Forming method for controlling thermal material system to improve internal structure of high temperature alloy forgings

Abstract

The present invention belongs to the field of forging hot processing, and relates to a forming method for controlling the hot material system to improve the internal structure of a high-temperature alloy forging. The method comprises: determining the grain size requirements required for the forging; selecting the corresponding deformation amount per fire, hot material system and cooling method according to the grain size requirements; and heat treating the forging according to the corresponding deformation amount per fire, hot material system and cooling method.

Description

Technical Field

[0001] The invention belongs to the field of forging hot processing and relates to a forming method for controlling a hot material system to improve the internal structure of a high-temperature alloy forging. Background Art

[0002] GH4099 is a nickel-based high-temperature alloy material, which is comprehensively strengthened with cobalt, tungsten, aluminum and titanium elements. It has high thermal strength and can be used for a long time at 900℃. The maximum working temperature can reach 1000℃. The alloy has stable structure and satisfactory cold and hot processing and welding process performance. It is suitable for high-temperature plate load-bearing welding structural parts such as aircraft engine combustion chambers and afterburner combustion chambers. Due to its excellent comprehensive performance, it has been widely used in aviation, aerospace and other fields, and is currently one of the most widely used high-temperature alloy materials in foreign aircraft engines.

[0003] Due to the different requirements of GH99 alloy forgings on the internal structure, the requirements for the thermal material system of forgings are relatively high. In particular, the heat treatment method and cooling method will affect the final internal structure of the forging. If the thermal material method and cooling method are not properly controlled, the change of each parameter will directly affect the internal structure of the forging, making the product unable to meet the final requirements, resulting in product scrapping and a great waste of resources.

[0004] GH99 is generally used in aviation for high-speed rotating load-bearing parts or rotating parts. In use, high requirements are placed on the grain size of forgings. However, the forging process and heat treatment process, especially the treatment method and cooling method, have obvious effects.

[0005] Conventional heat treatment of materials does not meet the requirements for the low-multiple structure and high-multiple grain size of the internal structure of the forging. Therefore, it is very important to select a reasonable treatment method and cooling method according to the shape and wall thickness of the forging to affect the structure and performance of the GH99 material. Especially for free forgings with multiple fires, adding a blanking step to form, in order to ensure that the final physical and chemical test requirements of the forging are met after the final heat treatment, it will cause the physical and chemical unqualified forgings, resulting in the scrapping of the forgings. Summary of the invention

[0006] The purpose of the present invention is to provide different processing methods and cooling modes according to the forgings formed after adding the blanking step to the free forgings with multiple fires, to improve the internal structure of the forgings by controlling the hot material process, and to use hot material methods to meet the control processing methods and cooling modes of the forgings formed after adding the blanking step to the free forgings with multiple fires, so as to obtain qualified and stable internal structure.

[0007] To solve this technical problem, the technical solution of the present invention is:

[0008] A forming method for controlling the thermal material system to improve the internal structure of a high-temperature alloy forging, comprising:

[0009] Determine the grain size requirements for forgings;

[0010] According to the grain size requirements, select the corresponding deformation amount per fire, thermal material system and cooling method;

[0011] The forgings are heat treated according to the corresponding deformation amount per fire, hot material system and cooling method.

[0012] Heat treatment of forgings is carried out according to the corresponding deformation amount per fire, hot material system and cooling method, including:

[0013] According to the process requirements of the specification of the blank within the deformation range of each fire;

[0014] Put the billet into the furnace at ≤700℃ and keep it at 700±50℃. Rise the temperature to 1120±50℃ with the furnace at 0.3min / mm~0.4 min / mm, and the insulation coefficient is 0.4min / mm. After keeping it for the set time, take it out of the furnace immediately and upset and punch it on the free forging hammer until it reaches Φ230×Φ80±5×80±2, and control the intermediate and final forging temperature at the same time;

[0015] After roughing and punching, the billet is machined to have an inner hole of Φ80, then put into the furnace at ≤700℃ and 700±50℃, and kept warm at 0.3min / mm~0.4 min / mm. The temperature is raised to 1120±50℃ with the furnace, and kept warm at a heat preservation coefficient of 0.4min / mm for the set time, then it is immediately taken out of the furnace and expanded on the free forging hammer to forge the intermediate billet to Φ360×Φ280±5×79±2, and the intermediate and final forging temperature is controlled at the same time;

[0016] Put the intermediate billet of Φ360×Φ280±5×79±2 into the furnace at ≤700℃ and keep it at 700±50℃ at 0.3min / mm~0.4 min / mm. Raise the temperature to 1120±50℃ with the furnace. Keep it at the setting time at the insulation coefficient of 0.4min / mm. Then take it out of the furnace and expand it to Φ488×Φ440×80 in the hole expander. Meanwhile, control the intermediate and final forging temperature.

