Hardened gh5605 high temperature alloy cold-rolled strip

Abstract

The application discloses a hard state GH5605 high-temperature alloy cold-rolled strip, which is cold-rolled by adopting a deformation rate of 30%-45%, and is heat-treated in a temperature range of 1165-1230 DEG C in a continuous heat treatment furnace in a protective atmosphere so as to continue cold-rolling; and then is annealed in a temperature range of 950-980 DEG C in a continuous heat treatment furnace in a protective atmosphere, so that the ability of bearing bending plastic deformation is improved under the premise that the strength and hardness are basically unchanged. The application has the following advantages: the process design is reasonable, including cold-rolling deformation process, intermediate softening annealing process and recovery heat treatment process; in particular, the recovery temperature is 950-980 DEG C, and the heat treatment at this temperature can improve the ability of bearing bending plastic deformation under the premise that the strength and hardness are basically unchanged, which cannot be achieved by the existing theoretical recovery temperature (0.25-0.3)T melting point (T melting point is the absolute temperature of the melting point of the metal).

Description

[0001] This application is a divisional application of application number: 202010149106.3, application date: 20200306, invention name: a heat treatment method of hard state GH5605 high temperature alloy cold rolled strip, applicant: northeast special steel group co., ltd. TECHNICAL FIELD

[0002] The application belongs to the technical field of heat treatment, and relates to a hard state GH5605 high temperature alloy cold rolled strip, which can improve the ability to withstand bending plastic deformation on the basis of ensuring high strength and high hardness of the strip. BACKGROUND

[0003] GH5605 is a Co-Cr-Ni-based solid solution strengthening type deformed high temperature alloy, 20% of chromium and 15% of tungsten are added to the alloy for solid solution strengthening, and the specific chemical composition (%) is as follows: carbon: 0.05-0.15, silicon: not more than 0.40, manganese: 1.00-2.00%, phosphorus: not more than 0.040, sulfur: not more than 0.03, chromium: 19.00-21.00, nickel: 9.00-11.00, tungsten: 14.00-16.00, iron: not more than 3.00, cobalt: balance; the alloy has moderate endurance and creep strength below 815 DEG C, and excellent oxidation resistance below 1090 DEG C. There are two existing production methods for GH5605 strip: one is to improve the strength and hardness of the strip by adopting a suitable cold working process through cold working deformation, but the bending test of the alloy cannot meet the standard requirements due to the large cold work hardening rate and poor plasticity of the alloy; the other is to adopt 1175 DEG C-1230 DEG C solid solution treatment or 1165 DEG C-1185 DEG C stress relief annealing treatment after cold working the strip to the finished size, which can meet the bending test requirements, but the hardness of the strip is lower than the standard requirements. At present, the main processing method of GH5605 high temperature alloy cold rolled strip is the second method, that is, cold working deformation, solid solution treatment and high temperature stress relief annealing. The above two methods cannot guarantee that the strip has high hardness (HV) 380-450 and sufficient bending performance. Therefore, the hard state GH5605 high temperature alloy cold rolled strip cannot meet the standard requirements, which affects the use in military engines. SUMMARY

[0004] The application discloses a hard state GH5605 high temperature alloy cold rolled strip, and aims to improve the ability to withstand bending plastic deformation on the basis of high strength and high hardness of the strip by controlling the cold rolling deformation rate and the heat treatment temperature.

[0005] To achieve the above-mentioned purpose, the application adopts the following specific methods and steps:

[0006] 1. The electrode blank is smelted by vacuum induction furnace, the electrode slag is remelted by electroslag furnace, the electroslag ingot is forged and opened by forging, and the 3.5mm thick strip blank is obtained after solid solution and water grinding to remove the surface oxide skin.

[0007] 2. The strip blank is rolled by four-roll reversible cold rolling mill, the cold rolling deformation rate is about 45%, the cold rolling deformation rate between each softening annealing is controlled to be 30%-45%, the intermediate softening annealing is carried out by using the protective atmosphere continuous heat treatment furnace, the heat treatment temperature is 1165-1230℃, and the cold rolling is carried out until the finished product thickness.

[0008] 3. The steel strip rolled to the finished product specification is annealed by using the protective atmosphere continuous heat treatment furnace, and the annealing temperature is 950-980℃.

[0009] The mechanism analysis and invention points of the present application are as follows:

[0010] The work hardening phenomenon in the plastic deformation process of metal changes the mechanical properties: with the increase of the deformation degree, the various plasticity indexes (such as elongation, reduction of area, impact toughness, etc.) which determine the plasticity are reduced, and the various mechanical indexes (such as proportional limit, elastic limit, yield point, strength, hardness, etc.) which determine the deformation resistance are increased.

[0011] The recovery phenomenon is to increase the atomic motion by heating the deformed metal, so as to increase the thermal vibration, so that all atoms return to the position with the minimum potential energy, the degree of lattice distortion is greatly reduced, the internal stress is reduced, the plasticity, toughness and elasticity are appropriately improved, and the high strength and high hardness properties left during work hardening are retained.

[0012] When the cold plastic deformation metal is heated to a high temperature by solid solution or annealing, new fine grains without distortion are formed from the distorted grains through nucleation and grain growth, and the performance of the cold deformation metal product can reach high strength, high hardness and sufficient bending plasticity index.

[0013] The invention point of the present application is to cold roll deformation at a deformation rate of 30%-45%, heat treatment at a temperature of 1165-1230℃ by using the protective atmosphere continuous heat treatment furnace, so as to ensure that the structure and performance of the GH5605 steel strip return to the state before cold working, and facilitate the continuous cold rolling process; the final cold rolling deformation is carried out to the finished product specification, the strength and hardness of the GH5605 strip are improved and meet the indexes, and then the heat treatment is carried out at a temperature of 950-980℃ by using the protective atmosphere continuous heat treatment furnace, so as to improve the bending plasticity deformation capacity under the premise that the strength and hardness are basically unchanged.

