JPH0236669B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is directed to Ni-Fe-
The present invention relates to a method for manufacturing Cr-based alloy plate material. [Prior art] In general, aircraft jet engines, etc.
Ni-Fe-Cr alloy plate material with excellent heat resistance is used. This Ni-Fe-Cr based alloy plate material contains, in weight% (hereinafter % indicates weight%), C: 0.01 to 0.15%, Fe: 10 to 45%, Cr: 10 to 25%, Nb and Ta. One or two types of: 2 to 6
%, one or two of Ti and Al: 0.05~
3%, B: 0.001 to 0.01%, and further contains Mo: 1 to 4% as necessary, and the remainder is Ni and inevitable impurities. , under normal conditions.
Cast into an ingot and sell this ingot for 1000~
Start blooming forging at a heating temperature of 1200℃ and width: 500
A slab with dimensions of ~600 mm x thickness: 150 to 200 mm is formed, and this slab is hot rolled at a heating temperature of 1000 to 1250°C to form a hot rolled plate with a thickness of 3 to 4 mm. The rolled plate is subjected to cold rolling at a rolling rate of 60 to 80% and intermediate annealing at a temperature of 900 to 980°C twice or more, and the final cold rolling rate is 65 to 80%.
It is manufactured by using a cold-rolled plate having a thickness of 0.5 to 2 mm as %, and subjecting the cold-rolled plate to a solution treatment at a temperature of 925 to 980°C. [Problems to be solved by the invention] However, Ni-Fe-Cr based alloy sheets produced by such conventional methods have poor cold formability and cannot be bent or bent under severe conditions. Cracks often occur when cold forming such as deep drawing is performed. [Means for Solving the Problems] Therefore, from the above-mentioned viewpoint, the present inventors focused on the conventional Ni-Fe-Cr alloy plate material, and
As a result of conducting research to improve the cold formability of this material, we found that the reason for the poor cold formability of conventional Ni-Fe-Cr alloy sheets is the presence of carbides in the base material even after the final solution treatment. This is due to not only the presence of secondary precipitates such as intermetallic compounds, but also the extremely fine crystal grain size, with an average grain size of 5 to 15 μm. When the intermediate annealing temperature is 1000 to 1200 °C, which is relatively high compared to the intermediate annealing temperature of 900 to 980 °C, the above-mentioned secondary precipitates will not exist at all after cold rolling and solution treatment, and at the same time, Furthermore, if the final cold rolling rate is set to 5 to 60%, which is relatively low compared to the conventional 65 to 80%, the grains after solution treatment will become coarse with an average grain size of 20 to 100 μm. ,
As a result, we obtained the knowledge that the Ni-Fe-Cr alloy sheet material has excellent cold formability. This invention was made based on the above findings, and includes: C: 0.01 to 0.15%, Fe: 10 to 45%, Cr: 10 to 25%, and one or two of Nb and Ta: 2 ~6
%, one or two of Ti and Al: 0.05~
3%, B: 0.001 to 0.01%, and if necessary, Mo: 0.1 to 4%, and the remainder is Ni and inevitable impurities. , under normal conditions,
Casting, blooming forging, hot rolling, cold rolling and intermediate annealing are repeated two or more times, and after final cold rolling, solution treatment is performed to produce Ni-Fe-Cr alloy sheet material. In doing so, by setting the annealing temperature in the intermediate annealing to 1000 to 1200°C and setting the rolling ratio in the final cold rolling to 5 to 60%, an average grain size of 20 to 100 μm and 2.
The present invention is characterized in that it produces a Ni-Fe-Cr alloy sheet material with excellent cold formability and a solution-treated structure free of secondary precipitates. Next, the reason why the component composition and the manufacturing conditions are limited as described above in the method for manufacturing a Ni-Fe-Cr alloy plate material of the present invention will be explained. A Component composition (a) C The C component has the effect of improving high-temperature creep elongation, but if its content is less than 0.01%, the desired high-temperature creep elongation cannot be secured; %, carbides precipitate at grain boundaries during use at high temperatures, resulting in an extreme decrease in ductility. Therefore, the content was set at 0.01 to 0.15%. (b) Fe Since the Fe component acts as a substitute component for Ni, its inclusion lowers the alloy price and forms the base together with the Ni component.
It has the effect of improving hot workability, but if its content is less than 10%, the desired effect will not be obtained, while if its content exceeds 45%, heat resistance will deteriorate. Therefore,
Its content was set at 10-45%. (c) Cr The Cr component has the effect of improving oxidation resistance, but when the content is less than 10%, the desired oxidation resistance can be secured, but on the other hand, when the content exceeds 25%, The content was set at 10 to 25% because it not only reduces hot workability but also makes it easier for brittle phases such as σ phase to precipitate. (d) Nb and Ta These components have the effect of improving high-temperature strength, but if their content is less than 2%, the desired high-temperature strength cannot be secured, but on the other hand, if their content exceeds 6%. Since the hot workability deteriorates, the content should be reduced to 2~
It was set at 6%. (e) Ti and Al These components have the effect of further improving high-temperature strength when coexisting with Nb and Ta, but if their content is less than 0.05%, the desired effect of improving the above effect cannot be obtained, On the other hand, if the content exceeds 3%, hot workability will decrease, so the content should be increased from 0.05 to 3%.
%. (f) B Component B has the effect of strengthening grain boundaries and improving creep strength, but its content is
If it is less than 0.001%, the desired improvement effect cannot be obtained;
On the other hand, if the content exceeds 0.01%, hot workability and weldability deteriorate, so the content was set at 0.001 to 0.01%. (g) Mo The Mo component has the effect of further improving high-temperature strength, so it is included as necessary when this property is particularly required, but if its content is less than 0.1%, the desired improvement effect will not be achieved. On the other hand, if the content exceeds 4%, cold formability deteriorates, so the content was set at 0.1 to 4%. B Manufacturing conditions (a) Intermediate annealing temperature If the temperature is less than 1000°C, solid solution of secondary precipitates such as carbides and intermetallic compounds is insufficient, and even after the final process of solution treatment, the secondary precipitates will not form. Not only does this result in a structure in which particles exist, but the crystal grains also become fine, with an average grain size of less than 20 μm, making it impossible to secure the desired excellent cold formability.
If it exceeds 100 μm, a structure without secondary precipitates can be obtained after solution treatment, but the average grain size will exceed 100 μm and the grains will become too coarse.
The temperature was set at 1000 to 1200°C because it would not only deteriorate the cold formability but also cause significant surface oxidation, making it impractical. (b) Final cold rolling ratio If the rolling ratio is less than 5%, rapid crystal grain growth occurs due to low strain during solution treatment, and the average grain size exceeds 100 μm, resulting in excessively coarse grain size. In addition to causing a decrease in formability, properties such as fatigue properties also deteriorate; on the other hand, when the rolling reduction exceeds 60%,
Recrystallization occurs during solution treatment, but due to the large processing strain, not only do the crystal grains become extremely fine with an average grain size of less than 20 μm, but also intermetallic compounds begin to precipitate during solution treatment. Since the cold formability deteriorates during rolling, the rolling ratio was set at 5 to 60%. As mentioned above, the Ni-Fe-Cr alloy sheet material has excellent cold formability when the average grain size is 20 to 100 μm and it has a solution-treated structure without secondary precipitates. It shows. [Example] Next, the method for manufacturing the Ni-Fe-Cr alloy plate material of the present invention will be specifically explained with reference to Examples. Using an ordinary vacuum high-frequency melting furnace, the first
A molten Ni-Fe-Cr alloy having the composition shown in the table is prepared and cast into an ingot with a diameter of 90 mmφ and a length of 350 mm.
Blown forged at a heating temperature of 1200℃ Width: 200mm
x Thickness: 25 mm x length: 450 mm. This slab is hot-rolled at a heating temperature of 1000 to 1250°C to form a hot-rolled plate with width: 200 mm x thickness: 4 mm, and then , this hot-rolled sheet is subjected to cold rolling and first
Intermediate annealing at the temperature indicated in the table (holding time: 20
width: 200 mm x thickness: 1 at the final cold rolling rate shown in Table 1.
mm cold-rolled plate and finally into this cold-rolled plate, temperature:
Methods 1 to 9 of the present invention and

