JPH0694579B2 - Corrosion resistant Ni-Cr alloy with excellent bending workability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention has excellent corrosion resistance and bending workability, and therefore handles corrosive liquids such as a pickling tank, an acid recovery device, and a dissolution device using an acid. The present invention relates to a Ni-Cr-based alloy suitable for use as a structural member particularly in a portion exposed to a corrosive liquid in various apparatuses, and as a deposition preventive plate in a chemical vapor deposition apparatus in which cleaning treatment for removing vapor deposition materials is often performed. It is a thing.

[Conventional technology]

The same applicant has previously found that as a material showing excellent corrosion resistance in the above-mentioned corrosion field, Cr found in Japanese Patent Publication No. 58-17247:
We have developed a Ni-Cr alloy containing 35 to 85% by weight.

[Problems to be Solved by the Invention]

However, the above-mentioned conventional Ni-Cr alloys, although exhibiting excellent corrosion resistance, do not necessarily have good moldability, particularly bending workability, and therefore require considerable man-hours for molding when applied to various fields. Not only is it satisfactory, but the current situation is that it is not completely satisfactory in terms of reliability.

[Means for Solving the Problems]

Therefore, from the viewpoints as described above, the present inventors
Focusing on conventional Ni-Cr alloys with high Cr content, we conducted research to develop a material that has corrosion resistance equivalent to the excellent corrosion resistance of this alloy and has excellent formability. (Hereinafter,% represents weight%), Cr: 38 to 50%, (preferably Cr: 43 to 47%, one or two kinds of Mo and W: 0.1 to 2%), and If necessary, (i) Cu: 0.1 to 2%, (ii) Ca: 0.001 to 0.01%, (iii) one or more of Zr, Nb, Ta and Hf:
0.1 to 3%, (iv) Y and one or more kinds of rare earth elements: 0.001 to 0.01%, containing one or more kinds of the above (i) to (iv), and the rest A Ni-Cr alloy having a composition consisting of Ni and unavoidable impurities and having C and N component contents as unavoidable impurities of C: 0.05% or less and N: 0.04% or less ensures corrosion resistance, We have obtained the knowledge that the moldability can be maintained.

The present invention has been made based on the above findings, and the reason why the component composition is limited as described above will be described below.

(A) Cr The Cr component has the effect of improving the corrosion resistance to various corrosive liquids, but if the content is less than 38%, the desired corrosion resistance cannot be secured, while the content of 50% increases. If the content exceeds the range, it becomes brittle and cracks are likely to occur during the forming process, so the content was set to 38 to 50%.

However, the content of the Cr component is preferably 38 to 47%, more preferably 43 to 47%, and if the area ratio of the precipitation of the α phase of the Cr group is 10% or less in this composition range, the maximum corrosion resistance and It is possible to obtain workability.

(B) Mo and W These components, both of which are solid-soluted in the base material, are Cr, Mo, and W.
Although it has the effect of further improving the corrosion resistance in the coexisting state, if the content is less than 0.1%, the desired excellent corrosion resistance cannot be secured, and if the content exceeds 2%, the formability is improved. However, the content was determined to be 0.1 to 2%.

(C) Cu The Cu component, together with Cr, Mo and W, has the effect of improving the corrosion resistance of the alloy, but if the Cu content is less than 0.1%, the desired effect cannot be obtained, while if it exceeds 2%. Since the effect is not further improved even if it is contained as
It was set at 2%.

(D) Ca The Ca component has a function of improving the deoxidizing and desulfurizing effects at the time of alloy melting, but if the content is less than 0.001%, the desired effect cannot be obtained, and on the other hand, if the content is If it exceeds 0.01%, it becomes brittle and cracks easily occur during molding, so the content was set to 0.001 to 0.01%.

(E) Zr, Nb, Ta and Hf These components have the effect of further improving the workability of the alloy, but if the content is less than 0.01%, the desired effect cannot be obtained, while 3 Even if it is contained in excess of%,
Since no further improvement of the effect is seen, its content is set to 0.1.
It was set at ~ 3%.

(F) Y and rare earth elements These components have the effect of improving the workability of the alloy, but if the content is less than 0.001% the desired effect cannot be obtained, while the content is 0.01 %, The effect was not further improved, so the content was set to 0.001 to 0.01%.

