Forging forming method for titanium alloy Ti175 bar

Abstract

The invention discloses a forming method for forging a titanium alloy Ti175 bar, which comprises the following steps of: accurately setting cogging, forging and forming temperatures, and quantitatively controlling key parameters such as transfer time, deformation and pressing speed in the forging process, so as to ensure that the material achieves ideal internal structure and performance in the forging and cooling processes; in addition, the method further comprises the steps of heat treatment, physical and chemical testing, machining, corrosion and flaw detection and the like. According to the device, the internal organization structure of a material is optimized by accurately controlling key parameters in the forging process, recrystallization and refinement of crystal grains are effectively promoted, the problem of overgrowth or uneven distribution of the crystal grains is avoided, the overall quality and performance of a product are improved, the production process is optimized, and the cost is reduced.

Description

Technical Field

[0001] The invention relates to the field of forging hot processing, in particular to a forging forming method of a titanium alloy Ti175 bar. Background Art

[0002] Titanium alloy Ti175 is an alloy material with titanium as the main component, which also contains aluminum (Al), molybdenum (Mo), chromium (Zr), tin (Sn), tungsten (W) and silicon (Si) and other added elements. The proportions of these elements are 6.2%-7.50% aluminum, 3.5%-4.50% molybdenum, 3.5%-4.50% chromium, 1.5%-3.0% tin, 0.9%-2.00% tungsten, 0.15%-0.35% silicon, and the remaining components are titanium and a small amount of impurities. Ti175 alloy has broad application prospects in the fields of aerospace, industrial equipment, etc. due to its high strength, low density and good corrosion resistance.

[0003] In the traditional forging process of titanium alloy Ti175 bars, simple forging is usually performed according to the required size requirements. However, this method has less control over the technical parameters during the forging process, resulting in insufficient research on the internal structure and performance of the final product. Since the internal structure and performance of titanium alloy Ti175 bars are crucial to the quality of the final product, it is necessary to ensure that the forging technology is finely controlled and the bars after forging are strictly tested for quality during the forging and subsequent heat treatment processes, so as to improve the internal structure and performance of titanium alloy Ti175 bars and meet high-demand applications. Summary of the invention

[0004] The object of the present invention is to provide a forming method for forging a titanium alloy Ti175 bar, which optimizes the internal structure of the bar by accurately controlling the technical parameters in the forging process, thereby improving the quality and performance of the final product.

[0005] In order to solve the above technical problems, the present invention provides a forming method for forging a titanium alloy Ti175 bar, comprising the following steps:

[0006] Forging temperature setting, including setting the temperature of blank forging, temperature of reforming forging and temperature of forming forging. The three types of temperature settings include four firing times, and each firing time includes the temperature setting of preheating and bar heating with furnace;

[0007] Forging parameter control, including control of parameters of the bar in the four firing processes of blanking forging, reforming forging and forming forging, the parameters of the blanking forging and reforming forging both include transfer time, feed amount, deformation amount and forging time, and the parameters of the forming forging include pressing speed, pressing amount, deformation amount and hammering interval time;

[0008] Post-forging cooling, including cooling the bar in stages during forging;

[0009] Heat treatment is used to improve the mechanical and physical properties of the rod.

[0010] Optionally, setting the temperature of the blank forging includes:

[0011] In the first firing, the furnace temperature is preheated to 700-850°C, the rod is added and the temperature is raised to 1120-1160°C along with the furnace;

[0012] In the second firing, the furnace temperature is preheated to 710-840°C, the bars forged in the first firing are added and the temperature is raised to 1080-1120°C along with the furnace;

[0013] In the third firing, the furnace temperature is preheated to 720-830°C, the rod forged in the second firing is added and the temperature is raised to 1000-1040°C along with the furnace;

[0014] In the fourth firing, the furnace temperature is preheated to 730-820°C, the rods forged in the third firing are added and the furnace temperature is raised to 960-1000°C.

[0015] Optionally, setting the temperature of the reforming forging includes:

[0016] In the first firing, the furnace temperature is preheated to 800-850°C, the rods are added and the temperature is raised to 900-950°C along with the furnace;

[0017] In the second firing, the furnace temperature is preheated to 750-800°C, the bars forged in the first firing are added and the temperature is raised to 850-900°C along with the furnace temperature;

[0018] In the third firing, the furnace temperature is preheated to 700-750°C, the bars forged in the second firing are added and the temperature is raised to 800-850°C along with the furnace temperature;

[0019] In the fourth firing, the furnace temperature is preheated to 650-700°C, the rods forged in the third firing are added and the furnace temperature is raised to 750-800°C.

