Metal Expansion Joints

Page Flexibility and Quality for the Global Market

®

I N D U S T R I A L Flexider

An IMCI Company Definition of terms

The Expansion Joint Manufacturers Association, Inc. has adopted the following definitions of Expansion Joint components and related equipment:

Any device containing one or more bellows used to absorb dimensional changes, such as those caused by thermal expansion or contraction of a pipeline, duct or vessel.


®


An IMCI Company Pressure thrust

With rigid pipe installed between two flanges pressure thrust is restrained by the strength of the pipe.

With a thin wall convoluted bellows welded to two flanges, the bellows reaction to pressure thrust results in the bellows growing in length .

Until the bellows “squirms” and/or the convolutions stretch out to become the tube from which they were formed.


®


An IMCI Company Metal bellows thrust loads and spring rate

An internal pressure p generates an end thrust load F equal to:

F = p × Am

Am: effective area

The measure is realized by measuring the load which, for a known internal pressure, does not allow movement of the free ends of the bellow.

In addition to longitudinal pressure thrust load movement within a bellows requires a force to cause the bellows to compress, extend or angulate.

Bellows spring rate is a design consideration.

To calculate the load (force) imposed on equipment adjacent to the expansion joint, use the equation below.

F = K × X

F: the load force imposed on equipment on either side of the bellows

K: the bellows spring rate

X: the anticipated or specific movement


®


An IMCI Company Bellows cycle lifeWhen a bellows moves it is absorbed by deformation of the side walls. This called bellows deflection bending stress (EJMA). This stress is highest at the “crest” and “root” of the bellows.

Metal bellows functions with a deflection bending stress value that far exceeds the yield strength of the bellows material.

Metal expansion joints are designed to deflect in the “plastic” range and the bellows will take a permanent “set” at the rated bellows movements.

Realistic cycle life should be specified for bellows design.

The “safest” bellows results from real-world cycle life, pressure, movement and temperature data


®


An IMCI Company Metal bellows pressure retaining

Metal bellows are designed to retain loads imposed by internal and/or external system pressure.

Main parameters to design a bellow are as follows:

• Bellows convolution geometry

• Number of convolutions

• Material type

• Material thickness

•No. of plies


®


An IMCI Company Common bellows materials

MATERIAL DESIGNATIONMATERIAL DESIGNATION CONTROLLED CHEMICAL COMPOSITIONCONTROLLED CHEMICAL COMPOSITIONCONTROLLED CHEMICAL COMPOSITIONCONTROLLED CHEMICAL COMPOSITIONCONTROLLED CHEMICAL COMPOSITIONCONTROLLED CHEMICAL COMPOSITIONCONTROLLED CHEMICAL COMPOSITION

ASME ASTM Ni Cr Mo C Si Mn Cu

SA240-304 Stainless A240-304 Stainless 8.0 max 18.0 max - 0.08 max 1.0 max 2.0 max -

SA240-304L Stainless A240-304L Stainless 8.0 max 18.0 max - 0.03 max 1.0 max 2.0 max -

SA240-316 Stainless A240-316 Stainless 10.0 max 16.0 max 2.0 0.08 max 1.0 max 2.0 max -

SA240-316L Stainless A240-316L Stainless 10.0 max 16.0 max 2.0 0.03 max 1.0 max 2.0 max -

SA240-321 Stainless A240-321 Stainless 9.0÷12.0 17.0÷19.0 - 0.08 max 1.0 max 2.0 max -

SA240-904L Stainless A240-904L Stainless 23.0÷28.0 19.0÷23.0 4.0÷5.0 0.02 max 1.0 max 2.0 max 1.0÷2.0

SB127-Alloy 400 B127-Alloy 400 63.0 min - - 0.15 max 0.50 max 1.25 max 28.0÷34.0

SB162-Alloy 200 B162-Alloy 200 99.0 min - - 0.15 max 0.35 max 0.35 max 0.25 max

SB162-Alloy 201 B162-Alloy 201 99.0 min - - 0.02 max 0.35 max 0.35 max 0.25 max

SB168-Alloy 600 B168-Alloy 600 72.0 min 14.0÷17.0 - 0.15 max 0.50 max 1.0 max -

SB443-Alloy 625 LCF B443-Alloy 625 LCF 58.0 min 20.0÷23.0 8.0÷10.0 0.03 max 0.50 max 0.50 max -

SB409-Alloy 800 B409-Alloy 800 30.0÷35.0 19.0÷23.0 - 0.10 max 1.0 max 1.50 max 0.75 max

SB409-Alloy 800 H B409-Alloy 800 H 30.0÷35.0 19.0÷23.0 - 0.05÷0.10 1.0 max 1.50 max 0.75 max

SB409-Alloy 800 HT B409-Alloy 800 HT 30.0÷35.0 19.0÷23.0 - 0.06÷0.10 1.0 max 1.50 max 0.75 max

SB424-Alloy 825 B424-Alloy 825 38.6÷46.0 19.5÷23.5 2.50÷3.50 0.05 max 0.50 max 1.00 max 1.5÷3.0


®


An IMCI Company

Axial

Pressure balanced axial

Pressure balanced axial with elbow

Our axial expansion joints


®


An IMCI Company

Angular (hinged)

Spherical angular (gimbal)

Our angular expansion joints


®


An IMCI Company

Lateral

Spherical lateral

Our lateral expansion joints


®


An IMCI Company

Universal

Pressure balanced universal

Pressure balanced universal with elbow

Our universal expansion joints


®


An IMCI Company

Universal expansion joint with integral intermediate anchors

Typical expansion joint applications

Pressure balanced axial expansion joint with elbow

Tied single expansion joint for lateral movement(just for example, more advisable solution with 2 bellows)


®


An IMCI Company

Tied universal expansion joint for lateral movement

Typical expansion joint applications

Two gimbal application Three hinge application


®


An IMCI Company Standards and licensors for design

Standards

EJMA 9th edition

ASME B31.3

ASME VIII

PED 97/23EC

Licensors

UOP

Kellogg Brown & Root

Shell

Stone & Webster


®


An IMCI Company Examination and testing

Non-destructive examination

Non-destructive testing

Destructivetesting

Radiographic

Liquid penetrant

Fluorescent penetrant

Ultrasonic

Magnetic particle

Halogen leak

Mass spectrometer

Air jet leak

Pressure testing Fatigue life

Squirm

Meridional yield rup.

Documents

Metal Expansion Joints