[0017] Heat treatment of forgings is carried out according to the hot material system and cooling method.

[0018] When the grain size requirement is level 3, the deformation range for each fire is 15%-20%, the hot material system is 1080℃, insulation for 60min, and the cooling method is air cooling.

[0019] When the grain size requirement is 3.5, the deformation range of each fire is 20%-25%, the hot material system is 1085℃, the heat preservation is 70min, and the cooling method is oil cooling;

[0020] When the grain size requirement is level 4, the deformation range of each fire is 25%-30%, the hot material system is 1090℃, the heat preservation is 80min, and the cooling method is air cooling;

[0021] When the grain size requirement is 4.5, the deformation range of each fire is 30%-35%, the hot material system is 1100℃, insulation time is 90min, and the cooling method is water cooling.

[0022] After heat treating the forging according to the corresponding deformation amount per fire, hot material system and cooling method, the method further includes:

[0023] Take samples for physical and chemical testing, that is, determine the accuracy level.

[0024] After heat treating the forging according to the corresponding deformation amount per fire, hot material system and cooling method, the method further includes:

[0025] 100% mechanical property inspection.

[0026] The beneficial effects of the present invention are:

[0027] GH4099 is a nickel-based high-temperature alloy material. Forgings have high requirements for grain size. However, in the forging process and heat treatment process, especially the treatment method and cooling method, the influence is obvious. According to the grain size requirements of the forgings, different heat treatment methods are provided to improve the internal structure of the forgings, obtain qualified and stable internal structure, improve the qualified rate of the internal structure of the forgings in physical and chemical determination to reduce scrap loss, and greatly improve the qualified rate of forgings. DETAILED DESCRIPTION

[0028] The control processing method and cooling method of the forgings formed after the blanking step are added to the GH99 forgings to provide different heat treatment system methods. Usually, GH99 is subjected to corresponding heat treatment according to the supply state. The supply state is different and the thermal material system is different. However, the conventional heat treatment method cannot meet the final physical and chemical test requirements of the forgings, which will cause the physical and chemical unqualified forgings and cause the forgings to be scrapped.

[0029] This paper adopts different treatment methods and cooling methods to solve the final physical and chemical test requirements of forgings formed after the free forging process step, as shown in Table 1.

[0030] Table 1

[0031]

[0032] By controlling the treatment method and cooling mode, the internal structure of the forging can be improved, and the heat treatment method can be used to meet the reasonable heat treatment forming plan required by the forging design to obtain a qualified and stable internal structure.

[0033] The method comprises the following steps:

[0034] Step 1: Determine the forging method based on the deformation amount of each fire in the forging blank making and forming production.

[0035] When the grain size requirement for forgings is level 3, the deformation amount per fire is controlled at 15%-20%; when the grain size requirement for forgings is level 3.5, the deformation amount per fire is controlled at 20%-25%; when the grain size requirement for forgings is level 4, the deformation amount per fire is controlled at 25%-30%; when the grain size requirement for forgings is level 4.5, the deformation amount per fire is controlled at 30%-35%;

[0036] Step 2: Determine the heat treatment method according to the grain size requirements of the forgings; the heat treatment temperature corresponding to the grain size requirement of level 3 is 1080℃, and the temperature is kept for 60 minutes; the cooling method is air cooling; the heat treatment temperature corresponding to the grain size requirement of level 3.5 is 1085℃, and the temperature is kept for 70 minutes; the cooling method is oil cooling; the heat treatment temperature corresponding to the grain size requirement of level 4 is 1090℃, and the temperature is kept for 80 minutes; the cooling method is air cooling; the hot material temperature corresponding to level 4.5 is 1100℃, and the temperature is kept for 90 minutes; the cooling method is water cooling;

[0037] Step 3: Heat treatment

[0038] According to step one and step two, select a suitable heat treatment system for heat treatment.

[0039] Step 4: Conduct 100% mechanical property inspection.

[0040] Example:

[0041] (1) Design process flow: The grain size requirement for forgings is level 4 → forging bars → sawing to the length required by the process → determining the forging plan (forging deformation is 20%-25%) → reforging → forming forging → heat treatment (determine the heat treatment system to be 1085℃, keep warm for 70min) → physical and chemical (determine the grain size).

