CN116810067A - GH4169D alloy brazing and heat treatment process methods - Google Patents

Abstract

The invention relates to a process method for brazing and heat treatment of GH4169D alloy, which comprises the following steps: the initial process treatment is carried out until the grain size of the GH4169D alloy matrix material is 8-12 grade; carrying out brazing process treatment, wherein the brazing temperature is 1020+/-10 ℃, and carrying out heat preservation for a preset time period, and cooling after heat preservation; intermediate treatment, wherein the intermediate treatment temperature is 870+/-10 ℃ and cooling is carried out; standard heat treatment. Solves the problems of reduced yield strength and notch sensitivity of GH4169D alloy after brazing, and improves the mechanical property of the material.

Description

GH4169D alloy brazing and heat treatment process methods

Technical field

The invention belongs to the technical field of material heat treatment, and in particular relates to a process method for brazing and heat treatment of GH4169D alloy.

Background technique

GH4169D alloy is a new type of alloy that can be used stably for a long time between 650 and 750°C. It is different from GH4169. GH4169D alloy has begun to be gradually used in the aerospace, aerospace and petroleum industries in recent years. During use, the alloy will inevitably be designed into a GH4169D alloy forging with a honeycomb structure. When the parts are processed, the base body and the honeycomb are connected by a brazing process. The brazing process uses a metal material with a lower melting point than the base metal as the filler metal. The base metal and the filler metal are heated to a temperature higher than the melting point of the filler metal but lower than the melting point of the base metal. The liquid filler metal is heated in or on the base metal. A welding technology that connects the base materials together by wetting, capillary flow, filling, spreading, interacting with the base material, and cooling and solidifying to form a strong connection.

When the existing high-temperature alloy brazing process is used for GH4169D alloy forgings, it will cause the strengthening phase η and γ' phase of the GH4169D material to change. The eta phase content is less than 1%, the γ' phase is uneven, and the large size γ' phase is about 128nm. The small size γ' phase is about 39nm, and the matrix structure is shown in Figure 1, which leads to a decrease in the yield strength of the alloy, sensitivity to notches, and a reduction in the mechanical properties of the material. To this end, it is necessary to study a brazing and heat treatment process using GH4169D alloy forgings to improve the mechanical properties of the forgings.

In view of this, the present invention is proposed.

Contents of the invention

The invention provides a process method for brazing and heat treatment of GH4169D alloy, which can improve the mechanical properties of forgings.

A process method for brazing and heat treatment of GH4169D alloy. The process method includes:

Initial process treatment, processing until the grain size of the GH4169D alloy matrix material is 8 to 12 levels;

Brazing process, the brazing temperature is 1020℃±10℃, and the heat preservation is carried out for a preset time, and then cooling is carried out after heat preservation;

Intermediate treatment, the intermediate treatment temperature is 870℃±10℃ and cooled;

Standard heat treatment.

Compared with the existing technology, the technical solution provided by the present invention includes the following beneficial effects:

The requirements for the grain size of the base material before brazing are 8-12, the brazing and heat treatment process, brazing temperature, holding time and cooling method, intermediate processing temperature, time and cooling method, the process solves the problem of brazing of GH4169D alloy The post-yield strength decreases and notch sensitivity problems are solved, and the mechanical properties of the material are improved.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a metallographic diagram of the GH4169D alloy in the prior art;

Figure 2 is a schematic diagram of the method of the present invention;

Figure 3 is a metallographic diagram of the GH4169D alloy produced by the method of the present invention.

Detailed ways

The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some of the embodiments of the present invention, but not all of the embodiments. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, as long as there is no conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

As shown in Figure 2, the process method of brazing and heat treatment of GH4169D alloy includes:

S101: Initial process treatment, which is carried out by conventional methods of the existing technology until the grain size of the GH4169D alloy matrix material is 8 to 12. The purpose is: the eta phase pins the grain boundaries in the GH4169D alloy and hinders the expansion of grain boundary cracks. , improve the yield strength and notch sensitivity of the alloy, and the eta phase precipitates at the grain boundaries. The finer the grains, the more grain boundaries there are, which is conducive to the precipitation of the eta phase.

S102: Brazing process, the brazing temperature is 1020℃±10℃, and the heat preservation is carried out for a preset period of time. After heat preservation, cooling treatment is carried out. Specifically:

The brazing temperature is 1020℃±10℃ and kept for 15 to 20 minutes. After the conventional brazing temperature of 1040℃, the eta phase is almost completely dissolved. Lowering the brazing temperature is beneficial to reducing the dissolution of the eta phase.

After insulation, slowly cool to 950°C, then cool quickly. Slow cooling (cooling in the furnace without filling cooling gas) to 950℃ is to prevent welding cracks and reduce stress at the weld, and rapid cooling (cooling with argon gas) to below 150℃ is used to improve production efficiency.

