阅读说明：本技术 一种镍基高温合金室温强度提升的热处理工艺 (Heat treatment process for improving room temperature strength of nickel-based high-temperature alloy ) 是由 郑磊 刘红亮 赵鑫 董建 孟晔 于 2021-09-07 设计创作，主要内容包括：本发明公开了一种镍基高温合金室温强度提升的热处理工艺,属于镍基高温合金热处理技术领域。本发明所述热处理工艺包括固溶及时效处理：合金首先在1010-1030℃范围内固溶处理20-50min,取出后吹强风冷却至室温；之后在740-760℃范围内时效处理14-16h,随炉冷却至室温。该热处理工艺中,固溶处理后合金的冷速介于水冷与空冷冷速之间；单阶段时效处理后采用炉冷的方式冷却,与固溶处理工艺之间匹配性较好。时效后在得到细小弥散分布的二次γ′相的同时,一次γ′相周围还分布有大量小尺寸的三次γ′相,起到补充强化的作用。与标准热处理工艺相比,该工艺简单高效,在提升合金室温强度方面具有意想不到的效果,其中抗拉强度、屈服强度提升幅度最高分别可达40、45MPa。(The invention discloses a heat treatment process for improving the room temperature strength of a nickel-based superalloy, and belongs to the technical field of heat treatment of the nickel-based superalloy. The heat treatment process comprises solid solution and aging treatment: firstly, carrying out solution treatment on the alloy within the temperature range of 1010-1030 ℃ for 20-50min, taking out the alloy, and then blowing strong wind to cool the alloy to room temperature; then aging for 14-16h in the range of 740 and 760 ℃, and cooling to room temperature along with the furnace. In the heat treatment process, the cooling rate of the alloy after the solution treatment is between the cooling rate of water cooling and the cooling rate of air cooling; after single-stage aging treatment, furnace cooling is adopted for cooling, and the matching performance with the solid solution treatment process is good. After aging, a secondary gamma ' phase which is finely dispersed and distributed is obtained, and meanwhile, a large amount of small-sized tertiary gamma ' phases are also distributed around the primary gamma ' phase, so that the effect of supplementary reinforcement is achieved. Compared with the standard heat treatment process, the process is simple and efficient, and has an unexpected effect on the aspect of improving the room temperature strength of the alloy, wherein the maximum improving amplitude of the tensile strength and the maximum improving amplitude of the yield strength can reach 40 MPa and 45MPa respectively.)

1. A heat treatment process for improving the room temperature strength of a nickel-based superalloy is characterized by comprising the following steps:

step 1: carrying out solution treatment on the alloy at the temperature of 1010 and 1030 ℃ for 20-50min, taking out the alloy, blowing strong wind and cooling to room temperature;

step 2: the alloy is aged for 14-16h in the range of 740-760 ℃ and then cooled to room temperature along with the furnace.

2. The heat treatment process for improving the room temperature strength of the nickel-base superalloy as claimed in claim 1, wherein the temperature rise rate in step 1 and step 2 is 10-30 ℃/min.

3. The heat treatment process for improving the room temperature strength of Ni-based superalloy as claimed in claim 1, wherein the cooling rate in step 1 is controlled within the range of 400-.

4. The heat treatment process for improving the room temperature strength of the nickel-base superalloy as claimed in claim 1, wherein the heat treatment process comprises: the nickel-based high-temperature alloy is GH4738 alloy, and comprises the following main components in percentage by mass: 0.03-0.10% of carbon, 18-21% of chromium, 12-15% of cobalt, 3.5-5% of molybdenum, 2.75-3.25% of titanium, 1.2-1.6% of aluminum, 0.003-0.01% of boron, 0.02-0.12% of zirconium and the balance of nickel.

Technical Field

The invention belongs to the technical field of heat treatment of nickel-based high-temperature alloys, and particularly relates to a heat treatment process for improving the room-temperature strength of a nickel-based high-temperature alloy.

