Industry information
Most titanium and titanium alloys require various forms of pressure processing such as forging, rolling, extrusion, forging, and stamping, among which forging and stamping are more commonly used in mechanical manufacturing plants.
The forging performance of titanium alloy is close to that of low-alloy steel, but it still has the following characteristics compared to the latter.
1. To prevent oxygen pollution, titanium alloys should be heated in a slightly oxidizing atmosphere. In order to reduce the degree of oxidation pollution, the heating time at high temperatures should be as short as possible. The process should also be designed reasonably to reduce the number of repeated heating cycles.
2. The deformation resistance of titanium alloys increases rapidly with the increase of deformation speed, and the plasticity of titanium alloys under dynamic conditions is twice as small as under static conditions. Therefore, a reasonable deformation processing rate is necessary. Titanium alloy has poor thermal conductivity. During pressure processing, if there is significant deformation in a local area, the temperature in that area will increase, causing grain growth and resulting in uneven microstructure of the alloy workpiece.
3. The microstructure and properties of titanium alloy parts are largely determined by the initial hot deformation processing conditions, so special attention should be paid to controlling the microstructure of the billet. If the structure of the defective material is coarse, it cannot be expected to be improved during the heat processing and heat treatment of the finished product in the future. The Weibull structure in the billet cannot be fully broken even if the deformation degree reaches 50% during the finished product processing. This feature is particularly important for products that require equiaxed organization to achieve fatigue performance in production.
The temperature for hot deformation processing should be determined based on the B-phase transition point of the alloy, with reference to the process plasticity diagram. Generally, the forging of a and a 10 β titanium alloys is carried out in the upper part of the a 10 β phase region. Excessive temperature can cause tissue coarsening; If the temperature is too low, the deformation resistance of the alloy is high and it is prone to cracking, so the forging temperature range of titanium alloy is narrow. In production, it is usually stipulated that the Z high heating temperature for the last heating of various alloys Z should not exceed this temperature.
