Forming method of GH4169 alloy thin-wall ring piece

Abstract

The invention relates to a method for forming a GH4169 alloy thin-wall ring piece, which comprises the following steps of: forging two pieces in the height direction in a combined manner, and designing a specific forging drawing, preparing a bar material, manufacturing a blank, rolling, carrying out heat treatment, turning and carrying out flaw detection, for example, designing the small allowance of the outer diameter and the inner diameter of the forging drawing, smelting the bar material in a specific specification by using a triple process, the method has the beneficial effects that the rolling stability is improved, the grain structure is refined, raw materials are saved, the production efficiency is doubled, the flaw detection requirement is met, and the method is suitable for manufacturing related parts in the aerospace field and has wide application prospects and important popularization value.

Description

Technical Field

[0001] The invention relates to the technical field of rolling forming of high temperature alloys, and in particular to a forming method of a GH4169 alloy thin-walled ring. Background Art

[0002] High-temperature alloy materials are widely used in the aerospace field to manufacture rotating parts, such as engine casings and combustion chambers. Among them, GH4169 alloy is the most widely used high-temperature alloy material. GH4169 alloy is a nickel-based high-temperature alloy strengthened by precipitation of body-centered tetragonal γ" and face-centered cubic γ' phases. It has good comprehensive properties in the temperature range of -253℃ to 700℃, and its yield strength below 650℃ ranks first among deformed high-temperature alloys. Another feature is that the structure of the alloy is particularly sensitive to hot working technology. At the same time, the alloy material contains a large amount of cobalt, niobium, nickel and other elements, so the material cost is relatively high. For the thin-walled rings required in actual production, the uniform grain size of the organization is required to reach level 4 or finer, and the single discontinuity displayed during ultrasonic flaw detection shall not exceed the equivalent 2.0mm flat-bottom hole index amplitude, and the bottom wave loss shall not exceed 6dB. The current rolled The forming technology is an effective method for producing the raw materials of such parts, especially the radial-axial horizontal ring rolling machine. Because the ratio of the wall thickness to the outer diameter and the ratio of the height to the outer diameter of the ring are about 1 / 20 and 1 / 10 respectively, it is easy to lose stability during the rolling process, resulting in the ring ellipse of 4 to 6 mm, and the high roller climbing causes warping of 3 to 4 mm. In severe cases, it cannot be formed. In addition, the wall thickness is thin and the temperature drops quickly, resulting in uneven forging structure and unable to meet the requirements of flaw detection. For this reason, the conventional method is to increase the processing allowance to meet the limit size and stable rolling requirements of the ring rolling equipment. The single-sided allowance of the ring with a diameter of about 500 mm in the industry is 5mm to 6mm. This is basically consistent with the standard JB / T 10478-2004 "Machining allowance and tolerance of hot-rolled ring parts".

[0003] Patent CN102500705 A provides a method for hot bulging of rectangular ring rolled pieces of high-temperature alloys. The rectangular ring rolled pieces are placed on the periphery of the bulging block in the bulging machine, and the bulging machine is started to extrude the ring rolled pieces radially. The dimensional accuracy can reach 1‰ to 2‰ of the corresponding size, but it increases the bulging process, wastes the energy consumption of reheating, and is not suitable for the situation where there is no bulging machine equipment. Patent CN 117123727 A discloses a forging method for grain refinement of thin-walled rings of high-temperature alloys, provides a grain refinement method for GH4099 alloy, and proposes that reducing the forging heating temperature can refine the grains, but at the same time it will increase the tendency of cracks. The patent does not study the grain refinement process parameters of the GH4169 alloy, and lacks attention to whether the structure is uniform and whether it can meet the requirements of ultrasonic flaw detection. Patent CN102085550 A discloses a rolling forming method for high-tube ring forgings of nickel-based high-temperature alloys, and formulates a technical solution for rolling and forming thin-walled and high-tube rings with excellent structure and performance. The minimum wall thickness of the ring forgings rolled by this method is 25mm, and the maximum height-to-thickness ratio is 25mm. The forgings are mainly used for rotating parts such as the front casing used in the aerospace field. However, the follower die sleeve is installed on the core roller, the rolling stability is poor, and it is not suitable for forming rings with a wall thickness of less than 25mm. Summary of the invention

[0004] In order to solve the above problems, the present invention discloses a forming method of a GH4169 alloy thin-walled ring.

