US2222472A - Corrosion resistant nickel base alloy - Google Patents

Description

OFFICE v UNITED I STATES FATE CORROSION RESISTANT NICKEL BASE ALLOY Claude R. Bishop, Niagara Falls, N. Y., assignorto Haynes Stellite Company, a corporation of Indiana No Drawing. Application August 24, 1939,

Serial No. 291,672

5 Claims. (Cl. 75-170) The invention relates to corrosion resistant alloys and particularly to nickel-base alloys hav- Corrosion rate in milliing improved corrosion resistance; l I g gzf gg ggg g;

Nickel-base alloys containing silicon, with or CmWsltwnfiemamder N1) aerated 10% aqueous without additions of aluminum or copper or mix- 32 5 6 temperature tures thereof, are particularly resistant to many v corrosive media, notably including hot aqueous solutions of hydrochloric acid. Alloys of the Si Cu Al Sb First Second Thud foregoing type are disclosed in Patents 1,514,064 1 and 1,753,904, issued to A. J. Mandell and C.

10 Plummer, respectively. While extensive use has 10- been made of the excellent resistance of such 7.8 3 None None 0.76 0.77 alloys to corrosion by hydrochloric acid, there is g Y3: 8& 8-3 8-2 a demand for alloys having even greater resist- 11' 3.4 None 6.5 0144 0: 27 0:22 to this we 2-: 21 is: 3-2: 8-33 h (P)- 41 15 The principal object of this invention is to pro- 1013 31 1 None 715 0123 0127 o 15 vide a nickel-base alloy having improved corro- 8:? 3:3 g3 3; 3'32 3- EI; sion resistance, particularly to hydrochloric acid, 10.8 13.7 3.7 1.4 013s 0148 v) and good physical properties. This and other objects are attained in the present invention by Not tested.

the applicationpf discfvery m the addition The corrosion rates shown in the above table 20 @ntlmony, wfthm certaln defimt? compPsitlon were determined by completely immersing the limits, greatly improves the corrosion reslstance specimen in the acid mm indicated therein a ot P ope s of the nickel-base y and maintaining that solution at constant tem Alloys included in the invention contain silicon perature for the periods of time indicated. The

in aproportion between 3% and 14%, preferably loss in weight was determined and reported as between 6% and 11%; antimony in a proportion the number of milligrams dissolved per square between 0.02% and 10%, preferably between 0.3% centimeter ,of surface per hour of time.

and 5%; copper in a proportion between 0.05% The addition of 0.3% to 5% antimony to the and 25%, preferably between 1% and 4%; w th alloys described herein, in accordance with the 0 or t t mi in proportion between preferred procedure of the invention, does not 0.02% and 5%, preferably between 0.5% a materially affect their mechanical properties,

3%; remainder nickel which may be partly r but greater proportions of antimony, that is, be-

placed by cobalt or iron or both. In addition to tween 5% and 10% usually lower Strength the foregoing elements a small proportion of of the alloy somewhat However m 35 manganese may be present to improve the hot stance the alloys possess excellent corrosion reworking characteristics of the alloy; slstance, and in apparatus constructed from alloys containing the greater proportions of anti- The following table indicates the composition of several representative alloys of the invention mony proper allowance m the deslgn of such a aratus ma .mad t 40 and also indicates the results of COIIOSlOIl tests g z i of g gg for the 40 made on samples of those alloys and on samples I claim;

of alloys containing no antimony but otherwise 1 An alloy comprising ili i a, proportion similar to those of the invention. between 3% and 14%; copper in a proportion between 0.05% and 25%; aluminum in}. proportion between 0.02% and 5%; antimony ina proportion, between 0.02% and 10%, serving to impart improved corrosion resistance to the alloy; the remainder nickel.

2. An' alloy as defined in claim 1 in which the silicon is in a. proportion between 6% and 11%. 3. An alloy as defined in claim 1 in which the copper is in a proportion between 1% and 4%.

10 4. An alloy as defined in claim 1 in which the nickel.

CLAUDE R. BISHOP. l0