ART
BEAUTY & WELLNESS
CRAFT
CULTURE & HISTORY
ENTERTAINMENT
ENVIRONMENT
FOOD & DRINKS
REVERSE ENGINEERING
SCIENCES
SPORTS
TECHNOLOGY
WEARABLES
Steel Pipe: Butt-Welded Through a Bell, Sized, Threaded and Tested (National Tube Co., 1921)
Butt-weld steel pipe, 1/8 to 3 inches, as National Tube made it in 1921: hot skelp is pulled by tongs and a draw-bench chain through a bell a little larger than the finished pipe, which curls it into a tube and presses its edges together into a weld. The pipe is then rolled to size, straightened, cleaned, threaded and pressure-tested.
Each length, 20 to 40 ft, is welded in one pull. Every pipe is tested inside at 700 to 800 lb per square inch.
Source: National Tube Co., "National" Modern Welded Pipe (1921), pp. 41-47. Picture: drawing butt-weld pipe.
Advanced
Unknown
Instructions
1
1
Heat the skelp
Heat the skelp
Charge the skelp from the rear into a long welding furnace, a little longer than the skelp, with a narrow opening at each end, and bring it to welding heat.
Materials for this step:
Steel Skelp1 one piece per length of pipeTools needed:
Welding Furnace2
2
Draw it through the bell
Draw it through the bell
Grip the trimmed end with long-handled tongs and pull it through a die, or bell, slightly larger than the finished pipe. Hook the tongs to the travelling chain of the draw bench, which pulls the whole length (20 to 40 ft) through. The skelp is a little wider than the bell's inside circumference, so it curls into a tube and its edges butt squarely and weld. Some sizes go through two bells at one heat, the second slightly smaller.
Tools needed:
Draw Bench
Forge TongsWelding Furnace3
3
For Double Extra Strong pipe
For Double Extra Strong pipe
Thick skelp needs so great a pull that a strong bar is welded on its end as a 'bait' for the tongs. Draw it several times through bells of decreasing size, reheating between draws, so the seam is thoroughly welded.
Tools needed:
Draw BenchForge TongsWelding Furnace4
4
Size and round
Size and round
Pass the pipe through sizing rolls, which reduce it slightly, lengthen it and loosen the heavy welding scale. Then roll it to its finished size and circular shape, which removes the scale and leaves the walls smooth.
Tools needed:
Rolling Mill5
5
Cool, straighten and clean
Cool, straighten and clean
Let the pipe cool slowly as it crosses a table, then straighten and smooth it in cross rolls. Wash off the loosened scale in a tank; blow it out of the smaller sizes with compressed air.
Tools needed:
Rolling Mill
Water
Air Compressor6
6
Cut, thread and test
Cut, thread and test
Cut off a short length at each end, where the tong jaws crushed it. Thread the pipe, then test it inside with water at 700 to 800 lb per square inch to prove the wall and the weld. Ours: hacksaw, die set and hand test pump; the booklet does not say how the ends are cut or threaded.
Tools needed:
Hacksaw
Tap and Die Set
Hand Pressure Test PumpMaterials
1- 1 one piece per length of pipePlaceholder
Connected Blueprint Materials
This blueprint makes
CC0 Public Domain
This blueprint is released under CC0. You are free to copy, modify, distribute, and use this work for any purpose, without asking permission.
Support the Maker by purchasing products through their Blueprint where they earn a Maker Commission set by Vendors, or create a new iteration of this Blueprint and include it as a connection in your own Blueprint to share revenue.