Precipitation-Hardened Copper Alloy Pipe Production via Underwater Extrusion
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Solution Overview
Problem
Current methods for producing heat exchanger pipes using Cu-DHP alloys are inefficient under high pressure conditions, leading to increased pipe thickness and production costs, while alternative alloys like precipitation-hardened alloys face energy-intensive processing challenges and reduced thermo-mechanical characteristics during welding.
Innovation Solution
A production method involving extrusion of Cu-Fe-P and Cu-Fe-Ni-P alloys under controlled temperature zones followed by rapid hydrostatic cooling, combined with cold drawing and final heat treatment for ageing, to achieve high mechanical resistance and thermal exchange capacity without the need for specific solution heat treatment and quench hardening processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Cu-DHP alloys are used for heat exchanger pipes, then ease of manufacture and brazing properties are improved, but mechanical resistance under high pressure deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the alloy composition parameters (adding precipitation-hardening elements like Al, Si, Mn, Zn in specific ranges) and heat treatment parameters (solution treatment temperature 800-950°C, ageing temperature 200-400°C) to achieve both good brazing properties and high mechanical resistance simultaneously
Solution Approach 2:
The patent creates a composite alloy system by combining Cu-DHP base alloy with precipitation-hardening elements (Al, Si, Mn, Zn), forming a multi-element composite material that exhibits both excellent brazing characteristics and high strength properties through precipitation hardening mechanism
2Strength
If pipe thickness is increased to withstand high pressure, then mechanical resistance is improved, but thermal exchange efficiency deteriorates
Solution Approach 1:
The patent changes the material parameters by introducing precipitation-hardening alloying elements and applying specific heat treatment parameters (solution treatment followed by ageing), which significantly improve mechanical strength, thereby enabling the use of thinner pipe walls that maintain both pressure resistance and thermal exchange efficiency
3Strength
If precipitation hardened alloys are used to improve mechanical resistance, then strength is improved, but processing complexity and energy consumption increase
Solution Approach 1:
The patent merges the alloying process with the heat treatment process by adding precipitation-hardening elements during standard copper alloy production and integrating solution treatment and ageing steps into the existing manufacturing workflow, thereby achieving high strength without significantly increasing overall process complexity
Solution Approach 2:
The patent optimizes heat treatment parameters (solution treatment temperature 800-950°C, ageing temperature 200-400°C, time ranges) to achieve effective precipitation hardening within reasonable processing time and energy consumption, balancing strength improvement with processing efficiency
4Strength
If traditional solution heat treatment and quench hardening are applied to precipitation hardened alloys, then mechanical resistance is improved, but energy consumption increases
Solution Approach 1:
The patent combines solution treatment and ageing into an integrated heat treatment process where the alloy is solution treated at 800-950°C followed by controlled cooling and ageing at 200-400°C, achieving precipitation hardening with optimized energy consumption by eliminating separate quenching and ageing operations
Solution Approach 2:
The patent optimizes the temperature and time parameters of the heat treatment process (solution treatment 800-950°C for controlled time, ageing 200-400°C) to achieve effective precipitation hardening with minimized energy consumption, balancing material strength improvement with energy efficiency
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 method results in pipes with improved mechanical resistance and thermal exchange efficiency, reducing energy consumption and production costs while maintaining high conductivity, and eliminates the drawbacks of traditional processes.
Implementation Method 1
a first heating stage at a temperature high enough to provoke complete solution heat treatment in the base metal of the constituent that makes the alloy susceptible to hardening (forming of a solid solution)
Implementation Method 2
a second cooling stage which may be shorter or longer, (quench hardening) wherein the solid solution is brought to oversaturation conditions and therefore thermodynamically metastable
Implementation Method 3
a last stage, for ageing, which creates the segregation of a precipitate, accompanied by a distortion of the base lattice which provokes a considerable increase in the hardening properties
Implementation Method 4
extrusion of Cu-Fe-P and Cu-Fe-Ni-P alloys under controlled temperature zones followed by rapid hydrostatic cooling
Data Source
Figure 1~3
AI summary
Production method for heat exchanger pipes comprising the following stages: a) production of a billet in an alloy suitable for hardening through precipitation; b) direct hot extrusion under hydrostatic head in a water bath, of the billet previously heated to a temperature equal to or higher than the solution heat treatment of the alloy, in order to construct an extruded pipe blank of a pre-determined size; c) cold rolling of the extruded pipe blank to obtain a rolled blank having a reduced transversal measurement and consequently having an increased length; d) subjecting the rolled blank to a straight drawing process to obtain a semi-finished pipe; e) subjecting the semi-finished pipe to spinner drawing to reduce the transversal measurement and consequently, to obtain a pipe having its definitive size; f) subjecting the pipe to annealing in a tunnel furnace in a manner to determine the hardening of the pipe through precipitation.