tube welding 2

7/26/2019 Tube Welding 2

1/8

Pro-Fusion: Fundamentals of Orbital Tube Welding Page 1of8

file://A:\Pro-Fusion Fundamentals of Orbital Tube Welding.htm 17-09-2002

Fundamentals of Orbital Tube Welding

U n d e r s t a n d i n g t h e b a s ic p r i n c ip l e s b e h i n d o r b i t a l t u b e w e l d i n g m a y

h e l p y o u a r r i v e m o r e r a p i d ly a t t h e o p t i m um w e l d p r o ce d u r e f o r y o u r

s p e c i f i c a p p l i c a t i o n .

Orbital welding was first used in the 1960's when the aerospace industryrecognized the need for a superior joining technique for aerospace hydrauliclines. A mechanism was developed in whi ch the arc from a tungsten electrodewas rotated around the tubing weld joint. The arc welding current wasregulated with a control system thus automating the entire process. Theresult was a more precision and reliable method than the manual weldingmethod it replaced.

Orbital welding became practical for many industries in the early 1980's whencombination power supply/control systems were developed that operated

from 110 VAC and were physically small enough to be carried from place toplace on a construction site for multiple in-place welds. Modern day orbital welding systems offercomputer control where welding parameters for a variety of applications can be stored in memory andcalled up when needed for a specific application. The skills of a certified welder are thus built into thewelding system, producing enormous numbers of identical welds and leaving significantly less room forerror or defects.

Orbital Welding Equipment

In the orbital welding process, tubes/pipes are clamped in place and anorbital weldhead rotates an electrode and electric arc around the weld joint tomake the required weld. An orbital welding system consists of a power supplyand an orbital weldhead.

Power Supply:The power supply/control system supplies and controls thewelding parameters according to the specific weld program created or recalled

from memory. The power supply provides the control parameters, the arcwelding current, the power to drive the motor in the weld head and switchesthe shield gas(es) on/off as necessary.

Weld Head:Orbital weld heads are normally of the enclosed type and providean inert atmosphere chamber that surrounds the weld joint. Standardenclosed orbital weld heads are practical in welding tube sizes from 1/16 inch(1.6mm) to 6 inches (152mm) with wall thickness' of up to .154 inches(3.9mm) Larger diameters and wall thickness' can be accommodated withopen style weld heads.

Reasons for Using Orbital Welding Equipment

There are many reasons for using orbital welding equipment. The ability tomake high quality, consistent welds repeatedly at a speed close to themaximum weld speed offer many benefits to the user:

l Productivity.An orbital welding system will drastically outperform manualwelders, many times paying for the cost of the orbital equipment in asingle job.

l Quality.The quality of a weld created by an orbital welding system withthe correct weld program will be superior to that of manual welding. Inapplications such as semiconductor or pharmaceutical tube welding, orbital welding is the onlymeans to reach the weld quality requirements.

l Consistency.Once a weld program has been established an orbita l welding system can repeatedlyperform the same weld hundreds of times, eliminating the normal variability, inconsistencies, errorsand defects of manual welding.

l Skill level.Certified welders are increasingly hard to find. With orbital welding equipment you don'tneed a certified welding operator. All it takes is a skilled mechanic with some weld training.

l Orbital welding may be used in applications where a tube or pipe to be welded cannot be rotated orwhere rotation of the part is not practical.

l Orbital welding may be used in applications where access space restrictions limit the physical size of

E-mail This

To A Friend

A typical orbital tube weld.

Note the pulsed arc f inish

on the weld surface.

Standard enclosed orbi tal

weld heads are practical

in welding tube sizes f rom

1/16 inch (1.6mm) to 6

inches (152mm) with wall

th ickness' o f up to .154

inches (3.9mm) Largerdiameters and wal l

th ickness' can be

accommodated with open

style weld head.


2/8

Pro-Fusion: Fundamentals of Orbital Tube Welding Page 2 of8


the welding device. Weld heads may be used in rows of boiler tubing where it would be difficult for amanual welder to use a welding torch or view the weld joint.

l Many other reasons exist for the use of orbital equipment over manual welding. Examples areapplications where inspection of the internal weld is not practical for each weld created. By making asample weld coupon that passes certification, the logic holds that if the sample weld is a cceptable,that successive welds created by an automatic machine with the same input parameters should alsobe sound.