(G) C and N In general, when a Ni-Cr alloy having a high Cr content of this kind is melted in the atmosphere using a high frequency furnace which is a common melting method, the raw materials to be melted are carefully selected. However, the contents of C and N components as unavoidable impurities are usually C: 0.06% or more and N: 0.05% or more, respectively. With a Cr-based alloy, the formability, especially the bendability, is poor, and cracking occurs even with a slight bending work.

However, when this Ni-Cr alloy is doubly melted using, for example, the vacuum melting method and the electroslag melting method, C: 0.05%
Hereafter, it is possible to make N: 0.04% or less, and thus Ni with a reduced content of C and N as unavoidable impurities.
-Cr-based alloys have dramatically improved formability. From this point, the C and N contents as inevitable impurities have been reduced to C: 0.05% or less and N: 0.04% or less, respectively. In this way, excellent moldability, especially bending workability is ensured.

Furthermore, the content of C and N components is C: 0.01%
Hereinafter, it is most preferable to reduce N to 0.01% or less, and the carbide can further improve the corrosion resistance by reducing the formation of nitride.

Incidentally, the Ni-Cr alloy of the present invention, as other unavoidable impurities, Fe: 0.3% or less, Mn: 0.3% or less, Ti: 0.3% or less, Al: 0.3% or less, and Mg: 0.05% or less, respectively. contains.

〔Example〕

Next, the alloy of the present invention will be specifically described by way of examples.

First, after preparing an alloy melt with a predetermined composition using a high frequency vacuum melting furnace, cast it in a mold to make an ingot of diameter: 60 mm × length: 200 mm, then remelt this ingot using an electroslag melting device. Then, an ingot with a diameter of 100 mm having the composition of components shown in Table 1, respectively,
After homogenizing this ingot under the condition of holding at a predetermined temperature within the range of 1150 to 1250 ° C for 10 hours, hot working was performed at the predetermined hot working start temperature within the range of 1150 to 1250 ° C. Forged and hot rolled to a hot rolled sheet with a thickness of 4 mm,
This hot-rolled sheet was homogenized at a predetermined temperature in the range of 1100 to 1200 ° C for 30 minutes and then cold-rolled to a cold rolled sheet with a thickness of 2 mm. Again on the plate 1100-1200
The alloy plates 1 to 54 of the present invention and the comparative alloy plates 1 to 12 were manufactured by subjecting to homogenization treatment under the condition of holding at a predetermined temperature within the range of C for 30 minutes.

Each of the comparative alloy sheet materials 1 to 12 has a composition in which any one of the constituent components (marked with * in Table 1) is out of the range of the present invention.

Next, with respect to the alloy sheets 1 to 54 of the present invention and the comparative alloy sheets 1 to 12 obtained as a result, in order to evaluate the formability, especially the bendability, the room temperature tensile elongation was measured and based on JIS standards. 180 degree contact bending test,
It was measured whether or not a crack was generated in the bent portion, and for those that were capable of contact bending, a contact bending test in the opposite direction was further performed, and the presence or absence of cracks in the bent portion was observed.

The 180 ° close contact bending test based on the JIS standard is that the alloy plate 1 shown in FIG. 1 (a) is bent as shown in FIG. 1 (b) to bring one surface into close contact, and a crack is generated at that time. This is a test for observing whether or not to do. In the reverse contact bending test, as shown in FIG. 1 (c), the alloy plate 1 that has been once subjected to close contact bending is further subjected to close contact bending in the reverse direction to check for cracks in the bent portion. It is a harsh test to check the existence.

The results of the 180 ° close contact bending test and the reverse close contact bending test are shown in Table 1. In Table 1, “X” indicates whether cracking has occurred. “X” indicates that cracking occurs before the contact bending is completed and contact bending cannot be performed. A crack was generated during the contact bending process, and a double circle indicates that the crack was not generated even by the contact bending in the opposite direction.

