DE1533256A1 - High temperature alloy - Google Patents

Description

Dipl.-Ing. MARTIN LICHT PATENT LAWYERS Dr. R E I N HOLD SCH M I DT Dipl.-Wirtsch.-Ing. AXEL HANSMANN PATENTANWÄLTE LICHT, HANSMANN, HERRMANN

8 Munich 2 THERESi ENSTRASSE 33 Dipl.-Phys. SEBAS TIA N HERRMANN

Munich, February 1, 1966

Your mark Our mark

/ di

aENERAL ELECTEIC COMPANY Schenectady 5, N.Y. River Road 1, V.St.A.

High temperature alloy

This invention relates to novel and useful alloys which have suitable high temperature strength and are resistant to oxidizing, sulfiding and other high temperature combustion gases are resistant.

It is known that machines that generate the driving force 909851/0830

Patent attorneys Dipl.-Ing. Martin Licht, Dipl.-Wirtsch.-Ing. Axel Hansmann, Dipl.-Phys. Sebastian

8 MÖNCHEN 2, THEITESLENSTRASSE 33 · TeWom »2192 · TaUgnMMt-Adraa ·: UpaHi / MSttdMn

Bank details"! Deutwfce Bank AG, Branch MOndwn, Dep.-Kaee VikhWlienKiorkt, account no. 7W3KN Bayer. Vereinsbank AHndm, branch. CHkor-wi-Miltor-Kna, KIc no. «B« S ■ PostodMck account i MSnaSwi No. 10397

OpfMiKMMr Office: PATENT ADVOCATE DR. REINHOLD SCHMIDT

-2- 15332 ^ 0

of · take advantage of combustion gases' work with better efficiency at higher temperatures and deliver more power. However, it is also known that at such elevated temperatures the strength of many materials decreases rapidly, with these corroding very quickly, which is due to oxidizing or other corrosion-causing constituents in the burned fuel or in the combustion air. In gas turbines, which are operated at temperatures of about 87O ⁰ C and at maximum values at about 1100 C, an improvement of about 38 ⁰ C with respect to the corrosion resistance of the materials used in the construction of a significant advantage. For example, causing the increase in operating temperature of about 82o C to about 87O ⁰ C ⁰ in a typical gas turbine, an increase in deliverable power by about 14 # and an increase in the efficiency by one to five percent.

It is an object of the present invention to provide novel and useful alloys that can be used in devices such as gas turbines allow a substantial increase in operating temperature.

This object is achieved by a heat-resistant alloy, which the following substances specified in percent by weight and essentially contains cobalt as the remainder:

909851/0830

0.10 "to $ 0.60 carbon; 26.5" to 35.0 # chromium; 6 to $ 9 tungsten; 8.5 to 11.5 nickel; 0.050 # boron maximum; 0.01 to 1.0 $ yttrium; maximum 6,095 irons.

It has been found that alloys which have carefully controlled the aforementioned metallurgical Have composition, are significantly more corrosion resistant, while at the same time one for operation Maintain appropriate tensile strength and ductility at high temperatures. These substances are also therefore particularly useful because they are easy to weld and therefore the production of very differently shaped structures enable.

It has also been found that those alloys containing about 26.5 to 35 # chromium are most useful in the sense set forth herein. This is in direct contrast to the statements corresponding to the state of the art, according to which alloys with a chromium content of over 25 percent by weight should increasingly flake off and wear out at higher temperatures. These prior art statements are further elaborated, for example, in “Journal of the Electrochemical Society”, Volume 103, No. 8, τοη Pfalnikar et al, entitled “High Temperature Scaling of Cobalt-Chromium Alloys ^11.

909851/0830

The present substances consist of a carefully Manufactured combination of different ingredients, each of which has the desired and achieved properties contributes. Deviations in the proportions of these components destroy this critical balance and lead on materials that leave something to be desired with regard to essential properties. For example, if the carbon content drops under the above-mentioned range, the strength undesirably decreases. On the other hand, impaired one Increased carbon content, both the weldability and the elongation at break, and reduces the resistance to oxidation. The additions of nickel, iron and tungsten are not particularly critical in terms of resistance to oxidation and corrosion, however, it is advisable to add them within the specified quantity limits in order to obtain suitable mechanical properties achieve. Boron imparts ductility to the alloy if so desired. If the boron content rises above the above Value, harmful, low-melting phases develop in the alloy. If you add less yttrium than stated above, the resistance to oxidation decreases. It is practically difficult to get larger amounts of yttrium than that to effectively melt the above-mentioned maximum amount into the product. The cobalt, which forms the basic substance, is known for that it contributes to the resistance to oxidation and sulphidation. Manganese proportions up to about 1.00? C can be accepted, However, manganese is never intentionally added.

909851/0830

Other impurities, such as those caused by phosphorus and sulfur, each amount to a maximum of about 0.04 *.