Background

The high-temperature alloy is a key structural material which can not be replaced by high-temperature parts of military and civil aircraft engines and gas turbines at present. With the rapid development of aviation and ship industries, the requirement on the high temperature resistance of key part materials is higher and higher. The nickel-based superalloy has excellent properties such as high use temperature, stable structure, less harmful phases, strong oxidation resistance and the like, and has been successfully applied to high-temperature end parts on aircraft engines and ship gas turbines. Therefore, a great deal of research and analysis has been carried out on how to improve the performance of the nickel-based superalloy in a high-temperature environment, for example, a patent (patent number CN110983107A) proposes a method for improving the high-temperature service performance of a GH4698 alloy forging, and the structural uniformity and the durability of the forging under the high-temperature and high-stress conditions are improved by controlling parameters such as the number of times of deformation of an alloy bar, the cooling speed after forging and heat treatment, and the like.

The heat treatment process of nickel-base high-temperature alloy generally comprises solid solution and aging treatment. The main purpose of the solution treatment is to dissolve carbide and gamma' in the matrix to obtain a uniform supersaturated solid solution, so as to precipitate a strengthening phase with fine and uniformly distributed particles in the aging process. Furthermore, control of solution treatment parameters is critical to achieving a suitable grain size. The main purpose of the aging treatment is to control the content and size of precipitated phases in the matrix. The precipitation hardening type nickel-based high-temperature alloy takes a gamma ' phase as a main strengthening phase, and the increase of the volume fraction of the gamma ' phase and the fine dispersion distribution of the gamma ' phase are beneficial to the improvement of the mechanical property performance of the alloy.

It should be noted that while the nickel-based superalloy is in service at high temperature, it is often used in low-temperature environments such as petroleum and chemical industries in the form of cold-rolled and hot-rolled plates, pipes, etc., under which high requirements are put on the room temperature strength of the alloy. According to the patent (No. CN109306399A), on the basis of a standard GH4738 alloy heat treatment process, one-step aging treatment at 730 ℃ is added, and the room-temperature tensile property of GH4738 bolt products is improved by increasing the volume fraction of a gamma' phase, but the heat treatment process has long aging time and is complicated. Therefore, it is necessary to develop a simple and efficient heat treatment system suitable for improving the room temperature strength of the nickel-based superalloy. The invention successfully realizes the simultaneous improvement of the room-temperature tensile strength and the yield strength of the alloy by utilizing the faster cooling speed after the solution treatment and matching with a reasonable aging treatment process.

Disclosure of Invention

Aiming at the problems in the background art, the invention provides a heat treatment process for improving the room temperature strength of a nickel-based high-temperature alloy, which is simple and efficient and can ensure the fracture resistance and the use safety of the alloy. The alloy is suitable for parts with higher requirements on the room temperature strength of the nickel-based superalloy.

In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:

step 1: carrying out solution treatment on the alloy at the temperature of 1010 and 1030 ℃ for 20-50min, taking out the alloy, blowing strong wind and cooling to room temperature;

step 2: the alloy is aged for 14-16h in the range of 740-760 ℃ and then cooled to room temperature along with the furnace.

Further, the temperature rise speed in the step 1 and the step 2 is 10-30 ℃/min.

Further, the cooling rate of the method in the step 1 is controlled within the range of 400-.

Further, the nickel-based high-temperature alloy is GH4738 alloy, and comprises the following main components in percentage by mass: 0.03-0.10% of carbon, 18-21% of chromium, 12-15% of cobalt, 3.5-5% of molybdenum, 2.75-3.25% of titanium, 1.2-1.6% of aluminum, 0.003-0.01% of boron, 0.02-0.12% of zirconium and the balance of nickel.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention discloses a heat treatment process for improving the room temperature strength of a nickel-based high-temperature alloy, which is characterized in that after solution treatment, a strong air blowing cooling mode is adopted to control the cooling speed within the range of 400-plus 600 ℃/min, wherein the cooling speed is between the cooling speed of water cooling and the cooling speed of air cooling, and the number of gamma 'phase nucleation is increased while the precipitation of gamma' phase is not inhibited; the subsequent aging stage adopts single-stage aging treatment, thereby avoiding the rapid increase of the size of the gamma 'phase in the alloy at the high-temperature aging stage in the original double-aging process, finally obtaining the secondary gamma' phase distribution with fine dispersion distribution, and effectively ensuring the precipitation strengthening effect.