[0020] Optionally, setting the temperature of the forming forging includes:

[0021] In the first firing, the furnace temperature is preheated to 750-800°C, the rod is added and the temperature is raised to 800-850°C along with the furnace;

[0022] In the second firing, the furnace temperature is preheated to 700-750°C, the bars forged in the first firing are added and the temperature is raised to 750-800°C along with the furnace temperature;

[0023] In the third firing, the furnace temperature is preheated to 650-700°C, the rod forged in the second firing is added and the temperature is raised to 700-750°C along with the furnace;

[0024] In the fourth firing, the furnace temperature is preheated to 600-650°C, the rods forged in the third firing are added and the furnace temperature is raised to 650-700°C.

[0025] Optionally, during the blank forging process, the control of the parameters includes:

[0026] In the first fire of the blanking forging temperature setting, the transfer time of the bar is 0 to 60 seconds, the feed amount is 425 mm, the deformation amount is 45 to 50%, and the forging time is 0 to 180 seconds;

[0027] In the second fire of the blanking forging temperature setting, the transfer time of the bar is 0 to 50 seconds, the feed amount is 400 mm, the deformation amount is 40 to 45%, and the forging time is 0 to 165 seconds;

[0028] In the third fire of the blanking forging temperature setting, the transfer time of the bar is 0 to 45 seconds, the feed amount is 375 mm, the deformation amount is 35 to 40%, and the forging time is 0 to 150 seconds;

[0029] In the fourth fire with the blank forging temperature set, the transfer time of the bar is 0 to 40 seconds, the feed amount is 350 mm, the deformation amount is 30 to 35%, and the forging time is 0 to 135 seconds.

[0030] Optionally, during the reforming forging process, the control of the parameters includes:

[0031] In the first fire of the forging temperature setting, the transfer time of the bar is 0 to 45 seconds, the feed amount is 0 to 250 mm, the deformation amount is 40 to 45%, and the forging time is 0 to 170 seconds;

[0032] In the second fire of the forging temperature setting, the transfer time of the bar is 0 to 40 seconds, the feed amount is 0 to 230 mm, the deformation amount is 35 to 40%, and the forging time is 0 to 150 seconds;

[0033] In the third fire of the forging temperature setting, the transfer time of the bar is 0 to 35 seconds, the feed amount is 0 to 210 mm, the deformation amount is 30 to 35%, and the forging time is 0 to 130 seconds;

[0034] In the fourth fire of the forging temperature setting, the transfer time of the bar is 0 to 30 seconds, the feed amount is 0 to 200 mm, the deformation amount is 25 to 30%, and the forging time is 0 to 110 seconds.

[0035] Optionally, during the forming and forging process, the control of the parameters includes:

[0036] In the first fire of the forming forging temperature setting, the pressing speed is 25-30 mm / s, the pressing amount a is 60-70 mm, the deformation amount is 25-30%, and the hammering gap time is 3-4 s;

[0037] In the second fire of the forming forging temperature setting, the pressing speed is 20-25 mm / s, the pressing amount a is 50-60 mm, the deformation amount is 20-25%, and the hammering gap time is 3-4 s;

[0038] In the third fire of the forming forging temperature setting, the pressing speed is 15-20 mm / s, the pressing amount a is 40-50 mm, the deformation amount is 15-20%, and the hammering gap time is 1-2 s;

[0039] In the fourth fire with the forming forging temperature set, the pressing speed is 10-15 mm / s, the pressing amount a is 30-40 mm, the deformation amount is 10-15%, and the hammer gap time is 1-2 s.

[0040] Optionally, the staged cooling method includes natural cooling after the blanking forging is completed, forced ventilation cooling after the reforming forging is completed, and liquid cooling after the forming forging is completed.

[0041] Optionally, the heat treatment includes primary annealing and secondary annealing;

[0042] The primary annealing comprises placing the rod into a furnace at 0-800°C, heating the rod to 867-877°C with the furnace, and keeping the rod within the range of 867-877°C for 108-132 minutes, taking the rod out of the furnace after the end of the keeping and cooling it in the air;

[0043] The secondary annealing includes placing the rod into a furnace at 0-500°C, heating the rod to 530-550°C with the furnace, and keeping the rod within the range of 530-550°C for 345-375 minutes. After the keeping time is completed, the rod is taken out of the furnace and cooled in the air.

[0044] Optionally, physical and chemical tests, mechanical processing, and corrosion and flaw detection are also included; the physical and chemical tests are used to evaluate the chemical and physical properties of the rod; the mechanical processing is used to accurately determine the size and surface finish of the rod; the corrosion and flaw detection is used to evaluate the corrosion resistance and integrity of the rod in a specific environment.

