Greetings all!

With the thread regarding forge welded seams having been locked I feel an opportunity for for further education of all has been lost. Perhaps this will further explain the difference in manufacturing of modern pipe products.

"Seamless (SMLS) Steel Pipe is made from a solid round steel ‘billet’ which is heated and pushed or pulled over a form until the steel is shaped into a hollow tube."

ASTM A106-99 / ASME SA106 Seamless Carbon Steel Pipe for High Temperature Service(ASTM A 106-99 / ASME SA 106 / ASTMA106-99/ASMESA106)

1.Scope

1.1 This specification covers seamless carbon steel pipe for high-temperature service (Note 1) in NPS 1/8 to NPS 48 inclusive, with nominal (average) wall thickness as given is ANSI B36.10. Pipe having other dimensions may be furnished provided such pipe complies with all other requirements of this specification. Pipe ordered under this specification shall be suitable for bending, flanging, and similar forming operations, and for welding. When the steel is to be welded, it is presupposed that a welding procedure suitable to the grade of steel and intended use or service will be utilized.

ASTM A192M-89 / ASME A192 SEAMLESS CARBON STEEL BOILER TUBES FOR HIGH PRESSURE SERVICE (ASTMA192 M - 89 / ASME A 192 /ASTMA192M-89/ASMEA192)

1.Scope

1.1 This specification covers minimum-wall-thickness, seamless carbon steel boiler and superheater tubes for high-pressure service.

ASTM A210M-88/ASME SA210 SEAMLESS MEDIUM CARBON STEEL BOILER AND SUPERHEATER TUBES (ASTM A 210 M - 88 / ASME SA 210 / ASTMA210M-88/ASMESA210)

1.Scope

1.1 This specification covers minimum-wall-thickness, seamless medium-carbon steel, boiler tubes and boiler flues, including safe ends (Note 1), arch and stay tubes, and superheater tubes.

Here is an example of one of the manufacturing processes:

http://www.youtube.com/watch?v=cMgHG1NydD4


ERW seamed pipe:

"ERW pipe cold formed from a ribbon of steel pulled through a series of rollers and formed into a tube which is fused through a electric charge."

ASTM A178 / A178M - 02(2007) Standard Specification for Electric-Resistance-Welded Carbon Steel and Carbon-Manganese Steel Boiler and Superheater Tubes

1. Scope

1.1 This specification covers minimum-wall-thickness, electric-resistance-welded tubes made of carbon steel and carbon-manganese steel intended for use as boiler tubes, boiler flues, superheater flues, and safe ends.


ASTM A53 / A53M - 10 Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless

1. Scope

1.1 This specification covers seamless and welded black and hot-dipped galvanized steel pipe in NPS 1/8 to NPS 26 [DN 6 to DN 650] (Note 1), inclusive, with nominal wall thickness (Note 2) as given in Table X2.2 and Table X2.3. It shall be permissible to furnish pipe having other dimensions provided that such pipe complies with all other requirements of this specification. Supplementary requirements of an optional nature are provided and shall apply only when specified by the purchaser.

Note 1—The dimensionless designators NPS (nominal pipe size) [DN (diameter nominal)] have been substituted in this specification for such traditional terms as “nominal diameter,” “size,” and “nominal size.”

Note 2—The term nominal wall thickness has been assigned for the purpose of convenient designation, existing in name only, and is used to distinguish it from the actual wall thickness, which may vary over or under the nominal wall thickness.


The difference between the welded and seamless is easily identifiable by looking inside the pipe. ERW has a "line" that stands proud from the I.D. running down the length, this has been called "flash" from the weld. The seamless has a smooth, yet possibly not perfectly smooth, I.D..

http://www.youtube.com/watch?v=QJ185xt8-F0

Hope this is informative to some.

Jason