Industries and Applications for Orbital Welding

Aerospace:As noted earlier, the aerospace industry was the first industry to recognize the requirement for

orbital welding. The high pressure systems of a single plane can have over 1,500 welded joints, allautomatically created with orbital equipment.

Boiler Tube:Boiler tube installation and repairs offer a perfect application for orbital welding. Compactorbital weld heads can be clamped in place between rows of heat exchanger tubing where a manualwelder would experience severe difficulty making repeatable welds.

Food, Dairy and Beverage Industries:The food, dairy and beverage industries require consistent fullpenetration welds on all weld joints. Most of these tubing/piping systems have schedules for cleaningand sterilization in place. For maximum piping system efficiency the tubing must be as smooth aspossible. Any pit, crevice, crack or incomplete weld joint can form a place for the fluid inside the tubing tobe trapped and form a bacteria harbor.

Nuclear Piping:The nuclear industry with its severe operating environment and associated specificationsfor high quality welds has long been an advocate of orbital welding.

Offshore Applications:Sub-sea hydraulic lines use materials whose properties can be altered during thethermal changes that are normal with a weld cycle. Hydraulic joints welded with orbital equipment offersuperior corrosion resistance and mechanical properties.

Pharmaceutical Industry:Pharmaceutical process lines and piping systems deliver high quality water totheir processes. This requires high quality welds to ensure a source of water from the tubes that isuncontaminated by bacteria, rust or other contaminant. Orbital welding ensures full penetration weldswith no overheating occurring that could undermine the corrosion resistance of the final weld zone.

Semiconductor Industry:The semiconductor industry requires piping systems with extremely smoothinternal surface finish in order to prevent contaminant buildup on the tubing walls or weld joints. Oncelarge enough, a build up of particulate, moisture or contaminant could release and ruin the batchprocess.

Tube/Pipe Fittings, Valves and Regulators:Hydraulic lines, and liquid and gas delivery systems all requiretubing with connector fittings. Orbital systems provide a means to ensure high productivity of weldingand improved weld quality. Sometimes the tubing may be welded in place to a valve or regulator body.

Here the orbital weldhead provides the ability to produce high quality welds in applications with restrictedaccess to the weld joint.

General Guidelines for Orbital Tube Welding

For orbital welding in many precision or high purity applications, the base material to be welded, the tubediameter(s), weld joint and part fit-up requirements, shield gas type and purity, arc length, and tungstenelectrode material, tip geometry and surface condition may already be written into a specificationcovering the specific application.

Each orbital welding equipment supplier differs slightly in recommended welding practices andprocedures. Where possible, follow the recommendations of your orbital equipment supplier forequipment set-up and use, especially in areas that pertain to warranty issues.

This section is intended as a gui deline for those applications where no specification exists and theengineer responsible for the welding must create the welding set-up, and derive the welding parameters

in order to arrive at the optimum welding solution.

Welding Basics and Set-Up


3/8



The Physics of the GTAW Process

The orbital welding process uses the Gas Tungsten Arc Welding process (GTAW) as the source of theelectric arc that melts the base material and forms the weld. In the GTAW process (also referred to asthe Tungsten Inert Gas process - TIG) an electric arc is established between a Tungsten electrode andthe part to be welded. To start the arc, an RF or high voltage signal (usually 3.5 to 7 KV) is used tobreak down (ionize) the insulating properties of the shield gas and make it electrically conductive inorder to pass through a tiny amount of current. A capacitor dumps current into this electrical path, whichreduces the arc voltage to a level where the power supply can then supply current for the arc. The powersupply responds to the demand and provides weld current to keep the arc established. The metal to bewelded is melted by the intense heat of the arc and fuses together.

Material Weldability

The material selected varies according to the application and environment the tubing must survive. Themechanical, thermal, stability, and corrosion resistance requirements of the application will dictate thematerial chosen. For complex applications a significant amount of testing will be necessary to ensure thelong term suitability of the chosen material from a functionality and cost viewpoint.

In general, the most commonly used 300 seri es stainless steels have a high degree of we ldability with

the exception of 303/303SE which contain additives for ease of machining. 400 series stainless steelsare often weldable but may require post weld heat treatment.

Accommodation must be made for the potential differences of different material heats. The chemicalcomposition of each heat batch number will have minor differences in the concentration of alloying andtrace elements. These trace elements can vary the conductivity and melting characteristics slightly foreach heat. When a change in heat number is made a test coupon should be made for the new heat.Minor changes in amperage may be required to return the weld to its original profile.

