阅读说明：本技术 一种FeCoNiAlNb高温合金均匀化处理方法 (FeCoNiAlNb high-temperature alloy homogenization treatment method ) 是由 李生志 丁丽锋 刘松锋 沈红卫 于 2019-03-22 设计创作，主要内容包括：本发明提供了一种FeCoNiAlNb高温合金均匀化处理方法,包括以下步骤：S1、预热处理：在热处理炉中将高温合金材料加热至1120℃±10℃；当高温合金材料在炉内的摆放间隙大于高温合金材料的厚度D时,预热时间t＝1.0+(1.5～2.0)D/60；当高温合金材料在炉内的摆放间隙小于高温合金材料的厚度D,且装炉量G(kg)大于300kg时,预热时间t＝1.0+(0.1～0.2)G/60+(1.5～2.0)D/60；S2、二级均匀化处理：第一级均匀化处理温度为1160℃±10℃,保温时间为30～40h；第二级均匀化处理温度为1190℃±10℃,保温时间为30～50h。本发明方法有效地消除了粗大枝晶组织、laves相和富Nb析出相,实现组织均匀化的目的,降低了能耗和生产成本。(The invention provides a FeCoNiAlNb high-temperature alloy homogenization treatment method, which comprises the following steps of: s1, preheating: heating the high-temperature alloy material to 1120 +/-10 ℃ in a heat treatment furnace; when the placing clearance of the high-temperature alloy material in the furnace is larger than the thickness D of the high-temperature alloy material, the preheating time t is 1.0+ (1.5-2.0) D/60; when the placing clearance of the high-temperature alloy material in the furnace is smaller than the thickness D of the high-temperature alloy material and the charging amount G (kg) is larger than 300kg, the preheating time t is 1.0+ (0.1-0.2) G/60+ (1.5-2.0) D/60; s2, secondary homogenization treatment: the temperature of the first-stage homogenization treatment is 1160 +/-10 ℃, and the heat preservation time is 30-40 h; the temperature of the second-stage homogenization treatment is 1190 +/-10 ℃, and the heat preservation time is 30-50 h. The method effectively eliminates coarse dendritic crystal structures, laves phases and Nb-rich precipitated phases, realizes the purpose of tissue homogenization and reduces energy consumption and production cost.)

1. A FeCoNiAlNb high-temperature alloy homogenization treatment method is characterized by comprising the following steps:

s1, preheating: heating the high-temperature alloy material to 1120 +/-10 ℃ in a heat treatment furnace; when the placing clearance of the high-temperature alloy material in the furnace is larger than the thickness D of the high-temperature alloy material, the preheating time t is 1.0+ (1.5-2.0) D/60, wherein the unit of D is mm, and the unit of t is h; when the placing clearance of the high-temperature alloy material in the furnace is smaller than the thickness D of the high-temperature alloy material and the charging amount G is larger than 300kg, the preheating time t is 1.0+ (0.1-0.2) G/60+ (1.5-2.0) D/60, wherein the unit of G is kg;

s2, secondary homogenization treatment: the temperature of the first-stage homogenization treatment is 1160 +/-10 ℃, and the heat preservation time is 30-40 h; the temperature of the second-stage homogenization treatment is 1190 +/-10 ℃, and the heat preservation time is 30-50 h.

2. The homogenization treatment method of claim 1, further comprising a step S3 of hot working deformation treatment: and (3) directly carrying out hot working deformation treatment on the high-temperature alloy material in the S2, wherein the temperature is not lower than 1110 ℃, and the equivalent deformation is not lower than 75%.

3. The homogenization treatment method according to claim 2, wherein the hot working deformation treatment is hot rolling or hot forging.