[0005] The specific technical solutions are as follows:

[0006] A forming method of a GH4169 alloy thin-walled ring, comprising the following steps:

[0007] Forging drawing design: master the tolerance of outer diameter and inner diameter; adopt the scheme of two-piece joint forging in height direction;

[0008] Bar preparation: Prepare the bar through vacuum induction, electroslag remelting, and vacuum consumable triple process smelting. The grain size difference between the edge, 1 / 2R and center of the bar cross section should not exceed two levels.

[0009] Blank making: The process route of using a fast forging machine to make blanks combined with a ring rolling machine to roll and form is adopted. The fast forging machine blanks require two fires to be completed. After heating in the first fire, they are upset and punched, and the deformation is 50%-65%; after heating in the second fire, the holes are expanded and shaped, the inner hole is expanded, and the flat height is made to the nominal size of the forging.

[0010] Ring rolling: After the ring blank is heated, it is rolled into shape on a CNC ring rolling machine. The stop forging temperature is controlled to be no less than 930°C. After the radial load is removed, the ring is rotated at least 2 circles to complete the circle.

[0011] Heat treatment: subject the forgings to solution treatment, heat preservation for 1 hour after thorough heating, and air cooling or faster cooling.

[0012] Turning: The forgings are turned, and the size tolerance after processing is ±0.5, and the surface roughness is not greater than Ra1.6μm. The last two rounds of processing are performed using a round head tool. After cutting in the height direction, an R tool is used to smooth the section.

[0013] Flaw detection: ultrasonic water immersion flaw detection is carried out at a frequency of 5MHz-10MHz, using GH4169 alloy comparison test blocks. The defect display does not exceed the equivalent 2.0mm flat bottom hole amplitude, and the bottom wave loss does not exceed 6dB.

[0014] Blank making temperature: first fire heating temperature 1000℃~1060℃, second fire heating temperature 1000℃~1060℃.

[0015] In the rolling process, the main roll speed is 0.8m / s-1.0m / s, the core roll feed speed is 0.5mm / s-0.7mm / s, the rolling time is 20s-30s, and the rolling deformation is 30%-35%;

[0016] The grain size of the bar material is level 4 or finer, and the fillet transition should be smooth.

[0017] After the heat treatment, the forgings are extracted for aging treatment, and the metallographic structure of the forgings is required to have a grain size of 7-7.5 and a uniform structure.

[0018] The advantages of the present invention are: for the GH4169 alloy thin-walled rings which are difficult to deform and have sensitive structures, the high-direction joint forging and low-temperature large-deformation final rolling are adopted, which not only increases the rigidity of the rings during the rolling process, but also improves the rolling stability. At the same time, a grain-refined structure is obtained. The small margin design in the diameter direction saves a lot of raw material consumption. When the raw material is produced, two parts can be processed from one raw material, which doubles the production efficiency. After the high-direction cutting, the automatic water immersion flaw detection is carried out, which meets the requirements of flaw detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a part diagram after processing in Example 1;

[0020] Figure 2 Figure of the forging designed for Example 1;

[0021] Figure 3 It is the metallographic structure diagram of Example 1;

[0022] Figure 4 This is a part diagram after processing in Example 2;

[0023] Figure 5 Figure of the forging designed for Example 2;

[0024] Figure 6 This is the metallographic structure diagram of Example 2. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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. Specific embodiment 1:

[0027] against Figure 1 For parts, first add machining allowance and design Figure 2 The forging diagram. To implement the forming method of the GH4169 alloy thin-walled ring of the present invention, it is necessary to provide a forging heating furnace, a fast forging machine, a ring rolling machine and other equipment, as well as simple tooling such as a punch, a drain plate and a horse frame. The specific implementation method is as follows:

[0028] Step 1: Cut the material on the sawing machine. The surface roughness should not be less than Ra6.3μm. No defects such as cracks, folds, and scars are allowed. The two sections are rounded to R10, and the corners are allowed to be up to R15 locally. The transition of the fillet should be smooth. The bar is smelted by the triple process, and the grain size is required to be 4 or finer. The grain size difference between the edge, 1 / 2R and the center of the cross section of the bar does not exceed 2 levels.

[0029] Step 2: Upsetting and punching after heating. The heating temperature after preheating is 1000°C, the upsetting height is 85±3mm, and the punch and the leak plate are used for punching. The punching bottom plate is about 9.3kg, and the upsetting deformation is about 60%.

[0030] Step 3: Return to the furnace for heating and then expand and shape. Heating temperature is 1000℃, expand the hole with a rack, the inner hole is Φ304±10, and the expansion deformation is about 50%. Level the height to 101±3mm.

[0031] Step 4: Roll the ring after heating in the furnace. The heating temperature is 1010℃, the holding time is not less than 30min, the main roller speed is 1.0m / s, the core roller feed speed is 0.5mm / s, the rolling time is 30s, the rolling deformation is about 34%, and the stop forging temperature is controlled not less than 930℃. After the radial load is removed, the ring is rotated at least 2 times to make the ring round.

[0032] Step 5: Heat treatment. The forgings are subjected to solution treatment at a temperature within the range of 950℃~980℃±10℃. After heating through, keep the temperature for 1h, and then air cool or cool faster. Take a forging and inspect the cross-section metallographic structure after aging. Figure 3 . Grain size is 7 to 7.5, and the structure is uniform.

[0033] Step 6: Turning. Figure 1 After turning, the size tolerance is ±0.5, the surface roughness is not greater than Ra1.6μm, and the last two turns are processed with round head tools. After cutting in the height direction, the R tool is used to smooth the section.

[0034] Step 7: Nondestructive testing. Ultrasonic water immersion testing Figure 1 The raw material shown is 5MHz~10MHz, and the GH4169 alloy comparison test block. The defect display does not exceed the equivalent 2.0mm flat bottom hole amplitude, and the bottom wave loss does not exceed 6dB.

[0035] Embodiment 2:

[0036] against Figure 4 For parts, first add machining allowance and design Figure 5 The forging diagram. To implement the forming method of the GH4169 alloy thin-walled ring described in the present invention, it is necessary to provide a forging heating furnace, a fast forging machine, a ring rolling machine and other equipment, as well as simple tooling such as a punch, a drain plate and a horse frame. Specific implementation method:

[0037] Step 1: Cut the material on the sawing machine. The surface roughness should not be less than Ra6.3μm. No defects such as cracks, folds, and scars are allowed. The two sections are rounded to R10, and the corners are allowed to be up to R15 locally. The transition of the fillet should be smooth. The bar is smelted by the triple process, and the grain size is required to be 4 or finer. The grain size difference between the edge, 1 / 2R and the center of the cross section of the bar does not exceed 2 levels.

[0038] Step 2: Upsetting and punching after heating. The heating temperature after preheating is 1020°C, the upsetting height is 77±3mm, and the punch and the leak plate are used for punching. The punching bottom plate is about 8.4kg, and the upsetting deformation is about 50%.

[0039] Step 3: Return to the furnace for heating and then expand and shape. Heating temperature is 1020℃, expand the hole with a frame, the inner hole is Φ306±10, and the expansion deformation is about 53%. Level the height to 92±3mm.