The following examples serve to illustrate this invention and are not intended to be limiting in any way the scope of the invention.

Examples 1-4

Alloys were produced whose composition in percent by weight based on the analysis of cast samples in shown in the following table. The alloys were in the form of pieces about 3 cm in diameter and cast about 13 cm in length. Discs with a diameter of about 2.5 cm and a thickness of about 1.5 mm were used for testing purposes cut off and compared with a state-of-the-art alloy, which has the following composition, expressed in percent by weight, the remainder being essentially cobalt: 0.23 * carbon; 25.52 * chromium; 10.5 * nickel; 6.9 * tungsten; 0.82 * iron; 0.007 * Boron and, as impurities, 0.54 * manganese; 0.02 * phosphorus; 0.02 * sulfur. It should be noted that this dem Prior art alloy does not contain yttrium, which is extremely advantageous for the present alloy Gives properties.

Samples of the above examples and a prior art corresponding to the above-mentioned Mater * with "their side faces a combustion gas stream, in a ^p l

909851/0830

153325

exposed and tested small burner device, wherein natural gas at an air-fuel weight ratio of 50: 1 and at a temperature of about 1100 ⁰ C was burned. The depth of corrosion of the prior art material was approximately 0.37 mm per side after 594 hours. The corresponding corrosion depths of the materials mentioned in the above examples are summarized in the table.

The breaking strength of the material corresponding to the state of the art was after 1000 hours and a temperature -

temperature of about 87O ⁰ C about 740 k_gp ·

cm

From the table it can be seen that the alloys corresponding to the present invention, which have relatively larger chromium additions have an excellent at higher temperatures Have corrosion resistance. It should also be noted that the breaking strength behavior in the above sense is equivalent to that of materials that correspond to the state of the art, but with the remarkable advantage the corrosion resistance is added. The elongation at break of the materials listed in the table is im Favorable compared to that of the material corresponding to the state of the art.

The present invention therefore provides novel and useful alloys, 'especially at high

909851/0830 0K ^ ^A - ~ ^{ltO 1} ^ * ^

Temperatures are very stable and also towards oxidizing and sulphidating combustion gas constituents are resistant. They are therefore particularly suitable for the production of gas turbine parts, such as nozzle partitions, and also for other parts and devices that are used in are exposed to high temperatures that cause corrosion and / or effects that cause oxidation. she can also be used in general in ovens as fans, runners or other devices that are similar exposed to extreme conditions.

909851/0830

Tabel

co in weight percent σ Cr 0.26 31.0 Y Ni W, Pe ι (D B. Co corrosion Corrosion strength Temp. Time until σ
co Chemical Analysis as a result depth ( ⁰ C) fracture Composition oo 3 0.23 28.9 0.05 10.4 8.4 0.65 0.0010 Heet < ² > oxidation (mm / side) Claim 790 (Hours) cn 110O ⁰ C approximately ung _o 870 331.4 Mn 0.15 (Kp / crn ^) 980 1726.0 00 0.24 29.6 0.38 10.4 8.4 0.70 approximately Rest ⁽²⁾ Time 1400 790 1490.8 Example, CO
o 5 0.40 0.002 (Hours) approximately 700 870 505.3 0.24! 28.6 0.39 10.5 8.3 0.66 0.0011 Remainder ^ 635 0.11 350 790 1075.6 2 ι
ι approximately 1400 870 409.1 0.17 8.5 7.9
I. 0.72 0.41 0.0025 Remainder < ² > 0.12 700 870 970.4 635 (3) 1400 35.26 * 0.41 7oo 609 1050 0.29 (3)

(1) Components and impurities with minor proportions in the common raw materials are approximately as follows: phosphorus at 0.02 percent by weight; Sulfur at 0.02 percent by weight.

(2) remainder essentially cobalt.

(3) Not checked.

CT)

Claims (1)

ρ tip, »um n Hι IHi-Hi— FT-π PATENT LAWYERS PATENTANWÄLTE LICHT, HANSMANN, HERRMANN MDNCHEN 2 THERESIENSTRASSE 33 General Electric Company Schenectady 5, NY River Road 1,
V.St.A. _: ] £ 33256 DipL4ng. MARTIN LIC] Dr. REINHOLD SCHMIDT DipI.-Wirtsch.-lng. AXELHANSMANN Diploma in Physics, SEBASTIAN HERRMANN Munich, February 1, 1966 Your woes Our sign / dl Patent application: high temperature alloy Claim Highly heat-resistant alloy, characterized in that it consists of the following substances given in percent by weight where the ester component is essentially cobalt * 0.10 # to 0.60? S carbon; 26.5 # to 35.0 # chromium; 6.0 ^ 6 to 9, Ο9έ tungsten; $ 8.5 to 11.53 * nickel; maximum Boron; $ 0.01 to 1.0 # yttrium; $ 6.0 iron maximum. 909851/0830 INSPECTED