[0045] Compared with the prior art, the present invention has at least the following beneficial effects:

[0046] The present invention effectively improves the original undeformed grain structure of the titanium alloy Ti175 remaining after smelting by precisely controlling the technical parameters in the forging process, such as temperature, deformation, forging speed, etc., thereby significantly improving the internal structure qualification rate of the bar, effectively reducing the energy consumption in the forging process, saving production costs and improving economic benefits; secondly, by comprehensively considering the mutual influence and matching relationship of various technical parameters in the forging process, the refined management of the forging process is realized, and the overall performance of the product is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a flow chart of a molding method in one embodiment of the present invention;

[0048] Figure 2 It is a block diagram of the components of forging temperature setting in one embodiment of the present invention. DETAILED DESCRIPTION

[0049] The following is a more detailed description of a titanium alloy Ti175 bar forging forming method of the present invention in conjunction with a schematic diagram, wherein a preferred embodiment of the present invention is shown, and it should be understood that those skilled in the art can modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art, and not as a limitation of the present invention.

[0050] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are in very simplified form and are not in exact proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0051] like Figure 1 to Figure 2 As shown, the embodiment of the present invention provides a forging forming method of titanium alloy Ti175 bar, comprising the following steps:

[0052] Forging setting temperature, including setting the temperature of blank forging, temperature of reforming forging and temperature of forming forging. The setting of the three types of temperature includes four firing times, and each firing time includes the temperature setting of preheating and bar heating with furnace;

[0053] Forging parameter control, including control of parameters of the bar during the four firings of blanking forging, reforming forging and forming forging, wherein the parameters of the blanking forging and reforming forging include transfer time, feed amount, deformation amount r and forging time, and the parameters of the forming forging include pressing speed, pressing amount a, deformation amount r and hammering gap time;

[0054] Post-forging cooling, including cooling the bar in stages during forging;

[0055] Heat treatment is used to improve the mechanical and physical properties of the rod.

[0056] In this embodiment, the forming method is used to forge a titanium alloy Ti175 bar, and the specific process is as follows:

[0057] Step 1: Forging

[0058] In the first firing, the furnace temperature is preheated to 700-850°C, the rods are added and the temperature is raised to 1120-1160°C along with the furnace.

[0059] In the first fire of the blank forging, the control of the parameters includes the transfer time of the bar being 0 to 60 seconds, the feed amount being 425 mm, the deformation amount being 45 to 50%, and the forging time being 0 to 180 seconds.

[0060] Specifically, during the first fire of the blank forging of the titanium alloy Ti175 bar, the bar is first put into the furnace at a temperature not exceeding 700°C, and gradually heated to 840°C with the furnace, and kept at this temperature for 120 minutes. Subsequently, the temperature is continued to be raised to the phase transition point of 1165°C with the furnace, and kept at this high temperature for 555 minutes. During the first fire of the blank forging, the transfer time is required to be no more than 60 seconds, the feed amount is 425 mm, the deformation amount is 46%, and the whole process must be completed within 180 seconds.

[0061] The specific blank forging process is: first, the bar with a diameter of 690mm and a length of 900mm is axially upset to make the diameter of the bar reach 700mm and the length of 680±5mm; then, the bar is forged in the axis to be drawn and stretched to a diameter of 585mm and a length of 995±5mm; then, the bar is axially upset again to make the diameter reach 790mm and the length reach 540±5mm; finally, the bar is forged and stretched to a diameter of 585mm and a length of 995±5mm.

[0062] In the second firing, the furnace temperature is preheated to 710-840°C, the bar forged in the first firing is added, and the temperature is raised to 1080-1120°C along with the furnace.

[0063] In the second fire of the blank forging temperature setting, the control of the parameters includes the transfer time of the bar being 0 to 50 s, the feed amount being 400 mm; the deformation amount being 40 to 45%; and the forging time being 0 to 165 s.

[0064] Specifically, during the second fire of the blank forging of the titanium alloy Ti175 bar, the bar is first put into the furnace at a temperature not exceeding 700°C, and gradually heated to 830°C with the furnace, and kept at this temperature for 120 minutes. Subsequently, the temperature is continued to be raised to the phase transition point of 1165°C with the furnace, and kept at this high temperature for 430 minutes. During the second fire of the blank forging, the transfer time is required to be no more than 50 seconds, the feed amount is 400 mm, the deformation amount is 46%, and the whole process must be completed within 165 seconds.

[0065] The specific blank forging process is: first, the bar with a diameter of 585mm and a length of 995mm is axially upset to make the diameter of the bar reach 755mm and the length of 590±5mm; then, the bar is forged in the axis to be drawn and stretched to a diameter of 490mm and a length of 1400±5mm; then, the bar is axially upset again to make the diameter reach 755mm and the length reach 590±5mm; finally, the bar is forged and stretched to a diameter of 490mm and a length of 1400±5mm.

