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Multiprocess 175. Operating manual.

Multiprocess 175. Operating manual.

2. Metal Inert Gas & Metal Active Gas arc 

welding (MIG/MAG).

 

Argon with oxygen mixtures (MAG) 

 

Argon with helium mixtures (MIG)

Each gas or gas mixture has specific advantages and limitations. Other 

forms of MIG/MAG welding include using a flux-cored continuous 

electrode and carbon dioxide shielding gas, or using self-shielding flux-

cored wire, requiring no shielding.

2.2 Introduction to Flux-Cored Arc Welding (FCAW)

How it works

Flux-cored arc welding (FCAW) uses the heat generated by a DC electric 

arc to fuse the metal in the joint area, the arc being struck between a 

continuously fed consumable filler wire and the workpiece, melting both 

the filler wire and the workpiece in the immediate vicinity. The entire arc 

area is covered by a shielding gas, which protects the molten weld pool 

from the atmosphere.

FCAW is a variant of the MIG/MAG process and while there are many 

common features between the two processes, there are also several 

fundamental differences.

As with MIG/MAG, direct current power sources with constant voltage 

output characteristics are normally employed to supply the welding 

current. With flux-cored wires the terminal that the filler wire is 

connected to depends on the specific product being used, some wires 

running electrode positive, others running electrode negative. The work 

return is then connected to the opposite terminal. It has also been found 

that the output characteristics of the power source can have an effect on 

the quality of the welds produced.

2.1 Introduction to Metal Inert Gas (MIG)  

& Metal Active Gas (MAG)

MIG/MAG welding embraces a group of arc welding processes in which 

a continuous electrode (the wire) is fed by powered feed rolls (wire 

feeder) into the weld pool. An electric arc is created between the tip of 

the wire and the weld pool. The wire is progressively melted at the same 

speed at which it is being fed and forms part of the weld pool. Both the 

arc and the weld pool are protected from atmospheric contamination by 

a shield of inert (non-reactive) gas, which is delivered through a nozzle 

that is concentric with the welding wire guide tube. 

Operation

MIG/MAG welding is usually carried out with a handheld torch as a semi-

automatic process. The MIG/MAG process can be suited to a variety of 

job requirements by choosing the correct shielding gas, electrode (wire) 

size and welding parameters. Welding parameters include the voltage, 

travel speed, arc (stick-out) length and wire feed rate. The arc voltage 

and wire feed rate will determine the filler metal transfer method.

This application combines the advantages of continuity, speed, 

comparative freedom from distortion and the reliability of automatic 

welding with the versatility and control of manual welding. The process 

is also suitable for mechanised set-ups, and its use in this respect 

is increasing.

MIG/MAG welding can be carried out using solid wire, flux-cored, or a 

copper-coated solid wire electrode. The shielding gas or gas mixture may 

consist of the following:

 

Argon (MIG)

 

Carbon dioxide (MAG)

 

Argon and carbon dioxide mixtures (MAG)

The wire feed unit takes the filler wire from a spool, and feeds it 

through the welding torch, to the arc at a predetermined and accurately 

controlled speed. Normally, special knurled feed rolls are used with flux-

cored wires to assist feeding and to prevent crushing the consumable.

Unlike MIG/MAG, which uses a solid consumable filler wire, the 

consumable used in FCAW is of tubular construction, an outer metal 

sheath being filled with fluxing agents plus metal powder. The flux fill 

is also used to provide alloying, arc stability, slag cover, de-oxidisation, 

and, with some wires, gas shielding.

In terms of gas shielding, there are two different ways in which this may 

be achieved with the FCAW process.

 

Additional gas shielding supplied from an external source, such as a 

gas cylinder 

 

Production of a shielding gas by decomposition of fluxing agents 

within the wire, self-shielding 

Gas shielded wires are available with either a basic or rutile flux fill, 

while self-shielded wires have a broadly basic-type flux fill. The flux 

fill dictates the way the wire performs, the properties obtainable, and 

suitable applications.

Gas shielded operation

Many cored wire consumables require an auxiliary gas shield in the same 

way that solid wire MIG/MAG consumables do. These types of wire are 

generally referred to as ‘gas shielded’.

Using an auxiliary gas shield enables the wire designer to concentrate 

on the performance characteristics, process tolerance, positional 

capabilities, and mechanical properties of the products.

In a flux-cored wire the metal sheath is generally thinner than that of a 

self-shielded wire. The area of this metal sheath surrounding the flux-

cored wire is much smaller than that of a solid MIG/MAG wire. This 

means that the electrical resistance within the flux-cored wire is higher 

than with solid MIG/MAG wires and it is this higher electrical resistance 

that gives this type of wire some of its novel operating properties.

