Mandrel Bar Inner-Surface Cooling for Uniform Seamless Pipe Temperature
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Solution Overview
Problem
Existing techniques for producing seamless metal pipes using piercing machines struggle to achieve uniform temperature distribution along the longitudinal direction of hollow shells during piercing-rolling and elongating rolling, leading to variations in mechanical properties.
Innovation Solution
A piercing machine with a mandrel bar featuring a coolant channel and an inner surface cooling mechanism that cools the inner surface of the hollow shell within a specific cooling zone, and an inner surface damming mechanism to prevent coolant contact after the shell leaves the zone, ensuring consistent cooling and reducing temperature differences between the fore and rear ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling is applied to the inner surface of the hollow shell during piercing-rolling, then the temperature distribution becomes more uniform, but the coolant may contact portions of the hollow shell that should not be cooled, causing nonuniform cooling
Solution Approach 1:
The mandrel bar is divided into multiple cooling zones along its length, with each zone having independent coolant supply and control. This segmentation allows precise control of cooling in different axial positions of the hollow shell, ensuring that only the desired portions are cooled while maintaining uniform temperature distribution without over-cooling or under-cooling any section.
Solution Approach 2:
Different cooling conditions are applied to different local regions of the hollow shell's inner surface. The cooling system provides localized cooling control where coolant is supplied to specific cooling zones based on the required temperature uniformity, allowing each portion of the hollow shell to receive appropriate cooling intensity tailored to its position and thermal requirements.
2Temperature
If the mandrel bar is made longer to cool the entire hollow shell, then temperature uniformity improves, but the device complexity and cooling control difficulty increase
Solution Approach 1:
The mandrel bar is divided into multiple cooling zones along its length, with each zone having independent coolant supply and control. This segmentation allows precise control of cooling in different axial positions of the hollow shell, ensuring that only the desired portions are cooled while maintaining uniform temperature distribution without over-cooling or under-cooling any section.
Solution Approach 2:
The cooling system incorporates dynamic control capabilities where coolant flow rates and temperatures can be adjusted for different cooling zones based on real-time process conditions. This dynamic adjustment allows the system to maintain optimal cooling performance without requiring excessive mandrel bar length or complex static structures.
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 suppresses temperature variations along the longitudinal direction of the hollow shell, resulting in a more uniform microstructure and mechanical properties of the seamless metal pipes.
Implementation Method 1
a coolant channel formed inside the bar body, the coolant channel allowing a coolant to pass therein; an inner surface cooling mechanism disposed inside a cooling zone in the bar body
Data Source
AI summary
A mandrel bar of a piercing machine includes: a bar body; a coolant channel formed inside the bar body and through which a coolant flows; an inner surface cooling mechanism which is disposed in a cooling zone and is connected to the coolant channel and which, during piercing-rolling or during elongating rolling, ejects the coolant to outside of the bar body to cool an inner surface portion of a hollow shell inside the cooling zone; and an inner surface damming mechanism which is disposed adjacent to the cooling zone on a rearward side of the cooling zone and which, during piercing-rolling or during elongating rolling, suppresses the coolant that is ejected to outside of the bar body from contacting the inner surface portion of the hollow shell that is positioned rearward of the cooling zone.