A method for preparing TC25 / TC25G titanium alloy cake with high flaw detection level

Abstract

The present invention belongs to the field of titanium alloy hot processing, specifically a method for preparing TC25 / TC25G titanium alloy cake with high flaw detection level. It includes: step one: blanking, detecting phase change temperature; step two: isothermal constrained upsetting: isothermal constrained upsetting of TC25 / TC25G titanium alloy rod, water cooling after forging, to obtain the first cake blank. Step three: β solid solution heat treatment: β solid solution heat treatment of the first forging blank in step two, water cooling after heat treatment, to obtain the second forging blank; step four: reforging: reforge the above-mentioned second forging blank m times, perform upsetting deformation once per fire, water cooling after forging, to obtain the third forging blank, wherein m is a positive integer; step five: reforge the above-mentioned third forging blank n times, perform upsetting deformation once per fire, air cooling after forging, to obtain the fourth forging blank, wherein n is a positive integer; step six: rounding, cake collection, to obtain the target cake blank. TC25 / TC25G titanium alloy cakes with uniform structure and high flaw detection level can be produced.

Description

Technical Field

[0001] The invention belongs to the field of titanium alloy hot processing, and in particular relates to a method for preparing a TC25 / TC25G titanium alloy cake material with a high flaw detection level. Background Art

[0002] Titanium alloys are mainly plastically deformed by hot deformation, but their hot working window is narrow and their deformation resistance is large. They are prone to cracking and wrinkling during hot deformation, making them one of the most difficult alloys to forge. The hot deformation process and forming method of titanium alloys have an important influence on their microstructure and mechanical properties. Therefore, during the hot deformation process, titanium alloys should choose reasonable forming methods, hot deformation parameters and heat treatment systems to achieve the expected microstructure and mechanical properties. TC25 / TC25G titanium alloys are heat-resistant titanium alloys, mainly used in engine disc forgings. The alloy contains 1% W. W is a high melting point metal and is easy to eutectoid with titanium. It is a β-stable element of titanium. β spots are formed during smelting and hot working, resulting in uneven organization. Titanium alloy compressor disc forgings are generally produced by die forging with cake blanks. Therefore, the microstructure and flaw detection uniformity of cake materials have a decisive influence on the organization, performance and flaw detection results of disc forgings. Summary of the invention

[0003] The technical problem to be solved by the present invention is: in view of the shortcomings of the above-mentioned prior art, a method for preparing TC25 / TC25G titanium alloy cakes with high flaw detection level is proposed. The method is reasonable and feasible, and can effectively reduce the number of cake reforging fires, improve the production efficiency and economic benefits of forgings, and the method can prepare TC25 / TC25G titanium alloy cakes with uniform structure and high flaw detection level.

[0004] The technical solution of the present invention is:

[0005] A method for preparing TC25 / TC25G titanium alloy cake with high flaw detection level, comprising:

[0006] Step 1: Unloading and testing phase change temperature;

[0007] Step 2: Isothermal constrained upsetting: The TC25 / TC25G titanium alloy bar is subjected to isothermal constrained upsetting, and water-cooled after forging to obtain the first cake blank.

[0008] Step 3: β solution heat treatment: performing β solution heat treatment on the first forging blank in step 2, and water cooling after heat treatment to obtain a second forging blank;

[0009] Step 4: reforging: reforging the second forging blank m times, performing upsetting deformation once in each time, and water cooling after forging to obtain a third forging blank, wherein m is a positive integer;

[0010] Step 5: reforging the third forging blank for n times, performing upsetting deformation once in each time, and air cooling after forging to obtain a fourth forging blank, wherein n is a positive integer;

[0011] Step 6: Roll into a round shape and fold the dough to obtain the target dough.

[0012] Furthermore, step one specifically includes:

[0013] The phase transition temperature was measured by quenching metallographic method.

[0014] Furthermore, in step 2 to step 4, the temperature difference of the heating furnace used is ±5°C.

[0015] Furthermore, step 2 is forged using a hydraulic press, and steps 4 to 6 are performed on a 2500t or 16MN fast forging machine.

[0016] Further, step 2 specifically includes: the forging temperature ranges from 10-25°C at the β phase transformation temperature, the holding time coefficient ranges from 0.7-1.2 min / mm, the isothermal forging deformation rate ranges from 0.5 mm / s-5 mm / s, the deformation amount is 35%-70%, and the mold heating temperature is 700-850°C.

[0017] Furthermore, in the β solution heat treatment in step 3, the specific heating system is: (Tβ-40~60)℃ / 0.5min / mm to (Tβ+5~10)℃ / 0.2~0.4min / mm.