4. The homogenization processing method according to claim 2, further comprising step S4 of homogenization annealing: the temperature is 1110 +/-10 ℃; when the placing clearance of the high-temperature alloy material in the furnace is larger than the thickness D of the high-temperature alloy material, the total time t1 of temperature equalization and heat preservation is 1.0+ (1.5-2.0) D/60, wherein the unit of t1 is h; when the placing clearance of the high-temperature alloy material in the furnace is smaller than the thickness D of the high-temperature alloy material and the charging amount G is larger than 300kg, the total time t1 of temperature equalization and heat preservation is 1.0+ (0.1-0.2) G/60+ (1.5-2.0) D/60, and then the high-temperature alloy material is rapidly cooled.

5. The homogenization treatment process of claim 4, wherein the rapid cooling is water-gas mixed cooling or stepwise alternate cooling.

6. The homogenization treatment method of claim 1, wherein the step S1 further comprises a second preheating treatment at 1140 ℃ ± 10 ℃; when the placing clearance of the high-temperature alloy material in the furnace is larger than the thickness D of the high-temperature alloy material, the second preheating time t2 is 1.0+ (1.5-2.0) D/60, wherein the unit of t2 is h; when the placing clearance of the high-temperature alloy material in the furnace is smaller than the thickness D of the high-temperature alloy material and the furnace loading amount G is larger than 300kg, the second preheating time t2 is 1.0+ (0.1-0.2) G/60+ (1.5-2.0) D/60, and then the temperature is rapidly increased along with the furnace.

7. The homogenization treatment method according to claim 1, wherein the heating in S1 is a stepwise heating, and the average temperature rise rate is 5 to 10 ℃/S.

Technical Field

The invention relates to the technical field of high-temperature alloys, in particular to a FeCoNiAlNb high-temperature alloy homogenization treatment method.

Background

The FeCoNiAlNb high-temperature alloy has the characteristics of low expansion coefficient, excellent high-temperature oxidation resistance, high strength and toughness, high-temperature endurance strength, high structural stability, good formability, good machinability and the like, and therefore, the FeCoNiAlNb high-temperature alloy becomes a selected material of key parts in aerospace and supercritical power generation equipment. The FeCoNiAlNb high-temperature alloy belongs to precipitation strengthening type high-temperature alloy, and the performance of the alloy is greatly influenced by alloy components, precipitated phases, hot working and heat treatment processes. Generally, the beta phase formed in the structure of the alloy after being subjected to high-temperature diffusion annealing, hot working and standard aging treatment after casting can block the sliding of a grain boundary, and is beneficial to improving the smoothness, the notch durability and the crack expansion resistance of the alloy.

The FeCoNiAlNb high-temperature alloy contains more Co and Ni, and the material cost is high. In addition, the control requirements on the material preparation and forming process, especially the heat treatment process, are very strict. The segregation of material components and unqualified performance can be caused by the problems in any preparation and process control links, and serious economic loss is caused. In the actual production process, an important problem easily caused by the alloy is that the structure is not uniform due to composition segregation, and even more serious beta phase strip-shaped precipitation occurs. The purpose of the high-temperature homogenizing diffusion annealing treatment before the material hot working deformation is to reduce or eliminate dendritic crystal segregation in the ingot and improve the hot working deformation capability of the material. However, long-term high-temperature diffusion annealing consumes large energy, the production period of the material is prolonged, and the material is seriously oxidized due to the long-term high-temperature diffusion annealing process. Therefore, it is a significant work to explore the alloy composition and structure homogenization treatment technology and optimize and improve the long-time high-temperature diffusion annealing process before and after forging or hot rolling. Researches show that the GH4169 alloy contains high Nb element, so that the solidification process of the alloy becomes complex, the segregation of an alloy structure in an as-cast state is serious, and the subsequent processing and heat treatment are difficult. However, the alloy is subjected to homogenization annealing treatment in the later period, micro solidification segregation is eliminated, uniform components and tissue morphology are obtained, and the hot workability and the high-temperature service performance of the alloy are obviously improved. U.S. patent application US5478417A provides an Al-containing FeCoNi controlled thermal expansion alloy that can be solutionized at 1010 ℃, 1066 ℃ or 1110 ℃ and then aged at a beta-phase precipitation temperature above 788 ℃ to optimize crack propagation resistance. The patent application mainly controls the expansion coefficient of the alloy by changing chemical compositions, and performs simple heat treatment to control the structure, and does not mention the homogenization treatment process. European patent application EP0856589a1 provides an age hardenable aluminium containing controlled low expansion superalloy with composition control and ageing to obtain the final finished material, and does not describe a homogenisation process. US7160400B2 provides a low coefficient of thermal expansion nickel-based superalloy and a method for making the same, and does not address the optimization of the homogenization process to achieve superior texture and properties. None of the above prior arts has been described with a perfect high-temperature homogenization treatment process, and especially a homogenization treatment process for eliminating band segregation in a FeCoNiAlNb high-temperature alloy containing Al and Nb is rarely reported.

