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Pipe Expansion Joint Design & Manufacturing

Engineering and designing is done per EJMA equations as well as per the latest revisions of the ASME B31.3, ASME B31.1, and ASME Section 8, Division 1. U.S. Bellows designs are performed using in-house developed design software and calculations further checked using hand calculations. U.S. Bellows also has full in-house finite element analysis capabilities and we often use this methodology to prove designs.

Manufacturing Capabilities

Metal Forming:

  • Hydraulic shears to handle 10 feet of plate up to 1 inch thick mild steel.
  • Break presses to handle 14 feet of plate up to ¾” thick mild steel.
  • Miscellaneous forming, cutting, and punching machines, including a 50-ton Mubea iron-worker and a 100-ton mechanical.
  • Two pyramid plate rollers handle 10 feet of plate up to 5/8 of an inch thick.
  • 350-ton radial expander.
  • Angle rolling to diameters in excess of 12 feet.
  • Plasma cutting up to 2 inches
  • Flame cutting 8 torch, computer controlled.
  • Horizontal and vertical band saws.

Bellows Forming:

  • Roll forming from 24 inches through 15 feet in diameter.
  • Expanding mandrel forming from 2 inches through 120 inches in diameter.
  • Automatic TIG flat bed welders.
  • Bellows reroll and planishing machines.


  • End Mill. 36 inch travel.
  • Bridgeport. Lateral boring to 6 inch diameter and milling with a tilt head on a 36 inch bed.
  • Drill presses with 48 inch bed height.
  • Surface tables.
  • General ability to mill, grind, turn, tap, thread, bore, and chamfer material up to 12 inches in diameter and 36 inches in length.

Quality Control
Additionally, U.S. Bellows does extensive physical testing to prove designs. Each bellows and pipe expansion joint unit goes through in-process quality control controlled using a system of travelers. Final in-house inspection and testing is performed prior to shipping, based on customer requirements. U.S. Bellows has performed a variety of tests on pipe expansion joints ranging from X-Ray tests and hydrotest to helium leak tests (using a mass spectrometer). Our manufacturing shop also has ASME Section VIII CODE certification for jobs requiring CODE certification.