A gh4080a alloy and a method of reducing hardness by heat treatment

Abstract

The application provides a heat treatment method for reducing the hardness of GH4080A alloy, comprising the following steps: S1: selecting GH4080A alloy to be reduced in hardness, and sampling and testing the actual hardness thereof; S2: starting a continuous solid solution heat treatment furnace, setting the furnace temperature to 900-1000 DEG C, setting the holding time to 30-60 min, and adding the GH4080A alloy in step S1 into the continuous solid solution heat treatment furnace for treatment; S3: the GH4080A alloy in step S2 enters the furnace from the furnace head of the continuous solid solution heat treatment furnace, and after the holding time, the GH4080A alloy is discharged from the furnace tail through a cooling liquid, and the heat treatment is completed. Sampling is conducted on the cooled steel material for hardness testing. According to the application, the hardness of the GH4080A alloy is reduced without affecting the grain size of the GH4080A alloy, and the application has high commercial value and popularization value.

Description

Technical Field

[0001] This invention relates to the field of high-temperature alloy heat treatment technology, and more specifically, to a GH4080A alloy and a heat treatment method for reducing hardness. Background Technology

[0002] GH4080A is an age-hardening nickel-based superalloy. It is mainly strengthened by adding Al and Ti elements to form the γ' phase with Ni elements. GH4080A alloy has good oxidation resistance and creep resistance in the range of 650-850℃ and is used to manufacture exhaust valves for diesel engines in automobiles and ships.

[0003] As an exhaust valve for diesel engines, this alloy requires a vacuum induction + electroslag remelting process. The product specification is round steel, and the delivery condition requires solution treatment + bright silver finish. One of the physical and chemical requirements is that the hardness HBW in the delivery state must be ≤325.

[0004] The Φ16mm round bright silver alloy produced for the user according to standard technical requirements, after solution treatment, had its delivery hardness measured on samples taken from different support rods. The results were 328.6, 329.4, 331.9, 335.2, and 336, with an average of 332.22, exceeding the standard requirements and thus unacceptable for delivery. Furthermore, this product requires a grain size of no more than grade 5 across the entire cross-section. If solution treatment is repeated according to the technical requirements, the grain size may increase, potentially leading to further defects. Currently, there is no conventional method to reduce the hardness of GH4080A alloy after delivery while simultaneously meeting the grain size requirements. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a heat treatment method for reducing the hardness of GH4080A alloy, so as to fill the gap in this field, and ensure that the grain size of GH4080A alloy does not increase while reducing the hardness of GH4080A alloy.

[0006] To address the above problems, this invention provides a heat treatment method for reducing the hardness of GH4080A alloy, comprising the following steps:

[0007] S1: Select the GH4080A alloy whose hardness needs to be reduced, and take a sample to test its actual hardness.

[0008] S2: Turn on the continuous solution heat treatment furnace, set the furnace temperature to 900℃-1000℃, set the holding time to 30min-60min, and add the GH4080A alloy from step S1 into the continuous solution heat treatment furnace for treatment.

[0009] S3: The GH4080A alloy in step S2 enters the furnace from the furnace head of the continuous solution heat treatment furnace. After the holding time, it exits the furnace from the furnace tail through the cooling liquid. A sample is taken from the cooled steel for hardness testing to complete the heat treatment.

[0010] As a preferred embodiment, in step S1, the GH4080A alloy comprises the following components:

[0011] C: 0.04%–0.10%; Si: ≤1.0%; Mn: ≤1.0%; S: ≤0.015%; P: ≤0.02%; Cr: 18.0%–21.0%; Al: 1.0%–1.8%; Ti: 1.8%–2.7%; B: ≤0.008%; Co: ≤2.0%; Fe: ≤1.5%; Cu: ≤0.2%; the balance being nickel and other unavoidable impurities.

[0012] As a preferred embodiment, the GH4080A alloy comprises the following components:

[0013] C: 0.04%; Si: ≤0.5%; Mn: ≤0.5%; S: ≤0.005%; P: ≤0.005%; Cr: 20.5%; Al: 1.4%; Ti: 2.3%; B: ≤0.005%; Co: ≤1.0%; Fe: ≤1.0%; Cu: ≤0.1%; balance is nickel and other unavoidable impurities.