[0018] Furthermore, the second forging blank is heated during forging at a temperature of (Tβ-10 to 30)°C and is water-cooled after forging.

[0019] Furthermore, the third forging blank is heated to a forging temperature of (Tβ-45~70)°C and air-cooled after forging.

[0020] Furthermore, m is 4-6, n is 2, and in all forging processes, the final forging temperature is not less than 850°C.

[0021] The beneficial effects of the present invention are:

[0022] The present invention effectively reduces the number of times a TC25 / TC25G titanium alloy cake is forged, is simple and easy to operate, effectively improves production efficiency and economic benefits, provides cake blanks for subsequent die forging production of the alloy disc forgings, and improves the uniformity of forging structure and the level of flaw detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of isothermal constrained upsetting of titanium alloy bars.

[0024] Among them, 1. upper mold; 2. blank; 3. fetal membrane; 4. lower mold DETAILED DESCRIPTION

[0025] Provided is a method for preparing TC25 / TC25G titanium alloy cake with high flaw detection level, comprising:

[0026] Step 1: Unloading and testing phase change temperature:

[0027] Step 2: Isothermal constrained upsetting: The TC25 / TC25G titanium alloy bar is subjected to isothermal constrained upsetting, and water-cooled after forging to obtain the first cake blank.

[0028] Step three: β solution heat treatment: In step two, the first forging blank is subjected to β solution heat treatment, and then water-cooled to obtain the second forging blank; W element is a strong eutectoid element of β phase in titanium alloy, and β element is easily enriched and forms intermetallic compounds with Ti, dissolving in the β phase region, and β stabilizing elements in titanium alloy diffuse and static recrystallization process occurs, thereby reducing the risk of "β spot" formation.

[0029] Step 4: Reforging: reforge the third forging blank m times, perform upsetting deformation once in each time, water cool after forging, and obtain the third forging blank, wherein m is a positive integer; adopt near-β forging, the forging heating temperature is relatively high, the diffusion of β-stabilizing elements in the titanium alloy (especially W element) is accelerated, the formation of "β spots" is effectively reduced, and the hot forming performance of the forging blank is better. Water cooling after forging stores a large amount of recrystallization activation energy for the next forging step.

[0030] Step 5: reforging the third forging blank for n times, performing upsetting deformation once in each time, and air cooling after forging to obtain a fourth forging blank, wherein n is a positive integer;

[0031] Step 6: Roll into a round shape and fold the dough to obtain the target dough.

[0032] Further: the phase transition temperature of the TC25 / TC25G titanium alloy in the forging process is measured by quenching metallography, the temperature difference of the heating furnace used is ±5°C, the first step is forged by a hydraulic press, and the rest of the forging is carried out on a 2500t or 16MN fast forging machine;

[0033] Further: the forging parameters of the isothermal constrained upsetting include: the forging temperature range is 10-25°C at the β phase transformation temperature, the holding time coefficient range is 0.7-1.2min / mm, the isothermal forging deformation rate range is 0.5mm / s-5mm / s, the deformation amount is 35%-70%, and the mold heating temperature is 700-850°C.

[0034] Further: the step 2 is β solution heat treatment, the heating system is: (Tβ-40~60)℃ / 0.5min / mm to (Tβ+5~10)℃ / 0.2~0.4min / mm.

[0035] Further: in the step 3, the heating temperature of the third forging blank is (Tβ-10~30)℃, and water cooling is performed after forging. The heating temperature of the fourth forging blank is (Tβ-45~70)℃, and air cooling is performed after forging.

[0036] Further: said m is 4-6, and n is 2.

[0037] Furthermore: during the forging process, the final forging temperature is not less than 850°C.

[0038] Embodiment 1:

[0039] The embodiment of the present invention discloses a method for preparing a TC25 titanium alloy cake with a high flaw detection level, which mainly includes the following steps:

[0040] Step 1: Use quenching metallographic method to measure the phase transition temperature Tβ of TC25 titanium alloy. Machined chamfer R5.

[0041] Step 2: Isothermal constrained upsetting: heating temperature (Tβ-15)℃ / 180min, put the rod into Figure 1 Isothermal constrained upsetting is performed in the fetal membrane, the deformation rate range is 1 mm / s, and the mold heating temperature is 800°C.

[0042] Forging steps: Water cooling after forging.

