The advantage of titanium is that it has very high strength, mass ratio (strength is high, but the mass is light) good corrosion resistance, non-magnetic thermal expansion and thermal conductivity is small, impact toughness (some domestic car friends call it metal reducibility) and fatigue resistance index is high main characteristics.In material science, titanium alloy is called allotropic metal because it can take on different crystal shapes, such as hexagon or cube.Titanium tubes and titanium alloy tubes are mainly used in military industry. PAW's method has not been applied to bicycle manufacturing for the time being and then carries out noble and complicated chemical processes.Pure titanium doesn't mean anything because it's too soft and in order for it to be useful, titanium is extremely difficult to extract because it has to be isolated.It must be supplemented with other metals.All this, of course, depends on the inherent properties of titanium itself.Therefore, titanium is usually called an alloy with special properties.
From a general point of view, the main difficulty is that titanium is very sensitive to wear and tear caused by friction. A simple example is that at high speeds, if the titanium pipe is applied to the industrial chain, the wear on a piece of pure titanium flywheel will be as severe as the reaction generated by welding.It would be easier to explain it with a chemical example like this, but not to scare people.The hexagonal crystal structure of titanium makes its property is excellent, but the temperature can change the structure (here is a chemical change, with the foregoing thermal expansion, thermal conductivity and other physical changes does not belong to the same category) for this reason, the crystal structure called the titanium saturation, so will not be able to have a bit of impurities in titanium alloy, even very small content.Otherwise, cracks will appear in the welding line of titanium tube.Now that we know about these difficulties, how to weld titanium alloy tubes?
Protective gases are not guaranteed to provide a completely airtight environment for manual welding.The gloves should still touch the tubing.In order to reduce this effect, the better welding workshop will first purify the air environment, and will be in the space into a large number of neutral gas, all of which brought about a significant problem is the cost of improvement (now you know why titanium alloy frame is expensive) are the use of arc.Cannot use the attitude of the approximation to treat, welding, a titanium alloy frame under high temperature environment, to put all the dangerous range in gas separation, make it not to be "infected" impurity called type molten bath (think of people, when washing bath, is the whole body is surrounded by water, as the name implies) with gas is known as the "supervision, gas welding and small environment, when the gas inert there are two ways to invent a welding environment, the first method is to use a bell jar, another way is to provide an inert gas welding parts maintain, requests coming from time to time, rich flow, continue to stability,Cover the whole environment with airflow.I usually use argon and helium because it's easy to supply and cheap.For some special cases, such as large welding area, arc will also be used to fill the gas environment in order to optimize the efficiency.