When welding, proper thermal management is an absolute essential. There are many reasons for this. The main ones, however, are regarding the safety of the weld should it take place at too high a temperature.
If a weld or the welding equipment is not properly cooled, the weld can be considerably weaker than it should be, not to mention unsightly. Too much heat being placed upon the welding process is thermal stress?
What Is Thermal Stress?
Thermal stress refers to the stress that is placed upon any material as a result of a change in temperature. It’s caused by either thermal expansion or thermal contraction, which are more advanced names for the processes of heating and cooling respectively.
The concept of thermal stress does not apply only to metals in the welding process, however, it applies to just about any material that you can think of. For example, if plastic is placed under thermal stress, it will melt. If wood is placed under thermal stress, it will smoulder or most likely catch fire. When metal is placed under thermal stress as it is in welding, it melts.
Thermal stress must, of course, take place on the metals that are being welded together in the welding process. It’s essential though that it’s a controlled level of thermal stress – too much will have an adverse effect on the weld and the two materials that are being joined together. Should there be too much thermal stress during welding, many things can go wrong with the welding including welds that are not properly formed, as well as cracking and rusting of the weld after completion. Not only will these affect the aesthetics of the weld, but they will also more importantly affect how strong it is – not something that you want to be unsure about. Thermal management, therefore, is extremely important indeed.
What Is Thermal Shock?
Thermal shock is when a large change in temperature takes place very quickly – this usually causes a change in state of the material that is experiencing the temperature change.
Thermal shock, if not intentional, is not a good thing. Due to the rapid and considerable change in temperature, the material that’s being placed under shock will experience cracking and breakages. An example of a thermal shock would be placing something that’s very hot straight into cold water. For example, removing glass from the dishwasher and dropping it into a sink full of freezing cold water would most likely cause it to crack and fall apart. This is since the glass itself is forced to contract rapidly due to the change from hot to cold – an example of a thermal shock.
Thermal Management Solutions
After reading about thermal stress and thermal shock, it’s easier to understand why proper thermal management is essential in welding. Welding must take place at the correct temperature. If the metals that are being welded together start off at the wrong temperature, they could experience thermal shock and their structural integrity would be adversely affected as a result of said thermal shock. For example, if you were to take a freezing cold piece of metal and place it under a welding gun, it could experience thermal shock as it’s going from extreme cold to extreme heat in a very short space of time.
The main purpose of thermal management in terms of welding, though, is to make sure that the process and welding equipment are kept cool and at the correct temperatures – the process of welding itself requires a massive amount of heat, as you will most likely already know. It is therefore very important that you understand properly how to keep your weld and welding equipment cool.
Chillers – A welding chiller is a perfect solution to keeping cooling solutions cool, on an industrial or commercial level. Chillers are used in a variety of situations, including refrigerators, for example. They work by passing the fluid that’s absorbed heat over/through a chiller in which the heat is then taken away from the solution, usually by means of a radiator.
Welding chillers are very effective at keeping your system cool, as well as being portable meaning that you can keep your equipment at the best possible temperature even whilst on the move. A good welding chiller that’s portable too is important, welding is often not workshop based. A high-quality portable chiller will mean that you can perform welds to the same standard and just as easily as you could in the workshop.
How Do Welding Chillers Work?
The general and most simple way to put the concept of welding chillers is that they move the heat that builds up in the welding equipment that is being cooled into the surrounding air that’s not already filled with heat. This is done by passing a solution/liquid of some sort in tubes over the hot equipment, allowing it to absorb the heat that’s being created, and then sending this solution back through the refrigeration to be cooled/for the heat to be removed.
The Cooling Fluid – The cooling fluid is what absorbs the heat from the hot equipment. It’s purpose after the absorption of the heat is to move this heat to the refrigerator, where it will be taken from the solution which will then be again output as cool, thus ready to absorb more heat in its next circulation. It’s made up usually of a combination of water and glycol.
The Refrigerator – contains a compressor, evaporator, condenser and an expansion valve. Together, these components work together to absorb the heat from the solution that is passed through it.