The advantages of titanium are that it has high strength, high mass ratio (high strength, but light mass) good corrosion resistance, non-magnetic thermal expansion and thermal conductivity coefficient is small, impact toughness (some domestic car friends called metal reducibility) and high fatigue resistance index.In materials science, titanium alloys are called allotropic metals because they can take on different crystal shapes, such as hexagons or cubes.Titanium tubes and titanium alloy tubes are mainly used in military industry, PAW this method has not been applied to bicycle manufacturing, and then to the noble and complex chemical process.Pure titanium means nothing 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.Another metal must be added as an assistant.Of course, all of this is premised on the intrinsic properties of titanium itself.So titanium is an alloy that has a very specific property.
From a general point of view, the main difficulty is that titanium is sensitive to friction losses. For example, if the titanium tube is applied to industry at high speed, the abrasion of a piece of pure titanium flywheel by a chain would be as severe as that produced by welding.Trying to explain it with a chemical example like this will make it easier to understand, 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 inside the welding line of the titanium tube.Now that we know about these difficulties, how to weld titanium alloy pipes?
The shielding gas is not guaranteed to provide a completely gas-tight environment when welding by hand.Gloves still need to touch the tube.In order to reduce this effect, a good welding workshop will first clean the air environment, and will be in the space to rush into a large number of neutral gas, all of which brings significant problems is the increase in cost (now you know why titanium alloy frame expensive bar) is 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 environment with air.I usually use argon and helium because it's easy to supply and it's cheap.A mixture of 75% argon and 25% helium is used. For some special cases, such as large welding areas, an arc is also used to fill the gas environment for optimal efficiency.