US1771773A - Unoxidizable alloy - Google Patents

Description

Patented July 29, 1930 UNITED STATES GAIILLE CONTAL, or sun. CLOUD, .rmcn

unoxrmzanm ALLOY in Drawing. Applicationfiled July 17, 1929, Serial No. 319,070, and in 1. June 21, 1929.

I 4 The present invention has for its object anunoxidizable alloy designed particularly for the manufacture of valves and other adj usting and packing members subjected to the action of steam, particularly superheated steam. A y

This alloy is substantially composed as "follows:

- Per cent Nickel .40 to 50 10 Copper ,30 to 40 Manganese 10 to 20 Antimony 5 to 15 Tin I r 1 to By way of example, the following exact ortions give an alloyhaving all the desira 1e qualities for the manufacture of'the above mentioned articles:

2o Nick l 40 Copper 31 Manganese 18 Antimony Tin p 2 Total 100 For preparing this alloy, use is preferably made of a copper-manganese alloy which is first melted; nickel is then added,

. and subsequently manganese, antimony and tin. "In order to avoid oxidation during melting, a deoxidizing agent for bronze, such as borax, canbe added.

The alloythus obtained has the 'followlng 5 properties:

Density: 8.28.

Melting oint: about 1000 C.

Texture gMicrographs show that the crystallization is homogeneous.

Colour: white.

HardnesszThe scleroscopic hardness is of 55 and the hardness as determined by BH- nells method is 210, that is to saya hardness near that of hard steel. If the metal is heated to a temperature of 800 C. and water hard ened it undergoes a material diminutionof hardness; the scleroscopic hardness then passes from 55' to 40. Utilization of this phenomenon can facilitate machining.

- attack the alloy only with great diificulty.

Resistance to chemical agentszTests have been efi'ected on a sample having an area of 8 square centimeters; an immersion for 8 hours in boiling potash at 22 B. has caused no loss of weight; an immersion for 48 hours in ammonia at 16 B. and an exposure during 4 hours to a vapour saturated with ammonia has caused only a loss of weight of 0.005 gr. Boiling nitric and sulphuric acids Resistance to the action of steamzIt is known that up tonow valves, gate valves, etc., as well as the'valveseats, exposed to the ac.- tion of-steam, particularly if it is'superheated, are corroded after a few days and no longer ensure the necessary fluid-ti htness.

This corrosive action 'is both of a c emical (and mechanical nature;v on the one hand, -steam exerts ahighly oxidizing action, and it acts, moreover, through the a kaline particles which it frequently contains. However, obturating and adjusting mem bers manufactured from the alloy in accordance with the invention, perfectly resist the k passage of superheated steam owing to the great hardness of this alloy and its resistance to the attack of oxidizing and alkaline agents. They have also the advantage of notbecoming distorted, as they are. not influenced by an increase of temperature to 350 C. This alloy is designed particularl for casting in molds; it may also be easi y worked on the lathe and other machi'ne-tools.

An addition of lead, not exceeding 1%, in-

sertedtowards the end of the preparation, i

has the eflfect of softening the alloy. It is to be understood that the proportions of the various -elements of the alloy can be varied within the limits indicated above and their choice can easily predetermined in each case so that the required qualities of .hardness and unalterability be obtained.

Claims: 1

1. Alloy comprising nickel (40 to 50%), copper (30 to 40%) manganese (10 to 20%), antimony (5 to 15%), and tin (1 to 10%).

2. Alloycomprising nickel (40 parts), copper (3l parts),'manganese (18 parts), antimony (9 parts), tin (2 parts).

3. Alloy comprising nickel (40 to 50%), copper (30 to 40%) manganese (10 to 20%), antimony (5 to tin (1 to 10%), and lead (less than 1%). y

In testimony whereof I have hereunto affixed my signature.

CAMILLE CONTAL.