Low-energy-consumption treatment method for synchronously improving obdurability of titanium alloy

Abstract

The invention relates to a low-energy-consumption treatment method for synchronously improving the obdurability of titanium alloy. The treatment method comprises the following steps: S1, blanking; s2, heating the material before forging; s3, forging is carried out; s4, upsetting and punching are carried out; s5, trestle chambering is conducted; step S6, ring rolling; and S7, annealing, heating the forge piece to 600-800 DEG C, preserving heat, and then cooling. The method has the advantages that deformation is performed firstly, then phase change is performed, a beta phase in the titanium alloy is subjected to martensite phase change through deformation, then annealing is performed, recovery and recrystallization are performed, a fine martensite phase is obtained, work hardening can be eliminated, the structure can be stabilized, and the strength and toughness of the titanium alloy can be greatly and synchronously improved; stress accumulated by previous deformation is eliminated through annealing, and the long-term stability and reliability of the material are improved.

Description

Technical Field

[0001] The invention relates to the field of titanium alloy manufacturing, and in particular to a processing method for simultaneously improving the strength and toughness of titanium alloy with low energy consumption. Background Art

[0002] People have developed a large number of applications for titanium alloys in various fields. The global titanium alloy industry market size has shown a steady growth trend in recent years. Due to its good mechanical properties, titanium alloys are widely used in aerospace, chemical and marine engineering, energy, chemical and automotive fields. Titanium alloys currently have a wide range of application backgrounds and development prospects.

[0003] With the development of industry, the requirements for titanium alloys are becoming more and more stringent. At present, the mainstream heat treatment methods for titanium alloys are solid solution and aging treatment. During the repeated heating and rapid cooling of the alloy, residual stress will be generated inside the alloy. These residual stresses will become the starting point for crack initiation and promote crack expansion, thereby reducing the toughness of the alloy. In addition, multiple solid solution and aging treatments also waste too much energy.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention discloses a processing method for simultaneously improving the strength and toughness of titanium alloy with low energy consumption.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for simultaneously improving the strength and toughness of titanium alloy with low energy consumption comprises the following steps:

[0008] Step S1, blanking;

[0009] Step S2, heating the material before forging;

[0010] Step S3, reforging;

[0011] Step S4, upsetting and punching;

[0012] Step S5, expanding the holes of the horse frame;

[0013] Step S6, ring rolling;

[0014] Step S7, annealing, the forging is heated to 600-800°C and kept warm, and then cooled.

[0015] Further, in step S2, the material is heated to 45°C below the β transformation point of the titanium alloy and kept warm.

[0016] Furthermore, in step S2, the heating time, material and material length are determined, the heating time of cold material is 0.8 min / mm, and the heating time of hot material is 0.5 min / mm.

[0017] Furthermore, in step S3, the cumulative deformation amount of the reforging is ≥ 60%.

[0018] Furthermore, in step S4, the accumulated deformation is 20-40%.

[0019] Furthermore, in step S5, the accumulated deformation is 20-50%.

[0020] Further, in step S6, the accumulated deformation is ≤20%.

[0021] Furthermore, in step S7, the forgings are charged into the furnace at a temperature of ≤750°C.

[0022] Furthermore, in step S7, the forging is kept warm for 0.5 to 5 hours.

[0023] Furthermore, in step S7, the forging is air-cooled after being taken out of the furnace, and the cooling rate is ≥55°C / min.

[0024] The beneficial effects of the present invention are as follows:

[0025] 1. Titanium alloy is deformed first and then transformed. The β phase in the titanium alloy undergoes martensitic transformation through deformation, and then annealing is performed to cause recovery and recrystallization to obtain a fine martensitic phase, which helps to eliminate work hardening and stabilize the organization. The strength and toughness of the titanium alloy can be greatly improved simultaneously. Annealing eliminates the stress accumulated by the previous deformation and improves the long-term stability and reliability of the material.

[0026] 2. Annealing treatment can heat the titanium alloy to above the recrystallization temperature. At this time, the grains inside the titanium alloy will undergo a recrystallization process to form new, fine equiaxed grains. The recrystallization process can eliminate the work hardening phenomenon, restore and improve the plasticity of the titanium alloy. At the same time, fine equiaxed grains also help to improve the strength and toughness of the titanium alloy.

[0027] 3. Annealing is carried out directly after deformation. Compared with traditional solution and aging treatment, it does not require more steps and more complicated control. The annealing parameter control is simpler. It also means that there is no need to use too much energy for heating, reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the steps of the treatment method for simultaneously improving the strength and toughness of titanium alloy with low energy consumption.

[0029] Figure 2 This is a sampling schematic diagram of Example 1.

[0030] Figure 3 This is a metallographic diagram of Example 1.

