Heat treatment method of N06625 nickel-based alloy plate

Abstract

The invention discloses a heat treatment method of an N06625 nickel-based alloy plate. The nickel-based alloy comprises the following chemical components in percentage by mass: more than or equal to 58.0% of Ni, 20.0-23.0% of Cr, less than or equal to 0.50% of Mn, less than or equal to 0.10% of C, less than or equal to 0.50% of Si, less than or equal to 0.015% of S, less than or equal to 5.0% of Fe, less than or equal to 0.40% of Ti, 8.0-10.0% of Mo, 3.15-4.15% of Nb + Ta, less than or equal to 0.015% of P, less than or equal to 0.40% of Al and less than or equal to 1.0% of Co. The heat treatment process specifically comprises the steps that after a heat treatment furnace is heated to 970 + / -10 DEG C, a steel plate is put into the furnace, after a furnace door is closed and the furnace temperature is recovered to 970 + / -10 DEG C, timing is started, heat preservation is conducted for 1T + / -5 min, T is the thickness of the steel plate * min / mm, and after the time is up, the steel plate is taken out of the furnace and subjected to water cooling. The method has the advantages that the mechanical property of the plate is stable, and field operation is easier.

Description

Technical Field

[0001] The present invention belongs to the field of metallurgical technology, and particularly relates to a heat treatment method for N06625 nickel-based alloy plates. Background Art

[0002] In recent years, the petrochemical industry, power plants and other industries have developed rapidly. High-corrosion environments such as oil tanks and pipelines in petrochemical industry require a large amount of corrosion-resistant metal materials. With the enlargement of equipment, users have put forward higher requirements for the corrosion resistance and service life of equipment. Therefore, ordinary stainless steel used for manufacturing equipment can no longer meet the requirements of users. N06625 nickel-based alloy has excellent corrosion resistance and high-temperature performance, good strength and toughness matching and welding performance, so it is often used in extreme service fields such as aircraft engines and chemical equipment.

[0003] N06625 nickel-based alloy is a solid solution strengthened alloy with Mo and Nb as the main strengthening elements added to Ni-Cr alloy. It can resist uniform corrosion and local corrosion in most environments, and is mainly applied in chemical equipment, ocean engineering, oil exploitation, environmental engineering, aerospace and other fields. In addition to being used in extreme corrosive environments, N06625 nickel-based alloy also has good high-temperature resistance. N06625 plates in Grade1 state need to be heat-treated above 871°C, and the service temperature can reach 593°C. N06625 plates in Grade2 state need to be heat-treated above 1093°C, and the service temperature can exceed 593°C.

[0004] For N06625 plates in Grade1 state, it is found in actual production that if the heat treatment process is improper, the mechanical properties are likely to be unqualified. Since N06625 alloy plates are expensive, unqualified performance will cause huge economic losses. Therefore, formulating a reasonable heat treatment system is a very crucial production link.

[0005] Chinese Patent with publication number CN112481566B discloses a heat treatment method for nickel-based alloy plates. This method mainly relates to the heat treatment process of N06625 nickel-based alloy plates. However, when controlling the heat treatment parameters, it needs to be determined according to the width and thickness, which is relatively complex. Moreover, the object is plates with a width of 1000-2500mm, and the control of performance stability is quite limited, and it is not conducive to on-site operation. Summary of the Invention

[0006] The object of the present invention is to solve the problems of complex heat treatment process and low performance stability of existing nickel-based alloy plates, and to provide a heat treatment method for N06625 nickel-based alloy plates, which can not only ensure the stable mechanical properties of the plates, but also be more convenient for on-site operation, so that the mechanical properties of N06625 alloy plates meet the requirements of Grade 1 in ASME SB443.

[0007] To achieve the above object, the present invention adopts the following technical solutions: A heat treatment method for N06625 nickel-based alloy plates, the chemical composition and mass fraction of the N06625 nickel-based alloy include: Ni≥58.0%, Cr: 20.0 - 23.0%, Mn≤0.50%, C≤0.10%, Si≤0.50%, S≤0.015%, Fe≤5.0%, Ti≤0.40%, Mo: 8.0 - 10.0%, Nb + Ta: 3.15 - 4.15%, P≤0.015%, Al≤0.40%, Co≤1.0%; the specific heat treatment process includes: after heating the heat treatment furnace to 970±10°C, putting the steel plate into the furnace, closing the furnace door, and starting timing after the furnace temperature returns to 970±10°C, keeping warm for 1T±5 min, where T is the steel plate thickness × min / mm, and taking out the furnace and cooling with water after the time is up.

[0008] Further, during the heat treatment process, the steel plate is quickly cooled with water to below 600°C after being taken out of the furnace.

[0009] Further, the room temperature yield strength of the steel plate after heat treatment is ≥379 MPa, the room temperature tensile strength is ≥758 MPa, and the room temperature elongation is ≥30%.

[0010] Further, the chemical composition and mass fraction of the N06625 nickel-based alloy include: Ni: 59.02%, Cr: 22.30%, Mn: 0.078%, C: 0.015%, Si: 0.051%, S: 0.001%, Fe: 3.65%, Ti: 0.175%, Mo: 9.15%, Nb + Ta: 3.62%, P: 0.0015%, Al: 0.147%, Co: 0.005%.

[0011] Further, the chemical composition and mass fraction of the N06625 nickel-based alloy include: Ni: 61.12%, Cr: 21.79%, Mn: 0.085%, C: 0.014%, Si: 0.043%, S: 0.001%, Fe: 3.85%, Ti: 0.159%, Mo: 9.25%, Nb + Ta: 3.87%, P: 0.0013%, Al: 0.151%, Co: 0.004%.

[0012] In the technical solution of the present invention, the mechanical properties of the N06625 nickel-based alloy plate after heat treatment by the method of the present invention are stable, and the heat treatment process has only a linear relationship with the plate thickness and is independent of the width, which is easier to operate on site, improves work efficiency, and at the same time enhances the performance stability of the plate, meeting the requirements that the room temperature yield strength of the plate is ≥ 379 MPa, the room temperature tensile strength is ≥ 758 MPa, and the room temperature elongation is ≥ 30%. Detailed implementation mode Example 1

[0013] To make the present invention more clearly understood, the heat treatment method of a N06625 nickel-based alloy plate of the present invention is further described below. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0014] In this embodiment, the experimental material is a hot-rolled N06625 alloy plate with a thickness of 20 mm and a width of 2800 mm.

[0015] The chemical composition and its mass fraction of the above N06625 nickel-based alloy include: Ni: 59.02%, Cr: 22.30%, Mn: 0.078%, C: 0.015%, Si: 0.051%, S: 0.001%, Fe: 3.65%, Ti: 0.175%, Mo: 9.15%, Nb + Ta: 3.62%, P: 0.0015%, Al: 0.147%, Co: 0.005%.

[0016] For the above nickel-based alloy, the heat treatment method adopted is as follows. It is characterized in that: after the heating furnace is heated to 970 °C, the furnace door is opened, the steel is quickly charged, and after the furnace temperature returns to 970 °C, it is kept warm for 20 min, and then quickly water-cooled after the steel is taken out. After testing, the room temperature yield strength of the steel plate is 510 MPa, the room temperature tensile strength is 910 MPa, and the room temperature elongation is 45%. Example 2

[0017] In this embodiment, the experimental material is a hot-rolled N06625 alloy plate with a thickness of 17 mm and a width of 3300 mm.

[0018] The chemical composition and its mass fraction of the above N06625 nickel-based alloy include: Ni: 61.12%, Cr: 21.79%, Mn: 0.085%, C: 0.014%, Si: 0.043%, S: 0.001%, Fe: 3.85%, Ti: 0.159%, Mo: 9.25%, Nb + Ta: 3.87%, P: 0.0013%, Al: 0.151%, Co: 0.004%.

[0019] For the above nickel-based alloy, the heat treatment method adopted is as follows, characterized in that: after heating the furnace to 970 °C, open the furnace door, quickly load the steel, keep it warm for 17 minutes after the furnace temperature returns to 970 °C, and quickly water-cool after tapping the steel. After testing, the room temperature yield strength of the steel plate is 532 MPa, the room temperature tensile strength is 920 MPa, and the room temperature elongation is 43%.

[0020] In addition to the above embodiments, the present invention can also have other implementation manners. Any technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. A heat treatment method for N06625 nickel-based alloy sheet, characterized in that: The chemical composition and mass fraction of the N06625 nickel-based alloy include: Ni≥58.0%, Cr: 20.0-23.0%, Mn≤0.50%, C≤0.10%, Si≤0.50%, S≤0.015%, Fe≤5.0%, Ti≤0.40%, Mo: 8.0-10.0%, Nb+Ta: 3.15-4.15%, P≤0.015%, Al≤0.40%, Co≤1.0%; the heat treatment process specifically includes: After the heat treatment furnace is heated to 970±10℃, the steel plate is put into the furnace. After the furnace door is closed, the timing starts after the furnace temperature returns to 970±10℃, and the temperature is kept for 1T±5min, where T is the thickness of the steel plate × min / mm. After the time is up, the steel plate is taken out of the furnace and water-cooled.

2. The heat treatment method of the N06625 nickel-based alloy sheet according to claim 1, characterized in that: During the heat treatment process, the steel plate is quickly water-cooled to below 600° C. after being taken out of the furnace.

3. The heat treatment method of N06625 nickel-based alloy sheet according to claim 1 or 2, characterized in that: The room temperature yield strength of the heat-treated steel plate is ≥379MPa, the room temperature tensile strength is ≥758MPa, and the room temperature elongation is ≥30%.

4. The heat treatment method of N06625 nickel-based alloy sheet according to claim 1 or 2, characterized in that: The chemical composition and mass fractions of the N06625 nickel-based alloy include: Ni: 59.02%, Cr: 22.30%, Mn: 0.078%, C: 0.015%, Si: 0.051%, S: 0.001%, Fe: 3.65%, Ti: 0.175%, Mo: 9.15%, Nb+Ta: 3.62%, P: 0.0015%, Al: 0.147%, and Co: 0.005%.

5. The heat treatment method of the N06625 nickel-based alloy sheet according to claim 1 or 2, characterized in that: Chemical composition and mass fraction of the N06625 nickel-based alloy Including: Ni: 61.12%, Cr: 21.79%, Mn: 0.085%, C: 0.014%, Si: 0.043%, S: 0.001%, Fe: 3.85%, Ti: 0.159%, Mo: 9.25%, Nb+Ta: 3.87%, P: 0.0013%, Al: 0.151%, Co: 0.004%.