Composite Pipe Weld Structure for Crack-Resistant Flaring and Bending
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Solution Overview
Problem
Conventional refrigeration system pipes, particularly copper-steel composite pipes, are prone to cracking at weld seams during reprocessing due to poor tensile strength and reprocessability, which limits their suitability for diverse and complex applications.
Innovation Solution
A pipe body design with welded portions that decrease in thickness from the inside to the outside and have an X-shaped weld seam, where the outer end of the welded portion is centered, enhancing tensile strength and reprocessability by distributing force and stress uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional pipe bodies with fan-shaped or inverted triangle weld seams are used, then the manufacturing process is simple, but the tensile strength at welded portions is poor and cracking occurs during reprocessing
Solution Approach 1:
The welded portion is segmented into multiple regions with different thicknesses: a first welded portion with greater thickness and a second welded portion with smaller thickness. This segmentation allows the thicker region to bear higher stresses while the thinner region facilitates welding, thereby improving tensile strength without excessive complexity.
Solution Approach 2:
Different regions of the welded portion are given different local qualities through varying thickness. The first welded portion has greater thickness for strength, while the second welded portion has smaller thickness for ease of welding. This local differentiation resolves the contradiction between strength and manufacturing simplicity.
2Ease of operation
If conventional pipe bodies with inclined weld faces are used, then the welding process is straightforward, but the reprocessability during flaring and bending is poor
Solution Approach 1:
The welded portion is divided into a first welded portion with greater thickness and a second welded portion with smaller thickness. This segmentation allows the pipe to be flared or bent at the thinner second welded portion without cracking, while the thicker first welded portion maintains structural integrity, thus improving reprocessability without sacrificing reliability.
Solution Approach 2:
The solution moves from a two-dimensional weld face inclination to a three-dimensional thickness variation within the welded portion. By creating thickness gradients in the radial direction, the patent enables localized flexibility for reprocessing while maintaining overall strength, resolving the contradiction between ease of reprocessing and crack resistance.
3Reliability
If copper materials are heavily used for valves and pipe fittings, then the thermal conductivity and corrosion resistance are excellent, but the product costs increase greatly
Solution Approach 1:
Copper material is applied locally only where corrosion resistance is critical (at the welded portions), rather than throughout the entire pipe. This localized application maintains reliability at joint surfaces while significantly reducing the total quantity of expensive copper material required.
Solution Approach 2:
The patent employs composite construction with copper material applied as a coating or layer on the welded portions of steel pipes. This composite approach combines the corrosion resistance of copper with the structural strength and cost-effectiveness of steel, achieving reliability while reducing copper consumption.
Data Source
AI summary
A pipe body, wherein the pipe body (10) has a welded portion (11) at both ends of the pipe body, aligned in a widthwise direction of the pipe body (10). The thickness of the welded portion (11) decreases gradually from the inside to the outside of the pipe, and an outer end of the welded portion (11) is located at a center portion of the pipe body (10) in a thickness direction. The configuration of the welding structure enhances the strength of the welded portion of the pipe, so that the pipe will not crack easily when it is reworked by flaring or bending, thus having high reworkability. In addition, a pipe (100) made of the pipe body (10) and a method of making the pipe (100) are disclosed.