Cold Working Pipe Sidewalls for High Load Engagement

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Solution Overview

Problem

Existing pipe designs with cold worked grooves for thinner walled pipe elements fail to provide adequate engagement for high load and pressure applications, as they do not match the performance of thicker walled pipe elements with cut grooves.

Innovation Solution

A device and method using rollers to cold work the pipe elements, forming a shoulder, groove, and bead configuration that enhances the mechanical coupling by creating a fluid-tight joint, allowing thinner walled pipe elements to be used in high pressure/high load applications, involving a combination of first and second rollers with specific outer diameters and annular surface orientations to deform the pipe element's sidewall.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If cold working is used to form grooves in thinner walled pipe elements, then weight and cost are reduced, but engagement strength and radial stiffness are insufficient for high load applications

Engineering Contradiction:

Improveweight of pipe elementVSAvoidengagement strength

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The patent changes the geometric parameters of the groove and the cold working process parameters (roller diameter, pressure, temperature) to optimize the groove formation. By controlling the roller diameter ratio (D2/D1 between 0.6-0.9) and applying specific pressures during cold working, the groove achieves adequate engagement strength while maintaining thin wall thickness for weight reduction.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The cold working process is segmented into multiple stages with different roller configurations. The process uses a sequence of rollers with varying diameters to progressively form the groove, allowing controlled deformation that strengthens the groove engagement while preserving overall pipe element strength.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If cold working is used to form grooves in thinner walled pipe elements, then manufacturing cost is reduced, but joint reliability under high pressure is insufficient

Engineering Contradiction:

Improvemanufacturing costVSAvoidjoint reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent optimizes process parameters including roller material composition, surface hardness (50-60 HRC), rolling pressure (1000-5000 psi), and temperature control to ensure the cold worked groove achieves adequate engagement strength while maintaining thin wall thickness for weight reduction.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The groove is formed by cold working before the pipe element is assembled into the coupling. This preliminary formation ensures the groove geometry is precisely controlled and optimized for engagement, improving joint reliability while maintaining the cost advantages of cold working over machining.

Inventive Principle:

Principle #10Preliminary action

3Strength

If cut grooves are used in thicker walled pipe elements, then engagement strength is adequate, but material is removed and weight increases

Engineering Contradiction:

Improveengagement strengthVSAvoidweight of pipe element

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent replaces the mechanical removal process (cutting, machining) with a mechanical deformation process (cold working). Instead of removing material to create the groove, rollers cold work the pipe element sidewall to form the groove geometry, preserving material and reducing weight while maintaining engagement strength.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables the use of thinner walled pipe elements in high pressure/high load applications by forming a configuration that provides a strong, fluid-tight joint with improved radial stiffness and reduced weight, while maintaining precise dimensions and lower residual stresses.

Implementation Method 1

Circumferential grooves are advantageously formed by cold working the sidewall of the pipe element because, unlike cut grooves, material is not removed from the pipe sidewall

Methodology Applied

Scientific EffectCold working: Cold-forming

Implementation Method 2

first and second rollers for imparting a shape to a sidewall of a pipe element... cold working an end of a pipe element so as to impart a shape to the sidewall of the pipe element

Methodology Applied

Scientific EffectDeformation: Deformation

Data Source

PatentUS10161547B2Device and method for forming pipe elements

Publication Date: 2018.12.25 VICTAULIC

AI summary

A combination of roller tools is used to cold work a pipe element and impart a desired shape to the sidewall. The roller tools are movably mounted on a frame. Segments of the roller tools align with one another during operation. The roller tools are used in a method of roll forming wherein the sidewall of the pipe element is compressed between the rollers.