In-situ configuration composite forming process for large-size heterogeneous titanium alloy component

Abstract

The invention discloses an in-situ configuration composite forming process of a large-size heterogeneous titanium alloy component, which comprises the following steps of: performing in-situ configuration on heterogeneous titanium alloy to obtain a preformed part which is similar to a final formed part in shape and has a heterogeneous titanium alloy gathering area at a functional structure position; the obtained preformed part is heated, so that the matrix titanium alloy and the electric arc additive titanium alloy in different areas of the preformed part are located in respective target temperature intervals; and integral die forging forming is conducted on the heated pre-forming piece, and a final forming piece is obtained. According to the method, the residual stress and solidification defects in the prepared heterogeneous titanium alloy component can be effectively eliminated, the grain structure of the component is improved, the connection / bonding strength of the dissimilar titanium alloy additive bonding interface can be improved, the interface tearing deformation defect caused by shear stress can be avoided, and the service life of the component is prolonged. And the uniformity of structures of all parts of the titanium alloy component can be obviously optimized.

Description

Technical Field

[0001] The invention relates to the technical field of heterogeneous titanium alloy component forming, and in particular to an in-situ configuration composite forming process for large-size heterogeneous titanium alloy components. Background Art

[0002] Titanium alloy forgings have many advantages, including excellent mechanical properties, high temperature resistance, corrosion resistance, good machinability, and high temperature strength. They are widely used in aviation, aerospace, energy, transportation, weapons and equipment and other industries. The main products involved include: aviation engine parts, missile parts, rocket parts, turbine blades, turbine discs, combustion chamber components, oil pump housings, cylinder blocks, pistons, aircraft landing gear, engine cases, disc-shaft assemblies, bucket teeth, chains and other complex forgings with complex structures such as variable cross-sections, multiple curved surfaces, high-rib thin walls, side walls with bosses, etc.

[0003] Existing large-size titanium alloy components (titanium alloy components with a length of not less than 600mm, a width of not less than 250mm, and a height of not less than 100mm) can be prepared by integral forging forming process, segmented forging and then splicing manufacturing, and local loading forming process. However, the overall forging has high requirements for equipment, technology, energy, etc., and the cost is relatively high; large and powerful forging equipment is required, the equipment requirements are high, the investment is large, the overall forging requires high temperature and high pressure conditions, consumes a lot of energy, and the environmental protection pressure is large. The overall forging may cause a lot of material waste and low material utilization, especially in the components of complex shapes. It has high requirements for process control and operation technology, and the operation is difficult; the segmented forging needs to be spliced, and the assembly process is relatively complicated, requiring precise process control and operation technology. The splicing is often the weakness of the component. The splicing manufacturing after segmented forging is easy to cause the overall strength and toughness of the component to decrease. The segmented forging and splicing may destroy the continuity and uniformity of the raw materials and affect the overall performance of the component. Stress concentration is easy to occur at the splicing, which increases the risk of fatigue failure of the component. The welding quality is difficult to fully guarantee, and there may be welding defects, which affect the overall performance of the component; the research on local loading forming is mainly limited to the die forging process, and the blanking process of large die forgings is long, the heating and deformation times are many, and the material flow and organizational changes are complex, which has a significant impact on the die forging forming.

[0004] More importantly, for large-sized and complex-functional titanium alloy components, one of the current challenges includes: it is difficult to achieve efficient combination and coordinated deformation / forming of dissimilar titanium alloys, it is difficult to control the uniformity of their structure, and it is especially difficult to accurately control the uniformity of the structure of the protruding parts of the titanium alloy components. Summary of the invention

[0005] At least in order to solve the problems mentioned in the background technology, the present invention aims to provide an in-situ configuration composite forming process for large-sized heterogeneous titanium alloy components.

[0006] The present invention adopts the following technical solution.

[0007] An in-situ composite forming process for a large-sized heterogeneous titanium alloy component comprises the following steps: Step 1, in-situ configuration of the heterogeneous titanium alloy is performed to obtain a preformed part having a shape similar to that of the final formed part and having a heterogeneous titanium alloy aggregation area at the functional structure position; Step 2, heating the obtained preform so that the base titanium alloy and the arc-added titanium alloy in different regions of the preform are respectively in their respective target temperature ranges; Step 3: The heated preform is integrally forged to obtain a final formed part.

