Piercing Mill Outer-Surface Cooling for Uniform Hollow Shell Temperature

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Solution Overview

Problem

Existing methods for producing seamless metal pipes using piercing machines often result in non-uniform temperature distributions along the axial direction of hollow shells, leading to variations in mechanical properties due to inadequate cooling techniques.

Innovation Solution

A piercing machine design that incorporates an outer surface cooling mechanism, where cooling fluid is ejected towards the upper, lower, left, and right parts of the outer surface of the hollow shell within a specific cooling zone, ensuring uniform cooling by preventing fluid accumulation and flow outside the zone, thereby reducing temperature differences between the fore and rear ends.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If cooling fluid is ejected towards the inner surface of the hollow shell from the plug or mandrel, then the inner surface temperature is reduced, but temperature difference between fore end portion and rear end portion arises

Engineering Contradiction:
Improveinner surface temperatureVSAvoidtemperature distribution uniformity
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The patent inverts the conventional cooling approach by ejecting cooling fluid towards the outer surface of the hollow shell instead of the inner surface. This reversal prevents the formation of temperature differences between the fore end portion and rear end portion while still achieving effective cooling of the hollow shell during piercing-rolling or elongation rolling.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent transitions from one-dimensional inner surface cooling to three-dimensional outer surface cooling by ejecting cooling fluid in multiple directions (upper, lower, left, right parts) of the outer surface. This multi-directional approach ensures uniform temperature distribution throughout the hollow shell.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If cooling fluid is ejected in multiple directions towards the outer surface, then temperature distribution uniformity is improved, but device complexity increases

Engineering Contradiction:
Improvetemperature distribution uniformityVSAvoidcooling mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs a universal cooling mechanism where a single cooling fluid ejection system serves multiple functions by ejecting cooling fluid in four different directions (upper, lower, left, right) towards the outer surface of the hollow shell. This multi-functional design achieves uniform temperature distribution without requiring separate cooling systems for each direction.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If conventional cooling methods are used, then equipment simplicity is maintained, but temperature variations in axial direction occur

Engineering Contradiction:
Improvecooling system simplicityVSAvoidaxial temperature variation
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent changes the cooling parameters by shifting from inner surface cooling to outer surface cooling, and from single-direction to multi-directional cooling. These parameter changes enable effective temperature control with reduced axial temperature variations while maintaining relative simplicity in the cooling system design.

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

The solution effectively reduces temperature variations along the axial direction of the hollow shell, enhancing the uniformity of microstructure and mechanical properties of the seamless metal pipes produced.

Implementation Method 1

cooling the hollow shell subjected to piercing-rolling or elongation rolling and passing the plug, by ejecting a cooling fluid toward an outer surface of the hollow shell

Methodology Applied
Scientific EffectConvection cooling: Convection

Data Source

PatentEP3718656B1Piercing machine, and method for manufacturing seamless metal pipe using the same
Publication Date: 2023.03.08 NIPPON STEEL CORPORATION
  • EP3718656B1 patent drawingFigure 1~2
  • EP3718656B1 patent drawingFigure 3~4
  • EP3718656B1 patent drawingFigure 5

AI summary

A piercing machine is provided that can suppress a temperature difference between a fore end portion and a rear end portion of a hollow shell after piercing-rolling or after elongation rolling. A piercing machine (10) includes a plurality of skewed rolls (1), a plug (2), a mandrel bar (3) and an outer surface cooling mechanism (400). The outer surface cooling mechanism (400) is disposed around the mandrel bar (3) at a position that is rearward of the plug (2), and with respect to an outer surface of a hollow shell (50) advancing through a cooling zone (32) which has a specific length in an axial direction of the mandrel bar (3) and which is located rearward of the plug (2), as seen from an advancing direction of the hollow shell (50), the outer surface cooling mechanism (400) ejects a cooling fluid (CF) toward an upper part of the outer surface, a lower part of the outer surface, a left part of the outer surface and a right part of the outer surface of the hollow shell (50) to cool the hollow shell (50) inside the cooling zone (32).