S103: Intermediate treatment, the intermediate treatment temperature is 870℃±10℃, and cooling is carried out, specifically:

The intermediate treatment temperature is 870℃±10℃, and the time is 4 to 6 hours; the intermediate treatment temperature of 870℃±10℃ is lower than the above-mentioned 950℃. In the GH4169D alloy, the joint action of the eta phase regulates the mechanical properties of the alloy, and the γ' in the alloy The +eta phase sum is unchanged. γ' improves the strength of the alloy, and the eta phase improves the plasticity of the alloy. 870℃±10℃ is the nucleation temperature of the eta phase, and 870℃±10℃ is to precipitate a certain amount of eta phase in the alloy. It should be pointed out that the holding time is critical. If the holding time is too long, the eta phase content in the alloy will increase, and the decrease in γ' content will reduce the tensile strength of the alloy.

After the heat preservation is completed, it is cooled by air cooling.

S104: Standard heat treatment, just use the known process in the GH4169D alloy standard specification. For example, the first stage heating temperature is 960±10°C, and the heat preservation is carried out for a preset time. After the heat preservation, cooling treatment is carried out; the second stage heating The temperature is 788±10℃, keep warm for at least 8h, then cool at 56±10℃ at 704±10℃, keep warm for at least 8h and then air cool.

This process method can solve the problem of reduced material yield strength and reduced notch sensitivity in durable performance after brazing of GH4169D material, and improve the mechanical properties of the material. It can be used for brazing honeycomb structure parts of GH4169D alloy forgings, solving the problems of reduced yield strength and notch sensitivity of GH4169D alloy after brazing, and improving the mechanical properties of the material.

The eta phase content of GH4169D alloy is 4.9%--5.1%, which is about 5%. The uniform size of γ' phase is about 50nm, such as between 49nm and 51nm. The improved matrix structure is shown in Figure 3. The tensile strength at room temperature is greater than 1338MPa, the yield strength is greater than 958MPa, the elongation after fracture is greater than 15%, and the end face shrinkage is greater than 15%; at the test temperature of 700°C, the yield strength is greater than 807MPa, the elongation after fracture is greater than 12%, and the end face shrinkage is greater than 15%; durable life Test conditions: temperature 700℃, stress 621MPa, lasting life greater than 50h. The above-mentioned process methods and processes solve the problems of reduced yield strength and notch sensitivity of GH4169D alloy after brazing, and improve the mechanical properties of the material.

The products provided by the present invention have been introduced in detail above. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the core idea of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications can be made to the invention without departing from the principles of the invention, and these improvements and modifications also fall within the protection scope of the invention claims.

Claims (7)

1. A process method for brazing and heat treatment of GH4169D alloy, characterized in that the process method includes, Initial process treatment, processing until the grain size of the GH4169D alloy matrix material is 8 to 12 levels; Brazing process, the brazing temperature is 1020℃±10℃, and the heat preservation is carried out for a preset time, and then cooling is carried out after heat preservation; Intermediate treatment, the intermediate treatment temperature is 870℃±10℃ and cooled; Standard heat treatment. 2. The process method according to claim 1, characterized in that in the brazing process, the brazing temperature is 1020°C ± 10°C, and the heat preservation is carried out for a preset time, and cooling treatment is performed after the heat preservation, including: The brazing temperature is 1020℃±10℃ and kept warm for 15 to 20 minutes; After insulation, slowly cool to 950°C, then cool quickly. 3. The process method according to claim 2, characterized in that the intermediate treatment further includes: The intermediate treatment temperature is 870℃±10℃, and the time is 4 to 6 hours; After the heat preservation is completed, it is cooled by air cooling. 4. The process method according to claim 1, characterized in that the eta phase content of the GH4169D alloy after standard heat treatment is 4.9%-5.1%, and the uniform size of the γ' phase is 50nm. 5. The process method according to claim 4, characterized in that the tensile strength of the standard heat-treated GH4169D alloy at room temperature is greater than 1338MPa, the yield strength is greater than 958MPa, the elongation after fracture is greater than 15%, and the end face shrinkage is greater than 15%. %. 6. The process method according to claim 4, characterized in that, when the test temperature of the GH4169D alloy after standard heat treatment is below 700°C, the yield strength is greater than 807MPa, the elongation after fracture is greater than 12%, and the end face shrinkage is greater than 15%. When the endurance life test conditions are a temperature of 700°C and a stress of 621MPa, the endurance life is greater than 50 hours. 7. The process method according to claim 1, characterized in that standard heat treatment includes: In the first stage, the heating temperature is 960±10℃, and the heat preservation is carried out for a preset period of time. After heat preservation, cooling is performed; In the second stage, the heating temperature is 788±10°C, and the temperature is maintained for at least 8 hours. Then the cooling rate is 704±10°C at 56±10°C, and the temperature is maintained for at least 8 hours and then air-cooled.