Rolling Mill Mandrel Rod Alignment for Pipe Quality
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Solution Overview
Problem
Existing rolling mills for producing pipe-like work pieces face challenges in achieving uniform temperature progression and minimizing interior defects, leading to suboptimal work piece quality due to inefficient mandrel rod changes and potential air introduction during the process.
Innovation Solution
The implementation of a rolling mill design where the threading line of the second rolling stage aligns with the extraction line of the first, allowing for quick and seamless mandrel rod changes without altering the work piece's direction or accelerating it, using a minimal distance between mandrel rods, and incorporating an intermediate rod to minimize air introduction and prevent rolling peels, along with a longitudinal transport system to maintain continuous processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mandrel rod is extracted completely from the work piece during rolling, then the mandrel rod can be removed fully, but air is drawn into the interior of the work piece causing scale formation and interior defects
Solution Approach 1:
The patent applies preliminary action by threading the second mandrel rod into the work piece before completely extracting the first mandrel rod. This ensures that the work piece interior remains sealed, preventing air from being drawn in and causing scale formation or interior defects during the mandrel rod exchange process.
Solution Approach 2:
The patent uses an intermediate state where the second mandrel rod is threaded in while the first is still partially in place. This intermediate configuration acts as a mediator to maintain the sealed environment of the work piece interior during the transition between mandrel rods, preventing harmful air introduction.
2Productivity
If the mandrel rod change-over is performed quickly, then productivity increases, but temperature uniformity in the work piece may be affected
Solution Approach 1:
The patent ensures continuity of useful action by aligning the threading line of the second rolling stage with the extraction line of the first rolling stage. This allows the mandrel rod exchange to occur without interrupting the continuous movement of the work piece through the rolling mill, maintaining temperature uniformity while enabling quick change-overs.
Solution Approach 2:
The patent creates an equipotential condition by having the work piece move continuously through both rolling stages without braking or changing direction. This maintains consistent kinetic energy and temperature distribution throughout the work piece during the mandrel rod exchange, preventing thermal gradients that would arise from stopping or reversing motion.
3Ease of operation
If the work piece is braked and accelerated during mandrel rod change-over, then the mandrel rod can be exchanged, but the process becomes time-consuming and reduces productivity
Solution Approach 1:
The patent eliminates the need for braking and acceleration by aligning the threading and extraction lines collinearly. The work piece maintains continuous motion through both rolling stages, allowing mandrel rod exchange to occur during steady-state movement without time-consuming stops or direction changes.
Solution Approach 2:
The patent creates equipotential conditions for motion by ensuring the work piece moves at constant velocity through the mandrel rod exchange zone. The collinear arrangement of threading and extraction lines means no change in direction or speed is required, eliminating kinetic energy losses and time delays associated with braking and re-acceleration.
Data Source
AI summary
In order to improve the quality of pipe-like work pieces, a rolling mill has at least two successive consecutive rolling stages that have mandrel rods. A threading line for the mandrel rod of the second rolling stage can lie on an extraction line for the mandrel rod of the first rolling stage. The same advantage can be achieved in a rolling method for the production of pipe-like work pieces, comprising at least two successive consecutive rolling stages, wherein the two rolling stages perform the rolling with the use of mandrel rods. The work piece is brought from the mandrel rod of the first rolling stage onto the mandrel rod of the second rolling stage, without entirely emptying an interior of the work piece and/or without changing the direction of movement of the work piece or braking the work piece in the meantime and accelerating it once again.