A GH4169 high temperature alloy hot-rolled bar and preparation method thereof

Abstract

The present invention provides a method for preparing a GH4169 high-temperature alloy hot-rolled bar billet, which specifically includes the following contents: smelting a GH4169 high-temperature alloy ingot through a triple smelting process of vacuum induction melting + electroslag remelting + vacuum consumable remelting; the ingot is subjected to high-temperature homogenization heat treatment in a natural gas furnace; the ingot is subjected to 5 to 7 fires of drawing and blanking forging in a fast forging machine, and is continuously returned to the furnace; the billet after blanking is kept warm and then rolled for the first time, and the billet diameter after rolling is 50 to 60 mm, and air-cooling is performed after rolling is completed; the billet after the first rolling is kept warm and then subjected to 1 fire rolling large deformation, and the billet diameter after the second rolling is completed is 16 to 20 mm, and air-cooling is performed after rolling is completed. The method adopts a triple smelting process of vacuum induction melting + electroslag remelting + vacuum consumable remelting to smelt the GH4169 high-temperature alloy ingot, and the composition on the cross section of the billet is uniform, and the content of harmful impurity elements is small.

Description

Technical Field

[0001] The invention relates to the technical field of nonferrous metal processing, in particular to a GH4169 high-temperature alloy hot-rolled bar blank and a preparation method thereof. Background Art

[0002] GH4169 alloy is the most widely used deformable high-temperature alloy at home and abroad, with an annual output of more than 20,000 tons, accounting for 50% of the total output of deformable high-temperature alloys. GH4169 alloy is a Ni-Cr-Fe-based high-temperature alloy. The alloy has good comprehensive properties from -253℃ to 650℃, and is an indispensable material in my country's new aircraft engines. The alloy has excellent mechanical properties, good processability and weldability, making it highly favored by aircraft engine designers. There are more than 260 types of parts made of GH4169 alloy in my country's engines, of which there are as many as 11 types of key disc forgings. GH4169 alloy parts account for more than 30% of the total weight of the engine.

[0003] Compared with other nickel-based high-temperature alloys, the Nb content in GH4169 alloy is as high as 50wt.% or more, and there are many strengthening phases, mainly γ' phase, γ", δ, and NbC phase. The strengthening phases are continuously dissolved and precipitated during the heating and hot working process of the alloy, affecting the recrystallization process of the alloy, thereby affecting the grain structure and performance. With the continuous improvement of the performance requirements of modern aircraft engines and the continuous increase in thrust-to-weight ratio, the simple forging forming process can no longer fully meet the requirements of the development of the aviation industry. Forging can enable metals to obtain comprehensive mechanical properties that cannot be surpassed by other metal processing processes, while rolling can obtain better surface of formed parts. The GH4169 alloy with a uniform grain size of about 8 and a proper amount of δ phase dispersed in the grain boundary in granular or short rod form has good comprehensive properties. Ordinary forging hot working methods are difficult to meet this demanding requirement. Therefore, the GH4169 alloy small billet produced by free forging + rolling process provides a new idea for improving the performance of GH4169. Summary of the invention

[0004] The technical problem solved by the present invention is to provide a GH4169 high-temperature alloy hot-rolled bar billet and a preparation method thereof, and to smelt the GH4169 high-temperature alloy ingot by a triple smelting process of vacuum induction melting + electroslag remelting + vacuum consumable remelting. Through forging and rolling process design, annealing and homogenization design, and forging and rolling process design, a qualified GH4169 alloy rolled bar billet with a specification of Φ16~Φ20mm, a flaw detection level not less than Φ0.8-8dB, a uniform structure from the center to the edge, a grain size finer than level 8, and no notch and persistent sensitivity is prepared to solve the problems in the above-mentioned background technology. To achieve the above-mentioned purpose, the present invention provides the following technical solutions: A method for preparing a GH4169 high-temperature alloy hot-rolled bar billet, specifically comprising the following steps:

[0005] (1) GH4169 high temperature alloy ingot smelted by a triple smelting process of vacuum induction melting + electroslag remelting + vacuum consumable remelting, the ingot diameter is 480 mm to 600 mm;