[0008] Furthermore, the step of in-situ configuration of the heterogeneous titanium alloy includes: Step 11, performing arc additive processing on the base titanium alloy to obtain an additive titanium alloy component having an additive structure; Step 12, high-frequency hammering is performed on the additive structure of the additive titanium alloy component.

[0009] Preferably, in the additive process: the diameter of the wire used for additive is 0.1-1 mm, the preheating temperature of the titanium alloy substrate is 400-600° C., the arc power is 1000-3000 W, the wire feeding speed is 1-5 m / min, the argon protective atmosphere flow rate is 5-20 L / min, the single additive layer height is 0.2 mm-0.5 mm, and the scanning speed is 400-1000 mm / s; In the high-frequency hammering process: the hammering frequency is 500~1500 times / min, the hammering pressure is 0.3~1mm, and the contact area between the hammer head and the additive surface is 100~900mm².

[0010] Furthermore, the upper wall and the lower wall of the obtained preform both have additive structures. In step 2, the heating temperature of the upper additive structure of the preform is 850~950°C, and the heating temperature of the lower additive structure of the preform is 950~1000°C.

[0011] Furthermore, the upper additive structure side of the obtained preform 2 has a 15° bevel, and the upper additive structure side and the top surface have a R10mm fillet transition; the upper additive structure side and the upper surface of the titanium alloy substrate have a R15mm fillet transition; the lower additive structure side of the obtained preform 2 has a 20° bevel, and the lower additive structure side and the top surface have a R10mm fillet transition, and the lower additive structure side and the lower surface of the titanium alloy substrate have a R15mm fillet transition. The upper additive structure side of the obtained final part has a 15° bevel, and the upper additive structure side and the top surface have a R8mm fillet transition; the upper additive structure side and the upper surface of the titanium alloy substrate have a R12mm fillet transition; the lower additive structure side of the obtained final part has a 20° bevel, and the lower additive structure side and the top surface have a R8mm fillet transition, and the lower additive structure side and the lower surface of the titanium alloy substrate have a R12mm fillet transition.

[0012] Preferably, the final formed part obtained has an arched structure.

[0013] Furthermore, the upper additive structure of the additive titanium alloy component is a grid structure.

[0014] Furthermore, in the additive process: the main path of each layer of additive is a plurality of continuously arranged arched paths, and an additive filling method is used between two adjacent and oppositely oriented arched paths.

[0015] Preferably, the base titanium alloy is TA32 titanium alloy, the upper additive structure is TA15 titanium alloy, and the lower additive structure is Ti65 titanium alloy.

