Does Cold Pressure Welding Really Work?
Cold pressure welding is a fairly new concept that is essentially a form of solid phase welding, but it can be traced back in some forms to the early Egyptians who prepared iron by hammering a metal sponge in order to weld hot particles together. However to look at this type of welding done at ambient pressures you have to go back to the Bronze Age (700BC).
Also known as the magical process because when you see cold pressure welding in action is looks impossible to conceive that two pieces of metal have been joined without heat, it has had several veteran welders shaking their heads. Those that have never heard of it rarely accept it as good methods of welding but can cold pressure welding really be the future or at least an alternative to what we already know?
To answer this question we need to look closer at some aspects of the cold welding process from how it’s used, where its used and just exactly how this method of welding really works.
What Materials Can Be Welded?
Due to the type of welding we are talking about there are restrictions to the metals that can be welded together. Nonferrous materials are the only real metals that can be used for this process, and you will normally see cold welding as part of Space programs. The satellites that orbit earth are usually joined together by cold welding techniques, although in more recent years the European Space Agency have detailed that this type of welding has caused significant issues to designs and mechanical problems.
Generally you should be able to weld soft irons that have no carbon content, and copper and aluminium are also common choices for cold welders. Aside from those some alloys can also be used during a cold welding process from Aldrey, Triple E, 70/30 brass, zinc, silver, nickels and golds.
Let’s Look at the Importance of Dies
Before we head into the section on how cold welding works (we have left the best until last), we wanted to touch upon the roles of dies in cold pressure welding. The dies have a big role to play in securing the materials firmly, and the gap between the two faces of the die also plays a fundamental role. If the gap happens to be too large the material will simply bend away or break down, and if it is too small it just simply won’t work from the outset.
Secondly the hardness of the die plays another major role in the cold welding process because die breakage was all too much a common thing of the past but in more recent times dies have been created and produced with higher tolerance rates in mind thanks to the advancements in wire technology and precision. This has meant that dies are now capable of joining even the most finest of wires together, whilst undergoing high tolerance standards.
How Cold Welding Works
Normal types of welding, which are usually described as fusion-welding will have liquid or molten phases as part of the overall join, however with cold welding none of these will be present. Cold welding works because if two clean and flat surfaces that are of similar metals strongly adhere if brought into contact under vacuum then they would join together. Essentially in simple terms it’s a process of forcing together two components of metal so that adhesion occurs.
In terms of whether it’s going to be an alternative the real answer lies in how fast future technology advances because at the present time general forms of fusion –welding is always going to take precedence over any forms of cold-welding techniques.
For this we need to look closer at recently discovered micro and nano-scale cold welding which is making leaps and bounds in the science world.
Cold welding is still a fairly new concept in the welding world and even though many welders have heard of this concept, many fusion based welders will turn their heads away at such a process because if the inconsistencies that are involved in the cold welding process. As technology begins to increase at a rapid rate so too will the improvements that are made to cold welding, but until then many welders prefer to use heat based solutions when it comes to joining together a selection of metals.
However, it’s worth noting that cold pressure welding is considerably more cheaper than fusion based welding processes, and it’s advisable that all welders should at least try out this revolutionary welding process to gain knowledge of the scientific process that two pieces of metal are brought together without the need of molten or hot liquids joining them.