[0014] The main advantages of the present application compared with the prior art are as follows:

[0015] ①In different production stages, according to the need, reasonably design and adopt cold working deformation process, intermediate softening annealing process and recovery heat treatment process to ensure the mechanical properties of the hard state GH5605 high temperature alloy cold rolled strip qualified. This is not possible in the prior art (traditional cold working deformation and softening annealing only).

[0016] ②The recovery temperature of GH5605 high temperature alloy cold rolled strip is 950℃-980℃, which is suitable for the alloy. After heat treatment at this temperature, the ability to withstand bending plastic deformation can be improved without changing the strength and hardness, which is not possible with the existing theoretical recovery temperature (0.25-0.3)T melting point (T melting point is the absolute temperature of the melting point of the metal). DETAILED DESCRIPTION

[0017] The following will be described and explained in detail in conjunction with specific embodiments.

[0018] Example 1, Example 2 and Example 3:

[0019] ⑴Vacuum induction furnace is used to smelt electrode billet, electroslag furnace is used to remelt electrode billet, electroslag ingot is used to forge and break down, and four-roll reversible hot rolling mill is used to roll, and after solid solution and water grinding to remove surface oxide skin, 3.5mm thick strip billet is obtained.

[0020] ⑵Cold rolling

[0021] ①The thickness of the billet is 3.5mm, the thickness is reduced to 1.9mm by the first cold rolling, the deformation rate is 45.7%, and the subsequent intermediate softening annealing and cold rolling are carried out, and the intermediate cold rolling deformation rate is 30%-45%;

[0022] ⑷Finished product inspection

[0023] ①Chemical composition (%): carbon: 0.07, silicon: 0.07, manganese: 1.59, phosphorus: 0.010, sulfur: 0.001, chromium: 19.79, nickel: 10.04, tungsten: 14.43, iron: 0.30, cobalt: balance;

[0024] Example 1

[0025] Finished product specification 0.5mm x 95mm;

[0026] ⑵Cold rolling

[0027] ②The finished product is rolled from 0.8mm to 0.5mm, and the finished product cold rolling deformation rate is 37.5%.

[0028] ⑶Heat treatment

[0029] ①Intermediate softening annealing is carried out in a protective atmosphere continuous furnace, the annealing temperature is 1200℃, and the moving speed is 1m / min-1.5m / min;

[0030] The finished product thickness 0.5 mm strip is heat treated by continuous furnace in protective atmosphere: annealing temperature 970 °C, moving speed 2.3 m / min.

[0031] ⑷Finished product inspection

[0032] ②Performance inspection: tensile strength (MPa) 1312 / 1311, hardness (HV) 405 / 409, bending performance qualified.

[0033] Example 2

[0034] Finished product specification 0.25 mm x 95 mm;

[0035] ⑵Cold rolling

[0036] ②The finished product rolling is from 0.4 mm to 0.25 mm, and the finished product cold rolling deformation rate is 37.5%.

[0037] ⑶Heat treatment

[0038] ①Intermediate softening annealing is by continuous furnace in protective atmosphere, annealing temperature 1200 °C, moving speed 1 m / min-2.2 m / min;

[0039] ②The finished product thickness 0.25 mm strip is heat treated by continuous furnace in protective atmosphere: annealing temperature 970 °C, moving speed 2 m / min.

[0040] ⑷Finished product inspection

[0041] ②Performance inspection: tensile strength (MPa) 1342 / 1355, hardness (HV) 415 / 411, bending performance qualified.

[0042] Example 3

[0043] Finished product specification 0.25 mm x 95 mm;

[0044] ⑵Cold rolling

[0045] ②The finished product rolling is from 0.4 mm to 0.25 mm, and the finished product cold rolling deformation rate is 37.5%.

[0046] ⑶Heat treatment

[0047] ①Intermediate softening annealing is by continuous furnace in protective atmosphere, annealing temperature 1200 °C, moving speed 1 m / min-2.2 m / min;

[0048] ②The finished product thickness 0.25 mm strip is heat treated by continuous furnace in protective atmosphere: annealing temperature 970 °C, moving speed 2 m / min.

[0049] ⑷Finished product inspection

[0050] 2. Performance test: tensile strength (MPa) 1267 / 1304, hardness (HV) 422 / 41, bending performance qualified.

Claims

1.A heat treatment method of hard state GH5605 high-temperature alloy cold-rolled strip, characterized in that, (1) an electrode billet is smelted by a vacuum induction furnace, electrically remelted by an electric slag furnace, forged by an electric slag ingot, and rolled by a four-high reversible hot rolling mill, to obtain a 3.5 mm thick strip blank after solid solution and water grinding to remove surface oxide scale; (2) the strip blank is rolled by a four-high reversible cold rolling mill, the deformation rate of the first cold rolling is 45.7%, and the subsequent cold rolling deformation rate is controlled at 30%-45% between each intermediate softening annealing, the intermediate softening annealing is carried out by a protective atmosphere continuous heat treatment furnace at a heat treatment temperature of 1165 ℃-1230 ℃, and then cold-rolled to a finished thickness; (3) the steel strip cold-rolled to the finished size is annealed by a protective atmosphere continuous heat treatment furnace at an annealing temperature of 950 ℃-980 ℃. 2.Application of the heat treatment method of hard state GH5605 high-temperature alloy cold-rolled strip according to claim 1 in the field of high-temperature alloys.