At present, the homogenization treatment process of the FeCoNiAlNb high-temperature alloy mainly adopts a one-step homogenization treatment mode of preserving heat for a long time at 1150-1250 ℃, although the process is simple, if the process is improperly controlled, the homogenization treatment temperature is too high, the alloy is locally over-burnt, crystal grains grow abnormally, the alloy is seriously oxidized, and the yield is low; if the treatment temperature is too low, coarse dendrites, Laves phases, coarse Nb-rich precipitate phases and other deleterious impurity phases cannot be eliminated. In addition, if the homogenization treatment is not proper, some 'genetic' coarse abnormal structures can appear in the alloy after subsequent cogging and hot working, and even the surface of the alloy bar can be cracked in the hot deformation process. Therefore, the reasonable homogenization treatment process of the FeCoNiAlNb superalloy, particularly the homogenization treatment before ingot cogging can enable the material to obtain a uniform and segregation-free tissue form, and plays an important role in obtaining excellent material performance subsequently.

Disclosure of Invention

In view of the above-mentioned defects, the present invention aims to provide a homogenization treatment method for FeCoNiAlNb superalloy, so as to effectively eliminate nonuniform components and structures in the alloy.

The invention provides a FeCoNiAlNb high-temperature alloy homogenization treatment method, which comprises the following steps of:

s1, preheating: heating the high-temperature alloy material to 1120 +/-10 ℃ in a heat treatment furnace; when the placing clearance of the high-temperature alloy material in the furnace is larger than the thickness D of the high-temperature alloy material, the preheating time t is 1.0+ (1.5-2.0) D/60, wherein the unit of D is mm, and the unit of t is h; when the placing clearance of the high-temperature alloy material in the furnace is smaller than the thickness D of the high-temperature alloy material and the charging amount G is larger than 300kg, the preheating time t is 1.0+ (0.1-0.2) G/60+ (1.5-2.0) D/60, wherein the unit of G is kg;

s2, secondary homogenization treatment: the temperature of the first-stage homogenization treatment is 1160 +/-10 ℃, and the heat preservation time is 30-40 h; the temperature of the second-stage homogenization treatment is 1190 +/-10 ℃, and the heat preservation time is 30-50 h.

Preferably, the method further comprises the step of S3, hot working deformation treatment: and (3) directly carrying out hot working deformation treatment on the high-temperature alloy material in the S2, wherein the temperature is not lower than 1110 ℃, and the equivalent deformation is not lower than 75%.

Preferably, the hot working deformation treatment mode is hot rolling or hot forging.

Preferably, the method further comprises step S4 of homogenizing annealing: the temperature is 1110 +/-10 ℃; when the placing clearance of the high-temperature alloy material in the furnace is larger than the thickness D of the high-temperature alloy material, the total time t1 of temperature equalization and heat preservation is 1.0+ (1.5-2.0) D/60, wherein the unit of t1 is h; when the placing clearance of the high-temperature alloy material in the furnace is smaller than the thickness D of the high-temperature alloy material and the charging amount G is larger than 300kg, the total time t1 of temperature equalization and heat preservation is 1.0+ (0.1-0.2) G/60+ (1.5-2.0) D/60, and then the high-temperature alloy material is rapidly cooled.