[0016] Beneficial effects: The scheme of the present invention can not only effectively eliminate the residual stress and solidification defects in the prepared heterogeneous titanium alloy components, improve the grain structure of the components, but also improve the connection / bonding strength of the interface of the heterogeneous titanium alloy additive bonding, avoid the interface tearing deformation defects caused by shear stress, and significantly optimize the uniformity of the organization of each part of the titanium alloy component; the large-sized heterogeneous titanium alloy components of the present invention are less affected by subjective factors during the forming process, the forming process is well controllable, the forming process optimizes the organizational structure evolution and flow process of the workpiece, and the formed components are stable, reliable and high in precision; the scheme of the present invention does not need to design and manufacture special pre-forming molds, the design is highly flexible, and the forming of complex structural features on the upper and lower surfaces of large heterogeneous titanium alloy components can be realized efficiently and at low cost, the material utilization rate is high, the operation difficulty is low, and the overall coordinated forging forming of heterogeneous titanium alloys in multiple process windows can be realized, and the scope of application is very wide. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the in-situ composite forming process flow of a large-sized heterogeneous titanium alloy component in the embodiment; Figure 2 It is a partial schematic diagram of the integral die forging of the preformed part 1 in the embodiment; Figure 3 It is a three-dimensional schematic diagram of the second structure of the preform in the embodiment; Figure 4 It is a schematic diagram of the main direction of the second structure of the preform in the embodiment; Figure 5 It is a three-dimensional schematic diagram of the final formed part structure in the embodiment; Figure 6 It is a schematic diagram of the main direction of the final formed part structure in the embodiment; Figure 7 This is a microstructure diagram of the heterogeneous titanium alloy bonding interface on the upper surface of the final formed part in the embodiment; Figure 8 This is a microstructure diagram of the heterogeneous titanium alloy bonding interface on the lower surface of the final formed part in the embodiment; Fig. 9 Schematic diagram of the additive path in the embodiment. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0019] An in-situ composite forming process for large-sized heterogeneous titanium alloy components, combined with Figures 1 to 6 As shown, the in-situ configuration composite forming of a large-sized heterogeneous titanium alloy component is performed using TA32 titanium alloy as a matrix (i.e., matrix titanium alloy 3), TA15 titanium alloy as a reinforcing rib on the upper surface of the matrix (i.e., an upper additive structure 4), and Ti65 titanium alloy as a boss on the lower surface of the matrix (i.e., a lower additive structure 5). The specific steps are as follows: Step 1, in-situ configuration of the heterogeneous titanium alloy is performed to obtain a preformed part 1 which has a shape similar to the final formed part and has a heterogeneous titanium alloy aggregation area at the functional structure position; The steps of in-situ configuration of heterogeneous titanium alloy include: Step 11, performing arc additive on the base titanium alloy, including using wire 1 to form (arc additive) an upper additive structure 4 on the upper surface of the base titanium alloy 3, and using wire 2 2 to form (arc additive) a lower additive structure 5 on the lower surface of the base titanium alloy 3, to obtain an additive titanium alloy component with an additive structure; in this step: all the upper additive structures 4 on the upper surface of the base titanium alloy 3 together constitute a grid structure; the diameter of the wire used for additive is 0.5 mm, the preheating temperature of the titanium alloy base is 500°C, the arc power is 2000 W, the wire feeding speed is 3 m / min, the argon protective atmosphere flow rate is 10 L / min, the single additive layer height is 0.25 mm, and the scanning speed is 600 mm / s; In the additive process of the upper additive structure 4, the main path of each layer of additive is a plurality of continuously arranged arched paths (such as Fig. 9 In the figure, adjacent and oppositely directed arched paths 15 are shown, and an additive filling method is used between two adjacent and oppositely directed arched paths (i.e., the irregular area 16 between the two adjacent and oppositely directed arched paths is directly filled with additive filling). This specific arched path can further improve the shear resistance of the additive structure itself in conjunction with subsequent processes, and can better adapt to the deformation caused during the overall die forging process; Step 12, high-frequency hammering is performed on the additive structure of the additive titanium alloy component; wherein the hammering frequency is 700 times / min, the hammering pressure is 0.4 mm, and the contact area between the hammer head and the additive surface is 200 mm²; Step 2, a heating coil 7 is provided on the matrix titanium alloy 3, a heating coil 6 is provided on the upper additive structure 4 of the preform one, and a heating coil 8 is provided on the lower additive structure 5 of the preform one, each heating coil is individually connected to a heating controller, and the obtained preform one is heated (the heating temperature of the matrix titanium alloy 3 is 850°C, the heating temperature of the upper additive structure 4 of the preform one is 900°C, and the heating temperature of the lower additive structure 5 of the preform one is 1000°C), so that the matrix titanium alloy and the arc additive titanium alloy in different regions of the preform one are respectively in their respective target temperature ranges; Step 3: Use a die (the die temperature is always controlled at 400°C) to perform integral die forging on the heated preform (the forming speed is controlled at 5mm / s, and the die underpressure is set to 0mm during forming). First, use die 12 to form Figure 3 and Figure 4The preform 2 13 (850mm×280mm×120mm) shown in the figure has an upper additive structure 4 (length 850mm and 280mm, height 50mm, thickness 30mm) of the obtained preform 2 13 having a 15° slope on the side, and a R10mm fillet transition between the side and the top surface of the upper additive structure 4; a R15mm fillet transition between the side and the upper surface of the titanium alloy substrate 3; a lower additive structure 5 (length 60mm, height 60mm, width 60mm) of the obtained preform 2 13 having a 20° slope on the side, and a R10mm fillet transition between the side and the top surface of the lower additive structure 5, and a R15mm fillet transition between the side and the lower surface of the titanium alloy substrate 3; Then, a mold (H13 hot working die steel, upper mold 9, lower mold 10) is used to form the following Figure 5 and Figure 6 The final formed part 14 shown (during the integral die forging process, the die applies a forming load to the matrix titanium alloy and the additive structure in situ, driving the matrix titanium alloy and the additive structure to fill the die cavity, and obtaining a final formed part 14 with an ideal geometric structure, with a size of 850mm×280mm×120mm); the side surface of the upper additive structure 4 of the final formed part 14 obtained has a 15° chamfer, and the side surface and the top surface of the upper additive structure 4 have a R8mm rounded corner transition; the side surface of the upper additive structure 4 and the upper surface of the titanium alloy matrix 3 have a R12mm rounded corner transition; the side surface of the lower additive structure 5 of the final formed part 14 obtained has a 20° chamfer, and the side surface and the top surface of the lower additive structure 5 have a R8mm rounded corner transition, and the side surface of the lower additive structure 5 and the lower surface of the titanium alloy matrix 3 have a R15mm rounded corner transition.

