we are focused throughout the day. We may also try table tennis and star jumps!
But what is it we can do for you? If you think that our company, staff or network can help push your business forward in 2017 then please get in touch.
As always we have a limited fund available for commission payments on both buying and selling. This is for successful introductions to your own network of welding and fabrication companies around the world.
A very fast week!
Well, already the first week of the year has been productive, creative and a winner.
It really feels our history of trading, riding those up and downs every so often is behind us and our Team are starting the year with great passion and dedication to make it the best ever.
It’s a time to feel positive about the future both at home and in the workplace.
Wishing you all a very happy, healthy and lucrative New Year
Don’t forget we Buy, Sell and Hire…. any type of welding, cutting or positioning machinery
Huge choice, unbeatable value with first class after-sales support.