Changing the parameters of copper annealed pipes during firing
The use of copper pipes in various industrial units, high-pressure feeding systems and in pipelines with chemically active( aggressive) coolant is justified. Comparable with the annealed copper pipes technological characteristics are only high-quality products made of brass and then not always.
According to GOST 617-2006( modern version), copper pipes of circular cross-section are normalized as follows:
- have seven grades of initial material, which are determined by the presence of other chemical impurities( bismuth, tin, sulfur, phosphorus, etc.) in a copper-based alloypurity of at least 99.5-99.9%;
- are manufactured by methods of cold deformation and pressing;
- allows three states in the cold-deformed version: solid, semi-solid and soft.
The first and last case just corresponds to the categories of unburnt and burned copper pipes. Technical characteristics, molding characteristics, sizes of finished pipe sections and, accordingly, the area of their application vary considerably.
The very process of annealing copper pipes is simple enough and is familiar to many people who tried to calcine steel wire or a grid at the stake. The finished tube rolled along the entire length is heated up to 650-700 degrees( for reference: the melting point of copper is 1083) and is cooled( released).
What an annealed copper pipe acquires and loses in terms of technical parameters after such a simple procedure:
- , the plasticity of the material increases approximately 1.5 times, although, due to the reduction of mechanical strength from 340 to 210-220 MPa;
- , the response to linear stretching of pipeline spreads becomes better, the possibility of transverse deformations increases;
- tubular rolling can be cut with long stretches and rolled into coils;The advantages of transporting, storing and installing annealed copper pipes in comparison with unannealed dimensional segments are obvious.
Application area for burnt copper pipes
Unique properties of copper tubular rolled products, after annealing, offer unlimited possibilities to designers and designers, especially if you recall the initial technical characteristics of the material stored in such products:
- Annealed copper pipes, the release of which was carried out with inert compounds,acquire additional anti-corrosion properties. Moreover, such tubes can operate in a wide temperature range( within - 200 + 250 degrees), with chemical active internal carriers( up to acids and alkalis).
- The internal hydraulic impact strength of pipelines, with proper installation, remains extremely high, therefore, those who have made a water pipe from copper pipes or have timely installed the heating system from copper, we are sincerely envious.
- Ease of installation: conventional low-temperature brazing( gas burner and flux) or long-term staff fittings and a wrench.
It is quite natural that the annealed copper pipes have found wide application in the industrial and philistine sphere, here are some of them:
- domestic domestic water supply networks( primarily hot) and heating, with high operating pressure and temperature;
- external network piping connections to private houses;
- air conditioning systems, where seamless copper tubes are simply irreplaceable;
- refrigeration equipment, car manufacturing, etc.
The traditional question: what are the disadvantages of such
pipes? To our regret, they are. Two negative parameters of such products: a large share and not always the lifting price, we have already discussed, so we turn to exploitation.
The fact that any kind of wiring is performed from annealed copper pipes, for which you can even make a pipe bender with your own hands - it's wonderful. But with the same ease, such a pipeline system will deform under any external mechanical stress. The frying pan fell, the hammer accidentally touched, and the design cross section no longer exists.
Copper has a very high coefficient of thermal conductivity. In high-temperature heating networks, the use of uninsulated pipelines is unsafe. The same can be said about the electrical properties of the material. Wiring from annealed copper pipes with unreasonable grounding becomes an excellent conductor and beats the master hands.
And yet, we have to admit that copper in any technological performance is solid, reliable, durable and very beautiful.