2. After the aging treatment is finished, the alloy part is cooled in a furnace cooling mode, and a large amount of fine three-time gamma ' phases are separated out around the primary gamma ' phase in the cooling process due to the low cooling speed, so that the content of the gamma ' phase in the matrix is increased. Meanwhile, the primary, secondary and tertiary gamma' phases are well matched with each other, and the method has an unexpected effect on improving the room temperature strength of the alloy.

Drawings

FIG. 1 is the distribution of the gamma prime phase in the alloy after solution + aging treatment of example 1.

FIG. 2 is the distribution of the gamma prime phase in the alloy after standard heat treatment.

Detailed Description

The following description of the embodiments of the present invention will be given in more detail with reference to specific examples so that aspects of the present invention and advantages thereof can be better understood. However, the specific embodiments and examples described below are for illustrative purposes only and are not limiting of the invention. Wherein, the alloy in the embodiment is prepared from the same batch of raw materials with the size ofThe composition of the GH4738 alloy forging is shown in Table 1.

GH4738 alloy composition used in the examples of Table 1

Composition (I)	C	Cr	Co	Mo	Ti	Al	Zr	B	Ni
										Content wt. -%)	0.05	19.25	14.10	4.05	2.85	1.49	0.05	0.008	Balance of

The invention relates to a heat treatment process for improving the room temperature strength of a nickel-based superalloy, which comprises the following steps:

step 1: heating the alloy to 1010-1030 ℃ at the speed of 10-30 ℃/min for solution treatment for 20-50min, taking out the alloy, and cooling the alloy to room temperature at the speed of 400-600 ℃/min by blowing strong wind;

step 2: the alloy is heated to 740-760 ℃ at the speed of 10-30 ℃/min for aging treatment for 14-16h, and then is cooled to room temperature along with the furnace.

The nickel-based high-temperature alloy is GH4738 alloy, and comprises the following main components in percentage by mass: 0.03-0.10% of carbon, 18-21% of chromium, 12-15% of cobalt, 3.5-5% of molybdenum, 2.75-3.25% of titanium, 1.2-1.6% of aluminum, 0.003-0.01% of boron, 0.02-0.12% of zirconium and the balance of nickel.

Detailed description of the preferred embodiment

Step 1: the temperature of the GH4738 alloy forging is raised to 1030 ℃ at the speed of 15 ℃/min for solution treatment for 30min, and the GH4738 alloy forging is cooled to room temperature at the speed of 400-600 ℃/min by blowing strong wind after being taken out;

step 2: the temperature of the GH4738 alloy forging piece is raised to 760 ℃ at the speed of 20 ℃/min for aging treatment for 14h, and then the GH4738 alloy forging piece is cooled to room temperature along with the furnace.

Detailed description of the invention

Step 1: the temperature of the GH4738 alloy forging is raised to 1020 ℃ at the speed of 20 ℃/min for solution treatment for 50min, and the GH4738 alloy forging is cooled to room temperature at the speed of 400-600 ℃/min by blowing strong wind after being taken out;

step 2: the temperature of the GH4738 alloy forging piece is raised to 750 ℃ at the speed of 25 ℃/min for aging treatment for 16h, and then the GH4738 alloy forging piece is cooled to room temperature along with a furnace.

The mechanical property test results of a plurality of groups of furnace-associated samples show that the strength value of the GH4738 alloy treated by the heat treatment process is obviously improved at room temperature, wherein the tensile strength reaches 1372MPa, the yield strength reaches 951MPa, and the lifting amplitudes can reach 40 MPa and 45MPa respectively.

The mechanical property results of the furnace sample test are shown in table 2;

TABLE 2 GH4738 alloy forging mechanical property detection results

In conclusion, the invention provides the heat treatment process for improving the room temperature strength of the nickel-based superalloy, and the room temperature tensile strength and the yield strength of the alloy are obviously improved on the basis of the existing process by optimizing the heat treatment process and the microstructure of the alloy.

In addition to the above, other embodiments of the present invention are possible. All technical solutions which adopt equivalent substitutions or equivalent transformations fall within the protection scope of the claims of the present invention.