Copper-Steel Composite Pipe Welding for Refrigeration
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Solution Overview
Problem
The existing welding methods for copper and steel pipes in refrigeration systems face issues such as poor welding quality, fatigue rupture of weld seams, and environmental concerns, limiting their application due to the use of copper and the inefficiency of copper plating on steel.
Innovation Solution
A novel copper and steel composite pipe design where a copper pipe is partially or totally sleeved on a steel pipe, with specific welding techniques and configurations to enhance strength and air tightness, allowing for effective flame brazing without the need for copper adjustments, using techniques like argon arc welding and incorporating a gas shielding device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If copper plating is applied on steel pipe surface to achieve copper welding effect, then welding compatibility is improved, but plated layer shedding occurs during flame brazing causing pipeline blockage and compressor jamming
Solution Approach 1:
The invention uses a composite structure consisting of a steel pipe and a copper pipe sleeve, where the copper pipe is sleeved on the steel pipe and they are welded together. This composite structure allows the copper portion to be flame brazed with other copper components while the steel portion provides structural strength, eliminating the plated layer shedding problem while maintaining welding compatibility.
2Ease of operation
If copper pipe is used for connection in refrigeration systems, then welding convenience and quickness are improved, but copper material consumption increases
Solution Approach 1:
The invention applies local quality by using copper only where welding convenience is needed (the sleeved portion that will be flame brazed with other copper components) while using steel for the main pipe body where structural strength is sufficient. This reduces overall copper consumption while maintaining welding convenience at critical connection points.
3Ease of manufacture
If copper plating process is used on steel products, then welding effect is achieved, but environmental pollution increases due to waste gas and waste water
Solution Approach 1:
The invention extracts the copper plating process entirely and replaces it with a copper pipe sleeve that is mechanically sleeved and then welded. This eliminates the harmful chemical plating process and its associated waste gas and waste water, while still achieving the desired welding effect through proper selection of the copper sleeve portion.
4Strength
If argon arc welding is used to butt weld copper and steel pipes, then strength requirement is met, but fatigue rupture of weld seam occurs during long-term use
Solution Approach 1:
The invention changes the welding parameters and approach by using flame brazing for the copper-copper connections and a different welding method for the copper-steel connection. The copper pipe sleeve is designed with specific dimensions and positioning that optimize the weld seam distribution and reduce stress concentration, thereby improving fatigue resistance during long-term use.
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 composite pipe achieves improved welding quality and reduced copper consumption, enhancing the reliability and longevity of the weld seams while minimizing environmental impact, allowing for efficient use in refrigeration systems without leakage issues during flame brazing.
Implementation Method 1
the copper pipe and the steel pipe are welded and connected in a way of melting base materials
Implementation Method 2
incorporating a gas shielding device
Data Source
AI summary
A novel copper and steel composite pipe, a manufacturing method, application and a welded structure body is described herein. The novel copper and steel composite pipe includes a copper pipe and a steel pipe. The steel pipe includes a first end, a second end and a middle part. The copper pipe includes a first end and a second end. The length of the copper pipe is less than that of the steel pipe. The copper pipe and the steel pipe are sleeved. The distance from an end surface of the first end of the copper pipe to an end surface of the first end of the steel pipe is less than 10 mm. The second end of the copper pipe is positioned at the middle part of the steel pipe, and the copper pipe and the steel pipe are welded and connected in a way of melting base materials.