[0066] In the third fire, the furnace temperature is preheated to 720-830° C., the bar forged in the second fire is added, and the temperature is raised to 1000-1040° C. with the furnace;

[0067] In the third fire of the blank forging temperature setting, the control of the parameters includes the transfer time of the bar being 0 to 45 s, the feed amount being 375 mm, the deformation amount being 35 to 40%, and the forging time being 0 to 150 s.

[0068] Specifically, during the third fire of the blank forging of the titanium alloy Ti175 bar, the bar is first put into the furnace at a temperature not exceeding 700°C, and gradually heated to 820°C with the furnace, and kept at this temperature for 120 minutes. Subsequently, the temperature is continued to be raised to the phase transition point of 1035°C with the furnace, and kept at this high temperature for 400 minutes. During the third fire of the blank forging, the transfer time is required to be no more than 45 seconds, the feed amount is 375 mm, the deformation amount is 36%, and the whole process must be completed within 150 seconds.

[0069] Specific blank forging process: first, the bar with a diameter of 490mm and a length of 1400mm is axially upset to make the diameter of the bar reach 610mm and the length of 900±5mm; then, the bar is forged in the axis to be drawn to a diameter of 525mm and a length of 1225±5mm; then, the bar is axially upset again to make the diameter reach 610mm and the length reach 900±5mm; finally, the bar is forged to be drawn to a diameter of 525mm and a length of 1225±5mm.

[0070] In the fourth firing, the furnace temperature is preheated to 730-820° C., the bar material forged in the third firing is added, and the temperature is raised to 960-1000° C. along with the furnace.

[0071] In the fourth fire of the blank forging temperature setting, the control of the parameters includes the transfer time of the bar being 0 to 40 s, the feed amount being 350 mm, the deformation amount being 30 to 35%, and the forging time being 0 to 135 s.

[0072] Specifically, during the fourth fire of the blank forging of the titanium alloy Ti175 bar, the bar is first put into the furnace at a temperature not exceeding 700°C, and gradually heated to 810°C with the furnace, and kept at this temperature for 120 minutes. Subsequently, the temperature is continued to be raised to the phase transition point of 995°C with the furnace, and kept at this high temperature for 575 minutes. During the fourth fire of the blank forging, the transfer time is required to be no more than 40 seconds, the feed amount is 350 mm, the deformation amount is 31%, and the entire forging process must be completed within 135 seconds.

[0073] The specific blank forging process is: first, the bar with a diameter of 525mm and a length of 1225mm is axially upset to make the diameter of the bar reach 630mm and the length of 845±5mm; then, the bar is forged in the axis to be drawn and stretched to a diameter of 550mm and a length of 1105±5mm; then, the bar is axially upset again to make the diameter reach 630mm and the length reach 845±5mm; finally, the bar is forged and stretched to a diameter of 550mm and a length of 1105±5mm.

[0074] Step 2: Forging

[0075] In the first firing, the furnace temperature is preheated to 800-850°C, and the rod is heated to 900-950°C along with the furnace.

[0076] In the first fire of the reforming forging, the transfer time of the bar is 0 to 45 seconds, the feed amount is 0 to 250 mm, the deformation amount is 40 to 45%, and the forging time is 0 to 170 seconds.

[0077] Specifically, during the first forging process of the titanium alloy Ti175 bar, the bar is firstly put into the furnace at a temperature not exceeding 700°C, and gradually heated to 840°C with the furnace, and kept at this temperature for 120 minutes. Subsequently, the temperature is continued to be raised to the phase transition point of 940°C with the furnace, and kept at this high temperature for 575 minutes. During the first forging process of the forging process, the transfer time is required to be no more than 45 seconds, the feed amount is no more than 250 mm, the deformation amount is 41%, and the entire forging process must be completed within 170 seconds.

[0078] The specific reforming and forging process is as follows: first, the bar with a diameter of 550 mm and a length of 1105 mm is axially upset to make the diameter of the bar reach 720 mm and the length of 650±5 mm; then, the bar is forged in-axis to be drawn and stretched to a diameter of 605 mm and a length of 915±5 mm; then, the bar is axially upset again to make the diameter reach 720 mm and the length reach 650±5 mm; finally, the bar is forged and stretched to a diameter of 605 mm and a length of 915±5 mm.

[0079] In the second firing, the furnace temperature is preheated to 750-800°C, the bars forged in the first firing are added and the temperature is raised to 850-900°C along with the furnace.

[0080] In the second fire of the forging temperature setting, the control parameters include the transfer time of the bar being 0 to 40 seconds, the feed amount being 0 to 230 mm, the deformation amount being 35 to 40%, and the forging time being 0 to 150 seconds.

[0081] Specifically, during the second forging process of the titanium alloy Ti175 bar, the bar is firstly put into the furnace at a temperature not exceeding 700°C, and gradually heated to 790°C with the furnace, and kept at this temperature for 120 minutes. Subsequently, the temperature is continued to be raised to the phase transition point of 890°C with the furnace, and kept at this high temperature for 575 minutes. During the second forging process, the transfer time is required to be no more than 40 seconds, the feed amount is no more than 230 mm, the deformation amount is 36%, and the whole process must be completed within 150 seconds.