For the purpose of further evaluating corrosion resistance, temperature: 60%, 17% HNO ₃
Corrosion amount was measured by conducting mixed acid immersion test of immersion in 3% HF aqueous solution for 24 hours and reverse aqua regia immersion test of immersion in 8% HCl-55% HNO ₃ aqueous solution at the same temperature: 60 ° C for 240 hours. . The results of these measurements are shown in Table 1.

〔The invention's effect〕

From the results shown in Table 1, the alloy sheet materials 1 to 54 of the present invention are
Both show excellent corrosion resistance, and show significantly excellent bending workability, while, as seen in Comparative Alloy Sheets 1 to 12, the content of any one of the constituent components is within the scope of the present invention. It is clear that when it is out of the range, at least one of the corrosion resistance and the bending workability becomes inferior.

As described above, the Ni-Cr alloy of the present invention, in addition to corrosion resistance, has excellent moldability, so molding into various members requiring corrosion resistance, without occurrence of cracks,
It is extremely easy to carry out and, in practical use, exhibits extremely excellent corrosion resistance and is stable over a long period of time, so that it is highly reliable and has industrially useful properties.

[Brief description of drawings]

1 (a) to 1 (c) are schematic diagrams showing a test method for evaluating the bending workability of an alloy plate. 1 ... Alloy plate

Continuation of the front page (56) References JP-A 61-276948 (JP, A) JP-A 55-113858 (JP, A) JP-A 48-81718 (JP, A)

Claims (19)

