Titanium basic heat treatment:

Heat treatment method of titanium

A basic heat titanium processing: pure titanium is a single-phase alpha type organization, although the polytype transition alpha beta in 890 ℃, but due to the phase transformation characteristics determine the strengthening effect of it is relatively weak, so you can't use tempering heat treatment can improve the mechanical strength of industrial pure titanium. Heat treatment of industrial pure titanium is the only annealing. There are three main methods of it: the 1 annealing recrystallization annealing 2 stress relieving annealing 3 vacuum annealing. At present, manufacturers generally titanium require annealing under vacuum atmosphere. In order to eliminate the residual titanium material in the process of stress, stress relieving heat treatment shall be carried out. Stress relieving annealing is generally not required in a vacuum or argon atmosphere, as long as you keep the atmosphere in the furnace for micro oxidation can be. Two. Heat treatment of titanium and titanium alloys titanium cn: in order to facilitate the machinery industry and has certain properties of titanium and titanium alloy, to meet the product requirements of material properties, the need for heat treatment of titanium and titanium alloy. (a) stress relieving annealing to eliminate stress of titanium and titanium alloys produced in the casting, cold working, machining and welding process, which is convenient for processing, and to avoid in the process of using the stress caused by the presence of cracking, alpha titanium should eliminate stress annealing processing. Xiao (two) recrystallization annealing alpha titanium parts used in annealing state, annealing can reduce the strength and improve the plasticity, get better comprehensive properties. In order to reduce as far as possible in the process of heat treatment of gas on the titanium surface contamination, heat treatment temperature as far as possible, choose low. The annealing temperature of industrial pure titanium is higher than the recrystallization temperature, but lower than the alpha to beta phase transition temperature of 120-200 ℃, then has a fine grain structure. The annealing temperature of industrial pure titanium is higher than the recrystallization temperature, but lower than the alpha to beta phase transition temperature of 120-200 ℃, then has a fine grain structure. Heating time depends on the thickness of the workpiece to be cooled by air, cooling way. For the industrial pure titanium, recrystallization annealing temperature is 680-700 ℃, holding time is 30-120 minutes. Specification for selection according to the actual circumstances, usually heated at high temperature, heat preservation time is shorter. Specification for selection according to the actual circumstances, usually heated at high temperature, heat preservation time is shorter. Needs to be pointed out is, the annealing temperature is higher than 700 ℃, and the holding time is long, will cause the grain coarsening, resulted in decreased mechanical properties, at the same time, the grain once coarsening, thinning for any heat treatment methods are difficult to make existing. In order to avoid the grain coarsening, can take the following two measures: 1) as far as possible the annealing temperature at 700 ℃. 2) annealing temperature in 700 ℃, holding time as short as possible, but in general, each mm thickness shall not be less than 3 minutes, for all the work, not less than 15 minutes. (three) no vacuum annealing hydrogen in titanium strengthening effect, but very dangerous, can cause hydrogen embrittlement. Solubility of hydrogen in alpha titanium is very small, is mainly the existence of TiH2 compounds, while TiH2 only under 300 ℃ stability. If the alpha titanium was heated in a vacuum, hydrogen can be reduced to below 0.1%. When the content of hydrogen in titanium content is excessive need for removal of hydrogen, hydrogen removal or prevent oxidation, must carry on the vacuum annealing. The heating temperature of vacuum annealing and heat preservation time, basically the same as the recrystallization annealing.