[0020] The RT test results of the special-shaped titanium alloy component formed in this embodiment show that there are no defects such as cracks and shrinkage holes at the interface between the additive structure and the matrix titanium alloy of the special-shaped titanium alloy component, and the composite quality requirements are met. Figure 7 and Figure 8 As shown in the figure, the structure at the interface between the upper additive structure 4 and the upper surface of the titanium alloy substrate 3 is fine and uniform, and the grain size at the interface is not greater than 2μm (the grain size at the detection point of the upper additive structure 4 is 3μm, and the grain size at the detection point of the titanium alloy substrate 3 is 5μm); the structure at the interface between the lower additive structure 5 and the upper surface of the titanium alloy substrate 3 is fine and uniform, and the grain size at the interface is not greater than 3μm. The mechanical properties of the special-shaped titanium alloy component formed in this embodiment were tested, and two parts were randomly tested. The results showed that the R m (tensile strength) = 985~991Mpa, A (elongation after fracture) = 13.3~13.6%, Z (notch sensitivity) = 28.9%, R p0.2(yield strength) = 880~898Mpa, E (elastic modulus) = 122~123.2GPa; R of the interface between the lower additive structure 5 and the lower surface of the titanium alloy substrate 3 m =800~813Mpa, A=15.8~16.5%, Z=35~35.3%, Rp0.2=671Mpa, E=123~124GPa.

[0021] In this embodiment, the "performance zoning + structural stratification" macrostructure and microstructure pre-distribution of high-performance complex special-shaped titanium alloy components is realized, with high material utilization rate, meeting the development direction of modern green manufacturing technology. Firstly, an electric arc is used to melt and solidify the additive alloy wire on the surface of the matrix alloy, and then the macro-micro characteristics of the additive alloy stacking are actively regulated by high-frequency hammering to induce local plastic deformation, so as to realize precise additive billet forming of component functional structure partitioning; by controlling the arc power, wire feeding speed and metallurgical bonding between the additive titanium alloy and the matrix titanium alloy, the residual stress, grain size, compound morphology and distribution of the additive titanium alloy and its interface with the matrix titanium alloy are actively intervened by controlling the hammering frequency and hammering force, so as to realize the macro-structure and micro-structure pre-distribution of each functional area of ​​high-performance complex special-shaped titanium alloy components; by controlling the forming temperature of each area of ​​the component, the preheating temperature of each area of ​​the mold, the press speed and the pressing amount, the macro-metal flow behavior and micro-structure evolution of the heterogeneous titanium alloy components are controlled, and the coordinated matching control of the coordinated deformation of multiple metals in each functional area is carried out to obtain forgings with precise appearance, uniform structure and excellent mechanical properties, so as to realize the in-situ configuration composite forming of large-sized complex functional heterogeneous titanium alloy components.