One often quoted property of fluxed cored wires are their higher 

deposition rates than solid MIG/MAG wires. What is often not explained 

is how they deliver these higher values and whether these can be 

utilised. For example, if a solid MIG/MAG wire is used at 250 amps, then 

exchanged for a flux-cored wire of the same diameter, and welding 

power source controls are left unchanged, then the current reading 

would be much less than 250 amps, perhaps as low as 220 amps. This 

is because of Ohms Law that states that as the electrical resistance 

increases if the voltage remains stable then the current must fall.

To bring the welding current back to 250 amps it is necessary to 

increase the wire feed speed, effectively increasing the amount of 

wire being pushed into the weld pool to make the weld. It is this affect 

that produces the ‘higher deposition rates’ that the flux-cored wire 

manufacturers claim for this type of product. Unfortunately in many 

instances the welder has difficulty in utilising this higher wire feed 

speed and must either increase the welding speed or increase the size of 

the weld. Often in manual applications neither of these changes can be 

implemented and the welder simply reduces the wire feed speed back 

to where it was and the advantages are lost. However, if the process 

is automated in some way then the process can show improvements in 

productivity.

It is also common to use longer contact tip to workplace distances with 

flux-cored arc welding than with solid wire MIG/MAG welding and this 

Typical MIG/MAG set up

1

 Torch, 

2

 Torch trigger, 

3

 Shroud, 

4

 Gas diffuser, 

5

 Contact tip, 

6

 Welding wire, 

7

 Shielding, 

8

 Weld, 

9

 Droplets, 

10

 Weld pool

1

2

3

4

5

6

7

9

10

8

Extended self shielded flux-cored wire nozzle

Summary of Contents for multiprocess 175

Page 1: ...Multiprocess 175 Operating Manual ...

Page 2: ...formation This document does not take into account the particular circumstances of the recipient and the recipient should not rely on this document in making any decisions including but not limited to business safety or other operations decisions Except insofar as liability under any statute cannot be excluded Ryval and its affiliates directors employees contractors and consultants do not accept a...

Page 3: ...rt Page 18 4 Manual Metal Arc Welding MMAW 4 1 Introduction 4 2 Process 4 3 Welding machine 4 4 Welding technique 4 5 Electrode selection 4 6 Types of joints 21 5 General welding information 5 1 Recommended welding parameters for MIG MAG 22 6 Package contents 23 7 Multiprocess 175 installation 7 1 Installation for MIG MAG process 7 2 Installation for TIG setup 7 3 Installation for MMA process 25 8...

Page 4: ...cylinder valve by hand by turning the valve hand wheel in a clockwise direction Use only reasonable force Remember NEVER tamper with the valve If you suspect the valve is damaged DO NOT use it Report the issue to Ryval and arrange for the cylinder to be returned to Ryval 1 4 Electrical shock Never touch live electrical parts Always repair or replace worn or damaged parts Disconnect the power sourc...

Page 5: ...led feed rolls are used with flux cored wires to assist feeding and to prevent crushing the consumable Unlike MIG MAG which uses a solid consumable filler wire the consumable used in FCAW is of tubular construction an outer metal sheath being filled with fluxing agents plus metal powder The flux fill is also used to provide alloying arc stability slag cover de oxidisation and with some wires gas s...

Page 6: ...h to the arc at a predetermined and accurately controlled speed Normally special knurled feed rolls are used with metal cored wires to assist feeding and to prevent crushing the consumable Unlike MIG MAG which uses a solid consumable filler wire the consumable used in MCAW is of tubular construction an outer metal sheath being filled entirely with metal powder except for a small amount of non meta...

Page 7: ...entre flows as a stream of smaller droplets into the weld pool This effect seems to give much better transfer of alloying elements into the weld In spray transfer as the current density increases an arc is formed at the end of the filler wire producing a stream of small metal droplets In solid wire MIG MAG this transfer mode occurs at higher currents Flux cored wires do not achieve a completely tr...

Page 8: ...veral methods between the tungsten and the workpiece During TIG welding the arc can be initiated by several means Scratch start With this method the tungsten electrode is physically scratched on the surface of the workpiece and the arc is initiated at the full amperage set by the operator The incidence of the tungsten melting at the high initiation amperage is high and tungsten inclusions in the w...

Page 9: ... this gas compared to helium Argon is the most commonly used gas for stainless steel Helium can be used if better penetration is required Argon produces a stable arc Helium is recommended for high speed welding DCEN Narrow bead deep penetration DCEP Wide bead shallow penetration Nozzle Nozzle Ions Ions Electrons Electrons 3 5 Consumable selection Filling rod Filler rod diameter mm Thickness of met...