[0082] The specific reforming forging process is as follows: first, the bar with a diameter of 605 mm and a length of 915 mm is axially upset to make the diameter of the bar reach 755 mm and the length of 590±5 mm; then, the bar is forged in-axis to be drawn and stretched to a diameter of 645 mm and a length of 805±5 mm; then, the bar is axially upset again to make the diameter reach 755 mm and the length reach 590±5 mm; finally, the bar is forged and stretched to a diameter of 645 mm and a length of 805±5 mm.

[0083] In the third firing, the furnace temperature is preheated to 700-750°C, the bars forged in the second firing are added and the furnace temperature is raised to 800-850°C.

[0084] In the third fire of the forging temperature setting, the control parameters include the transfer time of the bar being 0 to 35 s, the feed amount being 0 to 210 mm, the deformation amount being 30 to 35%, and the forging time being 0 to 130 s.

[0085] Specifically, during the third forging process of the titanium alloy Ti175 bar, the bar is firstly put into the furnace at a temperature not exceeding 700°C, and gradually heated to 740°C with the furnace, and kept at this temperature for 120 minutes. Subsequently, the temperature is continued to be raised to the phase transition point of 840°C with the furnace, and kept at this high temperature for 575 minutes. During the third forging process, the transfer time is required to be no more than 35 seconds, the feed amount is no more than 210 mm, the deformation amount is 31%, and the whole process must be completed within 130 seconds.

[0086] The specific reforming and forging process is as follows: first, the bar with a diameter of 645 mm and a length of 805 mm is axially upset to make the diameter of the bar reach 770 mm and the length of 560±5 mm; then, the bar is forged in-axis to be drawn and stretched to a diameter of 670 mm and a length of 740±5 mm; then, the bar is axially upset again to make the diameter reach 770 mm and the length reach 560±5 mm; finally, the bar is forged and stretched to a diameter of 670 mm and a length of 740±5 mm.

[0087] In the fourth firing, the furnace temperature is preheated to 650-700°C, the bars forged in the third firing are added and the temperature is raised to 750-800°C along with the furnace.

[0088] In the fourth fire of the forging temperature setting, the control parameters include the transfer time of the bar being 0 to 30 s, the feed amount being 0 to 200 mm, the deformation amount being 25 to 30%, and the forging time being 0 to 110 s.

[0089] Specifically, during the fourth forging process of the titanium alloy Ti175 bar, the bar is firstly put into the furnace at a temperature not exceeding 700°C, and gradually heated to 690°C with the furnace, and kept at this temperature for 120 minutes. Subsequently, the temperature is continued to be raised to the phase transition point of 790°C with the furnace, and kept at this high temperature for 575 minutes. During the fourth forging process, the transfer time is required to be no more than 30 seconds, the feed amount is no more than 200 mm, the deformation amount is 26%, and the whole process must be completed within 110 seconds.

[0090] The specific reforming and forging process is as follows: first, the bar with a diameter of 670 mm and a length of 740 mm is axially upset to make the diameter of the bar reach 780 mm and the length 550±5 mm; then, the bar is forged in-axis to be drawn and stretched to a diameter of 650 mm and a length of 720±5 mm; then, the bar is axially upset again to make the diameter reach 780 mm and the length 550±5 mm; finally, the bar is forged and stretched to a diameter of 650 mm and a length of 720±5 mm.

[0091] Step 3: Forming and Forging

[0092] In the first firing, the furnace temperature is preheated to 750-800°C, the rods are added and the temperature is raised to 800-850°C along with the furnace.

[0093] In the first firing time of the forming forging temperature setting, the control parameters include the pressing speed of 25-30 mm / s, the pressing amount of 60-70 mm, the deformation amount of 25-30%, and the hammer gap time of 3-4 s.

[0094] Specifically, during the first forging process of the titanium alloy Ti175 bar, the bar is first put into the furnace at a temperature not exceeding 600°C, and gradually heated to 790°C with the furnace, and kept at this temperature for 120 minutes. Subsequently, the temperature is continued to be raised to the phase transition point of 840°C with the furnace, and kept at this high temperature for 575 minutes. In the specific process step of forging the titanium alloy Ti175 bar for the first time, the pressing speed is 25-30 mm / s to ensure uniform deformation of the material; the pressing amount is 60-70 mm, the deformation amount is 29%, and the hammering interval time is 3s-4s, allowing the bar to have enough time for stress release and temperature adjustment between each hammering.