[0006] (2) The ingot is subjected to high temperature homogenization heat treatment in a natural gas furnace;

[0007] (3) The ingot after homogenization heat treatment is subjected to 5-7 fires of drawing and blanking forging in an 80MN fast forging machine, the blanking temperature is 1100°C-1140°C, and it is continuously returned to the furnace, and the deformation amount of each fire is 10%-50%;

[0008] (4) The billet after being opened is kept at 1100°C to 1140°C and then subjected to the first rolling, i.e., two rounds of continuous re-melting rolling, with a deformation amount of 60% to 75% in each round. After rolling, the billet diameter is 50 mm to 60 mm, and air cooling is performed after rolling;

[0009] (5) After the first rolling, the billet is kept at 1040℃~1060℃ and then rolled for a large deformation with a deformation of 85%~95%. After the second rolling, the billet diameter is 16~20mm. After rolling, it is air-cooled to obtain GH4169 high temperature alloy hot-rolled bar billet.

[0010] Preferably, the specific content of the high temperature homogenization heat treatment in step (2) is: heating the ingot to 650°C with a thermal insulation coefficient of 0.6 min / mm, then heating to 1140°C-1160°C at a heating rate of 2°C-6°C / min, with a thermal insulation time of ≥24h, then heating to 1180°C-1200°C at a heating rate of 2°C-6°C / min, with a thermal insulation time of ≥48h, furnace cooling to 650°C after the thermal insulation is completed, and then air cooling.

[0011] Preferably, in the step (4), the specific method of keeping the blank at 1100°C to 1140°C is as follows: heating the cold forging blank to 850°C with a thermal insulation coefficient of 0.6 min / mm, and then heating it to 1100°C to 1150°C at a heating rate of 5°C to 8°C / min with a thermal insulation coefficient of 0.6 min / mm; the thermal insulation coefficient of the continuously recycled hot material is 0.4 min / mm.

[0012] Preferably, the specific method of keeping the blank at 1040°C to 1060°C after the first rolling in step (5) is: heating the blank after the first rolling of the cold material to 850°C with a thermal insulation coefficient of 1 min / mm, and then heating it to 1040°C to 1060°C at a heating rate of 5°C to 8°C / min, with a thermal insulation coefficient of 1 min / mm.

[0013] Preferably, the room temperature tensile strength of the GH4169 high temperature alloy hot-rolled bar obtained after the second rolling in step (5) is 1400MPa-1500MPa, the room temperature tensile elongation is 22%-24%, the room temperature tensile section shrinkage is 45%-50%, the 650°C high temperature tensile strength is 1150MPa-1190MPa, the 650°C high temperature tensile elongation is 30%-39%, and the 650°C high temperature section shrinkage is 37%-65%.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) The GH4169 high-temperature alloy ingot is smelted by a triple smelting process of vacuum induction melting + electroslag remelting + vacuum consumable remelting. After homogenization and free forging, the composition of the cross section of the bar is uniform and the content of harmful impurity elements is small.

[0016] (2) By controlling the rolling process, a hot rolling process with two large deformations at high temperature is added. During the deformation process, the billet is rapidly deformed, and the grain size of the Φ16mm~Φ20mm specification billet is controlled within 8~10 levels, and the grain distribution is uniform, thereby improving the uniformity of the structure of the large billet.

[0017] (3) The performance of GH4169 alloy is stable, with room temperature tensile strength of 1400MPa~1500MPa, room temperature tensile elongation of 22%~24%, room temperature tensile cross-sectional shrinkage of 45%~50%, 650℃ high temperature tensile strength of 1150MPa~1190MPa, 650℃ high temperature tensile elongation of 30%~39%, and 650℃ high temperature cross-sectional shrinkage of 37%~65%. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is the high-magnification structure of 100× at the edge of a Φ16mm bar;

[0020] Figure 2 It is the high-magnification structure of Φ16mm rod blank R / 2 100×.

[0021] Figure 3 This is a 100× high-magnification structure of the core of a Φ16mm rod. DETAILED DESCRIPTION

[0022] In order to make the technical means, creative features, workflows, and methods of use of the present invention easy to understand and understand, the technical solutions in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work, and other conclusions obtained by non-creative expansion, are within the scope of protection of the present invention.