〔Effect of the invention〕

As is clear from the results shown in Table 1, the plates manufactured by methods 1 to 9 of the present invention all have relatively coarse crystal grains, and are difficult to ensure excellent cold formability. In contrast to the sheet materials manufactured by conventional methods 1 to 7, which have the essential average grain size of 20 to 100 μm and also have a solution-treated structure with no secondary precipitates. teeth,
It has fine crystal grains with an average grain size of less than 20 μm, and has a structure in which secondary precipitates exist in the matrix, and these results appear in the Erichsen value, and are All plate materials manufactured using this method are generally considered to have good cold formability.
While the plate materials produced by conventional methods 1 to 7 have an Erichsen value of 11.5 mm or more, the Erichsen values are lower than this. As described above, according to the method of the present invention, it is possible to produce a Ni-Fe-Cr alloy sheet material having an average grain size of 20 to 100 μm and a structure free of secondary precipitates. The resulting Ni−Fe
-Cr-based alloy sheet materials have industrially useful effects such as excellent cold formability.

Claims (1)

[Claims] 1 C: 0.01 to 0.15%, Fe: 10 to 45%, Cr: 10 to 25%, one or two of Nb and Ta: 2 to 6
%, one or two of Ti and Al: 0.05~
3%, B: 0.001 to 0.01%, and the rest is Ni and unavoidable impurities (weight %).
Cast under normal conditions, bloomed forged, hot rolled,
Then, cold rolling and intermediate annealing are repeated two or more times, and after final cold rolling, solution treatment is performed.
When manufacturing Ni-Fe-Cr alloy sheet materials, the annealing temperature in the above intermediate annealing is set at 1000 to 1200℃.
and the rolling ratio in the final cold rolling is 5.
~60%, a cold formable Ni-Fe-Cr alloy plate material having an average grain size of 20 to 100 μm and a solution-treated structure without secondary precipitates is produced. Excellent manufacturing method for Ni-Fe-Cr alloy sheet material. 2 C: 0.01-0.15%, Fe: 10-45%, Cr: 10-25%, one or two of Nb and Ta: 2-6
%, one or two of Ti and Al: 0.05~
3%, B: 0.001 to 0.01%, and further contains Mo: 0.1 to 4%, and the remainder is Ni and unavoidable impurities (weight %). of,
Cast under normal conditions, bloomed forged, hot rolled,
Then, cold rolling and intermediate annealing are repeated two or more times, and after final cold rolling, solution treatment is performed.
When manufacturing Ni-Fe-Cr alloy sheet material, the annealing temperature in the above intermediate annealing is set at 1000 to 1200℃.
and the rolling ratio in the final cold rolling is 5.
~60%, a cold formable Ni-Fe-Cr alloy plate material having an average grain size of 20 to 100 μm and a solution-treated structure without secondary precipitates is produced. Excellent manufacturing method for Ni-Fe-Cr alloy sheet material.