US2190840A

US2190840A - Corrosion resistant alloys

Info

Publication number: US2190840A
Application number: US270844A
Authority: US
Inventors: Kay William Marriott
Original assignee: Driver Harris Co
Current assignee: Driver Harris Co
Priority date: 1938-05-02
Filing date: 1939-04-29
Publication date: 1940-02-20
Anticipated expiration: 1957-02-20

Description

Patented Feb. 20, 1549 UNITED STATES PATENT OFFICE CORROSION RESISTANT ALLOYS William Marriott Kay, Manchester, England, as-

signor to Driver-Harris Company, Harrison, 7 N. J., a corporation of New Jersey No Drawing. Application April 29, 1939, Serial No. 270,844. In Great Britain May 2, 1938 3 Claims. (01. 75-171) This invention relates to corrosion resistant; minute. The evaporation loss was continuously nickel-chromium alloys. replaced by boiled water and the liquid was con- For certain purposes alloys are required which tinuously stirred. In two series of tests the liqhave high heat resistance and also corrosion reuid contained 2 /2% by weight of sulphuric acid sistance, as for example, in the manufacture of and the liquid temperatures were room tempera- 5 conveyor chains, which have to carry goods ture and 60 C. In two other series of tests, the

through a furnace for annealing or other heat liquid contained 5% by weight of sulphuric acid treatment and then through a spray which may and the liquid temperatures were room temperaconsist of a dilute solution of one or more acids. ture and 60 C.

0 Although the corrosion resistance of the straight It should be remarked that it is a matter of nickel-chromium alloys is quite good, it may, in general knowledge that the difference in corrosion examples such as that above referred to, be the resistance of nickel chromium alloys is not atcorrosion resistance which determines the life of tributable to relatively small difierences in chro the alloy rather than the heat resistance, and mium content. It can be attributed therefore in 5 the present invention is concerned with improvthe following test figuresto difierences in silicon ing such corrosion resistance. content.

The invention comprises the addition to nickelchromium alloys of from 3% to 6% of silicon. Test results The best results appear to be achieved when the D addition of silicon is approximately 4%. E??? z The nickel-chromium alloy may contain from brea 11g ff tt fif 10% to 30% of chromium. The remainder of the iiigas 831163 Pmmds alloy may be nickel save for the silicon. The nickel content may be partly replaced by iron, Low menu 3 648 319 cobalt, tungsten, vanadium, molybdenum, zirmaterial {High 7,250 698 3 conium, manganese and uranium. The alloy may also contain traces of alkaline earth metals, or TESTS I 36% H1504 FOR 500 HOURS the rare earth metals, and may also contain the 630 3 0 usual small quantities of impurities of such ele- Roomt m we Lowsil con.- 5,895 1 ments as carbon, sulphur, phosphorus and aluo w a pa E :,fjjjj 11% 28 2 minium High sillcom.-. 6,940 691 351 30 Experimental tests have shown that a siliconaddition within the range 3-6% reduces the at- TESTS IN 1 4 FOR 500 HOURS tack of acid upon nickel-chromium alloys to a I 90 m6 235 considerable extent. 'Roomtem Low silicon- 5,8 For this purpose four series of tests were made, 0 O W iggg sil i gifI 51 3 22 5 each upon six pieces of metal of two difierent H1811 6,760 634 282 compositions as follows:

The above results show the marked superiority Chromium gg Chromium 3 of the higl?1 silicondfilloy particularly under the 40 Silicon; 4 Silicon 1 wi gfi g i gf Balance Nlckel Balance 1. ,A heat resistant, corrosion resistant alloy 1 being taken as n p e of the Preferred capable of being worked into strip or wire form alloy and N 2 as n pl of a known allfiy in consisting essentially of 10 to 30 percent chrouse y for such purposes. mium, 3 to 6 percent silicon, balance nickel.

The e a i 2. A heat resistant, corrosion resistant alloy mg g i i g i mig gg had the follow capable of being worked into strip or wire form consisting essentially of substantially 20 percent (1) Heavy Stnp x inch x t chromium 3 to 6 percent silicon,'balance nickel.

(2) Light strip 3 1nchesx0.25 inch x .020 inch 3. A a resistant, corrosion resistant alloy (3) Round wire 8 inches x .057 inch diameter capable of being Worked into strip or wire f r Each sample was fastened by a wire of the same consisting essentially of substantially'20 percent composition as the sample, to the periphery of chromium, substantially 4 percent silicon, bala fibre disc partly immersed in the test liquid ance nickel.

I and revolved once every tour minutes. A given WILLIAM MARRIO'II K point on any specimen was immersed tor one