US310433A - Napoleon c - Google Patents

Description

UNITED STATES PATENT OFFICEQ/ NAPOLEON O. HUBBELL, OF HARTFORD, CONNECTICUT, ASSIGNOR TO LOUIS F. HEUBLEIN, OF SAME PLACE.

PROCESS OF HARDl-ZNING STEEL.

EPECIFIUATEQN forming part of Letters Patent No, 310,433, dated January 6, 1885.

Application filed April 2 1884. (No specimens.)

To all whom, it may concern:

Be it known that I, NAPOLEON C. HUBBELL, of Hartford, in the'county of Hartford and State of Connecticut, have invented a new Im- 5 provement in the Process of Hardening Steel; and 1 do hereby declare the following to be a full,- clear, and exact description of the same.

This invention relates to an in'iprovemeut in the process of hardening steel. The usual method of hardening steel is to heat it to a high degree, then plunge it into cold water. It is to this method of hardening that my invention particularly relates. Cold-water hardening cannot be employed with any degree of satisfaction in the lower grades of steel, and, owing to the high degree of heat necessary in the higher grades, the steel is frequently cracked on its immersion into the cold water. For tools and like purposes only the higher '20 grade of steel can be employed, and a serious difficulty in such tools arises from the cracking before mentioned during .the process of hardening.

The object of my invention is to avoid the high degree of heat usually employed in hardening, as well as to enable the use of lower grades of steel; and my invention consists in hardening the heated steel in a bath composed of shell-marl and water in the proportions substantially as hereinafter described.

I take what is commonly known as shellmarl as it comes from the bed, and preferably reduce it to a powder. Of this powder I take in the proportion of about three and one- 3 5 half pounds to ten gallons of water, and thoroughly mix it with the water, which mixture forms the bath for-hardening. The steel to be hardened is heated in the usual manner, but to a much lower degree than in tempering in cold water. It is then plunged into the marl 4o bath in the usual manner of introducing into the water bath until 0001. The action of the combined marl and water upon the steel is to produce the same degree of hardness by a much lower degree of heat, and because of this lower 5 heat the cracking as experienced in dies, tools, &c., is entirely avoided. Again, it is found by actual use that the lower grades of steel, even to the lowest, may be hardened in my improved bath and employed for dies, tools, &c., with equal success to the finer grades of steel. In fact, the lower grades of steel hardened under my improved process are more durable and less liable to break than the best steel hardened by cold water alone, and with out possibility of cracking in the process of hardening.

Vhile my improved process is speciallyadapted to hardening tools, dies, &c., equally beneficial results attend its use in hardening steel for other purposes.

lt will be understood that after hardeningthe temper is drawn in the usual manner.

The proportions of marl to water may be varied to a considerable extent; butI find that the proportions of marl to the water above named is about what the water will take up.

I claim- The herein-described improvement in the process of hardening steel, consisting in immersing the hot steel in a bath composed of water and shell marl, substantially as described.

NAPOLEON C. HUBBELL.

W i tn csses G. Invruc BLAKE, TARIL HEISSMA NN.