US2115749A - Method of coating ferrous articles - Google Patents

Description

Patented May 3, was

METHOD OF COATING FERROUS ARTICLES Michael M. Rubin, Warren, Ohio, assimor to The Thomas Steel Company, Warren, Ohio, a

corporation of Ohio No Drawing. Application May 8, 1936,

This invention relates, as indicate of applying alloy coatings to ferro'u has reference moreparticularly to the production of a brass'coatingon such ferrous articles as wire and strip.

QR has heretofore been proposed coatings on ferrous articles by electrodeposition on the articles of the alloy, or by immersing the articles to be coated in a molten bath 'of the aly. These methods have generally .provenunsatisfactory, as they do not result in the production of a coating of uniform thickness and homogeneity or one that adheres to the base metal with sufllcient tenacity to render the article capable of being subjected to bending and other fabricating operations.

It is an object of the present A further object of the invention a method of the characterdescribed which is preferably continuous in characte may, if desired, consist of separate, di

ous steps or operations.

To the accomplishment of tion setting forthin detailon'e an of carryingj out, the invention method, however, constituting various ways in which the principle tion may be used.

The method, broadly stated,.

rately electrodepositing. .on thei feifrous.afiicle, such as strip or wire, the metals" forming thegalg loy or brass coating, and subsequentlyheattreat ing the coated article in a controlle free from oxidizing gases.

.In providing, for example, a commercial yellow brass coating on steel strip, 1 first deposit on the strip, by any of the approved methods of electroplating, a coating of copper in a about .1 oz. of copper per square surface. I then deposit upon the ing thus formed, and in a similar manner; a coating of zinc in an amount of about .05 oz. per square foot' of surface. I then the article, thus provided with coatings of copper and zinc, through a controlled atmosphere, fr ee,from oxig' dizing gases, such as oxy emcarboni' dioxide, etc; a and having atemperature of about 700- F. to'

about 1500 F., and maintain'the. article :a't-thi's temperature from about 10 to about 30 minutes;

invention to provide a method whereby ferrous articles, such as wire and strip, are coated with a bright,-uniform, closely adherent coating of brass.

the foregoing and related ends, said invention, then,gconsists steps hereinafter described and a pointed ioutinthe claims, the'jfo'llo in "descrip- (1, to methods s articles, but

or for a period of time sufllcient to permit a complete alloying of the coatings to form yellow brass, the period of time of heating depending f upon the thickness of the separate coatings and the specific temperatures employed. to formsuch The brass coating, thus formed, is bright, of uniform thickness, homogeneous in character, and adheres to the ferrous base metal with a tenacity sufflcient to render the article capable of being subjected to bending and various other 10 operations employed in fabricating the article.

Because of the ease and accuracy with which the electrodeposition of the individual metals, copper and zinc in this instance, may be controlled, the composition of the alloy coating may bemore closely and readily controlled than in the case of the method previously referred to in which an alloy coating is directly deposited on the base metal. Thus, coatings of any.of the well-known forms of brass may be obtained by merely varying the thickness of the coating of each of the individual metals, since in this manner any desired ratio of such metals ,may be obtained, and it is unnecessary to change the composition of the plating baths. The method, as 26 thus described, is preferably carried out in a il 1 continuous manner, that is by causing the ferrous strip to travel continuously and uninterruptedly through the separate plating baths and the con- -t'roll'ed heated atmosphere, but it will be under- 30 f stood that the method may also be carried out in a series of separate or discontinuous steps or operations. It will be also understood that ina 1 stead of firstdepositing the copper, as described, the basemetal may be initially coated with zinc"; e Other modes of applying the principle of my invention may be employed, instead of the one 'eirplained, change being made as' regards the methodherein' disclosed, provided the stepor 40 1 steps statedby-any of the following claims or the equivalent of such stated step or steps be employed.

Itherefore particularly point out and distinctlyf claim, as my invention:

1 Themetho'd of coating ferrous strip and the likewhich comprises continuously moving and consecutively-subjecting the strip to the action of a copper electro-plating' bath to form a coating of, copper directly thereon and then to the 50 action of a' zinc electro-plating bath to form a coating of zinc directly on the copper and finally to heating at a temperature of about'lOO" F. to about 1500 F.'in an non-oxidizing atmosphere,

for from about 10 to about 30 minutes, whereby 66 is to provide r, but' which scontinuwherea if amount offoot of strip copper coatj-I $410,? to cause an alloying of the'copper and zinc to form a non-peeling coetin plating bath to a of brass. on the copper 2. The method oi coating ferrous strip and pe'reture or! the like which comprises consecutively sublectnon-oxidizing e 5 in: the strip to the action of I. copper electroall of the plating bath to form a coating or copper directly peeling coating thereon and then to the ection of p zinc electro-'