Practical TIG Welding: Titanium
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Titanium
04.38
| 00:00 | - Titanium is an extremely light and strong material that's widely used in high end motorsport components where weight and strength are crucial to performance. |
| 00:08 | This is a highly reactive metal and must be shielded from the atmosphere when heated in order to protect it. |
| 00:15 | The shielding gas needs to be prolonged until the temperature drops below 500°C so purging and cooling under shielding gas is very important. |
| 00:25 | Titanium has very low thermal conductivity and is ideal for manufacturing exhaust and turbo plumbing. |
| 00:33 | A lot of care must be taken to make every process of titanium preparation as clean as it can be. |
| 00:39 | Always use scotch brite to clean the surface then wipe with acetone on a clean rag to remove any oils, finger prints or contaminants that could be on the part. |
| 00:49 | Finally select your filler rod and wipe this down before putting the acetone rag away. |
| 00:54 | Since titanium is a very reactive material, the cup size we use needs to be increased quite drastically. |
| 01:01 | We suggest starting at a number 18 cup as a minimum. |
| 01:04 | This is to ensure you're fully covering the whole heat affected area with shielding gas at all times. |
| 01:10 | In some instances, and this is more apparent on tube work where the shielding gas runs away over the tube surface, titanium specialists use a trailing cup which is a secondary attachment for the torch that supplies a longer trailing supply of argon to the weld. |
| 01:26 | This will only really be necessary if you want to specialise in titanium welding. |
| 01:31 | Purging titanium is essential for sealing the back side of the weld on tubing, tanks as well as flat sections. |
| 01:38 | This requires argon to be fed into the lower portion of the tank or pipe at around 12 litres per minute for 30 seconds per litre of your component's volume. |
| 01:48 | The reason for doing this is to clear our any residual atmospheric air that may be left inside. |
| 01:54 | Once the part has been filled with argon, the flow rate can then be reduced to around 8 litres per minute for the duration of the weld. |
| 02:01 | You also need to ensure that the other end of the tube is vented to prevent the build up of pressure inside the tube causing your weld to blow back towards the tungsten. |
| 02:11 | This process of purging can be quite tricky on flat sections and may sometimes need another shielding gas cup set up on the back side of the weld so that both front and back sides are shielded from oxidisation. |
| 02:23 | In a lot of ways, titanium is just a lightweight version of stainless steel that requires more argon shielding so the technique is essentially the same. |
| 02:33 | If you're proficient at stainless TIG welding then there's no reason you won't be able to weld titanium. |
| 02:39 | If the part isn't structural and your fit up is close to perfect, you may not need filler rod for your weld because small intricate titanium welds can be done through fusion welding. |
| 02:49 | You can check back to the fusion welding module in the practical skills section before trying this out for yourself. |
| 02:56 | If you are using filler rod, care needs to be taken when introducing it into the weld pool as you'll find that it has a tendency to stick to the base metal if you're not careful. |
| 03:06 | One way around this is to hold the filler rod in a more upright position and make sure that it's only applied directly to the weld pool itself. |
| 03:14 | It's also imperative that we keep the end of the filler rod within the gas shielded area between each dab. |
| 03:21 | If the filler rod leaves the shielded gas area, it'll oxidise. |
| 03:25 | Then, on the next dab you'll be adding impurities directly into your weld pool. |
| 03:29 | Try to weld in a uniform motion using your pulse controls to time the inclusion of filler rod and always be mindful of your torch angle to maintain shielding gas flow evenly over your completed weld as well as your incoming filler rod. |
| 03:44 | You're probably going to find the extra costs of sourcing the material leads to a greater emphasis on preparation which in turn leads to increased nerves when it comes time to weld. |
| 03:55 | Once you've done it a few times though, you'll be able to relax and you'll be able to weld without any hesitation. |
| 04:00 | A properly shielded weld will look silver or straw coloured with a uniform bead structure. |
| 04:05 | Any blue, purple or green colours in the weld indicates a lack of shielding gas. |
| 04:11 | This could be due to poor torch positioning, poor shielding gas coverage or excess heat. |
| 04:17 | Severe discolouration or sugaring with a green powder appearance points to inadequate shielding gas coverage so check your gas flow rate for any gas path obstructions. |
| 04:28 | In our resources section you'll find a PDF that lists suitable baselines for all settings when you're working with titanium. |