[Claims] 1. A composition containing Cr: 38 to 50%, one or two kinds of Mo and W: 0.1 to 2%, and a balance of Ni and inevitable impurities, and as an inevitable impurity. The content of C and N components of C: 0.05% or less, N: 0.04% or less, (above weight%) is a corrosion-resistant Ni-Cr alloy having excellent bendability. 2. A composition containing Cr: 38 to 50%, one or two of Mo and W: 0.1 to 2%, Cu: 0.1 to 2%, and the balance Ni and inevitable impurities. Corrosion resistance Ni- with excellent bending workability, characterized in that the content of C and N components as unavoidable impurities is C: 0.05% or less, N: 0.04% or less (above weight%) Cr-based alloy. 3. A composition containing Cr: 38 to 50%, one or two of Mo and W: 0.1 to 2%, Ca: 0.001 to 0.01%, and the balance Ni and inevitable impurities. Corrosion resistance Ni- with excellent bending workability, characterized in that the content of C and N components as unavoidable impurities is C: 0.05% or less, N: 0.04% or less (above weight%) Cr-based alloy. 4. Cr: 38 to 50%, 1 or 2 kinds of Mo and W: 0.1 to 2%, 1 or 2 or more kinds of Zr, Nb, Ta and Hf: 0.1 to 3
%, With the balance being Ni and inevitable impurities, and the content of C and N components as inevitable impurities is C: 0.05% or less, N: 0.04% or less, (above weight%) Corrosion resistant Ni-Cr alloy with excellent bending workability. 5. Cr: 38-50%, one or two of Mo and W: 0.1-2%, one or more of Y and rare earth elements: 0.001
Content of Ni and unavoidable impurities, and the content of C and N components as unavoidable impurities is C: 0.05% or less, N: 0.04% or less, %) Is a corrosion-resistant Ni-Cr alloy with excellent bending workability. 6. A Cr content of 38 to 50%, one or two of Mo and W: 0.1 to 2%, Cu: 0.1 to 2%, Ca: 0.001 to 0.01%, and the balance of Ni. Bending process characterized by having a composition consisting of unavoidable impurities and the content of C and N components as unavoidable impurities: C: 0.05% or less, N: 0.04% or less, (above weight%) Corrosion resistant Ni-Cr alloy with excellent properties. 7. Cr: 38-50%, one or two of Mo and W: 0.1-2%, Cu: 0.1-2%, one or two of Zr, Nb, Ta and Hf. Species or higher: 0.1-3
%, With the balance being Ni and inevitable impurities, and the content of C and N components as inevitable impurities is C: 0.05% or less, N: 0.04% or less, (above weight%) Corrosion resistant Ni-Cr alloy with excellent bending workability. 8. Cr: 38-50%, one or two of Mo and W: 0.1-2%, Cu: 0.1-2%, one or more of Y and rare earth elements: 0.001
Content of Ni and unavoidable impurities, and the content of C and N components as unavoidable impurities is C: 0.05% or less, N: 0.04% or less, %) Is a corrosion-resistant Ni-Cr alloy with excellent bending workability. 9. Cr: 38-50%, one or two of Mo and W: 0.1-2%, Ca: 0.001-0.01%, one or two of Zr, Nb, Ta and Hf. Species or higher: 0.1-3
%, With the balance being Ni and inevitable impurities, and the content of C and N components as inevitable impurities is C: 0.05% or less, N: 0.04% or less, (above weight%) Corrosion resistant Ni-Cr alloy with excellent bending workability. 10. Cr: 38 to 50%, one or two of Mo and W: 0.1 to 2%, Ca: 0.001 to 0.01%, one or more of Y and rare earth elements: 0.001
Content of Ni and unavoidable impurities, and the content of C and N components as unavoidable impurities is C: 0.05% or less, N: 0.04% or less, %) Is a corrosion-resistant Ni-Cr alloy with excellent bending workability. 11. Cr: 38-50%, one or two kinds of Mo and W: 0.1-2%, one or more kinds of Zr, Nb, Ta and Hf: 0.1-3.
%, Y and one or more of rare earth elements: 0.001
Content of Ni and unavoidable impurities, and the content of C and N components as unavoidable impurities is C: 0.05% or less, N: 0.04% or less, %) Is a corrosion-resistant Ni-Cr alloy with excellent bending workability. 12. Cr: 38-50%, one or two of Mo and W: 0.1-2%, Cu: 0.1-2%, Ca: 0.001-0.01%, Zr, Nb, Ta and Hf. One or more of the above: 0.1 to 3
%, With the balance being Ni and inevitable impurities, and the content of C and N components as inevitable impurities is C: 0.05% or less, N: 0.04% or less, (above weight%) Corrosion resistant Ni-Cr alloy with excellent bending workability. 13. Cr: 38-50%, one or two of Mo and W: 0.1-2%, Cu: 0.1-2%, Ca: 0.001-0.01%, Y and rare earth elements 1 type or 2 or more types: 0.001
Content of Ni and unavoidable impurities, and the content of C and N components as unavoidable impurities is C: 0.05% or less, N: 0.04% or less, %) Is a corrosion-resistant Ni-Cr alloy with excellent bending workability. 14. Cr: 38-50%, one or two of Mo and W: 0.1-2%, Cu: 0.1-2%, one or two of Zr, Nb, Ta and Hf. Species or higher: 0.1-3
%, Y and one or more of rare earth elements: 0.001
Content of Ni and unavoidable impurities, and the content of C and N components as unavoidable impurities is C: 0.05% or less, N: 0.04% or less, %) Is a corrosion-resistant Ni-Cr alloy with excellent bending workability. 15. Cr: 38 to 50%, one or two of Mo and W: 0.1 to 2%, Ca: 0.001 to 0.01%, one or two of Zr, Nb, Ta and Hf. Species or higher: 0.1-3
%, Y and one or more of rare earth elements: 0.001
Content of Ni and unavoidable impurities, and the content of C and N components as unavoidable impurities is C: 0.05% or less, N: 0.04% or less, %) Is a corrosion-resistant Ni-Cr alloy with excellent bending workability. 16. Cr: 38-50%, one or two of Mo and W: 0.1-2%, Cu: 0.1-2%, Ca: 0.001-0.01%, Zr, Nb, Ta and Hf. One or more of the above: 0.1 to 3
%, Y and one or more of rare earth elements: 0.001
Content of Ni and unavoidable impurities, and the content of C and N components as unavoidable impurities is C: 0.05% or less, N: 0.04% or less, %) Is a corrosion-resistant Ni-Cr alloy with excellent bending workability. 17. A corrosion-resistant Ni-Cr alloy having excellent bending workability according to claims 1 to 16, wherein Cr: 38 to 47%. 18. A corrosion-resistant Ni-Cr-based alloy having excellent bending workability according to claim 1, wherein Cr: 43-47%. 19. The corrosion resistant nickel having excellent bending workability according to claim 1, wherein Cr: 43 to 47%, C: 0.01% or less, and N: 0.01% or less.
-Cr alloy.