Difference between welded and seamless stainless steel tubing?

What is the difference between welded and seamless stainless steel tubing?

Seamless stainless steel tubing is extruded and drawn from a billet.  Welded stainless steel tubing is produced from a strip that is roll formed and welded to produce a tube.

Welded stainless steel tubing is generally less expensive than seamless.  However, seamless stainless steel tubing is preferred for most instrument applications.

There are two main reasons for this:

 

1. Welded stainless steel tubing is considered to be inhomogeneous in the weld area, thus making it less corrosion resistant and giving it different malleability properties than seamless stainless steel tubing.  Recognized standards for the working of the weld area of stainless steel tubing are very open and allow for a wide range of homogeneity in the finished tube.
   
2. By code, the allowable working pressure of welded tubing is 20% less than that of seamless stainless steel tubing.
   

 

 

Forberg Scientific carries a large varietity of stainless steel tubing in both welded and seamless.  We can also provide different types of hard to find exotic material.  Please contact our customer service to receive pricing and lead times.

Toll Free: 1-855-288-5330

Email: mechanicalsales@forberg.com



Where to Buy Stainless Steel Tubing

Think Forberg Scientific, Inc. next time you need stainless steel tubing.

Forberg Scientific, Inc. has established itself as a premiere supplier in the stainless steel tubing arena; serving our customer's needs for over 40 years. Forberg has proven to our customers to be a trusted stainless steel tubing source to a variety of markets.

 

Forberg Stocks a Variety of Stainless Steel Tubing:

316
304
Welded
Seamless
Foreign
Domestic

Tubing Training Classes available in Michigan, Ohio, Indiana, Kentucky, Pennsylvania & West Virginia

Forberg Scientific Tube Fabrication Seminars can be scheduled at your location to teach the right way to measure, cut and tube bending.  The class is designed to demonstrate the proper method of installing tube fittings in various system applications. Attendees will learn the right way to measure, cut and bend tube, as well as the correct tube fitting make-up and remake procedures. Plus all attendees will receive a free training guide. Please contact us to schedule a training class.

Parker Tube Fabricating Equipment

At Forberg Scientific, Inc. we feel the correct tube selection and installation are key ingredients to building leak-free, reliable systems. We offer a full compliment of tube cutters, deburring, tube benders and assembly equipment and the quality of these Parker tools are second to none.

If you would like to receiving pricing and availability on stainless steel tubing please contact our customer service.
Toll Free: 855-288-5330
Fax:          248-288-4204
Email: mechanicalsales@forberg.com

Tubing vs Pipe

Standard fluid line systems, whether for simple household use or for the more exacting requirements of industry, were for many years constructed from threaded pipe of assorted materials and were assembled with various standard pipe fitting shapes, unions and nipples. Such systems under high pressures were plagued with leakage problems besides being cumbersome, inefficient and costly to assemble and maintain. Therefore, the use of pipe in these systems has largely been replaced by tubing because of the many advantages it offers.

Old Method - Each connection is threaded – requires numerous fittings – system not flexible or easy to install and service connections not smooth inside – pockets obstruct flow.


Modern Method - Bendable tubing needs fewer fittings - no threading required - system light and compact - easy to install and service - no internal pockets or obstructions to free flow. (Use a Parker Tube Bender)

Major Advantages of Tubing vs. Pipe

1. Bending Quality - Tubing has strong but relatively thin walls: is easy to bend. Tube fabrication is simple. (Parker Tube Bender)
2. Greater Strength - Tubing is stronger. No weakened sections from reduction of wall thickness by threading.
3. Less Turbulence - Smooth bends result in streamlined flow passage and less pressure drop.
4. Econmy of Space and Weight - With its better bending qualities and a smaller outside diameter, tubing saves space and permits working in close quarters. Tube fittings are smaller and also weigh less.
5. Flexibility - Tubing is less rigid, has less tendency to transmit vibration from one connection to another.
6. Fewer Fittings - Tubing bends substitute for elbows. Fewer fittings mean fewer joints, fewer leak paths.
7. Tighter Joints - Quality tube fittings, correctly assembled, give better assurance of leak-free systems.
8. Better Appearance - Tubing permits smoother contours with fewer fittings for a professianal look to tubing systems.
9. Cleaner Fabrication - No sealing compounds on tube fitting connections. Again no threading: minimum chance of scale, metal chips, foreign particles in system.
10. Easier Assembly and Disassembly - Every tube fittings connection serves as a union. Tube fitting connections can be reassembled repeatedly with easy wrench action.
11. Less Maintance - Advantages of tubing and tube fittings add up to dependable, trouble-free installations.

If you would like to receive more information about Parker Instrumentation Tube Fittings or Tubing please contact Forberg Scientific customer service.
Toll Free: 855-248-5330
Email: mechancialsales@forberg.com

Proper Tubing Preparation

Tube end preparation is essential in assuring leak-free systems. Some important points to consider are:

• Handling Tubing
• Cutting Tube End with either a tube cutter or hacksaw
• Deburring the tube end
• Cleaning the tube end

Handling Tubing

After tubing has been properly selected and ordered, careful handling is important.

From the receiving dock to point of installation, special attention is necessary to prevent scratching and burring the O.D. of the tubing. This is especially important for gas service. Low-density gases such as helium and argon cannot be sealed with damaged tubing.

Make certain not to drag tubing across any surfaces such as truck beds, shelves, or storage racks, the floor and (or) ground of any plant/construction site.This is important for tubing of all materials, particularly for copper and aluminum. Besides scratching, improper handling can create out-of-round tubing. Out-of-round tubing will not fit the I.D. of the ferrule(s) or the body bore properly and will cause leakage.

Cutting the Tube End

To insure a good joint, tube must be cut off square. This can be accomplished with either a tube cutter or hacksaw.

Figure 4 Enlarged section of tube showing differences in tubing cut with a tube cutter (a) and a hacksaw (b).

Tubing Cutters are more commonly utilized on softer tubing such as copper, aluminum or even “soft” steel tubing. If a tube cutter is utilized with stainless steel tubing, remember that a special cutting wheel, designed for use with stainless steel tubing should be employed. The use of dull or improper cutting wheels can work harden the S.S. tubing near the cut area. This CAN adversely affect the fittings sealing ability.

Cutting with a Hacksaw - When using a hacksaw to cut off tubing, it is essential to use a guide to assure square cutoffs. We recommend Parker's Tru-Kut vise Model #710439. (See below) Further, to minimize the residual burrs, a hacksaw blade of 32 teeth per inch minimum is suggested.

Deburring the Tube End

The burrs formed by either the tube cutter or hacksaw must be removed prior to assembly to prevent those burrs from eventually damaging the system. O.D. burrs can prevent tubing from seating properly in a fitting body. I.D. burrs can restrict flow, as well as possibly break loose and damage fine filtration elements.
Note: Do not over deburr the O.D. of tubing.

You may deburr the tubing with your choice of file(s), or utilize Parker’s IN-EX De-Burring tool Model #226. This tool can be used to deburr both the I.D. & O.D. of tubing sizes 1/8” thru 1-1/2”.

 

 

Cleaning the Tube End

After you deburr the tubing, it is essential to remove burrs from the tubing line. This can be accomplished by:

1. Flushing with solvent or low pressure compressed air.
2. Swab with lint-free cloth.

Again, this should prevent entrapping one of these small burrs down-stream where it might do some system damage.

If you would like more information about Parker Tube Fitting Tools or other Parker Products please contact Forberg Scienfitic customer service.
Toll Free: 855-288-5330
Email: mechanicalsales@forberg.com