Search

CN-121992317-A - Method for inhibiting abnormal growth of GH6783 alloy crystal grains

CN121992317ACN 121992317 ACN121992317 ACN 121992317ACN-121992317-A

Abstract

The invention belongs to the technical field of high-temperature alloy heat treatment, and relates to a method for inhibiting abnormal growth of GH6783 alloy grains. The method comprises the following steps of 1, determining the non-growth temperature of GH6783 alloy grains, 2, placing GH6783 alloy bars in a furnace after the temperature of a heat treatment furnace reaches the non-growth temperature, starting timing and preserving heat for a designated time A after the temperature in the furnace reaches the non-growth temperature again, 3, slowly cooling the GH6783 alloy bars to beta-phase aging temperature along with the furnace, preserving heat for 8-10 h, and discharging and air-cooling after the heat preservation is finished. The invention can obviously inhibit abnormal growth of grains of GH6783 alloy bar after solution heat treatment and improve the structural uniformity of GH6783 alloy.

Inventors

  • CAO GUOXIN
  • LIN SICONG
  • NIU SHAOQIANG
  • LIANG CHEN
  • SHI XINBO
  • HE YONGSHENG
  • FU BAOQUAN

Assignees

  • 西安聚能高温合金材料科技有限公司

Dates

Publication Date
20260508
Application Date
20260127

Claims (7)

  1. 1. A method for inhibiting abnormal growth of GH6783 alloy grains, which is characterized by comprising the following steps: Step 1, determining the growth temperature of GH6783 alloy grains; Step 2, placing the GH6783 alloy bar in a furnace after the temperature of the heat treatment furnace reaches the non-growth temperature, starting timing and preserving heat for a designated time A after the temperature in the furnace reaches the non-growth temperature again; and 3, gradually cooling the GH6783 alloy bar to beta-phase aging temperature along with a furnace, preserving heat for 8-10 h, and discharging and air cooling after the heat preservation is finished.
  2. 2. The method of inhibiting the abnormal growth of GH6783 alloy grains according to claim 1, wherein the specific manner of determining the temperature at which the GH6783 alloy grains do not grow is as follows: step 1.1, obtaining a sample block from a GH6783 alloy bar with a forged grain size of 6-9, and performing heat treatment at 1000-1100 ℃ for 1+/-0.25 h, and air cooling in a cooling mode, wherein 6 temperature points are recorded as T 1 、T 2 ……T 6 in the heat treatment process, and the interval between adjacent temperature points is 20 ℃; And 1.2, chemically corroding the polished sample block to observe whether the grain size grows, wherein if the grains do not grow when the temperature is kept at a temperature point T m and the grains grow at a temperature point T m+1 , the temperature T m is determined to be the grain non-growth temperature, and m=1, 2,3,4,5 and 6.
  3. 3. The method for inhibiting the abnormal growth of GH6783 alloy grains according to claim 1, wherein the specified time A in the step 2 is determined according to the specification of the GH6783 alloy bar, concretely by defining the specification of the GH6783 alloy bar as phi, If 50 is less than or equal to phi <200mm, A=0.75xphi, and the unit is min; if 200≤Φ <300mm, A=1×Φ, in min.
  4. 4. The method for inhibiting abnormal growth of GH6783 alloy grains according to claim 3, wherein if the specification phi of the GH6783 alloy bar is more than or equal to 300mm, the heating mode adopts step heating, and the corresponding heat preservation strategy is that after heat preservation is carried out for 120-150 min at 200 ℃ below the non-growth temperature, the total power is increased to the non-growth temperature and the heat preservation is carried out for a specified time B, wherein B=1.25 x phi, and the unit is min.
  5. 5. The method for inhibiting abnormal growth of GH6783 alloy crystal grains according to claim 1, wherein the chemical composition of the GH6783 alloy bar and the mass percentage thereof are that carbon is less than or equal to 0.03%, manganese is less than or equal to 0.50%, silicon is less than or equal to 0.50%, phosphorus is less than or equal to 0.015%, sulfur is less than or equal to 0.005%, chromium is 2.50% -3.50%, nickel is 26.00% -30.00%, niobium is 2.50% -3.50%, aluminum is 5.00% -6.00%, boron is 0.003% -0.012%, iron is less than or equal to 24.00% -27.00%, titanium is less than or equal to 0.40%, tantalum is less than or equal to 0.05%, copper is less than or equal to 0.50%, and the balance is cobalt.
  6. 6. The method of inhibiting abnormal grain growth of GH6783 alloy according to claim 1, wherein in step 3, the cooling rate is 40-60 ℃ per hour.
  7. 7. The method of inhibiting abnormal grain growth of a GH6783 alloy of claim 1, wherein in step 3, the β -phase aging temperature of the GH6783 alloy rod is ‌ ℃.

