US1696297A - Compound for tempering tools and tool steel - Google Patents

Description

Patented Dec. 25, 1928.

UNITED STATES PATENT OFFICE.

JOHN F. EDWARDS, OF WARREN, ARKANSAS.

No Drawing.

A solution this compound is somewhat effective 0 in tempering but by the addition of such other ingredients to these com ounds and by treating the tool in a very di ute bath steel of a high carbon content may be'hardened by the usual quenching procedure to effect a fine, granular texture containing the various carbides in proper proportion to render the tool effective and durable.

A tool treated by quenching in a bath containing the ingredients above noted and a density used for carbur'etting is too soft even when sulphate of copper is added to the bath as a hardener. I have discovered that the compound if used in a very dilute form gives v better results, but with the addition of other in redients which I have successfully added I lind that greatlyimproved results are obtained. The solution I have referred to as used for carburetting contains three ounces of commercial glycerine, one and a half ounces of spirit of nitre, one and one half ounces of aqua. ammonia,'two ounces of chloride of ammonia, one and one half ounces of sulphate of zinc, one and one half ounces of 40 sulphate of alumina and'auunoniaor alu-,

nnnuln ammonium alum dissolved in a half gallon of water.

A bath of these materials if used in the density employed for earburetting applied in hardening tool steel articles is not at all effective leaving them too soft. If, however, the bath is diluted the hardening efiect begins to show and when it reaches the very high degree of dilution taking only two to ounces of the mixture above described to a gallon of water better results in hardening Application filed December 13, 1926. Serial No. 154,657;

may be effected. I have found now, however, that by adding to a solution of this kind highly diluted one ounce of pure glycerine, one half ounce of table salt, one eighth ounce of copper sulphate andone halt ounce of alum that the best results will be obtained. I have given the formula employed in the carburetting process to distinguish between a bath for raising the carbon content and a for mula suitable for tempering tool steel which already has a high carbon content. According to my experience the quality of glycerine 1s important, it being essential to best results to employ pure glycerine. Some of the ingredients may be reduced or omitted but I have found that the addition of table salt and copper sulphate in substantial proportion is important to successful results.

My invention therefore consists in a solution or bath for quenching tool steel consistmg of a very dilute solution containing glyc-- erine, nit-re, ammonia, sal-ammoniae, alum and zinc sulphate to which is added common salt, alum and copper sulphate in very much larger proportions for tempering. The implement or tool is brought to a chei'ry red and immersed in the bath of the dilution described. It is then reheated to a color depending on the temper desired, and chilled in pure water. i

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

A liquid bath for quenching tool steel, consisting of the following ingredients in the following approximate proportions:

Approximate metric equivalents. Glycerin 3 fluid ounces"- 96 c. 0. Sweet spirit of ultra I5 fluid ounccs 48 c. c. Anunonium (lll0llll0 1-; ounces 48 gm. Zinc sulphate 1; ounces 48 gm. Aluminum and ammonium sulpli c 1 ounw.-:.. i 48 gm. Water .s. gallon 2, 000 c. c.

of the foregoing .twofluid ounces is added to one gallon of water containing: