Preparation process of GH4738 alloy special-shaped wire

Abstract

The invention provides a preparation technology of a GH4738 alloy special-shaped wire, which comprises the following specific technological processes: smelting, forging, hot rolling, repeated cold drawing annealing and finished product heat treatment, and is characterized in that the forging and hot rolling temperature is 1050-1150 DEG C, and the deformation amount per heating number is 4-70%; carrying out cold drawing at room temperature; the annealing temperature in the intermediate annealing process between every two passes of cold drawing of the wire is 1050-1070 DEG C, and the heat preservation time is 1.5 h; the hot-rolled round wire is cold-drawn into the special-shaped wire material for five passes; large deformation is adopted for rolling of the first pass and the second pass, the rolling deformation is controlled to be 32%-39%, and the rolling deformation of the third pass to the fifth pass is controlled to be 5%-26%. And hydrogen protection annealing heat treatment is carried out after the finished product is finished, and the heat treatment temperature is 1050-1080 DEG C. The method has the advantages that the batch stability of the wires is guaranteed, and matched use of model engines is facilitated. And meanwhile, the wire produced by the process is good in surface quality, and the process is simple and easy to operate.

Description

Technical Field

[0001] The present invention relates to the field of alloy preparation technology, and in particular to a preparation technology of GH4738 alloy special-shaped wire. Background Art

[0002] GH4738 is a nickel-based high-temperature alloy strengthened by γ” phase precipitation. It has high yield strength and fatigue resistance at 760℃~870℃. It has good oxidation resistance and corrosion resistance in gas turbine atmosphere below 870℃. The main products are wire, cold-rolled and hot-rolled plates, pipes, strips, forgings, castings, bolts and fasteners. Only GH738 alloy bars and round wires are used in engine manufacturing, and special-shaped wires have never been used.

[0003] For GH4738 alloy shaped wire, there are several main problems:

[0004] (1) Material processing is difficult:

[0005] GH4738 alloy special-shaped wire contains more strengthening elements such as Al, Ti, and Mo, and is difficult to hot and cold process. The temperature range of hot processing is narrow, the deformation resistance is large, and the special-shaped wire is difficult to form.

[0006] (2) The research on wire forming process is not systematic, and the batch stability of tensile strength index is poor

[0007] During the production process, special-shaped wires usually need to go through smelting, forging, hot rolling, cold drawing (intermediate annealing is required between each pass), and heat treatment of the finished product. Among them, the process parameters of each link will affect the final performance indicators and batch stability of the wire. The reasonable selection of equipment parameters, the optimal design of size and materials, the deformation of wires in different passes, the system of intermediate annealing, the time of heat treatment, etc., all need in-depth and systematic research. For example: The technical standard of GH4738 alloy special-shaped wire does not clearly stipulate the heat treatment system. Therefore, if the matching relationship between temperature and time is not clear during the heat treatment process of the finished product, it will significantly affect the tensile strength of the delivered wire, and ultimately lead to returns due to non-compliance with the standard requirements. In addition, for wires used in aircraft engines, batch stability is very important. If the delivery performance is unstable, the subsequent strips will still be unusable. Summary of the invention

[0008] The purpose of the present invention is to solve the problems existing in the background technology. The present invention proposes a preparation process of GH4738 alloy profiled wire. The process adopts a cold drawing and annealing method, controls the deformation of the alloy rolling pass and the heat treatment process, and obtains GH4738 alloy profiled wire that is qualified and has high batch stability.

[0009] The present invention provides a preparation process of GH4738 alloy special-shaped wire, the specific process flow of which is: smelting, forging, hot rolling, repeated cold drawing annealing, and finished product heat treatment, and the characteristics are:

[0010] The forging and hot rolling temperatures are 1050°C to 1150°C, and the deformation per fire is 4% to 70%.

[0011] Cold drawing is carried out at room temperature.

[0012] The annealing temperature of the intermediate annealing process between each cold drawing of the wire is 1050℃~1070℃, and the holding time is 1.5h.

[0013] There are five passes in total to cold-draw the hot-rolled round wire into the special-shaped wire. The first and second rolling passes use large deformation, and the rolling deformation is controlled at 32% to 39%, and the subsequent third to fifth rolling deformations are controlled at 5% to 26%.

[0014] After the finished product is processed, hydrogen protection annealing heat treatment is carried out, the heat treatment temperature is 1050℃~1080℃, and the hydrogen protection annealing wire speed is 24mm / s~45mm / s.

[0015] In order to improve the use quality and batch stability of GH4738 alloy profiled wire, the preferred process flow of the present invention is as follows:

[0016] (1) Smelting: vacuum induction melting plus vacuum consumable remelting;

[0017] (2) Forging: The forging temperature is 1050℃~1150℃, the deformation is controlled at 18%~70%, and the square bar is forged;

[0018] (3) Hot rolling: The hot rolling temperature is 1050℃~1150℃, the deformation is controlled at 4%~38%, and the wire is rolled into round wire;

[0019] (4) Repeated cold drawing annealing: There are 5 passes to cold draw the hot-rolled round wire into the shaped wire. The first and second rolling passes use large deformation, and the rolling deformation is controlled at 32% to 39%. The subsequent third to fifth rolling deformations are controlled at 5% to 26%. During the cold rolling process, intermediate annealing is required after each rolling pass, and the annealing temperature is 1050℃ to 1070℃, and the holding time is 1.5h.

[0020] (5) Finished product heat treatment: The hydrogen protection annealing heat treatment temperature is 1050℃~1080℃, and the hydrogen protection annealing wire speed is 24mm / s~45mm / s.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] In the cold rolling process, the batch stability of the wire is ensured by reasonably controlling the deformation amount of each pass and adjusting the heat treatment temperature and time. At the same time, compared with the technical standard requirements, a larger use margin is left, which is conducive to the matching use of model engines. At the same time, the surface quality of the wire produced by this process is good. Figure 1 , the process is simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0024] Figure 1 Finished wire material in delivery state;

[0025] Figure 2 The tensile strength of the finished wire materials of Examples 1 to 3 as delivered. DETAILED DESCRIPTION

[0026] The present invention will be further explained below in conjunction with specific implementation plans, but the present invention is not limited thereto. The structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the restrictive conditions under which the present invention can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0027] The GH4738 alloy ingots, which are smelted by vacuum induction melting and vacuum consumable remelting, are forged into 50mm×50mm square bars at 1050℃, with a deformation of about 95%. They are hot rolled into Ø8.5mm round wires at 1050℃, and then cold drawn (intermediate annealing is performed between each cold drawing pass). The final product is 2.3mm×6.4mm GH4738 alloy special-shaped wires. The finished product tensile strength is shown in Figure 2 (Technical requirement ≤1300MPa, wire material detection performance is 1159MPa and 1158MPa respectively), rolling process parameters are shown in Table 1.

[0028] Table 1 Rolling process parameters of Example 1

[0029]

[0030] Example 2

[0031] The GH4738 alloy ingots, which are smelted by vacuum induction melting and vacuum consumable remelting, are forged into 50mm×50mm square bars at 1050℃, with a deformation of about 95%. They are hot rolled into Ø8.5mm round wires at 1050℃, and then cold drawn (intermediate annealing is performed between each cold drawing pass). The final product is 2.3mm×6.4mm GH4738 alloy special-shaped wires. The finished product tensile strength is shown in Figure 2 (Technical requirement ≤1300MPa, wire material detection performance is 1176MPa and 1182MPa respectively), rolling process parameters are shown in Table 2.

[0032] Table 2 Rolling process parameters of Example 2

[0033]

[0034] Example 3

[0035] The GH4738 alloy ingots, which are smelted by vacuum induction melting and vacuum consumable remelting, are forged into 50mm×50mm square bars at 1100℃, with a deformation of about 95%. They are hot rolled into Ø8.5mm round wires at 1100℃, and then cold drawn (intermediate annealing is performed between each cold drawing pass). The final product is 2.3mm×8.0mm GH4738 alloy special-shaped wires. The finished product tensile strength is shown in Figure 2 (Technical requirement ≤1300MPa, wire material detection performance is 1215MPa and 1212MPa respectively), rolling process parameters are shown in Table 3.

[0036] Table 3 Rolling process parameters of Example 3

[0037]

[0038] Matters not covered by the present invention are known technologies.

[0039] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for preparing GH4738 alloy special-shaped wire, characterized in that: The specific process flow is: smelting, forging, hot rolling, repeated cold drawing annealing, and heat treatment of finished products; The forging and hot rolling temperatures are 1050℃~1150℃, and the deformation per fire is 4%~70%; Cold drawing is performed at room temperature; The annealing temperature of the intermediate annealing process between each cold drawing of the wire is 1050℃~1070℃, and the holding time is 1.5h; Cold drawing of hot-rolled round wire into shaped wire includes 5 passes in total; the first and second passes use large deformation, and the rolling deformation is controlled at 32% to 39%, and the subsequent third to fifth passes have rolling deformations controlled at 5% to 26%.

2. The preparation process of the GH4738 alloy special-shaped wire according to claim 1, characterized in that: The preferred process flow is as follows: (1) Smelting: vacuum induction melting plus vacuum consumable remelting; (2) Forging: The forging temperature is 1050℃~1150℃, the deformation is controlled at 18%~70%, and the square bar is forged; (3) Hot rolling: The hot rolling temperature is 1050℃~1150℃, the deformation is controlled at 4%~38%, and the wire is rolled into round wire; (4) Repeated cold drawing annealing: There are five passes in total to cold draw the hot-rolled round wire into the shaped wire. The first and second rolling passes use large deformation, and the rolling deformation is controlled at 32% to 39%. The subsequent third to fifth rolling deformations are controlled at 5% to 26%. During the cold rolling process, intermediate annealing is required after each rolling pass, and the annealing temperature is 1050°C to 1070°C, and the holding time is 1.5h. (5) Finished product heat treatment: The hydrogen protection annealing heat treatment temperature is 1050℃~1080℃, and the hydrogen protection annealing wire speed is 24mm / s~45mm / s.

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