Piercing Plug With Through Hole For Seamless Steel Pipe
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Solution Overview
Problem
Existing piercing apparatuses for producing seamless steel pipes often result in inner surface flaws due to Mannesmann fractures and center defects in the billet, which are difficult to eliminate, leading to flaws in the hollow shell.
Innovation Solution
A piercing apparatus with a plug featuring a through hole along its central axis, allowing the central portion of the billet to pass through, which reduces the occurrence of inner surface flaws by compressing and guiding the billet to minimize contact and heat input, thereby reducing defect elongation and melting loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the draft ratio of the plug nose is decreased to reduce inner surface flaws caused by Mannesmann fracture, then the inner surface quality of the hollow shell is improved, but the thrusting ability of the round billet between the inclined rolls decreases
Solution Approach 1:
The plug nose is divided into multiple sections with different draft ratios along its length. The front portion has a smaller draft ratio to reduce inner surface flaws, while the rear portion has a larger draft ratio to maintain thrusting ability. This segmentation allows each section to perform its specific function optimally without compromising the other.
Solution Approach 2:
Different portions of the plug nose are given different geometric properties (draft ratios) according to their specific functional requirements. The front section has a smaller draft ratio for quality improvement, while the rear section has a larger draft ratio for force transmission, achieving local optimization of both quality and thrusting ability.
2Force
If conventional piercing methods are used to maintain thrusting ability, then the billet can be effectively pushed through the rolls, but inner surface flaws occur due to Mannesmann fracture and center defect elongation
Solution Approach 1:
The plug nose is divided into multiple sections with different draft ratios along its length. The front portion has a smaller draft ratio to reduce inner surface flaws, while the rear portion has a larger draft ratio to maintain thrusting ability. This segmentation allows each section to perform its specific function optimally without compromising the other.
Solution Approach 2:
Different portions of the plug nose are given different geometric properties (draft ratios) according to their specific functional requirements. The front section has a smaller draft ratio for quality improvement, while the rear section has a larger draft ratio for force transmission, achieving local optimization of both quality and thrusting ability.
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 use of a plug with a through hole effectively suppresses the formation of inner surface flaws in the hollow shell, even when piercing billets with center defects, by compressing and guiding the central portion through the hole, resulting in a smoother inner surface and reduced re-cutting needs for the plug.
Implementation Method 1
compressing and guiding the central portion through the hole
Data Source
AI summary
There is provided a piercing apparatus in which the occurrence of an inner surface flaw in a hollow shell is suppressed. A piercing apparatus (10) according to an embodiment of the present invention is the piercing apparatus (10) which pierces a billet (18). The piercing apparatus (10) has a plug (14). The plug (14) has a through hole (30). The through hole (30) extends along the central axis, and allows the central portion of the billet (18) being pierced to pass therethrough.