[0095] The specific forming and forging process includes: first, forging the rod with a diameter of 650 mm and a length of 720 mm to make the diameter of the rod reach 600 mm and the length reach 935±5 mm; then, the rod is forged in the shaft to make the diameter reach 530 mm and the length reach 1200±5 mm.

[0096] In the second firing, the furnace temperature is preheated to 700-750° C., the bar forged in the first firing is added, and the temperature is raised to 750-800° C. with the furnace;

[0097] In the second fire of the forming forging temperature setting, the parameter control includes the pressing speed of 20-25 mm / s, the pressing amount of 50-60 mm, the deformation of 20-25%; the hammer gap time is 3-4 s;

[0098] Specifically, during the second forging process of the titanium alloy Ti175 bar, the bar is first put into the furnace at a temperature not exceeding 600°C, and gradually heated to 740°C with the furnace, and kept at this temperature for 120 minutes. Subsequently, the temperature is continued to be raised to the phase transition point of 790°C with the furnace, and kept at this high temperature for 200 minutes. In the specific process step of forging the titanium alloy Ti175 bar for the second time, the pressing speed is 20-25mm / s to ensure uniform deformation of the material; the pressing amount is 50-60mm, the deformation amount is 24%, and the hammering interval time is 3s-4s, allowing the bar to have enough time for stress release and temperature adjustment between each hammering.

[0099] The specific forming and forging process includes: first, forging the rod with a diameter of 530 mm and a length of 1200 mm to make the diameter of the rod reach 480 mm and the length of 1730±5 mm; then, the rod is forged in the shaft to be drawn to a diameter of 440 mm and a length of 1730±5 mm.

[0100] In the third firing, the furnace temperature is preheated to 650-700° C., the bar forged in the second firing is added and the temperature is raised to 700-750° C. with the furnace;

[0101] In the third fire of the forming forging temperature setting, the control parameters include the pressing speed of 15-20 mm / s, the pressing amount of 40-50 mm, the deformation amount of 15-20%, and the hammer gap time of 1-2 s.

[0102] Specifically, during the third forging process of the titanium alloy Ti175 bar, the bar is first put into the furnace at a temperature not exceeding 600°C, and gradually heated to 690°C with the furnace, and kept at this temperature for 120 minutes. Subsequently, the temperature is continued to be raised to the phase transition point of 745°C with the furnace, and kept at this high temperature for 575 minutes. In the specific process step of forging the titanium alloy Ti175 bar for the third time, the pressing speed is 15-20 mm / s to ensure uniform deformation of the material; the pressing amount is 40-50 mm, the deformation amount is 20%, and the hammering interval time is 1s-2s, allowing the bar to have enough time for stress release and temperature adjustment between each hammering.

[0103] The specific forming and forging process includes: first, forging the rod with a diameter of 440 mm and a length of 1730 mm to make the diameter of the rod reach 400 mm and the length of 2080±5 mm; then, forging and drawing the rod to a diameter of 365 mm and a length of 2500±5 mm.

[0104] In the fourth firing, the furnace temperature is preheated to 600-650°C, the bars forged in the third firing are added to the forming forging and the temperature is raised to 650-700°C along with the furnace.

[0105] In the fourth fire of the forming forging temperature setting, the control parameters include the pressing speed of 10-15 mm / s, the pressing amount of 30-40 mm, the deformation amount of 10-15%, and the hammer gap time of 1-2 s.

[0106] Specifically, during the fourth forging process of the titanium alloy Ti175 bar, the bar is first put into the furnace at a temperature not exceeding 600°C, and gradually heated to 640°C with the furnace, and kept at this temperature for 120 minutes. Subsequently, the temperature is continued to be raised to the phase transition point of 690°C with the furnace, and kept at this high temperature for 575 minutes. In the specific process step of forging the titanium alloy Ti175 bar for the fourth time, the pressing speed is 10-15mm / s to ensure uniform deformation of the material; the pressing amount is 30-40mm, the deformation amount is 15%, and the hammering interval time is 1s-2s, allowing the bar to have enough time for stress release and temperature adjustment between each hammering.

[0107] The specific forming and forging process includes: first, forging the rod with a diameter of 440 mm and a length of 1730 mm, so that the diameter of the rod reaches 365 mm and the length is 2500±5 mm; then, forging and drawing the rod to a diameter of 365 mm and a length of 3010±5 mm; thereafter, dividing the rod into two pieces, each with a diameter of 330 mm and a length of 1500±5 mm; finally, using a special hammer to axially draw each piece of the rod, so that the diameter of the rod is 272-282 mm and the length is 2740-2760 mm.

[0108] In this embodiment, the staged cooling method includes natural cooling after the blank forging is completed, forced ventilation cooling after the reforming forging is completed, and liquid cooling after the forming forging is completed.

[0109] In this embodiment, the heat treatment includes primary annealing and secondary annealing, and is performed according to industry standards.