It is important that certain elements of the material be held to close tolerances. Minor deviations inelements such as sulfur can vary the fluid flow in the weld pool thus completely changing the weld profileand also causing arc wander.

Weld Joint Fit-Up

Weld joint fit-up is dependent on the weld specification requirements on tube straightness, weldconcavity, reinforcement and drop through. If no specification exists the laws of physics will require thatthe molten material flow and compensate for tube mismatch and any gap in the weld joint.

Tubing is produced according to tolerances that are rigid or loose according to the application for whichthe tube was purchased. It is important that the wall thickness is repeatable at the weld joint from partto part. Differences in tube diameter or out-of-roundness will cause weld joint mismatch and arc gapvariations from one welding set up to another.

Tube and pipe end prep facing equipment is recommended in order to help ensure end squareness andend flatness. Both the ID and OD should be burr free with no chamfer.

This weld profi le shows a single level of weld time.

Orbital welding normal ly uses a minimum of 4

levels of weld time with each level decreasing in

weld amperage as the tube heats up during the

welding process.

Low Sulfur Content

( less than .01% - 100 PPM)

Surface tension temperature

coeff icient negative

Normal Sul fur Content

(greater than .01% - 100 PPM)

Surface tension temperature

coeff icient posit ive

Minor changes in sul fur content can change weld

pool f low characteristics with a dramatic effect on

penetrat ion (the Maragoni ef fect)


4/8



When two tubes are butted together for welding, two of the main considerations are mismatch and gaps.In general, the following rules apply:

l Any gap should be less than 5% of the wal l thickness. It is possible to weld with gaps of up to 10%(or greater) of wall thickness, but the resultant quality of weld will suffer greatly and repeatabilitywill also become a significant challenge.

l Wall thickness variations at the weld zone should be +/- 5% of nominal wall thickness. Again, thelaws of physics will allow welding with mismatch of up to 25% of wall thickness if this is the onlychallenge but again, the resultant quality of weld will suffer greatly and repeatability will alsobecome a significant issue.

l Alignment mismatch (high-low) should be avoided by using engineering stands and clamps to align

the two tubes to be welded. This system also removes the mechanical requirement of aligning thetubes from the orbital weldhead.

Shield Gas(es)

An inert gas is required on the tube OD and ID during welding to prevent the molten material fromcombining with the oxygen in the ambient atmosphere. The objective of the welder should be to create aweld which has zero tint at the weld zone ID.

Argon is the most commonly used shield gas (for the OD of the tube)and the purge gas (for the ID ofthe tube). Helium is often used for welding on copper material. Mixed gases such as 98% Argon/2%Hydrogen, 95% Argon/5% Hydrogen, 90% Argon/10% Hydrogen or 75% Helium/25% Argon my be usedwhen the wall thickness to be welded is heavy (.1" or above). Using mixtures of 95% Argon/5%Hydrogen is incompatible with carbon steels and some exotic alloys, often causing hydrogenembrittlement in the resultant weld. As a general rule, for simplicity and reduction of shield gas cost, use100% argon gas.

Gas purity is dictated by the application. For high purity situations where the concern for micro-contamination is paramount, such as semiconductor and pharmaceu tical applications, the shield andpurge gases must minimize the heat tint that could otherwise be undesirable. In these applications,ultra high purity gas or gas with a local purifier are employed. For non-critical applications, commercialgrade argon gas may be used.

Tungsten Electrode

The tungsten welding electrode, the source of the welding arc, is one of the most important elements ofthe welding system that is most commonly ignored by welding systems users. While no one would refutethe importance of the ignition device on an automobile airbag, the rip cord for a parachute, or qualitytires for automobiles, the importance of tungsten electrode for quality welding is often overlooked. Userscontinue to manually grind and wonder why they produce inconsistent results. Whether in manual orautomatic welding, this is the area where manufacturing organizations can improve the consistency oftheir welding output with minor effort.

The objective for the choice of tungsten parameters is to balance the benefits of a clean arc start andreduced arc wander with good weld penetration and a satisfactory electrode life.

Electrode Materials:For quite some time, tungsten manufacturers have added an oxide to pure tungstento improve the arc starting characteristics and the longevity of pure tungsten electrodes. In the orbitalwelding industry, the most commonly used electrode materials are 2% thoriated tungsten and 2%ceriated tungsten.

