JPS5833304B2 - Katanseiko SoR-CO Gokin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high Cr-Co alloy which has excellent ductility at room temperature, excellent corrosion resistance and high temperature strength at high temperatures, and good workability.

Alloys used in the heat treatment industry, ceramic industry, etc. are required to have excellent high-temperature strength and to resist corrosion by oxidation, sulfur, vanadium, and the like.

25Cr-2ONi is an alloy suitable for this purpose.
-Fe alloy, 50Co-28Cr-Fe alloy, etc. are used, but 25Cr-20Ni-Fe alloy has poor high-temperature strength and high-temperature corrosion, and 50Co-28Cr-Fe alloy has insufficient ductility at room temperature. However, it has disadvantages such as poor cold workability and insufficient high temperature strength.

The present invention aims to improve cold ductility and high temperature strength without impairing the excellent corrosion resistance of Co-based alloys.
This invention relates to a new alloy in which Ni and Ta are mainly added to an r-Co alloy.

Next, the reason for limiting the range of added components will be described.

Cr is added as an element that improves the high-temperature corrosion resistance of Co, and the higher the amount added, the better the high-temperature corrosion resistance is.

However, if added in excess of 30%, hot workability gradually deteriorates and harmful phases such as σ phase begin to precipitate, so the upper limit of the amount added is 32%.

On the other hand, if the Cr content is less than 2626%, the desired properties regarding corrosion resistance cannot be obtained, so the composition range of Cr is 26 to 26%.
32%, preferably 28-30%.

Ni is an element that is effective in improving cold ductility, workability, and high-temperature strength by stabilizing the face-centered cubic structure phase, which is a high-temperature summation of Co. Exceeding this will result in deterioration of corrosion resistance.

The preferred range is 17-22%.

Ta is an element that improves high-temperature strength without deteriorating corrosion resistance, and if it is less than 0.5% it is ineffective and if it exceeds 3% it becomes difficult to process, so the preferred composition range is 0.7%.
~2.5%.

Y and La contribute to improving the corrosion resistance of the alloy by increasing the adhesion of the formed oxide film.
% or a total of 0.2% or less, preferably each individual or a total of 0.05 to 0.15%.

C is an alloying element that, together with Ta, makes a significant contribution to improving the strength of the alloy. If it is less than 0.03%, it is ineffective and if it exceeds 0.3%, hot working becomes difficult. Therefore, the preferred composition range is 0. It is .05 to 0.25%.

Fe is an element that is effective in improving oxidation resistance, and is usually
% or less, preferably 1 to 2%.

Mn and Si are elements added as deoxidizing and desulfurizing agents, and usually Mn is 2% or less and Si is 1% or less, preferably Mn
It is added so that n 0.5 to 1.5% and Si 0.1 to 0.6% remain.

1 is added as a deoxidizing agent, and Ti is added as a deoxidizing and denitrifying agent to reduce oxygen content and nitrogen content and contribute to improving hot workability and high temperature creep strength. If the content exceeds 5%, processability will be impaired.

Preferably, each content is in the range of 0.03 to 0.5%.

In addition to the above specific components, other elements can be added without departing from the spirit of the invention.

These elements are Zr 0.5% or less, Mg 0.03% or less, and Bo 0.03% or less.

Next, in order to demonstrate the effectiveness of the present invention, an alloy having the components shown in Table 1 was prepared at a vacuum degree of 10-2 to 110-3rrrrrnH.
The product was vacuum induction melted, cast into a tapered mold of nominal weight 2.5 kg, heated at 1150 to 1200°C for 3 hours, and then forged into a square bar with a cross section of 15 mm x 15 M.

From this, a round bar specimen with a diameter of 6.4 m and a gage length of 25 mm was cut out, held at 1200°C for 1 hour, subjected to solution treatment by water cooling, and subjected to a mechanical test.

In the table, alloy number 1 is a comparative alloy.

This is a 50Co-28Cr-Fe alloy that is widely used in this field, and alloy number 4 is an alloy with a composition that deviates from the present invention.

Alloy numbers 2 and 3 are alloys of the present invention.

Table 2 shows the results of the room temperature mechanical test.

Compared to the comparative alloy No. 1, the alloy of the present invention has higher strength and
It is clear that both ductility and ductility are excellent.

Table 3 shows the results of a creep rupture strength test conducted at a temperature of 900°C and a stress of 4.5 kg/-.

Table 3 High temperature creep rupture strength test results It is clear that the alloys of the present invention are significantly superior in high temperature strength compared to the comparative alloys.

Although this example concerned a forged material, the alloy of the present invention
It has been confirmed that it can be easily processed into rods and plates, and the properties of these processed materials are similar to those of this example.

Claims (1)

[Claims] 1% by weight, Cr26-32%, Ni15-23%,
Ta 0.5-3%, CO 0.03-0.3% Fe 3% or less, Mn 2% or less, Si 1% or less, Y or La individually or in total 0.2% or less, A [0.5% or less, TiO ,5%
The following is substantially C except for residual accompanying impurities. Highly malleable Cr-C with excellent room temperature ductility and high temperature strength.
o Alloy.