[0110] The primary annealing comprises placing the rod into a furnace at 0-800° C., heating the rod to 867-877° C. with the furnace, and keeping the rod within the range of 867-877° C. for 108-132 minutes. After the keeping time is completed, the rod is taken out of the furnace and cooled in the air.

[0111] The secondary annealing includes placing the rod into a furnace at 0-500°C, heating the rod to 530-550°C with the furnace, and keeping the rod within the range of 530-550°C for 345-375 minutes. After the keeping time is completed, the rod is taken out of the furnace and cooled in the air.

[0112] In the four firings of the forming forging, if forging once ensures that the final performance of the bar reaches the expected standard, only one annealing process may be performed during the heat treatment process.

[0113] In this embodiment, the forming method further includes physical and chemical testing, mechanical processing, and corrosion and flaw detection. The physical and chemical testing is used to evaluate the chemical and physical properties of the rod; the mechanical processing is used to accurately determine the size and surface finish of the rod; and the corrosion and flaw detection is used to evaluate the corrosion resistance and integrity of the rod in a specific environment.

[0114] The physical and chemical tests include chemical composition analysis, mechanical property test, and high-magnification and low-magnification structure inspection. A sample with a diameter of 130 mm and a height of 150 mm is selected from below the end of the rod in each furnace batch for physical and chemical testing.

[0115] The machining includes turning, grinding or other cutting operations on the outer cylindrical surface and two end faces of the bar material, so that the roughness of the outer cylindrical surface and two end faces of the bar material reaches Ra3.2.

[0116] The corrosion test is performed by performing two low-power inspections on the rod according to the standard, and the flaw detection test is performed by performing ultrasonic flaw detection acceptance on the rod according to the standard.

[0117] The following are four finished products forged according to the forming method, and the test results at room temperature are shown in Table 1.

[0118] Table 1

[0119]

[0120] The standards under normal temperature conditions are: tensile strength (Rm) ≥ 1050Mpa, yield strength (Rp0.2) ≥ 900MPa, elongation (A) ≥ 10%, cross-sectional shrinkage (Z) ≥ 20%, fracture toughness (KIC) ≥ 24MPa√m.

[0121] The following are two finished products forged according to the forming method, and the test results under high temperature conditions of 550°C are listed as shown in Table 2.

[0122] Table 2

[0123]

[0124] The standards under high temperature conditions of 550℃ are: tensile strength (Rm) ≥ 750Mpa, yield strength (Rp0.2) ≥ 580MPa, elongation (A) ≥ 12%, and section shrinkage (Z) ≥ 20%.

[0125] It can be seen from Tables 1 and 2 that the titanium alloy Ti175 rod forged according to the forming method has various indicators that are better than the standard requirements at room temperature and high temperature, that is, the forming method can effectively improve the performance of the rod, making it suitable for occasions with high requirements on strength, plasticity and toughness.

[0126] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A forming method for forging a titanium alloy Ti175 bar, characterized in that: The steps include: Forging temperature setting, including setting the temperature of blank forging, temperature of reforming forging and temperature of forming forging. The three types of temperature settings include four firing times, and each firing time includes the temperature setting of preheating and bar heating with furnace; Forging parameter control, including control of parameters of the bar in the four firing processes of blanking forging, reforming forging and forming forging, the parameters of the blanking forging and reforming forging both include transfer time, feed amount, deformation amount and forging time, and the parameters of the forming forging include pressing speed, pressing amount, deformation amount and hammering interval time; Post-forging cooling, including cooling the bar in stages during forging; Heat treatment is used to improve the mechanical and physical properties of the rod.

2. The molding method according to claim 1, characterized in that: Setting the temperature of the blank forging includes: In the first firing, the furnace temperature is preheated to 700-850°C, the rod is added and the temperature is raised to 1120-1160°C along with the furnace; In the second firing, the furnace temperature is preheated to 710-840°C, the bars forged in the first firing are added and the temperature is raised to 1080-1120°C along with the furnace; In the third firing, the furnace temperature is preheated to 720-830°C, the rod forged in the second firing is added and the temperature is raised to 1000-1040°C along with the furnace; In the fourth firing, the furnace temperature is preheated to 730-820°C, the rods forged in the third firing are added and the furnace temperature is raised to 960-1000°C.

3. The molding method according to claim 1, characterized in that: Setting the temperature of the reforming forging includes: In the first firing, the furnace temperature is preheated to 800-850°C, the rods are added and the temperature is raised to 900-950°C along with the furnace; In the second firing, the furnace temperature is preheated to 750-800°C, the bars forged in the first firing are added and the temperature is raised to 850-900°C along with the furnace temperature; In the third firing, the furnace temperature is preheated to 700-750°C, the bars forged in the second firing are added and the temperature is raised to 800-850°C along with the furnace temperature; In the fourth firing, the furnace temperature is preheated to 650-700°C, the rods forged in the third firing are added and the furnace temperature is raised to 750-800°C.

