Titanium Welding Argon Gas
Titanium has to be very clean from oil, grease, coatings, and oxides before welding. Oil or grease will cause porosity in the weld. You can see this in an x-ray negative of a titanium weld. Porosity is only one of your problems. Contamination from your fingers, lubricants, cutting fluid, paint, dirt and many other substances causes embrittlement in the weld. Contamination is a leading cause of weld failure. When working with titanium follow the three Cs of welding:
clean, clean, clean.
Keep the work area clean, free from dust, debris and excess air movement that could interfere with the argon shielding gas. Clean the base metal. Bag parts not immediately welded. Clean the filler rod. Wear nitrile gloves when handling the filler rod and parts. Titanium fabrication demands exacting attention to cleanliness of the metal itself and the shop environment. It is best set an area aside exclusively for titanium fabrication that is free of air drafts, moisture, dust, grease, and other contaminants. Machining, painting, grinding, and torch cutting should not occur in the same area. Ideally, you should minimize humidity to maintain a low dew point.
A complete argon environment around the weld area was absolutely a must (as shown in the video above). Shielding gas is necessary in GTAW to protect the welding area from atmospheric gases such as nitrogen and oxygen. These gases cause defects, porosity, and weld embrittlement. These gasses can inadvertently come in contact with the electrode, the arc, or the welding metal. Argon is the most commonly used shielding gas for GTAW. Argon helps prevent weld defects. When used in conjunction with alternating current argon gas yields the highest quality titanium welds.
Titanium falls into a family of metals called reactive metals. Reactive metals have a strong affinity for oxygen. At room temperature titanium reacts with oxygen to form titanium dioxide. This is an impervious coating that resists interacting with the atmosphere. It gives titanium its corrosion resistance. The oxide layer must be removed prior to welding because it melts at a much higher temperature than the base metal. The oxide coating can enter the molten weld pool and reduce weld integrity. The titanium weld pool tends to be sluggish similar to welding stainless steel. Use a dab technique. Excessive heat can cause the weld to crack. Minimize input as much as possible.
Titanium is about 45 percent lighter than steel. It is 60 percent heavier than aluminum. It is three times stronger than both of them. Titanium lowers life cycle cost because of its long service life, reduced maintenance, and lower repair costs.