Page 10: ...lectrode and rough deposits that are associated with slag inclusions For downhand welding it will be found that an arc length not greater than the diameter of the core wire will be most satisfactory Overhead welding requires a very short arc so that a minimum of metal will be lost Certain Ryval electrodes have been specially designed for touch welding These electrodes may be dragged along the work...

Page 11: ...meters Dip transfer Spray transfer Material thickness mm Welding position Wire diameter mm Current amps Voltage volts Wire feed speed m min Gas rate flow L min Travel speed mm min 1 1 6 Horizontal Vertical 0 8 0 9 45 80 14 16 3 5 5 0 15 350 500 2 Horizontal Vertical 0 8 0 9 60 100 16 17 4 0 7 0 15 350 500 3 Horizontal Vertical 0 8 0 9 80 120 16 18 4 0 7 0 15 320 500 4 Horizontal Vertical 0 9 1 0 8...

Page 12: ...elect the appropriate feed roller to suit the wire being used This machine comes complete with two types of wire feed rollers V groove for use with solid carbon manganese and stainless steels U groove for use with soft wires such as aluminium 5 Loosen the wire feed tension screws and insert the wire Re fit and tension the rollers ensuring the wire is gripped sufficiently so as not to slip but avoi...

Page 13: ...t panel and fasten it clockwise Connect the other end of the clamp 1 to the workpiece Installation for MMA process 7 3 Installation for MMA process 1 Connect the electrode holder 1 to the positive 4 on the machine and fasten it clockwise tightly 2 Connect the work return lead 3 into the negative 3 on the machine and fasten it clockwise Please note that for manual metal arc MMA welding the electrod...

Page 14: ...perage Fig 5 Lift TIG mode Current preset 3 5 6 2 1 7 8 4 Fig 2 MMA mode VRD enabled 3 5 6 2 1 7 8 4 Fig 3 MMA mode VRD disabled 3 5 6 2 1 7 8 4 Fig 4 MMA mode Display status when welding 3 5 6 2 1 7 8 4 Fig 6 Lift TIG mode Status when welding is performed 3 5 6 2 1 7 8 4 Fig 7 Lift TIG mode Status after welding is stopped 3 5 6 2 1 7 8 4 9 3 Operation instruction under LIFT TIG mode Press the MMA...

Page 15: ... 2 0m min to 25 8V 12m min Fig 9 MIG mode Wire check 3 5 6 2 1 7 9 8 4 Fig 11 MIG mode Fine adjustment of inductance presetting range 3 5 6 2 1 7 9 8 4 Fig 10 MIG mode Fine adjustment of voltage range 3 5 6 2 1 7 9 8 4 Use of the Data selection button 5 MIG mode only Pressing the Data selection button 5 will enable you to switch between 1 Arc welding adjustment mode 2 Inductance 3 Preset voltage a...

Page 16: ...se post flow time before turning off valve Change to proper gas no oxygen or CO Maintain short arc length Use smaller electrode or increase current Remove contaminated portion then prepare again Open joint groove The most common cause is moisture or aspirated air in gas stream Use welding grade gas only Find the source of the contamination and eliminate it promptly Use appropriate chemical cleaner...

Page 17: ...sulphur phosphorous lead and zinc Excessive travel speed with rapid freezing of weld trapping gases before they escape Contaminated shield gas Hot cracking in heavy sections or welding on metals prone to hot cracking Post weld cold cracking due to excessive joint restraint rapid cooling or hydrogen embrittlement Centreline cracks in single pass weld Underbead cracking from brittle microstructure G...

Page 18: ...onnections or in the hose porosity in the weld Cause Blocked inlet stem leaking inlet stem to body thread bullnose not properly seated in cylinder valve Poorly fitted loose connections damaged hose air drawn into gas stream Welding wire Component Wire basket and spool Wire Wire Fault symptom Erratic wire feeding or wire stoppages Wire sticks in contact tip erratic feeding Weld has excessive amount...

Page 19: ...od This warranty does not cover direct or indirect expenses loss damage or costs including but not limited to daily allowances or accommodation and travelling costs Modification of the primary input plug or fitment of a lower rated primary input plug will render the warranty null and void NOTE Under the terms of warranty welding torches and their consumables are not covered Direct or indirect dama...

Page 20: ...EN Multiprocess 175 Operating manual Multiprocess 175 Operating manual 39 38 Notes Notes ...

Page 21: ...custserv boc com The stripe symbol and the letters BOC are registered trade marks of The BOC Group Limited Both BOC Limited and The BOC Group Limited are members of The Linde Group the parent company of which is Linde AG Reproduction without permission is strictly prohibited BOC Limited 2014 ...

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