[0040] Step 4: Roll the ring after heating in the furnace. The heating temperature is 1020℃, the holding time is not less than 30min, the main roller speed is 0.9m / s, the core roller feed speed is 0.6mm / s, the rolling time is 25s, the rolling deformation is about 31%, and the stop forging temperature is controlled not less than 930℃. After the radial load is removed, the ring is rotated at least 2 times to make the ring round.

[0041] Step 5: Heat treatment. The forgings are subjected to solution treatment at a temperature within the range of 950℃~980℃±10℃. After heating through, keep the temperature for 1h, and then air cool or cool faster. Take a forging and inspect the cross-section metallographic structure after aging. Figure 6. The grain size is 6.5 to 7, and the structure is uniform.

[0042] Step 6: Turning. Figure 4 After turning, the size tolerance is ±0.5, the surface roughness is not greater than Ra1.6μm, and the last two turns are processed with round head tools. After cutting in the height direction, the R tool is used to smooth the section.

[0043] Step 7: Nondestructive testing. Ultrasonic water immersion testing Figure 4 The raw material shown is 5MHz~10MHz, and the GH4169 alloy comparison test block. The defect display does not exceed the equivalent 2.0mm flat bottom hole amplitude, and the bottom wave loss does not exceed 6dB.

Claims

1. A forming method for a GH4169 alloy thin-walled ring, characterized in that: The following steps are involved: Forging drawing design: master the tolerance of outer diameter and inner diameter; adopt the scheme of two-piece joint forging in height direction; Bar preparation: prepare the bar through vacuum induction, electroslag remelting, vacuum consumable triple process smelting, requiring the grain size difference between the edge, 1 / 2R and center of the bar cross section to not exceed two levels; Blank making: The process route of using a fast forging machine to make blanks combined with a ring rolling machine to roll and form is adopted. The fast forging machine blank making requires two fires to be completed. After heating in the first fire, it is upsetting and punching, and the deformation is 50%-65%; after heating in the second fire, the hole is expanded and shaped, the inner hole is expanded, and the flat height is leveled to the nominal size of the forging; Ring rolling: After the ring blank is heated, it is rolled into shape on a CNC ring rolling machine. The stop forging temperature is controlled to be no less than 930°C. After the radial load is removed, the ring is rotated at least 2 circles to complete the circle. Heat treatment: subject the forgings to solid solution treatment, heat thoroughly and keep them warm for 1 hour, then air cool or cool faster; Turning: Turn the forgings, the size tolerance after processing is ±0.5, the surface roughness is not greater than Ra1.6μm, the last two rounds of processing are performed with a round head tool, and after cutting in the height direction, the R tool is used to smooth the section; Flaw detection: ultrasonic water immersion flaw detection is carried out at a frequency of 5MHz-10MHz, using GH4169 alloy comparison test blocks. The defect display does not exceed the equivalent 2.0mm flat bottom hole amplitude, and the bottom wave loss does not exceed 6dB.

2. The forming method of GH4169 alloy thin-walled ring according to claim 1 is characterized in that Blank making temperature: first fire heating temperature 1000℃~1060℃, second fire heating temperature 1000℃~1060℃.

3. The forming method of GH4169 alloy thin-walled ring according to claim 1 is characterized in that In the rolling process steps: the main roll speed is 0.8m / s-1.0m / s, the core roll feed speed is 0.5mm / s-0.7mm / s, the rolling time is 20s-30s, and the rolling deformation is 30%-35%.

4. The forming method of GH4169 alloy thin-walled ring according to claim 1, characterized in that: The grain size of the bar material is level 4 or finer, and the fillet transition should be smooth.

5. The forming method of GH4169 alloy thin-walled ring according to claim 1, characterized in that: After the heat treatment, the forgings are extracted for aging treatment, and the metallographic structure of the forgings is required to have a grain size of 7-7.5 and a uniform structure.

Images