[0014] As a preferred embodiment, in step S1, the GH4080A alloy is GH4080A bright silver steel.

[0015] As a preferred embodiment, in step S2, the furnace temperature is 950°C and the holding time is 40 minutes.

[0016] As a preferred embodiment, in step S3, the coolant is water.

[0017] Another technical problem to be solved by the present invention is to provide a GH4080A alloy that solves the problem that the hardness of GH4080A alloy prepared by conventional methods exceeds the standard and cannot be delivered, and that solution treatment will lead to grain enlargement.

[0018] To address the aforementioned problems, this invention provides a GH4080A alloy, which is prepared by the heat treatment method described above.

[0019] As a preferred embodiment, the hardness of the GH4080A alloy is ≤305HBW.

[0020] Compared with the prior art, the present invention has the following technical advantages:

[0021] This invention controls the solution treatment temperature of GH4080A alloy within a temperature range below the recrystallization temperature (the temperature at which grain growth does not occur) and above the temperature at which the main strengthening phase γ' phase can completely dissolve. By combining this with actual heat treatment equipment and cooling conditions, a suitable heat treatment temperature is selected to reduce the material hardness, meeting delivery requirements. Furthermore, the GH4080A alloy prepared using this invention has a hardness ≤305HBW, far below the relevant hardness requirements of the technical standard, without affecting the grain size of the GH4080A alloy. This invention provides a heat treatment method that can effectively reduce the hardness of GH4080A alloy, possessing high commercial and promotional value. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the solution treatment process of the present invention.

[0023] Figure 2 The image shows the hardness test results of an embodiment of the present invention. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] This invention provides a heat treatment method for reducing the hardness of GH4080A alloy, comprising the following steps:

[0026] S1: Select the GH4080A alloy whose hardness needs to be reduced, and take a sample to test its actual hardness.

[0027] S2: Turn on the continuous solution heat treatment furnace, set the furnace temperature to 900℃-1000℃, set the holding time to 30min-60min, and add the GH4080A alloy from step S1 into the continuous solution heat treatment furnace for treatment.

[0028] S3: The GH4080A alloy in step S2 enters the furnace from the furnace head of the continuous solution heat treatment furnace. After the holding time, it exits the furnace from the furnace tail through the cooling liquid. A sample is taken from the cooled steel for hardness testing to complete the heat treatment.

[0029] Preferably, in step S1, the alloy comprising GH4080A has the following components:

[0030] C: 0.04%–0.10%; Si: ≤1.0%; Mn: ≤1.0%; S: ≤0.015%; P: ≤0.02%; Cr: 18.0%–21.0%; Al: 1.0%–1.8%; Ti: 1.8%–2.7%; B: ≤0.008%; Co: ≤2.0%; Fe: ≤1.5%; Cu: ≤0.2%; the balance being nickel and other unavoidable impurities.

[0031] Preferably, the GH4080A alloy comprises the following components:

[0032] C: 0.04%; Si: ≤0.5%; Mn: ≤0.5%; S: ≤0.005%; P: ≤0.005%; Cr: 20.5%; Al: 1.4%; Ti: 2.3%; B: ≤0.005%; Co: ≤1.0%; Fe: ≤1.0%; Cu: ≤0.1%; balance is nickel and other unavoidable impurities.

[0033] Preferably, in step S1, the GH4080A alloy is GH4080A bright silver steel.

[0034] Preferably, in step S2, the furnace temperature is 950°C and the holding time is 40 minutes.

[0035] Preferably, in step S3, the coolant is water.

[0036] The present invention also provides a GH4080A alloy, which is prepared by the above-described heat treatment method.

[0037] Preferably, the hardness of the GH4080A alloy is ≤305HBW.

[0038] The technical solution of the present invention will be described in detail below with reference to specific data ranges. In the following embodiments, the GH4080A silver bright material is a Φ16mm round GH4080A silver bright material:

[0039] Example 1:

[0040] This embodiment provides a heat treatment method for reducing the hardness of GH4080A alloy, including the following steps:

[0041] S1: Select GH4080A silver bright material whose hardness needs to be reduced, and take samples to test its actual hardness;

[0042] S2: Turn on the continuous solution heat treatment furnace, set the furnace temperature to 950℃ and the holding time to 40min, and add the GH4080A alloy from step S1 into the continuous solution heat treatment furnace for treatment.