[0042] (2) The production batch number is 2020-08-1245; the forging method is determined to be 20%-25% deformation per fire; the following process requirements are for the specification of the blank: Φ190mm×130mm;

[0043] (3) Put the bar into the furnace at ≤700℃ and keep it at 700±50℃. Raise the temperature to 1120±50℃ with the furnace at 0.3min / mm~0.4min / mm. The insulation coefficient is 0.4min / mm. After the forging is kept warm for the set time, it is immediately taken out of the furnace and upset and punched on the free forging hammer until the forging reaches ~Φ230×Φ80±5×80±2. At the same time, the intermediate and final forging temperature is controlled;

[0044] (4) After the above-mentioned billet is machined with an inner hole to Φ80, it is put into the furnace at ≤700℃ and kept at 700±50℃ at 0.3min / mm~0.4min / mm. The temperature is raised to 1120±50℃ with the furnace, and the insulation coefficient is 0.4min / mm. After the forging is kept for the set time, it is immediately taken out of the furnace and expanded on the free forging hammer to forge to ~Φ360×Φ280±5×79±2, and the intermediate and final forging temperature is controlled at the same time;

[0045] (5) Place the above-mentioned intermediate billet of Φ360×Φ280±5×79±2 into the furnace at ≤700℃ and keep it at 700±50℃. Raise the temperature to 1120±50℃ with the furnace at 0.3min / mm~0.4min / mm, and the insulation coefficient is 0.4min / mm. After the forging is kept warm for the set time, it is immediately taken out of the furnace and expanded to Φ488×Φ440×80 in the reamer, while controlling the intermediate and final forging temperature;

[0046] (6) Heat treatment of forgings: keep the temperature at 1090℃ for 80min, take samples out of the furnace and air cool them for physical and chemical analysis. The results show that both the macrostructure and the macrograin size are qualified.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the field can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A forming method for controlling the thermal material system to improve the internal structure of a high-temperature alloy forging, characterized in that: include: Determine the grain size requirements for forgings; According to the grain size requirements, select the corresponding deformation amount per fire, thermal material system and cooling method; Heat treat the forgings according to the corresponding deformation amount per fire, hot material system and cooling method; Heat treatment of forgings is carried out according to the corresponding deformation amount per fire, hot material system and cooling method, including: Forging the blank according to the process requirements and specifications within the deformation range of each fire; Put the billet into the furnace at ≤700℃ and keep it at 700±50℃. Raise the temperature to 1120±50℃ with the furnace at 0.3min / mm~0.4 min / mm, and the insulation coefficient is 0.4min / mm. After keeping it for the set time, take it out of the furnace immediately and punch it on the free forging hammer to ~Φ230×Φ80±5×80±2, and control the final forging temperature at the same time; After roughing and punching, the billet is machined to have an inner hole of Φ80, then put into the furnace at ≤700℃ and 700±50℃, and kept warm at 0.3min / mm~0.4min / mm. The temperature is raised to 1120±50℃ with the furnace, and kept warm at a heat preservation coefficient of 0.4min / mm for the set time, then it is immediately taken out of the furnace and expanded to an intermediate billet of ~Φ360×Φ280±5×79±2 on the free forging hammer, and the final forging temperature is controlled at the same time; Put the intermediate billet of Φ360×Φ280±5×79±2 into the furnace at ≤700℃ and keep it at 700±50℃ at 0.3min / mm~0.4min / mm. Raise the temperature to 1120±50℃ with the furnace. Keep it at the setting time at the insulation coefficient of 0.4min / mm. Then take it out of the furnace and expand it to Φ488×Φ440×80 in the hole expander. Meanwhile, control the final forging temperature. Heat treatment of forgings is carried out according to the hot material system and cooling method.

2. The method according to claim 1, characterized in that When the grain size requirement is level 3, the deformation range for each fire is 15%-20%, the hot material system is 1080℃, insulation for 60min, and the cooling method is air cooling.

3. The method according to claim 1, characterized in that When the grain size requirement is level 3.5, the deformation range of each fire is 20%-25%, the hot material system is 1085℃, the insulation time is 70min, and the cooling method is oil cooling.

4. The method according to claim 1, characterized in that When the grain size requirement is level 4, the deformation range for each fire is 25%-30%, the hot material system is 1090℃, the insulation is 80min, and the cooling method is air cooling.

5. The method according to claim 1, characterized in that When the grain size requirement is 4.5, the deformation range of each fire is 30%-35%, the hot material system is 1100℃, insulation time is 90min, and the cooling method is water cooling.

6. The method according to claim 1, characterized in that After heat treating the forging according to the corresponding deformation amount per fire, hot material system and cooling method, the method further includes: Take samples for grain size determination.

7. The method according to claim 1, characterized in that After heat treating the forging according to the corresponding deformation amount per fire, hot material system and cooling method, the method further includes: 100% mechanical property inspection.

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