Mandrel Bar Cooling Zone for Uniform Seamless Tube Piercing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing seamless metal pipes using piercing machines struggle to achieve uniform temperature distribution along the longitudinal direction of hollow shells, leading to variations in mechanical properties due to non-uniform cooling during piercing-rolling and elongating rolling processes.
Innovation Solution
A piercing machine with a mandrel bar featuring a cooling zone and an inner surface damming mechanism to control coolant ejection and prevent coolant contact with the inner surface beyond the cooling zone, ensuring consistent cooling and reducing temperature differences between the fore and rear ends of the hollow shell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolant is ejected to cool the inner surface of the hollow shell during piercing-rolling or elongating rolling, then the temperature of the inner surface is reduced, but non-uniform temperature distribution in the longitudinal direction occurs
Solution Approach 1:
The mandrel bar is divided into a cooling zone and a non-cooling zone along the longitudinal direction. The cooling zone is located at the fore end portion and has a specific length, while the non-cooling zone is located at the rear end portion. This local differentiation allows uniform cooling in the cooling zone while preventing excessive cooling in the non-cooling zone, thereby achieving uniform temperature distribution along the longitudinal direction of the hollow shell.
Solution Approach 2:
The mandrel bar surface is segmented into distinct functional zones: a cooling zone with coolant ejection holes at the fore end portion, and a non-cooling zone at the rear end portion. This segmentation enables precise control of cooling locations, ensuring that coolant is ejected only where needed to achieve uniform temperature distribution without causing temperature variations in different longitudinal sections.
2Temperature
If cooling is applied during piercing-rolling or elongating rolling, then the temperature difference between fore end portion and rear end portion is reduced, but the cooling process becomes complex
Solution Approach 1:
The cooling function is integrated directly into the mandrel bar structure by forming coolant ejection holes within the mandrel bar body itself. The mandrel bar combines the functions of structural support and coolant delivery, eliminating the need for separate cooling apparatus and simplifying the overall cooling system while achieving uniform temperature distribution.
Solution Approach 2:
The mandrel bar serves as an intermediary component that facilitates heat removal from the hollow shell inner surface. By incorporating coolant ejection holes in the mandrel bar, it acts as a mediator between the coolant supply system and the hollow shell, enabling efficient and uniform cooling without requiring direct contact between the coolant supply system and the workpiece.
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 stabilizes the cooling process, reducing temperature variations and enhancing the uniformity of the microstructure and mechanical properties of the seamless metal pipes produced.
Implementation Method 1
the inner surface cooling mechanism ejects coolant supplied from the coolant channel to outside of the bar body to cool the inner surface of the hollow shell that is advancing within the cooling zone
Implementation Method 2
the inner surface damming mechanism suppresses contact of coolant that has been ejected to outside of the bar body with the inner surface of the hollow shell after the hollow shell leaves from the cooling zone
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
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 elongating rolling. A mandrel bar (3) of a piercing machine includes: a bar body (31); a coolant channel (34) formed inside the bar body (31) and through which a coolant flows; an inner surface cooling mechanism (340) which is disposed in a cooling zone (32) and is connected to the coolant channel (34) and which, during piercing-rolling or during elongating rolling, ejects the coolant to outside of the bar body (31) to cool an inner surface portion of a hollow shell (50) inside the cooling zone (32); and an inner surface damming mechanism (350) which is disposed adjacent to the cooling zone (32) on a rearward side of the cooling zone (32) and which, during piercing-rolling or during elongating rolling, suppresses the coolant that is ejected to outside of the bar body (31) from contacting the inner surface portion of the hollow shell (50) that is positioned rearward of the cooling zone (32).