Description

Method for inhibiting abnormal growth of GH6783 alloy crystal grains Technical Field The invention belongs to the technical field of high-temperature alloy heat treatment, and relates to a method for inhibiting abnormal growth of GH6783 alloy grains. Background GH6783 alloy (foreign brand IN 783) is a fourth generation low expansion superalloy with oxidation resistance and high strength, the thermal expansion coefficient is about 20% lower than that of IN718 alloy, and the density is the lowest (7.81 g/cm 3) IN the existing superalloy. Because of higher Al content in the alloy, a unique beta phase (beta CC, niAl phase) can be separated out from both the intragranular and the grain boundaries in the GH6783 alloy, and the beta phase can improve the stress acceleration grain boundary oxidation resistance of the alloy, so that the alloy has excellent oxidation resistance, tissue stability and high-temperature creep durability. However, the GH6783 alloy has a problem of abnormal grain growth in the structure during solution heat treatment, and individual grains even exceed grade 2, resulting in failure of grain size detection at bar delivery. In addition, the uneven grain size also affects the cooperative deformability of the microstructure of the material, so that the unstable fluctuation problem of mechanical property data is caused. In view of this, the present invention has been made. Disclosure of Invention The invention aims to overcome the defects of the prior art, and provides a method for inhibiting the abnormal growth of GH6783 alloy grains, which can obviously inhibit the abnormal growth of the grains of the GH6783 alloy in the solution heat treatment process and improve the uniformity of microstructure. In order to achieve the above purpose, the present invention provides the following technical solutions: A method for inhibiting abnormal growth of GH6783 alloy crystal grains, which specifically comprises the following steps: Step 1, determining the growth temperature of GH6783 alloy grains; Step 2, placing the GH6783 alloy bar in a furnace after the temperature of the heat treatment furnace reaches the non-growth temperature, starting timing and preserving heat for a designated time A after the temperature in the furnace reaches the non-growth temperature again; and 3, gradually cooling the GH6783 alloy bar to beta-phase aging temperature along with a furnace, preserving heat for 8-10 h, and discharging and air cooling after the heat preservation is finished. Specifically, the specific mode of determining the grain non-growth temperature of the GH6783 alloy in the step 1 is as follows: step 1.1, obtaining a sample block from a GH6783 alloy bar with a forged grain size of 6-9, and performing heat treatment at 1000-1100 ℃ for 1+/-0.25 h, and air cooling in a cooling mode, wherein 6 temperature points are recorded as T 1、T2……T6 in the heat treatment process, and the interval between adjacent temperature points is 20 ℃; And 1.2, chemically corroding the polished sample block to observe whether the grain size grows, wherein if the grains do not grow when the temperature is kept at a temperature point T m and the grains grow at a temperature point T m+1, the temperature T m is determined to be the grain non-growth temperature, and m=1, 2,3,4,5 and 6. Specifically, the designated time A in the step 2 is determined according to the specification of the GH6783 alloy bar, specifically, the specification of the GH6783 alloy bar is defined as phi, If 50 is less than or equal to phi <200mm, A=0.75xphi, and the unit is min; if 200≤Φ <300mm, A=1×Φ, in min. Further, if the specification phi of the GH6783 alloy bar is more than or equal to 300mm, the heating mode adopts step heating, and the corresponding heat preservation strategy is that after the temperature is kept for 120-150 min at 200 ℃ below the non-growth temperature, the temperature is raised to the non-growth temperature with full power and kept for a specified time B, and the unit is min, wherein B=1.25 x phi. It is additionally stated that when the bar specification phi is more than or equal to 300mm, the heat preservation time can be adaptively adjusted according to actual requirements, for example, 120min, 125min, 130min, 135min, 140min, 145min, 150min and the like can be adopted, and the heat preservation time is not listed here. The GH6783 alloy bar comprises, by mass, 0.03% or less of carbon, 0.50% or less of manganese, 0.50% or less of silicon, 0.015% or less of phosphorus, 0.005% or less of sulfur, 2.50% to 3.50% of chromium, 26.00% to 30.00% of nickel, 2.50% to 3.50% of niobium, 5.00% to 6.00% of aluminum, 0.003% to 0.012% of boron, 24.00% to 27.00% of iron, 0.40% or less of titanium, 0.05% or less of tantalum, 0.50% or less of copper, and the balance cobalt. Further, in the step 3, the cooling rate is 40-60 ℃ per hour. Further, in step 3, the beta-phase aging temperature of the GH6783 alloy bar is ‌ ℃ at 845 ℃. Compared with the prior art, the