N08120 heat-resistant alloy sheet and heat treatment method therefor

Abstract

Disclosed in the present invention is an N08120 heat-resistant alloy sheet. The chemical component range of the heat-resistant alloy sheet is calculated according to the mass fraction: Ni: 35.0-39.0%, Cr: 23.0-27.0%, Mn≤1.5%, C: 0.02-0.10%, Cu≤0.50%, Si≤1.0%, S≤0.03%, Al≤0.40%, Ti≤0.20%, Mo≤2.50%, Nb: 0.4-0.9%, P≤0.040%, W≤2.50%, Co≤3.0%, N: 0.15-0.30%, and B≤0.010%. The present invention has the advantages of enabling steel plates to have a more uniform grain size, improving the strength-toughness balance thereof, and reducing the risk caused by mixed grain structures.

Description

N08120 heat-resistant alloy plate and heat treatment method thereof TECHNICAL FIELD

[0001] The present application belongs to the technical field of heat treatment process of heat-resistant alloy plate, and particularly relates to an N08120 heat-resistant alloy plate and a heat treatment method thereof. BACKGROUND

[0002] With the rapid development of China's photovoltaic industry, the market demand for polycrystalline silicon is increasing year by year, thereby driving the rapid growth of demand for N08120 wide plate of iron-nickel-based alloy for cold hydrogenation reactor, a core production device of polycrystalline silicon. N08120 is an upgraded version of N08810, and the two have similar oxidation resistance, but N08120 has higher high-temperature strength, excellent high-temperature strength and oxidation resistance, and a service temperature of more than 593 DEG C. Through high-temperature heat treatment, relatively coarse grains can be obtained, and the material also has high creep strength due to the high content of C, N and Nb. N08120 plate is widely used in various fields, such as heat treatment furnace parts, petrochemical furnace cracking pipes, electric heating element sheaths, cold hydrogenation reactors, etc. The alloy was basically dependent on imports before, and with the rapid advancement of domestication, the market share of imported products has also decreased significantly.

[0003] Because of the short time of domestication, experience needs to be accumulated in smelting, processing, heat treatment and other links of N08120. Considering the use in high-temperature environment, the grain size of N08120 plate is required to be not more than 5 levels. The processes of different manufacturers are quite different, some are short-time holding at high temperature such as 1260 DEG C, and some are long-time holding at lower temperature such as 1800 DEG C. However, a common problem of various processes is that mixed grains are easy to appear. In actual production, it is found that the grains of N08120 after solid solution treatment are prone to mixed grain phenomenon, and there are a small amount of fine or abnormally coarse grains in the local, which brings certain safety hazards to the use of the material. In order to obtain uniform organization and performance, in addition to reducing segregation in smelting link and uniform deformation in rolling link, formulating a reasonable heat treatment system is also a key link.

[0004] SUMMARY

[0005] The purpose of the present application is to solve the problems of easy mixed grain phenomenon, poor performance and large safety hazard of existing N08120 plate, and to provide an N08120 heat-resistant alloy plate, which can make the grain size of the steel plate more uniform, improve the matching degree of its strength and toughness, and reduce the risk of mixed grains.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] The N08120 heat-resistant alloy plate has a chemical component range, in terms of mass fraction, as follows: Ni: 35.0-39.0%, Cr: 23.0-27.0%, Mn≤1.5%, C: 0.02-0.10%, Cu≤0.50%, Si≤1.0%, S≤0.03%, Al≤0.40%, Ti≤0.20%, Mo≤2.50%, Nb: 0.4-0.9%, P≤0.040%, W≤2.50%, Co≤3.0%, N: 0.15-0.30%, and B≤0.010%.

[0008] Further, the N08120 heat-resistant alloy plate has a chemical component range, in terms of mass fraction, as follows: Ni: 37.3%, Cr: 25.1%, Mn: 0.68%, C: 0.04%, Cu: 0.03%, Si: 0.17%, S: 0.001%, Al: 0.07%, Ti: 0.01%, Mo: 0.40%, Nb: 0.6%, P: 0.013%, W: 0.07%, Co: 0.06%, N: 0.24%, and B: 0.001%.

[0009] In order to further achieve the purpose of the present application, a heat treatment method for the N08120 heat-resistant alloy plate is also provided, and the specific steps include: after the heat treatment furnace is heated to 1200±10℃, the steel plate is put into the furnace, the furnace door is closed, and then the furnace temperature is recovered to 1200±10℃, and the timing is started, and the heat preservation is performed for 2T±5min, wherein T is the thickness of the steel plate×min / mm, and then the furnace is discharged and water-cooled after the time.

[0010] Further, the steel plate is rapidly water-cooled to below 600℃ after being discharged from the furnace.