[0023] The room temperature tensile test in the embodiment of the present invention is carried out at room temperature using ASTM E 8 / E 8M standard.

[0024] In the embodiments of the present invention, the high temperature tensile test is carried out at 650° C. and then kept at this temperature for 30 minutes according to the ASTM E 21 national standard.

[0025] In the embodiment of the invention, the grain size rating adopts the ASTM E 112 standard, and samples are taken from the center, R / 2, and edge of the rod blank respectively, and then the structure is observed under a metallographic microscope after corrosion.

[0026] Example 1

[0027] The diameter of the GH4169 alloy ingot smelted by vacuum induction melting + electroslag remelting + vacuum consumable remelting process is 490mm. The ingot homogenization process is as follows: heating to 650℃, holding for 300min, then heating to 1150℃ at a heating rate of 6℃ / min, holding for 24h, then heating to 1195℃ at a heating rate of 6℃ / min, holding for 48h, furnace cooling to 650℃ after holding, and then air cooling;

[0028] The ingot is kept warm at 1100℃ and then forged. The forging process is 5 times in total, and the deformation settings are as follows: Φ490×1060→420×1365→340×2080→270×3300. The material is chopped and then forged: 270×1650→210×2728→Φ160×4965. The deformation of each fire is 22%, 35%, 37%, 39%, and 41%, respectively. After completion, it is air-cooled and the billet is peeled to Φ150×L.

[0029] After the billet is kept at 1140°C, it is subjected to two rounds of rolling deformation, with the following settings: Φ 150mm×L→90×75×L→Φ53mm×L, and the deformation amounts of each round are 70% and 58% respectively, and then air-cooled.

[0030] After the billet is kept at 1040°C, it is subjected to one rolling deformation, and the setting is as follows: Φ 53mm×L→Φ16mm×L: the deformation amount of each single rolling is 91%, and air cooling is performed after completion.

[0031] The grain size of the finished bar blank is rated according to ASTM E 112, with the center and R / 2 being 8.5 and the edge being 10. The specific performance parameters are shown in Table 1.

[0032] Example 2

[0033] The diameter of the GH4169 alloy ingot smelted by vacuum induction melting + electroslag remelting + vacuum consumable remelting process is 530mm. The ingot homogenization process is as follows: heating to 650℃, keeping warm for 300min, then heating to 1160℃ at a heating rate of 6℃ / min, keeping warm for 28h, then heating to 1190℃ at a heating rate of 6℃ / min, keeping warm for 54h, furnace cooling to 650℃ after the end of keeping warm, and then air cooling;

[0034] The ingot is heat-insulated at 1120℃ and then forged. The forging process is performed for 6 times in total. The deformation settings are as follows: Φ530×1060→440×1240→400×1505→350×1965→270×3300. The material is chopped and then forged: 270×1650→210×2728→Φ160×4965. The deformation of each fire is 15%, 17%, 23%, 40%, 40%, and 41%. After completion, the billet is air-cooled and peeled to Φ150×L.

[0035] After the billet is kept at 1130℃, it is subjected to two rounds of rolling deformation, with the following settings: Φ 150mm×L→95×65×L→Φ53mm×L, and the deformation amounts of each round are 73% and 55% respectively, and then air-cooled.

[0036] The billet is kept at 1060℃ and then subjected to one rolling deformation, the setting is as follows: Φ 53mm×L→Φ18mm×L: the deformation amount of each single rolling is 88%, and air cooling is performed after completion. The high-multiple structure of the obtained billet is as follows Figure 1-Figure 3 shown.

[0037] The grain size of the finished bar blank is rated as 8 for the center and R / 2 and 9.5 for the edge according to ASTM E 112. The specific performance parameters are shown in Table 1.