Preferably, the rapid cooling adopts water-gas mixed cooling or sectional alternate cooling.

Preferably, the S1 further comprises a second preheating treatment, wherein the temperature is 1140 +/-10 ℃; when the placing clearance of the high-temperature alloy material in the furnace is larger than the thickness D of the high-temperature alloy material, the second preheating time t2 is 1.0+ (1.5-2.0) D/60, wherein the unit of t2 is h; when the placing clearance of the high-temperature alloy material in the furnace is smaller than the thickness D of the high-temperature alloy material and the furnace loading amount G is larger than 300kg, the second preheating time t2 is 1.0+ (0.1-0.2) G/60+ (1.5-2.0) D/60, and then the temperature is rapidly increased along with the furnace.

Preferably, the heating mode in S1 is segmented heating, and the average heating rate is 5-10 ℃/S

In conclusion, the method comprises the steps of preheating treatment, secondary homogenization treatment, hot working deformation treatment and homogenization annealing treatment on the cast alloy, and on one hand, aiming at the dissolution characteristics of coarse dendrites, laves phases and Nb-rich precipitated phases at different temperatures, the method of heating to different temperatures is adopted for targeted elimination, so that the purpose of tissue homogenization is realized; on the other hand, by adopting the two-stage homogenization treatment, the alloy is heated more uniformly, the phenomena of overburning and abnormal growth of crystal grains are eliminated, and the components and the structure after the treatment are more uniform. Meanwhile, in consideration of the condition that the alloy is oxidized seriously at high temperature, the method has relatively short heat preservation time of the high-temperature alloy at a higher temperature section, obviously reduces the oxidation degree of the FeCoNiAlNb high-temperature alloy material, and increases the yield of the material. In addition, the average heating temperature of the method is relatively low, and the energy consumption and the production cost are reduced.

Drawings

FIG. 1 is a schematic view of a method for homogenizing a superalloy in accordance with the present invention;

FIG. 2a is an as-cast structure diagram of FeCoNiAlNb superalloy in example 1 of the present invention;

FIG. 2b is an as-cast metallographic structure diagram of a FeCoNiAlNb superalloy in example 1 of the present invention;

FIG. 3 is a metallographic structure of the FeCoNiAlNb superalloy of FIG. 2b after a first homogenization treatment;

FIG. 4 is a metallographic structure of the FeCoNiAlNb superalloy of FIG. 3 after a second homogenization treatment;

FIG. 5 is a metallographic structure of a FeCoNiAlNb superalloy treated only by hot work deformation;

FIG. 6 is a metallographic structure of the FeCoNiAlNb superalloy of FIG. 4 after hot working deformation and homogenizing annealing.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be understood that the processing equipment or apparatus not specifically identified in the following examples is conventional in the art. Furthermore, it is to be understood that one or more method steps mentioned in the present invention does not exclude that other method steps may also be present before or after the combined steps or that other method steps may also be inserted between these explicitly mentioned steps, unless otherwise indicated; it is also to be understood that a combined connection between one or more devices/apparatus as referred to in the present application does not exclude that further devices/apparatus may be present before or after the combined device/apparatus or that further devices/apparatus may be interposed between two devices/apparatus explicitly referred to, unless otherwise indicated. Moreover, unless otherwise indicated, the numbering of the various method steps is merely a convenient tool for identifying the various method steps, and is not intended to limit the order in which the method steps are arranged or the scope of the invention in which the invention may be practiced, and changes or modifications in the relative relationship may be made without substantially changing the technical content.

The invention provides a homogenization treatment method of FeCoNiAlNb superalloy, which aims to effectively eliminate uneven components and structures in the alloy by adopting a preheating treatment and a multi-stage homogenization treatment method and solves the problems of zonal segregation, uneven distribution of precipitated phases and the like in the final structure of the alloy caused by insufficient homogenization treatment as shown in figure 1.