[0043] Step 3: β solution heat treatment: Step 2 The first forging blank is subjected to β solution heat treatment, and the heat treatment system is: (Tβ-40)℃ / 150min to (Tβ+10)℃ / 60min, and water cooling after heat treatment;

[0044] Step 3: Reforging: reforge the second forging blank in the above step 3, heating temperature (Tβ-15)℃ / 240min.

[0045] First step: Water cooling after forging;

[0046] Second step: Water cooling after forging;

[0047] Repeat the second step 3 times;

[0048] Step 4: reforging the third forging blank for n times, performing upsetting and drawing deformation once in each time, and air cooling after forging;

[0049] The third step: Heating temperature: (Tβ-50)℃ / 240min

[0050] Air cooling after forging;

[0051] Repeat the third step once;

[0052] Step 5: Roll into a ball and fold into a cake.

[0053] Fourth step: Heating temperature: (Tβ-50)℃ / 240min

[0054] Air cooling after forging;

[0055] Example 2

[0056] The embodiment of the present invention discloses a method for preparing a TC25G titanium alloy cake with a high flaw detection level, which mainly includes the following steps:

[0057] Step 1: Use quenching metallographic method to measure the phase transition temperature Tβ of TC25 titanium alloy. Machined chamfer R5.

[0058] Step 2: Isothermal constrained upsetting: heating temperature (Tβ-10)℃ / 180min, put the rod into Figure 1 Isothermal constrained upsetting is carried out in the fetal membrane, the deformation rate range is 5 mm / s, and the mold heating temperature is 800 °C.

[0059] Forging steps: Water cooling after forging.

[0060] Step 3: β solution heat treatment: The first forging blank in step 2 is subjected to β solution heat treatment, and the heat treatment system is: (Tβ-60)℃ / 160min to (Tβ+5)℃ / 120min, and water cooling after heat treatment.

[0061] Step 3: Reforging: reforge the second forging blank in the above step 3, heating temperature (Tβ-25)℃ / 270min.

[0062] First step: Water cooling after forging;

[0063] Second step: Water cooling after forging;

[0064] Repeat the second step 3 times.

[0065] Step 4: reforging the third forging blank for n times, performing upsetting and drawing deformation once in each time, and air cooling after forging;

[0066] The third step: Heating temperature: (Tβ-70)℃ / 270min

[0067] Air cooling after forging;

[0068] Repeat the third step once;

[0069] Step 5: Roll into a ball and fold into a cake.

[0070] Fourth step: Heating temperature: (Tβ-70)℃ / 240min

[0071] Air cooling after forging.

Claims

1. A method for preparing TC25 / TC25G titanium alloy cake with high flaw detection level, characterized in that: include: Step 1: Unloading and testing phase change temperature; Step 2: Isothermal constrained upsetting: isothermal constrained upsetting of TC25 / TC25G titanium alloy bars, water cooling after forging, to obtain the first blank, specifically including: the forging temperature range is 10-25°C at the β phase transformation temperature, the holding time coefficient adopts a range of 0.7-1.2min / mm, the isothermal forging deformation rate range is 0.5mm / s-5mm / s, the deformation amount is 35%-70%, and the mold heating temperature is 700-850°C; Step 3: β solution heat treatment: The first forging blank in step 2 is subjected to β solution heat treatment, and then water-cooled to obtain a second forging blank. The specific heating system of the β solution heat treatment is: (Tβ-40~60)℃ / 0.5min / mm to (Tβ+5~10)℃ / 0.2~0.4min / mm; Step 4: reforging: reforging the second forging blank m times, performing upsetting deformation once in each time, and water cooling after forging to obtain a third forging blank, wherein m is a positive integer; Step 5: reforging the third forging blank for n times, performing upsetting deformation once in each time, and air cooling after forging to obtain a fourth forging blank, wherein n is a positive integer; Step 6: Roll and collect the dough to obtain the target dough; Among them, in the steps 2 to 4, the temperature difference of the heating furnace used is ±5°C, m is 4-6, n is 2, and in all forging processes, the final forging temperature is not less than 850°C.

2. The method according to claim 1, characterized in that Step 1 specifically includes: The phase transition temperature was measured by quenching metallographic method.

3. The method according to claim 1, characterized in that Step 2 is forged using a hydraulic press, and steps 4 to 6 are performed on a 2500t or 16MN fast forging machine.

4. The method according to claim 1, characterized in that The second forging blank forging heating temperature is: (Tβ-10~30)℃, and water cooling after forging.

5. The method according to claim 1, characterized in that The third forging blank is heated to a forging temperature of (Tβ-45~70)°C and air-cooled after forging.

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