Coated Steel Pipe End Lining for Corrosion-Protected Welding
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Solution Overview
Problem
Existing methods for connecting internally coated steel pipes are complex, costly, and require additional corrosion-resistant material, which is inefficient and difficult to implement, especially when dealing with non-metallic coatings that need protection from heat during welding.
Innovation Solution
A method that simplifies the connection of internally coated steel pipes by applying a lining to the pipe ends using thermal, chemical, electrochemical, physical-chemical, or mechanical plating, eliminating the need for matching corrosion-resistant pipe sections, and ensuring corrosion protection in the weld seam area with a lining that extends at least 5 mm along the pipe end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pipe section made of corrosion-resistant steel is welded to the pipe ends to protect the coating during welding, then corrosion protection in the weld seam area is improved, but device complexity and manufacturing cost increase due to the need for matching corrosion-resistant pipe sections and complex welding procedures
Solution Approach 1:
The solution divides the pipe end into two functional zones: a coated area for corrosion protection and an uncoated weld seam area for welding operations. The coating is selectively removed only from the immediate weld seam area rather than using separate corrosion-resistant pipe sections, simplifying the overall structure while maintaining both corrosion protection and weldability
Solution Approach 2:
The coating is removed in advance from the weld seam area before welding takes place. This preliminary preparation allows the coating to be strategically positioned only where needed for corrosion protection, eliminating the need for complex corrosion-resistant pipe sections and simplifying the welding procedure
2Reliability
If pipe ends are made of corrosion-resistant material to withstand operational loads, then reliability under operational conditions is improved, but material cost and weight increase due to using more material than required for pure corrosion protection
Solution Approach 1:
The pipe structure employs local quality by applying different properties to different areas: the majority of the pipe uses standard steel material for structural strength, while only the immediate weld seam area receives enhanced corrosion protection through selective coating removal. This eliminates the need to make entire pipe ends from expensive corrosion-resistant material, reducing material consumption while maintaining operational reliability
Solution Approach 2:
The solution creates a composite structure at the pipe end where the uncoated base metal provides structural strength and the selectively applied coating provides corrosion protection. This composite approach allows the pipe to withstand operational loads while using minimal corrosion-resistant material only where the coating is removed, optimizing both strength and material efficiency
3Manufacturing precision
If the coating is kept free in the weld seam area to ensure perfect welding, then welding quality is improved, but corrosion protection is worsened requiring recoating after welding which is effort-intensive and often impossible inside pipelines
Solution Approach 1:
The coating is removed in advance from the weld seam area before welding, ensuring perfect welding conditions. The key innovation is that this selective coating removal is done strategically so that the coating remains intact in the overlap areas adjacent to the weld seam, providing ongoing corrosion protection without requiring post-welding recoating operations
Solution Approach 2:
The selectively positioned coating acts as an intermediary that separates the welding zone from the corrosion-prone areas. By removing coating only from the immediate weld seam while preserving it in overlap areas, the coating mediates between the conflicting requirements of welding quality and corrosion protection, allowing both to be achieved simultaneously
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
This approach reduces production effort and costs by providing effective corrosion protection in the weld seam area without the need for additional corrosion-resistant material, ensuring a seamless and cost-effective pipeline connection regardless of pipe diameter.
Implementation Method 1
the lining is carried out using thermal plating. The plating itself can advantageously include deposition welding, soldering or thermal spraying
Implementation Method 2
The deposition welding can be carried out, for example, by means of electroslag welding, submerged arc welding, laser beam welding, plasma welding or gas metal arc welding
Implementation Method 3
The deposition welding can be carried out, for example, by means of electroslag welding, submerged arc welding, laser beam welding, plasma welding or gas metal arc welding
Implementation Method 4
The deposition welding can be carried out, for example, by means of electroslag welding, submerged arc welding, laser beam welding, plasma welding or gas metal arc welding
Data Source
Figure 1
AI summary
1. Method for joining the ends of internally coated steel pipes and steel pipelines, wherein the ends of internally coated steel pipes (1) provided with a non-metallic coating (2) are welded, wherein the pipe ends are joined with a corrosion-resistant metal (3) in the area of the weld seam of the pipe joint before the internal coating is applied to the pipes, the internal coating is then applied in such a way that the coating covers the corrosion-resistant metal, leaving the weld seam area of the pipe ends uncovered, and subsequently the ends of the steel pipes are welded; the corrosion-resistant metal is applied as a lining to the inside of the pipe ends, at least in the weld seam area, before the pipe ends are welded.