Machining is one of the most important engineering solutions in the modern age. Because of it we have access to a huge array of parts and products in various metals, plastics, and more. However, the processes can be challenging. This is especially likely with certain tricky materials. You need to be careful with things like titanium alloy machining if you want the best results.
One of the biggest concerns with titanium is galling. It can cause huge problems and, in the worst cases, means that items can’t provide the necessary level of performance. That can result in accidents or a huge amount of waste if production needs to start all over again.
What we want to do here is take a closer look at galling, what it is, why it happens, and what to do about it. The knowledge could help to improve everything for you.
What is it?
Like other processes, titanium alloy machining uses different tools to remove material to create parts. The problem here is friction. You want to cut efficiently but without excessive friction because it can cause heat, wear tools, and even seize-up parts. The worst issue though is galling.
What happens here is the metals can adhere together where the two surfaces meet. This can occur with your tool and the titanium. As they slide apart it can physically tear the crystal structure of the metal. It can gouge material or leave torn lumps of metal from the tool behind. We call this galled, hence the name.
What causes it?
As we said above, the galling occurs because of a high amount of friction. It is most common when there are very heavy loads on the tools during machining. The increase in pressure means more friction and more heat. Metals are therefore more likely to adhere.
For galling to happen the material must be ductile and have a crystal structure. Titanium and some of its alloys sadly tick both boxes. You can also have issues when you work with aluminium and austenitic stainless steel.
One of the major causes of galling is a lack of lubrication. Generally you need sufficient lubricant to allow surfaces to slide together without adhesion. It can also reduce the build up of heat and wash away metal chips.
Galling is also more likely if metals have had passivation to improve the corrosion resistance. What this does is create an external oxide layer on the metal. However, the harder layer can be more likely to gall during machining.
What to do about it?
The main problem with galling is it ruins the surface finish of products. When a tight tolerance is necessary it can be a huge issue. It can massively hurt performance too, even if it is only microscopic galling.
There are a few different ways to reduce the risk of it happening, whether you are looking at titanium alloy machining or other metals. One option is to choose metals that are less susceptible. This is probably the best choice but is not always viable, especially if you identify the specific alloy as the most effective for your end needs.
If you do need to use a metal that is susceptible to galling, you need to machine it carefully. Using enough lubricant is vital. You also need to make sure you prepare the metal before use to get rid of any debris that could increase friction and the risk of adhesion. You can also choose tooling from materials that are not prone to galling.
Another thing you can try is reducing the load when you machine. One way to do this is to ensure you have sharp tooling that can cut as effectively as possible without needing excessive pressure.
Speak to us if you need to arrange titanium alloy machining
Brindley Metals is one of the UK’s most approachable metal suppliers. As a family run business we understand the value of good service. It is what we aim to provide every single time. Most importantly, we are always happy to suggest what materials to use for different projects. We can then help to arrange delivery or processing if you need anything other than raw materials.
A big part of our service is we can organise titanium alloy machining. We can give clients access to reliable services that can offer tight tolerances and great surface and edge finishes. If you would like to find out more, please contact us.