[0038] Example 3

[0039] The ingot is kept warm at 1140℃ and then forged. The forging process is a total of 7 fires, and the deformation settings are as follows: Φ490×1060→440×1240→400×1505→350×1965→270×3300. The material is chopped and then forged: 270×1650→240×2085→210×2725→Φ160×4965. The deformation of each fire is 15%, 17%, 23%, 21%, 21%, 23%, and 45%, respectively. After completion, it is air-cooled and the billet is peeled to Φ150×L.

[0040] After the billet is kept at 1100°C, it is subjected to two rounds of rolling deformation, with the following settings: Φ 150mm×L→90×70×L→Φ53mm×L, and the deformation amounts of each round are 72% and 56% respectively, and then air-cooled.

[0041] After the billet is kept at 1050°C, it is subjected to one rolling deformation, and the setting is as follows: Φ 53mm×L→Φ20mm×L: the deformation amount of each single rolling is 86%, and it is air-cooled after completion.

[0042] The grain size of the finished bar blank is rated as 9 for the center and R / 2 and 10 for the edge according to ASTM E 112. The specific performance parameters are shown in Table 1.

[0043] Table 1

[0044]

[0045] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing GH4169 high temperature alloy hot-rolled bar billet, characterized in that: The specific steps include: (1) GH4169 high temperature alloy ingot smelted by a triple smelting process of vacuum induction melting + electroslag remelting + vacuum consumable remelting, the ingot diameter is 480 mm to 600 mm; (2) The ingot is subjected to high temperature homogenization heat treatment in a natural gas furnace; (3) The ingot after homogenization heat treatment is subjected to 5-7 fires of drawing and blanking forging in an 80MN fast forging machine, the blanking temperature is 1100°C-1140°C, and it is continuously returned to the furnace, and the deformation amount of each fire is 10%-50%; (4) The billet after being opened is kept at 1100°C to 1140°C and then subjected to the first rolling, i.e., two rounds of continuous re-melting rolling, with a deformation amount of 60% to 75% in each round. After the rolling, the billet diameter is 50 mm to 60 mm, and air cooling is performed after the rolling is completed; wherein the specific method of keeping the billet at 1100°C to 1140°C is as follows: the cold forging billet is heated to 850°C, with a thermal insulation coefficient of 0.6 min / mm, and then the temperature is increased to 1100°C to 1150°C at a heating rate of 5°C to 8°C / min, with a thermal insulation coefficient of 0.6 min / mm; the thermal insulation coefficient of the continuously re-melted hot material is 0.4 min / mm; (5) After the first rolling, the billet is kept at 1040℃~1060℃ and then rolled for a large deformation, with a deformation of 85%~95%. After the second rolling, the billet diameter is 16~20mm. After the rolling is completed, it is air-cooled to obtain the GH4169 high-temperature alloy hot-rolled bar billet; wherein the specific method of keeping the billet at 1040℃~1060℃ after the first rolling is as follows: the cold billet after the first rolling is heated to 850℃, with a thermal insulation coefficient of 1min / mm, and then heated to 1040℃~1060℃ at a heating rate of 5℃~8℃ / min, with a thermal insulation coefficient of 1min / mm.

2. The method for preparing a GH4169 high temperature alloy hot rolled bar according to claim 1, characterized in that: The specific content of the high temperature homogenization heat treatment in the step (2) is as follows: heating the ingot to 650°C with a thermal insulation coefficient of 0.6 min / mm, then heating it to 1140°C-1160°C at a heating rate of 2°C-6°C / min, with a thermal insulation time of ≥24h, then heating it to 1180°C-1200°C at a heating rate of 2°C-6°C / min, with a thermal insulation time of ≥48h, and after the thermal insulation is completed, furnace cooling to 650°C is performed, followed by air cooling.

3. The method for preparing a GH4169 high temperature alloy hot rolled bar according to claim 1, characterized in that: After the second rolling in step (5), the room temperature tensile strength of the GH4169 high temperature alloy hot-rolled bar obtained is 1400MPa-1500MPa, the room temperature tensile elongation is 22%-24%, the room temperature tensile cross-sectional shrinkage is 45%-50%, the 650°C high temperature tensile strength is 1150MPa-1190MPa, the 650°C high temperature tensile elongation is 30%-39%, and the 650°C high temperature cross-sectional shrinkage is 37%-65%.

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