Process of cementing of steel and products obtained by this process

FRENCH REPUBLIC.

MINISTRY OF INDUSTRY AND COMMERCE.

Patent,

Gr. 8.-Cl. 2. [...] 933,457

Carburising process and steel products obtained by this process. M. Alexandre- [...] - [...][...] (Seine-et-Oise) residing in France.

Demanded 28 August 1946, to 16^{m h 44,} to Paris.

[Patent of invention delivery of which has been fabric covering execution of the article 11, _AOUNI167AO> 7, outside law of 5 July [...] modified by the Law of 7 April1902.]

The present invention relates to a method

that allows obtaining steels and above all the

tool steels of a hardness with extraordinary

using a cement whose cost is

b particularly low.

An essential peculiarity

is the use of a cement compound

of potassium cyanide, and horn of

ammonium-, the case ' appropriate with addition

10 a little hydrochloric acid.

The cement is one product

new industrial and is a part of the invention; it

is preferably, made with the proportions

following components, which is reduced

1 h. powder:

Cyanide potassium: 675 parts by weight;

Horn: 225 parts by weight;

Ammonia salt, 60 parts by weight.

When the cement is to contain acid

has 0 hydrochloric, thereof preferably figure

an amount of 60 parts by weight.

The horn is selected because of its low cost

of returns, since it is supplied as is the

in the form of shoes, nail, etc, in the screening-

2 [...] 5. It could however replace the [...],

in whole or in part, by other keratins

such as hair, hair, wool, of

feathers, andc.

For treating a tool for carburizing,

3 0 advantageously is carried out as follows:

or heated to a temperature in the range of 350 °, i.e. at cherry red, whether it is molten steel or wrought, in particular steels for woodworking tools, or at a temperature somewhat higher in the range of 450 °, that is say red white, for the high-speed steels, and inserting the tool or the cutting edge of the tool which, alone, has been heated in the cement having the composition as described above.

The hydrochloric acid is utilized when the steel to be treated is not exposed to shocks (case of lathe tools) while it is preferable to not be used for the tools working impact (for example: bits, machine tool planing or mortise, tools vice [...], etc).

The tool is allowed for a short period of time (about one minute) and door again at the temperature indicated above and is resumed a second and a third time the same processing. Three times generally sufficient for a good result but is possible to operate a greater number of times if it is desired to further cure the tool. In the case of woodworking tools, and perform only an, [...] times ia contacting the tool with the cement.

After carburization thus carried out, quenching is carried out and it is recommended to previously carefully removing of the tool