[0031] Figure 4 This is a metallographic diagram of Example 1.

[0032] Figure 5 This is a sampling schematic diagram of Example 2.

[0033] Figure 6 This is a metallographic diagram of Example 2.

[0034] Figure 7 This is a metallographic diagram of Example 2.

[0035] Figure 8 This is a sampling schematic diagram of Comparative Example 1.

[0036] Fig. 9 This is a metallographic diagram of Comparative Example 1.

[0037] Fig.10 This is a metallographic diagram of Comparative Example 1.

[0038] Fig.11 This is a sampling schematic diagram of Comparative Example 2.

[0039] Fig.12 This is a metallographic diagram of Comparative Example 2.

[0040] Fig.13 This is a metallographic diagram of Comparative Example 2. DETAILED DESCRIPTION

[0041] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0042] In order to make the purpose, technical solution and advantages of the present invention more clear, the solution proposed by the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. According to the following description, the advantages and features of the present invention will be more clear.

[0043] Embodiment 1:

[0044] A method for simultaneously improving the strength and toughness of titanium alloy with low energy consumption comprises the following steps:

[0045] Step S1, cutting, select titanium alloy material, cut and cut by sawing machine, its chemical composition is as follows

[0046] As shown in Table 1:

[0047]

[0048] Table 1

[0049] Step S2, heating the material before forging, the cut rods are placed in a resistance box heating furnace, the cold material holding time is calculated as 0.8min / mm, and the hot material is calculated as 0.5min / mm during heating, and the furnace is loaded when the temperature reaches the temperature, the rods are kept at 45°C below the β phase transformation point of the titanium alloy, and the holding time is 370min.

[0050] Step S3, reforging, ensuring that the cumulative deformation of reforging is ≥ 60%.

[0051] Step S4, upsetting and punching, ensuring the punching quality without cracks, folds, and deformation of 20% to 40%.

[0052] Step S5, the frame is expanded, and the flat section ensures that the end surface is flat, and the deformation amount is 20% to 50%.

[0053] Step S6, ring rolling, controlling the final forging temperature and deformation amount ≤ 20%.

[0054] Step S7, annealing, resistance box heating furnace, material is loaded into the furnace at ≤750℃, heated to 600℃ according to power, kept warm for 0.5h, and air-cooled after being taken out of the furnace, ensuring the cooling rate is ≥55℃ / min.

[0055] Embodiment 2:

[0056] A method for simultaneously improving the strength and toughness of titanium alloy with low energy consumption comprises the following steps:

[0057] Step S1, cutting, select titanium alloy material, cut and cut by sawing machine, its chemical composition is as follows

[0058] As shown in Table 2:

[0059]

[0060] Table 2

[0061] Step S2, heating the material before forging, the cut rods are placed in a resistance box heating furnace, the cold material holding time is calculated as 0.8min / mm, and the hot material is calculated as 0.5min / mm during heating, and the furnace is loaded when the temperature reaches the temperature, the rods are kept at 45°C below the β phase transformation point of the titanium alloy, and the holding time is 370min.

[0062] Step S3, reforging, ensuring that the cumulative deformation of reforging is ≥ 60%.

[0063] Step S4, upsetting and punching, ensuring the punching quality without cracks, folds, and deformation of 20% to 40%.

[0064] Step S5, the frame is expanded, and the flat section ensures that the end surface is flat, and the deformation amount is 20% to 50%.

[0065] Step S6, ring rolling, controlling the final forging temperature and deformation amount ≤ 20%.

[0066] Step S7, annealing, resistance box heating furnace, material is loaded into the furnace at ≤750℃, heated to 800℃ according to power, kept warm for 5h, and air-cooled after being taken out of the furnace, ensuring the cooling rate is ≥55℃ / min.

[0067] Comparative Example 1:

[0068] The same bar material as in Example 1 is used, and the same deformation process is completed, and solid solution and aging treatment are performed:

[0069] Solution treatment: the rods are placed in a resistance box heating furnace, heated to 910℃ and kept at this temperature for 1 hour, then taken out of the furnace and cooled by air.

[0070] Aging: After the solid solution is completed, the rod is heated to 550℃ according to the power and kept warm for 2 hours, and then air-cooled out of the furnace.

[0071] Comparative Example 2:

[0072] The same bar material as in Example 2 is used, and the same deformation process is completed, followed by solution treatment and aging treatment:

[0073] Solution treatment: the rods are placed in a resistance box heating furnace, heated to 910℃ and kept at this temperature for 1 hour, then taken out of the furnace and cooled by air.

[0074] Aging: After the solid solution is completed, the rod is heated to 550℃ according to the power and kept warm for 2 hours, and then air-cooled out of the furnace.