Safety:The safety issues of tungsten electrode material are now being looked at more closely. Manyusers of the Tig welding process do not realize that the welding electrode they use contains Thorium, aradioactive element added to the tungsten. While the radioactivity is of a low level, it brings an issue ofdanger especially with the radioactive dust generated when grinding the electrodes to a point for welding.

Alternative, non-radioactive tungsten materials are now available, such as 2% ceriated electrodes, whichoften offer superior arc welding. While these materials are commercially available they have been largely

ignored until recently.

Recommended Electrode Materials:Cerium, as a base material, has a lower work function than thorium,thus it offers superior emission characteristics. Thus, not only do ceriated electrodes offer an advance inelectrode safety, they also improve the arc starting ability of the orbital equipment. However, asmentioned earlier, it is always best to follow the advice of your orbital equipment manufacturer. 2%ceriated and 2% thoriated electrodes are the most commonly recommended materials for orbital weldingequipment.

Electrode Tip Geometry:Given the ever increasing weld quality requirements of the final weld, more andmore companies are looking for ways to ensure that their weld quality is up to par. Consistency andrepeatability are key to welding applications. The shape and quality of the tungsten electrode tip isfinally being recognized as a vital process variable. Once a weld procedure has been established, it isimportant that consistent electrode material, tip geometry and surface condition be used.


5/8



Welding Basics and Set-Up

Welders should follow an equipment supplier's suggested procedures and dimensions first, because theyhave usually performed a significant amount of qual ifying and troubleshooting work to optimizeelectrode preparation for their equipment. However, where these specifications do not exist or the welderor engineer would like to change those settings to possibly improve and optimize their welding, thefollowing guidelines apply:

A. Electrode Taper - This is usually called out in degrees of included angle (usually anywhere between14 and 60). Below is a summary chart that illustrates how different tapers offer different arcshapes and features:

In addition, to demonstrate graphically how the taper selection will effect the size of the weld beadand the amount of penetration, below is a drawing that shows typical representations of the arcshape and resultant weld profile for different tapers.

B. Electrode Tip Diameter - Grinding an electrode to a point is sometimes desirable for certainapplications, especially where arc starting is difficult or short duration welds on small parts areperformed. However in most cases it is best for a welder to leave a flat spot or tip diameter at theend of electrode. This reduces erosion at the thin part of a point and reduces the concern that thetip may fall into the weld. Larger and smaller tip diameters offer the following trade-offs:

Tungsten Electrode Grinders and Pre-Ground Electrodes:Using electrodes pre-ground to requirements or adedicated commercial electrode grinder to provide electrode tip quality and consistency offers thefollowing benefits to the user in their welding process:

1. Improved arc starting, increased arc stability and more consistent weld penetration.2. Longer electrode life before electrode wear or contamination.3. Reduction of tungsten shedding. This minimizes the possibility of Tungsten inclusions in the weld.4. A dedicated electrode grinder helps ensure that the welding electrodes will not become

contaminated by residue or material left on a standard shop grinder wheel.5. Tungsten electrode grinding equipment requires less skill to ensure that the tungsten electrode is

ground correctly and with more consistency.

To produce high consistent welds the Tungsten

electrode must provide the fol lowing:

1. High qual i ty e lectrode material 2. The electrode t ip dimensions shown must be

held to c lose to lerances 3. The surface f in ish (ground or po l ished) of the

electrode grind must be consistent.

Sharper Electrodes Blunter Electrodes

Easy arc starting Usually harder to start the arc

Handle less amperage Handle more amperage

Wider arc shape Narrower arc shape

Good arc stability Potential for more arc wander

Less weld penetration Better weld penetration

Shorter electrode life Longer electrode life

Smaller Tip Larger Tip

Easier arc starting Usually harder to start the arc

Potential for more arc wander Good arc stability

Less weld penetration More weld penetration

Shorter electrode life More electrode life


6/8



Pre-Ground Electrodes:Rather than risk electrode radioactivity issues and alsoconstantly endure the variability of each operator grinding the electrodes witha slightly different touch, many manufacturing organizations have chosen topurchase electrodes pre-ground. In addition, since a small difference in thedimensions of an orbital electrode can produce a big difference in the weldresults, pre-ground electrodes are the preferred electrode choice to maintainthe consistency of your welding. This low cost option ensures that theelectrode material quality, tip geometry and ground electrode surface input tothe welding process is constant. Consult electrode charts or a pre-groundelectrode supplier to obtain the electrode diameter and tip geometry that ismost suitable for your welding application.

