Selecting the Best Stainless Steel Material (A Guide by Eagle Stainless Tube & Fabrication)

April 04, 2017 - "Press Releases"

Seamless Vs. Welded Stainless Steel (By Eagle Stainless)
 

Welded, Welded & Drawn Steel and Seamless Pipe – Eagle Supplies Them All!

The many unique values provided by stainless steel make it a powerful candidate in materials selection. Corrosion resistance, hygiene and strength of stainless steel make it an ideal choice in the Medical, Aerospace and Industrial industries. To learn more about these benefits see here. The two major categories for tubing and pipe are seamless and welded. The major difference being the seam that is on a welded tube and not on a seamless tube just as the names indicate. Seamless pipe has the increased ability to withstand pressure; because there is no weld seam it is equally strong around the entire circumference. On welded tubing the weld seam is not recognized by the naked eye and takes on the appearance of seamless. Welded tubes have excellent concentricity, are more readily available and cost effective for most applications.

SEAMLESS STAINLESS STEEL TUBING

Seamless Vs. Welded Stainless Steel (By Eagle Stainless)Seamless tube start out as solid metal bars that are produced into tubes by extrusion or rotary piercing. Seamless stainless steel tubing is ordered to specifications that make the product versatile for general usage and capable of ready certification for more stringent requirements. These specifications ensure that mechanical property tests have been made, such as tensile, yield and elongation, as well as flaring, flanging, hardness, flattening and hydrostatic or non-destructive electrical tests etc.

WELDED STAINLESS STEEL TUBING

Welded tubes are produced from a strip that is rolled formed and welded. Eagle welded tubing is ordered to meet high quality standards for a multitude of end uses. Welded sizes up to and including 5” O.D. are certified to ASTM A -249/A-269 (average wall).

This specification also ensures that tensile, yield and elongation tests have been performed, in addition to flaring, flanging, hardness, flattening and hydrostatic or non-destructive electrical tests.

Welded and Drawn Tubing – ?available is a size range of .202” O.D. to 8” O.D. and wall thickness of .015” to 1”

Cold-rolled strip in long coils is rolled to a tube form, then passed under the welding head, which melts the edges of the open seam to form a fusion weld. No filler metal or flux is used, and the weld bead is of the same analysis as the parent metal. All tubing is carefully inspected for weld porosity or other damaging faults before being approved for redrawing.

The welded tubing is then cold drawn in exactly the same way as seamless. As it undergoes repeated cold drawing and annealing it takes on the appearance and qualities of seamless tubing. The weld can be detected only by etching or by microscopic examination. Cold work and annealing cause the weld area to recrystallize with ductility and mechanical properties that are equivalent to the parent metal.

Cold Worked and Annealed Tubing -?available in a size range of 5/8” O.D. to 4” O.D. and wall thickness of .035” to .120”

This manufacturing method starts in the same manner as welded and drawn tubing. Cold-rolled strip is rolled into tube form and fusion welded without the addition of filler metal. It is then selectively cold worked in the weld area and given a full solution anneal, causing this area to recrystallize. With this controlled processing, the strength, ductility and corrosion resistance of the weld area is equal or superior to the parent metal. This similarity between parent and weld zone structures gives cold worked, annealed tubing uniformity and makes it ideally suitable for condenser tube or other heat exchange applications.

Cold worked annealed tubing meets the requirements of ASTM A-249 and tolerances of ASTM A -450. Required minimum mechanical properties – 75,000 psi tensile strength, 30,000 psi yield strength and 35% elongation – are met in both the base metal and the weld area.

Whether you need seamless, welded and welded and drawn, you need quality material. Eagle Stainless has had quality management systems in place since 1998. Both quality systems and sustainable manufacturing practices emphasize efficient use of resources. Our quality management system helps us achieve sustainability goals through thorough examination of operations, employee empowerment and “right-the-first-time” processes.

 

 

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