Die forging is usually used to make the final blanks with shapes and dimensions close to the product, and then only heat treatment and cutting. The casting temperature and the degree of deformation are the fundamental factors that determine the arrangement and function of the titanium alloy. The heat treatment of titanium plate blank products factory is different from that of steel, and it has no effect on the arrangement of titanium alloys. Therefore, the process standard of the final step of the forging of titanium plate blank products in the factory has a unique and important effect.
In order to make the die forgings of titanium plate blank products factory achieve high strength and plasticity together, it is necessary to make the total deformation of the blank not less than 30%, the deformation temperature does not exceed the phase transition temperature, and the temperature and the degree of deformation should be The deformed blank can be evenly distributed.
Arrangement of die forgings and functional uniformity stainless steel forgings of titanium plate blank products factory. In the violent metal activity area, after recrystallization heat treatment, the low magnification is ambiguous crystals and the high magnification is equiaxed fine crystals; in the hard deformation area, due to the small amount of deformation or no deformation, the arrangement often saves the state before deformation. Therefore, when die forging some important titanium plate blank products factory parts (such as compressor disks, blades, etc.), in addition to controlling the deformation temperature below TB and the appropriate degree of deformation, the arrangement of controlling the original blank is very important, otherwise, The coarse grain arrangement or some shortcomings will be inherited into the forging, and the subsequent heat treatment cannot be eliminated, which will cause the forging to be scrapped.
When forging forged titanium plate blank products with forged shapes on the hammer, in a sharply deformed area where some thermal effects are concentrated, even if the heating temperature is strictly controlled, the temperature of the metal can still exceed the alloy’s TB. For example, when forging a blank for a titanium plate blank product factory with an I-shaped cross section, the hammer is too heavy, and some of the temperature in the center (web area) is about 100 ° C higher than the margin due to the deformation thermal effect. In addition, in the hard-to-deform regions and regions with critical deformation degrees, it is easy to form coarse-grained arrangements with relatively low plasticity and durable strength during the heating process after die forging. Therefore, the mechanical function of the forgings with complicated shapes on the hammer is often very unstable.
Reducing the die forging heating temperature can eliminate the risk of overheating of the blank, but it will lead to a rapid improvement in deformation resistance, add things to wear and power consumption, and it is necessary to use more powerful equipment.
When hammer forging, select the method of repeated tapping can also reduce some overheating of the blank. However, it is necessary to add heat to heat to compensate for the heat lost by the blank and the colder mold.
Die forgings with relatively simple shapes, and the demand for plasticity and durability strength of the deformed metal is not too high, it is better to choose hammer forging. However, hammer forging should not be used for β alloy, because repeated heating during die forging will affect the mechanical function. Compared with the forging hammer, the working speed of the press (hydraulic machine, etc.) is greatly reduced, which can reduce the deformation resistance and deformation thermal effect of the alloy. In the factory forging titanium plate blank products on hydraulic presses, the unit forging force of the blanks is about 30% lower than that of the hammers, and then the life of the mold can be improved. The reduction in thermal effects also reduces the risk of metal overheating and temperature rise exceeding TB.
When die forging with a press, the unit heating pressure can be lowered by 50 ～ 100 ℃ under the same conditions as the forging hammer die forging. In this way, the mutual effect of the heated metal and the periodic gas and the temperature difference between the blank and the mold also decrease accordingly, and then the uniformity of the deformation is improved, the uniformity of the arrangement of the die and forging parts is also greatly improved, and the consistency of the mechanical function is also improved. . Decreasing the deformation speed, the most significant addition of the numerical value is the area reduction rate, which is the most sensitive to the shortcomings of the arrangement caused by overheating.
The characteristic of the factory deformation of titanium plate blank products is that it is more difficult to flow into deep and narrow mold grooves than steel. This is because the deformation resistance of titanium is high, the friction force with things is large, and the touch surface of the blank cools too quickly. In order to improve the activity of the titanium plate blank products factory and improve the die life. The usual practice is to increase the swaging pitch and fillet radius and use lubricant: the height of the burr bridge on the forging die is larger than that of steel, usually about 2mm larger.
In order to make the profile groove easy to overflow, sometimes the non-uniform burr groove of the bridge part can be used to restrict or accelerate some activities of the metal profile groove. For example, a rectangular box-shaped forging (as shown in Figure 12) has thinner front and rear side walls; thicker left and right side walls. When the burr groove shown in B-B is selected around the box-shaped member, because the resistance of metal flowing into the left and right side walls is small, it is difficult for the metal to move to the thinner front and rear side walls, and the filling is not full. Later, the burr grooves shown in BB were still used for the front and rear side walls, and the burr grooves shown in AA were used for the left and right side walls. Because the bridge is wide in size and coupled with the damping groove, the thinner side walls are completely overflowing It is more economical to choose the above-mentioned raw edge groove method.
One of the most useful ways to improve the activity of the titanium plate blank products factory and reduce the deformation resistance is to increase the preheating temperature of the mold. Isothermal die forging and hot die forging developed in the past two or three decades at home and abroad have provided a feasible method for forming fine forgings in factories dealing with large and disordered titanium plate blank products. This method has been widely used to produce titanium wire in forgings of titanium plate blank products factories.
When the closed die forging method is adopted to die forge the titanium plate blank product factory, the life of the die is reduced because of the high pressure. Therefore, closed die forging must strictly limit the volume of the original blank, which complicates the preparation process. Whether to choose closed die forging depends on both cost and process feasibility. In open die forging, the burr loss accounts for 15% to 20% of the blank component, and some process scraps (if necessary according to the die forging conditions) must be held for 10% of the blank component. The relative loss of burr metal is usually added with the reduction of the blank component. For some asymmetry layouts, large cross-sectional area differences, and some forgings that are difficult to fill, the burr cost can be as high as 50%. Although the closed die forging has no burr loss, but the blank making process is messy, it is necessary to add more transition grooves, which will undoubtedly add auxiliary costs.