4. The molding method according to claim 1, characterized in that: Setting the temperature of the forming forging includes: In the first firing, the furnace temperature is preheated to 750-800°C, the rod is added and the temperature is raised to 800-850°C along with the furnace; In the second firing, the furnace temperature is preheated to 700-750°C, the bars forged in the first firing are added and the temperature is raised to 750-800°C along with the furnace temperature; In the third firing, the furnace temperature is preheated to 650-700°C, the rod forged in the second firing is added and the temperature is raised to 700-750°C along with the furnace; In the fourth firing, the furnace temperature is preheated to 600-650°C, the rods forged in the third firing are added and the furnace temperature is raised to 650-700°C.

5. The molding method according to claim 2, characterized in that: During the blank forging process, the control of the parameters includes: In the first fire of the blanking forging temperature setting, the transfer time of the bar is 0 to 60 seconds, the feed amount is 425 mm, the deformation amount is 45 to 50%, and the forging time is 0 to 180 seconds; In the second fire of the blanking forging temperature setting, the transfer time of the bar is 0 to 50 seconds, the feed amount is 400 mm, the deformation amount is 40 to 45%, and the forging time is 0 to 165 seconds; In the third fire of the blanking forging temperature setting, the transfer time of the bar is 0 to 45 seconds, the feed amount is 375 mm, the deformation amount is 35 to 40%, and the forging time is 0 to 150 seconds; In the fourth fire with the blank forging temperature set, the transfer time of the bar is 0 to 40 seconds, the feed amount is 350 mm, the deformation amount is 30 to 35%, and the forging time is 0 to 135 seconds.

6. The molding method according to claim 3, characterized in that: During the forging process, the control of the parameters includes: In the first fire of the forging temperature setting, the transfer time of the bar is 0 to 45 seconds, the feed amount is 0 to 250 mm, the deformation amount is 40 to 45%, and the forging time is 0 to 170 seconds; In the second fire of the forging temperature setting, the transfer time of the bar is 0 to 40 seconds, the feed amount is 0 to 230 mm, the deformation amount is 35 to 40%, and the forging time is 0 to 150 seconds; In the third fire of the forging temperature setting, the transfer time of the bar is 0 to 35 seconds, the feed amount is 0 to 210 mm, the deformation amount is 30 to 35%, and the forging time is 0 to 130 seconds; In the fourth fire of the forging temperature setting, the transfer time of the bar is 0 to 30 seconds, the feed amount is 0 to 200 mm, the deformation amount is 25 to 30%, and the forging time is 0 to 110 seconds.

7. The molding method according to claim 4, characterized in that: During the forming forging process, the control of the parameters includes: In the first fire of the forming forging temperature setting, the pressing speed is 25-30 mm / s, the pressing amount a is 60-70 mm, the deformation amount is 25-30%, and the hammering gap time is 3-4 s; In the second fire of the forming forging temperature setting, the pressing speed is 20-25 mm / s, the pressing amount a is 50-60 mm, the deformation amount is 20-25%, and the hammering gap time is 3-4 s; In the third fire of the forming forging temperature setting, the pressing speed is 15-20 mm / s, the pressing amount a is 40-50 mm, the deformation amount is 15-20%, and the hammering gap time is 1-2 s; In the fourth fire with the forming forging temperature set, the pressing speed is 10-15 mm / s, the pressing amount a is 30-40 mm, the deformation amount is 10-15%, and the hammer gap time is 1-2 s.

8. The molding method according to claim 1, characterized in that: The staged cooling method includes a natural cooling method after the blank forging is completed, a forced ventilation cooling method after the reforming forging is completed, and a liquid cooling method after the forming forging is completed.

9. The molding method according to claim 1, characterized in that: The heat treatment includes primary annealing and secondary annealing; The primary annealing comprises placing the rod into a furnace at 0-800°C, heating the rod to 867-877°C with the furnace, and keeping the rod within the range of 867-877°C for 108-132 minutes, taking the rod out of the furnace after the end of the keeping and cooling it in the air; The secondary annealing includes placing the rod into a furnace at 0-500°C, heating the rod to 530-550°C with the furnace, and keeping the rod within the range of 530-550°C for 345-375 minutes. After the keeping time is completed, the rod is taken out of the furnace and cooled in the air.

10. The molding method according to claim 1, characterized in that: It also includes physical and chemical testing, mechanical processing, and corrosion and flaw detection; the physical and chemical testing is used to evaluate the chemical and physical properties of the rod; the mechanical processing is used to accurately determine the size and surface finish of the rod; the corrosion and flaw detection is used to evaluate the corrosion resistance and integrity of the rod in a specific environment.

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