Welding Parameter Development

Many welding equipment suppliers offer a series of pre-calculated weldprograms for a variety of tube diameters, wall thicknesses and materials.Welders should always follow an equipment supplier's suggested proceduresfirst, because they have usually performed a significant amount of qualifyingand troubleshooting work to optimize electrode preparation for theirequipment.

However, it is impossible for the equipment suppliers to have welding procedures for every weldingapplication and there will always exist a trade off in maximum weld speed possible versus weld qualityand repeatability. Where weld parameter specifications do not exist or the welder or engineer would liketo change those settings to possibly improve or optimize their welding, the guidelines noted below giveinformation on how to modify the welding parameters for a desired result.

Note:The "rules of thumb" noted below are general guidelines only and will not apply to everywelding application and mix of parameters chosen. Although the welding parameters are oftenchosen and changed according to the specific needs of the application, there are someindustry standards that have been developed as starting points. Experimentation andexperience will determine the final weld parameters.

Arc Length

The arc gap setting is dependent on weld current, arc stability and tube concentricity/ovality. Theobjective of the welding engineer is to keep the electrode at a constant distance from the tube surfacewith sufficient gap to avoid stubbing out.

As a "rule of thumb" use a base arc gap of 0.010" and add to this half the penetration required (usuallythe tube wall thickness) expressed in thousandths of an inch. Thus i f the tube wall is .030" then a goodstarting arc gap would be 0.010" + 0.015" = .025". For a wall thickness/penetration requirement of .154"the arc gap would be 0.010" + .070" = 0.080"

Weld Speed

The weld speed is dependent on flow rate of material to be welded, and wall thickness. The objective isto weld as fast as possible while still yielding a quality output.

As a starting point the tungsten surface speed should be 4 - 10 inches per minute with the faster weldingspeeds used for thinner wall materials and the slower welding speeds used for heavy wall thickness. As agood starting point, use 5 inches per minute.

Welding Current

The welding current is dependent on the material to be welded, wall thickness, weld speed, and theshield gas chosen. The objective is to achieve full penetration, defect free welds.

As a starting point use 1 average current per 0.001" wall thickness if the material is stainless steel. Thusfor a 0.030" wall tubing the average weld current will be 30 amps in the first level.

Weld Current Levels

Orbital welding normally uses multiple levels of weld current to compensate for heat building up in thetube during the welding process. If the weld current used to initially penetrate the tubing was held at thesame level for the complete weld, the weld penetration would increase as the weld progressed aroundthe tube, producing too much penetration.

Normally orbital welding uses a minimum of 4 levels of weld time with each level decreasing in weldamperage

Starting parameters: Set weld level 4 to be at 80% of weld level 1 amperages. Set weld level 2 and weldlevel 3 to gradually decrease the current from level 1 to level 4.

Using pre-ground

electrodes ensures that

the electrode material

qual i ty, t ip geometry and

ground electrode surface

input to the welding

process is constant


7/8



Arc Pulsing

Arc pulsing involves using the welding power supply to rapidly alternate the weld current from a high(peak current) to a low (background current) value. This creates a seam of overlapping spot welds. Thistechnique reduces the overall heat input to the base material and can also allow for increases in weldspeed. This welding technique brings many benefits to the welding procedure, often improving weldquality and repeatability. In some cases materials and weld joints with poor fit-up that are difficult tosuccessfully weld with a non-pulsed arc can easily be welded with a pulsed arc technique. The result isimproved weld quality and increased output.

In orbital welding, arc pulsing also offers another advantage due to the fact that the gravity pulls theweld puddle in different directions as the weld is created around the tube. When pulsing at peak currentthe base material(s) melt and flow together, at the lower background current the puddle can solidifybefore becoming liquid at the next peak current pulse. This diminishes the effect of gravity on themolten weld, minimizes the weld sagging at the 12 and 6 o clock positions, and reduces the molten weldpuddle running/slumping downhill at the 3 and 9 o'clock positions and effectively alters the electrode toweld puddle distance. The arc pulsing technique thus becomes more advantageous as the wall th icknessincreases resulting in a larger weld puddle.

