Hot Pipe Manufacturing Plug with Composite Coating for Wear and Heat Shielding
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Solution Overview
Problem
Existing plugs for hot tube-making in the Mannesmann process experience wear, seizure, and melting loss due to high heat and pressure, leading to a shortened service life, especially when handling high-alloy billets, and current coatings like oxidized scale and arc-sprayed coatings have limitations in high-temperature strength and heat-shielding properties.
Innovation Solution
A plug design featuring a build-up layer with high-temperature strength and a sprayed coating that provides enhanced heat-shielding, where the build-up layer is formed on the front portion with a tapered surface and the sprayed coating covers the entire surface, including a second region adjacent to the build-up layer, to suppress heat input and prevent distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an oxidized scale coating is formed on the plug main body, then heat shielding is improved and seizure/melting loss is suppressed, but wear resistance deteriorates and the coating is significantly worn during piercing-rolling
Solution Approach 1:
The invention applies a composite coating structure consisting of an oxidized scale coating layer and an arc-sprayed coating layer. The oxidized scale coating provides heat shielding to suppress seizure and melting loss, while the arc-sprayed coating layer provides wear resistance. This composite structure resolves the contradiction by combining materials with complementary properties.
Solution Approach 2:
The coating is divided into two functional layers: an inner oxidized scale coating layer for heat shielding and an outer arc-sprayed coating layer for wear resistance. This segmentation allows each layer to specialize in its respective function, with the heat shielding layer protecting against thermal damage and the wear-resistant layer protecting against mechanical wear.
2Object-affected harmful factors
If the oxidized scale coating is worn, then heat shielding deteriorates and temperature of the plug main body increases, but re-forming the coating through heat treatment takes several hours to several tens of hours
Solution Approach 1:
The arc-sprayed coating layer is applied in advance to protect the oxidized scale coating. This preliminary protective layer prevents wear of the heat-shielding oxidized scale coating, eliminating the need for frequent re-forming through time-consuming heat treatment and maintaining heat shielding without production stoppage.
Solution Approach 2:
The arc-sprayed coating serves as a protective cushion layer that absorbs wear damage before it reaches the oxidized scale coating. This beforehand cushioning prevents degradation of the heat shielding function and avoids the need for lengthy heat treatment to restore the coating.
3Reliability
If arc-sprayed coating is applied to improve wear resistance, then wear resistance is improved, but high-temperature strength deteriorates and seizure/melting loss occurs easily
Solution Approach 1:
The invention uses a composite coating where the arc-sprayed coating layer provides wear resistance and the oxidized scale coating layer provides high-temperature strength and heat shielding. This composite material approach allows both wear resistance and high-temperature strength to be achieved simultaneously through the synergistic combination of different coating materials.
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 combination of high-temperature strength from the build-up layer and improved heat-shielding from the sprayed coating extends the service life of the plug by reducing heat input and preventing seizure and melting loss during piercing and rolling of high-alloy billets.
Implementation Method 1
a sprayed coating which provides enhanced heat-shielding
Implementation Method 2
the sprayed coating covers the entire surface, including a second region adjacent to the build-up layer, to suppress heat input
Implementation Method 3
A plug design featuring a build-up layer with high-temperature strength
Implementation Method 4
extends the service life of the plug by reducing heat input and preventing seizure and melting loss during piercing and rolling of high-alloy billets
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A plug for hot tube-making includes: a plug main body; a build-up layer formed around an axis of the plug main body on a surface of the plug main body; and a sprayed coating formed on a surface of the build-up layer.