[0022] The scheme of the embodiment can not only effectively eliminate the residual stress and solidification defects in the prepared heterogeneous titanium alloy components, improve the grain structure of the components, but also improve the connection / bonding strength of the heterogeneous titanium alloy additive bonding interface, avoid the interface tearing deformation defects caused by shear stress, and significantly optimize the uniformity of the organization of each part of the titanium alloy component; the forming process is less affected by subjective factors, the forming process is well controllable, the forming process optimizes the organizational structure evolution and flow process of the workpiece, and the formed components are stable, reliable and high in precision; there is no need to design and manufacture special pre-forming molds, the design is highly flexible, and the forming of complex structural features on the upper and lower surfaces of large heterogeneous titanium alloy components can be realized efficiently and at low cost, the material utilization rate is high, the operation difficulty is low, and the overall coordinated forging forming of heterogeneous titanium alloys in multiple process windows is realized, which has a wide range of applications.

Claims

1. An in-situ composite forming process for large-sized heterogeneous titanium alloy components, characterized in that the steps include: Step 1, in-situ configuration of the heterogeneous titanium alloy is performed to obtain a preformed part having a shape similar to that of the final forging and having a heterogeneous titanium alloy aggregation area at a functional structure position; Step 2, heating the obtained preform so that the base titanium alloy and the arc-added titanium alloy in different regions of the preform are respectively in their respective target temperature ranges; Step 3: The heated preform is integrally forged to obtain a final forging.

2. The in-situ composite forming process according to claim 1, characterized in that: The steps for in-situ configuration of heterogeneous titanium alloys include: Step 11, performing arc additive processing on the base titanium alloy to obtain an additive titanium alloy component having an additive structure; Step 12, high-frequency hammering is performed on the additive structure of the additive titanium alloy component.

3. The in-situ composite forming process according to claim 2, characterized in that: In the additive process: the diameter of the wire used for additive is 0.1~1mm, the preheating temperature of the titanium alloy substrate is 400~600°C, the arc power is 1000~3000W, the wire feeding speed is 1~5m / min, the argon protective atmosphere flow rate is 5~20L / min, the single additive layer height is 0.2~0.5mm, and the scanning speed is 400~1000mm / s; In the high-frequency hammering process: the hammering frequency is 500~1500 times / min, the hammering pressure is 0.3~1mm, and the contact area between the hammer head and the additive surface is 100~900mm².

4. The in-situ composite forming process according to claim 3, characterized in that: The upper wall and the lower wall of the obtained preform both have additive structures. In step 2, the heating temperature of the upper additive structure of the preform is 850~950°C, and the heating temperature of the lower additive structure of the preform is 950~1000°C.

5. The in-situ composite forming process according to claim 4, characterized in that: The upper additive structure side of the obtained preform adopts a 15° inclined surface, and the upper additive structure side and top surface adopt a rounded transition; the upper additive structure side and the upper surface of the titanium alloy substrate adopt a rounded transition; the lower additive structure side of the obtained preform adopts a 20° inclined surface, and the lower additive structure side and the top surface adopt a rounded transition, and the lower additive structure side and the lower surface of the titanium alloy substrate adopt a rounded transition.

6. The in-situ composite forming process according to claim 5, characterized in that: The final forging obtained has an arched structure.

7. The in-situ composite forming process according to any one of claims 2 to 6, characterized in that: The additive structure of the additive titanium alloy component is a grid structure.

8. The in-situ composite forming process according to claim 7, characterized in that: In the additive process: the main path for each layer of additive is a plurality of continuously arranged arched paths, and an additive filling method is used between two adjacent arched paths facing opposite directions.

9. The in-situ composite forming process according to claim 8, characterized in that: The base titanium alloy is made of TA32 titanium alloy, the upper additive structure is made of TA15 titanium alloy, and the lower additive structure is made of Ti65 titanium alloy.

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