[0075] Comprehensive mechanical properties testing of forgings:

[0076] Example 1 and Comparative Example 1 are used as control groups, and their comprehensive mechanical properties tests are shown in Table 3.

[0077] Experimental Group <![CDATA[R m / MPa]]> <![CDATA[R 0.2 / MPa]]> A / ％ Z / ％ <![CDATA[α k / J.cm -2 ]]> Comparative Example 1 663.58 557.79 19.44 48.65 92.5 Example 1 784.52 672.34 24.31 65.84 110.6

[0078] Table 3

[0079] Example 2 and Comparative Example 2 are used as control groups, and their comprehensive mechanical properties tests are shown in Table 4.

[0080] Heat treatment system <![CDATA[R m / MPa]]> <![CDATA[R 0.2 / MPa]]> A / ％ Z / ％ <![CDATA[α k / J.cm -2 ]]> Comparative Example 2 663.58 557.79 19.44 48.65 92.5 Example 2 768.77 657.95 20.72 57.83 119.9

[0081] Table 4

[0082] Mechanical testing data analysis:

[0083] Compared with direct annealing in this application, the tensile strength and yield strength of the rods after fixing and aging treatment are slightly improved, the cross-sectional shrinkage rate A / % is similar, and the elongation Z / % is improved, which is evidence from the side that the titanium alloy rods have better toughness.

[0084] Metallographic testing:

[0085] Example 1: Sampling size Figure 2 As shown, the magnification ratio is 50μm. Two different locations on the sample were randomly selected for testing. The metallographic structure is as follows Figure 3 and Figure 4 As shown, the microstructure is fine and uniform, without coarse crystals and miscellaneous crystals.

[0086] Example 2: Sampling size Figure 5 As shown, the magnification ratio is 50μm. Two different locations on the sample were randomly selected for testing. The metallographic structure is as follows Figure 6 and Figure 7 As shown, the microstructure is fine and uniform, without coarse crystals and miscellaneous crystals.

[0087] Comparative Example 1: Sampling size is as follows Figure 8 As shown, the magnification ratio is 50μm. Two different locations on the sample were randomly selected for testing. The metallographic structure is as follows Fig. 9 and Fig.10 As shown, the microscopic crystal structure is coarser than that of Example 1.

[0088] Comparative Example 2: Sampling size Fig.11 As shown, the magnification ratio is 50μm. Two different locations on the sample were randomly selected for testing. The metallographic structure is as follows Fig.12 and Fig.13 As shown, the microscopic crystal structure is coarser than that of Example 2.

[0089] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for simultaneously improving the strength and toughness of titanium alloy with low energy consumption, characterized in that: The following steps are involved: Step S1, blanking; Step S2, heating the material before forging; Step S3, reforging; Step S4, upsetting and punching; Step S5, expanding the hole of the horse frame; Step S6, ring rolling; Step S7, annealing, the forging is heated to 600-800°C and kept warm, and then cooled.

2. The low-energy consumption and simultaneous improvement of the toughness of titanium alloy according to claim 1 is characterized in that: In step S2, the material is heated to 45°C below the β transformation point of the titanium alloy and kept warm.

3. The low-energy consumption and simultaneous improvement of the toughness of titanium alloy according to claim 2 is characterized in that: In step S2, the heating time, material and material length are determined, the heating time of cold material is 0.8 min / mm, and the heating time of hot material is 0.5 min / mm.

4. The low-energy consumption and simultaneous improvement of the toughness of titanium alloy according to claim 1 is characterized in that: In step S3, the cumulative deformation amount of the reforging is ≥ 60%.

5. The low-energy consumption and simultaneous improvement of the toughness of titanium alloy according to claim 1 is characterized in that: In step S4, the deformation amount is accumulated to 20 to 40%.

6. The low-energy consumption and simultaneous improvement of the toughness of titanium alloy according to claim 1 is characterized in that: In step S5, the deformation amount is accumulated to 20 to 50%.

7. The low-energy consumption and simultaneous improvement of the toughness of titanium alloy according to claim 1 is characterized in that: In step S6, the accumulated deformation amount is ≤ 20%.

8. The low-energy consumption and simultaneous improvement of the toughness of titanium alloy according to claim 1 is characterized in that: In step S7, the forgings are charged into a furnace at a temperature of ≤750°C.

9. The low-energy consumption and simultaneous improvement of the strength and toughness of titanium alloy according to claim 8 is characterized in that: In step S7, the forging is kept at temperature for 0.5 to 5 hours.

10. The method for simultaneously improving the strength and toughness of titanium alloy with low energy consumption according to claim 1, characterized in that: In step S7, the forging is air-cooled after being taken out of the furnace, and the cooling rate is ≥55°C / min.

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