[0043] S3: The GH4080A alloy from step S2 enters the continuous solution heat treatment furnace from the furnace head, and after a holding time, it exits the furnace through water cooling, completing the heat treatment. Samples are taken from the cooled steel for hardness testing.

[0044] As a preferred embodiment, the GH4080A alloy comprises the following components:

[0045] C: 0.04%; Si: ≤0.5%; Mn: ≤0.5%; S: ≤0.005%; P: ≤0.005%; Cr: 20.5%; Al: 1.4%; Ti: 2.3%; B: ≤0.005%; Co: ≤1.0%; Fe: ≤1.0%; Cu: ≤0.1%; balance is nickel and other unavoidable impurities.

[0046] Example 2:

[0047] This embodiment provides a heat treatment method for reducing the hardness of GH4080A alloy, including the following steps:

[0048] S1: Select GH4080A silver bright material whose hardness needs to be reduced, and take samples to test its actual hardness;

[0049] S2: Turn on the continuous solution heat treatment furnace, set the furnace temperature to 900℃ and the holding time to 60min, and add the GH4080A alloy from step S1 into the continuous solution heat treatment furnace for treatment.

[0050] S3: The GH4080A alloy from step S2 enters the continuous solution heat treatment furnace from the furnace head, and after a holding time, it exits the furnace through water cooling, completing the heat treatment. Samples are taken from the cooled steel for hardness testing.

[0051] As a preferred embodiment, in step S1, the GH4080A alloy comprises the following components:

[0052] C: 0.04%; Si: ≤1.0%; Mn: ≤1.0%; S: ≤0.015%; P: ≤0.02%; Cr: 18.0%; Al: 1.0%; Ti: 1.8%; B: ≤0.008%; Co: ≤2.0%; Fe: ≤1.5%; Cu: ≤0.2%; balance is nickel and other unavoidable impurities.

[0053] Example 3:

[0054] This embodiment provides a heat treatment method for reducing the hardness of GH4080A alloy, including the following steps:

[0055] S1: Select GH4080A silver bright material whose hardness needs to be reduced, and take samples to test its actual hardness;

[0056] S2: Turn on the continuous solution heat treatment furnace, set the furnace temperature to 1000℃ and the holding time to 30min, and add the GH4080A alloy from step S1 into the continuous solution heat treatment furnace for treatment.

[0057] S3: The GH4080A alloy from step S2 enters the continuous solution heat treatment furnace from the furnace head, and after a holding time, it exits the furnace through water cooling, completing the heat treatment. Samples are taken from the cooled steel for hardness testing.

[0058] As a preferred embodiment, in step S1, the GH4080A alloy comprises the following components:

[0059] C: 0.10%; Si: ≤1.0%; Mn: ≤1.0%; S: ≤0.015%; P: ≤0.02%; Cr: 21.0%; Al: 1.8%; Ti: 2.7%; B: ≤0.008%; Co: ≤2.0%; Fe: ≤1.5%; Cu: ≤0.2%; balance is nickel and other unavoidable impurities.

[0060] Example 4:

[0061] This embodiment provides a heat treatment method for reducing the hardness of GH4080A alloy, including the following steps:

[0062] S1: Select GH4080A silver bright material whose hardness needs to be reduced, and take samples to test its actual hardness;

[0063] S2: Turn on the continuous solution heat treatment furnace, set the furnace temperature to 1000℃ and the holding time to 40min, and add the GH4080A alloy from step S1 into the continuous solution heat treatment furnace for treatment.

[0064] S3: The GH4080A alloy from step S2 enters the continuous solution heat treatment furnace from the furnace head, and after a holding time, it exits the furnace through water cooling, completing the heat treatment. Samples are taken from the cooled steel for hardness testing.

[0065] As a preferred embodiment, the GH4080A alloy comprises the following components:

[0066] C: 0.04%; Si: ≤0.5%; Mn: ≤0.5%; S: ≤0.005%; P: ≤0.005%; Cr: 20.5%; Al: 1.4%; Ti: 2.3%; B: ≤0.005%; Co: ≤1.0%; Fe: ≤1.0%; Cu: ≤0.1%; balance is nickel and other unavoidable impurities.