Arc Pulsing Parameters: Arc pulsing involves four welding parameters: peak current, background current,pulse width (duty cycle), and pulse frequency. Here again, opinions vary from one welding organizationto another and indeed from welder to welder. Many welders arrive at the same welding result havingsomewhat different welding parameters.

It is important to understand how to choose convenient weld development starting parameters and theeffect on the weld by changing each parameter.

The primary objective is to use the benefits of weld pulsation to improve weld quality and output.

Peak/Background Current Ratios:The peak to background current ratios basically provide a means for thewelding current to pulse from one level to another. Industry usage generally varies from 2:1 ratios to5:1 ratios. A good starting point is to use 3:1 ratios, make the required weld and test other parametersto see if any benefit can be gained.

Pulse Frequency:The pulse frequency is dependent on spot overlap requi red. Good starting parametersare to attempt for a 75% spot overlap. Pulse rate for thin wall tube is often equal to the weld speed inipm (5 ipm = 5 pps)

Pulse Width:The pulse width (the percentage of time spent on the peak current) is dependent on heatsensitivity of material and available current from power supply. Higher heat sensitivity requires lowerpulse width % on peak current. Standard pulse widths are often 20% to 50%. A good starting parameterswould be to set a pulse width of 35%.

Free arc pulsation software is available from the internet that pre-calculates a variety of arc pulsationparameters for any given amperage of an application. In this fashion, welders can arrive at anacceptable weld program and quickly obtain a variety of alternative arc pulsation options to examinewithout requiring lengthy calculations or tedious empirical "try it and see" test welding.

Conclusion

One of the best methods for a company to assume a superior position in the marketplace is to developa competitive advantage by optimizing the welding process in manufacturing. This will improve weldquality, increase weld speed, and reduce scrap and rework costs. From this, a company can realize lowercosts per unit of product, quicker delivery of product, and less defects in workmanship. All of this can beaccomplished through the use of orbital welding systems using the consistency and repeatability of fine-tuned weld programs, control of input material and shield gas quality, and properly prepared pre-groundelectrodes.

Pro-Fusion Technologies provides pre-ground tungsten electrodes for orbital and tube mill applications.

The company offers free access to a welding web site with over 75% of the site dedicated to offeringinformation on welding processes and even allows the user to input data on what they are welding andreceive welding parameters. The site also gives information on various welding applications withrecommendations on the best techniques to use and handbooks for troubleshooting welding systems.The web site may be accessed at www.Pro-fusionOnline.com

For free sample Tungsten electrodes, or more information on any of the above contact Pro-Fusion, 1090Lawrence Drive #104, Newbury Park, CA 91320 U.S.A. Tel (805) 376-8021 Fax (805) 376-0619 Email:[email protected]

Welding Parameter Development Example

For 1" Tube/.030" Tube Wall Thickness:

1. Arc Length/Gap= .010" + (0.5 x penetration required)Starting Parameters: .010" + (0.5 x .030") = .025"


8/8



2. Weld Speed= 5 ipm surface speedRPM = ipm/(3.1415 x dia.)Starting Parameters: 5/(3.1415 x 1") = 1.59 RPM

3. Welding Current LevelsLevel 1 = 1 amp per .001" of wall thickness for level 1 currentLevel 4 = 80% of Level 1 currentLevels 2 and 3 gradually decrease the current from Level 1 to Level 4Starting Parameters:Level 1 Peak Current = .030" wall thickness = 30 ampsLevel 4 Peak Current = 30 amps x 80% = 24 amps

Level 2 Peak Current = 28 ampsLevel 3 Peak Current = 26 amps

Background Current will be 1/3rd of peak current. Pulse width/duty cycle is 35%

4. Tungsten Electrode Diameter & Tip Geometry- Use your equipment manufacturer's specificationsor consult your pre-ground electrode supplier

The above data gives starting parameters. On completion of the first test weld, the parameters w ill bemodified to obtain the final result desired.

We can provide free samplesof various tungsten materials, electrode tip geometries, and surfacefinishes for you to test. Call or e-mailto review your specific application and to obtain the most suitablesamples for your needs.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - -Return to Top

About Pro-Fusion

Copyright 2001 Pro-Fusion Technologies, Inc.

3825 O ld Conejo Road

Newbury Park, CA 91320 USA

Tel (805) 376-8021

Fax (805) 376-0619

emai l : [email protected]

tube welding 2

Documents