[0011] Further, after the heat treatment, the room temperature yield strength of the steel plate is ≥276MPa, the room temperature tensile strength is ≥621MPa, the room temperature elongation is ≥30%, the high-temperature yield strength at 600℃ is ≥142MPa, and the grain size is 3-5 levels.

[0012] Further, the heat preservation time of the 20mm-thick heat-resistant alloy steel plate after being loaded into the furnace and after the furnace temperature is recovered to 1200℃ is 40min.

[0013] In the technical scheme of the present application, the grain size of the N08120 steel plate after the heat treatment is more uniform, the mechanical properties of the N08120 alloy plate meet the requirements of ASME SB409, the average grain size is in the best range of 3-5 levels, the strength-toughness matching is improved, and the risk caused by mixed grains is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0014] Fig. 1 is a metallographic picture of the N08120 heat-resistant alloy plate according to the present application. DETAILED DESCRIPTION

[0015] Example 1

[0016] In order to make the present application more clear, the present application of a N08120 heat-resistant alloy plate and a heat treatment method thereof is further described below in conjunction with the accompanying drawings. The specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0017] In this embodiment, the experimental material is a hot-rolled 20mm-thick N08120 heat-resistant alloy steel plate.

[0018] In this embodiment, the smelting composition of the N08120 heat-resistant alloy steel plate is calculated by mass fraction as follows:

[0019] Ni 37.3%, Cr 25.1%, Mn 0.68%, C 0.04%, Cu 0.03%, Si 0.17%, S 0.001%, Al 0.07%, Ti 0.01%, Mo 0.40%, Nb 0.6%, P 0.013%, W 0.07%, Co 0.06%, N 0.24%, B 0.001%.

[0020] During the heat treatment, the heating furnace is heated to 1200℃, then the furnace door is opened, the steel is quickly loaded, the furnace temperature is restored to 1200℃ after the furnace temperature is restored to 1200℃, and the steel is quickly water-cooled after the furnace temperature is restored to 1200℃ for 40min.

[0021] After detection, the yield strength of the steel plate at room temperature after heat treatment is 312MPa, the tensile strength at room temperature is 710MPa, the elongation at room temperature is 58%, the high-temperature yield strength at 600℃ is 165MPa, and the average grain size is 3.5, which meets the range of the best grain size of 3-5.

[0022] The above embodiments are only used to illustrate but not limit the technical solutions of the present application. Although the present application is described in detail with reference to the above embodiments, those skilled in the art should understand that the present application can still be modified or equivalently replaced without departing from the spirit and scope of the present application, and any modification or partial replacement should be covered in the scope of the claims of the present application.

[0023] In addition to the above embodiments, the present application can have other embodiments. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope of the present application.

Claims

1. A heat-resistant alloy plate of N08120, characterized in that, Its chemical composition range, calculated by mass fraction, is as follows: Ni: 35.0~39.0%, Cr: 23.0~27.0%, Mn≤1.5%, C: 0.02~0.10%, Cu≤0.50%, Si≤1.0%, S≤0.03%, Al≤0.4 0%, Ti≤0.20%, Mo≤2.50%, Nb: 0.4~0.9%, P≤0.040%, W≤2.50%, Co≤3.0%, N: 0.15~0.30%, B≤0.010%.

2. The N08120 heat-resistant alloy plate according to claim 1, characterized in that: Its chemical composition, calculated by mass fraction, is as follows: Ni: 37.3%, Cr: 25.1%, Mn: 0.68%, C: 0.04%, Cu: 0.03%, Si: 0.17%, S: 0.001%, Al: 0.07%, Ti: 0.01%, Mo: 0.40%, Nb: 0.6%, P: 0.013%, W: 0.07%, Co: 0.06%, N: 0.24%, B: 0.001%.

3. A heat treatment method for N08120 heat-resistant alloy plate as described in claim 1, characterized in that, The specific steps include: After heating the heat treatment furnace to 1200±10℃, the steel plate is put into the furnace. After closing the furnace door, the timer is started after the furnace temperature returns to 1200±10℃. The plate is held at this temperature for 2T±5min, where T is the thickness of the steel plate × min / mm. After the time is up, the plate is taken out of the furnace and water-cooled.

4. The heat treatment method for N08120 heat-resistant alloy plate according to claim 3, characterized in that: After the steel plate is taken out of the furnace, it is quickly water-cooled to below 600°C.

5. The heat treatment method for N08120 heat-resistant alloy plate according to claim 3, characterized in that: After heat treatment, the steel plate has a room temperature yield strength ≥276MPa, a room temperature tensile strength ≥621MPa, a room temperature elongation ≥30%, a high temperature yield strength at 600℃ ≥142MPa, and a grain size of 3 to 5.

6. The heat treatment method for N08120 heat-resistant alloy plate according to claim 3, characterized in that: After the 20mm thick heat-resistant alloy steel plate is loaded with steel, the holding time after the furnace temperature recovers to 1200℃ is 40 minutes.

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