[0067] Example 5:

[0068] This embodiment provides a heat treatment method for reducing the hardness of GH4080A alloy, including the following steps:

[0069] S1: Select GH4080A silver bright material whose hardness needs to be reduced, and take samples to test its actual hardness;

[0070] S2: Turn on the continuous solution heat treatment furnace, set the furnace temperature to 900℃ and the holding time to 30min, and add the GH4080A alloy from step S1 into the continuous solution heat treatment furnace for treatment.

[0071] S3: The GH4080A alloy from step S2 enters the continuous solution heat treatment furnace from the furnace head, and after a holding time, it exits the furnace through water cooling, completing the heat treatment. Samples are taken from the cooled steel for hardness testing.

[0072] As a preferred embodiment, the GH4080A alloy comprises the following components:

[0073] C: 0.04%; Si: ≤0.5%; Mn: ≤0.5%; S: ≤0.005%; P: ≤0.005%; Cr: 20.5%; Al: 1.4%; Ti: 2.3%; B: ≤0.005%; Co: ≤1.0%; Fe: ≤1.0%; Cu: ≤0.1%; balance is nickel and other unavoidable impurities.

[0074] Figure 1 This is a schematic diagram of the solution treatment process of the present invention. Figure 2 The image shows the hardness test results of an embodiment of the present invention.

[0075] The hardness of the GH4080A alloys in Examples 1-5 above was tested before and after heat treatment. The test results are as follows:

[0076] Table 1. Comparison of hardness before and after improvement of 16mm silver bright GH4080A alloy.

[0077]

[0078] As can be seen from the table above, when the Φ16mm round GH4080A silver bright material of Examples 1-5 was retreated using the heat treatment method of the present invention, the measured hardness was lower than the standard requirement, and all met the technical standard HBW≤325 requirement. This further illustrates that the present invention provides a heat treatment method that can effectively reduce the hardness of GH4080A alloy, and has high commercialization and promotion value.

[0079] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A heat treatment method for reducing the hardness of GH4080A alloy, characterized in that: Includes the following steps: S1: Select the GH4080A alloy whose hardness needs to be reduced, and take a sample to test its actual hardness; S2: Turn on the continuous solution heat treatment furnace, set the furnace temperature to 950℃, and the holding time to 40 minutes. Add the GH4080A alloy from step S1 into the continuous solution heat treatment furnace for processing; S3: The GH4080A alloy from step S2 enters the furnace from the furnace head, and after the holding time, exits from the furnace tail through the cooling liquid, completing the heat treatment; take a sample from the cooled steel for hardness testing. In step S1, the GH4080A alloy is GH4080A bright silver steel; In step S3, the coolant is water.

2. The heat treatment method for reducing the hardness of GH4080A alloy according to claim 1, characterized in that: In step S1, the GH4080A alloy comprises the following components: C: 0.04% to 0.10%; Si: ≤1.0%; Mn: ≤1.0%; S: ≤0.015%; P: ≤0.02%; Cr: 18.0%~21.0%; Al：1.0％-1.8％； Ti: 1.8%-2.7%; B: ≤0.008%; Co: ≤2.0%; Fe: ≤1.5%; Cu: ≤0.2%; balance is nickel and other unavoidable impurities.

3. The heat treatment method for reducing the hardness of GH4080A alloy according to claim 2, characterized in that: The GH4080A alloy comprises the following components: C: 0.04%; Si: ≤0.5%; Mn: ≤0.5%; S: ≤0.005%; P: ≤0.005%; Cr: 20.5%; Al：1.4％； Ti: 2.3%; B: ≤0.005%; Co: ≤1.0%; Fe: ≤1.0%; Cu: ≤0.1%; balance is nickel and other unavoidable impurities.

4. A GH4080A alloy, characterized in that: The GH4080A alloy is prepared by any one of the heat treatment methods according to claims 1-3.

5. The GH4080A alloy according to claim 4, characterized in that: The hardness of the GH4080A alloy is ≤305HBW.

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