DE1533257B1 - PROCESS FOR MANUFACTURING A Sintered NITROGEN STEEL FINISHER, IN PARTICULAR A FERRO-ALLOY WITH A HIGH NITROGEN CONTENT - Google Patents

Description

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The invention relates to a method for producing mixtures are advantageously used

Positioning of a sintered nitrogen-containing steel, which consists of 30 to 40 percent by weight steel refiner, in particular a ferro alloy with high refiners, the remainder technical calcium carbide, with min-nitrogen content. at least 65%> CaC _2, preferably 72 to 74 _{% CaC 2} ,

When embroidering steels, e.g. B. structural steels, 5 exist.

with calcium cyanamide, the nitrogen yield is relative The grain size of the calcium carbide to be used

low. When using such a sintered product, it should expediently be below 0.1 mm, tes with a high nitrogen content and steel content

refinement increases the nitrogen yield to the grain size below 0.25 mm used. 2 to 3 times the nitrogen yield when using io Metals can be used as steel refiners Calcium cyanamide. Another benefit is the. Preferably ferro alloys are used that at the same time with the embroidery the steel refiners use, z. B. Ferromanganese and Ferrochrome (types get into the steel, whereby by using affine, suraffine, carbure), further ferrovanadium, Lumpy sintered goods are easier to bring in, without ferroniobtantalum, ferro-manganese vanadium, ferro-titanium, Dust nuisance to the furnace operator and 15 ferronickels.

due to the high specific weight of the sintering

good an easier penetration into the liquid steel, see homogenized (e.g. in plow shovel mixers, as well as a homogeneous final nitrogen distribution - mixing drums, tumble mixers, screw devices), is performed. filled into reaction vessels and locally,

For the production of a sintered nitrogen ^{steel refiner containing 20 preferably per m 2} cross-sectional area of the batch, in particular a ferrous steel in 3 to 5 places, brought to the reaction temperature, alloy with a high nitrogen content was already. B. 1100 to 1300 ° C,

proposed that the starting mixture of calcium is made by ignition by means of an ignition mixture carbid and steel refiners achieved by heating. Can take the place of an ignition mixture to bring the outside up to temperature and they also step into an electrical resistance heater. To expose to nitrogen atmosphere. This is how ignition mixtures have proven to be particularly advantageous that the starting mixture in shallow adhesive mixtures of alkaline earth metal carbides with oxygen tubs or pipes are introduced. These reac- emitting substances have been proven. Preferably get tion vessels are on or in powdered, the mixture of calcium carbide with calcium nitrate for calcium carbide for calcium cyanamide 30 application.

used. In the exothermic reaction, the process according to the invention can both

of the calcium surrounding the tubs or pipes - discontinuously as well as continuously, in suitable. carbids to calcium cyanamide released in the oven. B. insert ovens, tunnel ovens me heats the one located in the tubs or pipes. etc., can be performed. When carrying out mixing in the atmosphere present in the process in tunnel kilns, the mixture is in excess nitrogen from the outside. After this mobile reaction car is filled, ignited and suggested, only small amounts of sintering furnace can be produced under a nitrogen atmosphere, since the trains are driven through from the outside. In this case, even between the heated wagons charged with high levels of the reaction mixture, individual beds in the tub or in the pipes with 40 wagons that are only filled with calcium carbide, due to a larger diameter than z. B. 50 cm an equal tunnel oven can be sent to achieve moderate reaction. When using _R. . ..

of pipes ejects removing them. Example

the calcium cyanamide block for difficulties, since the 1520 kg technical calcium carbide with a grain Calcium cyanamide 45 size smaller than 0.1 mm formed around the pipes was strong at 650 kg is sintered together. common ferromanganese (76% Mn) with a grain

To eliminate these disadvantages, a double-wave process for the production of nitrogen mixers in a double-wave process for the production of nitrogen mixers in a nitrogen atmosphere could not stimulate compounds of carbides, since the mixture was not a process for calcium cyanamide for the production of a stick-50 production according to Polzeniusz-Krause, substance-containing sintered product for the purpose of the steel-open-topped reaction car with box top finishing, but obviously filled with the looser. The box was 1.2 m high and produced a fertilizer. had an average cross-section of about 1.2 m ² .

In order to avoid the process, which was not previously known to the older, 5 ignition points were placed in the mixture from above, To circumvent the disadvantages still adhering, according to 55 is evenly distributed over the cross section, for the the invention proposed a mixture of 90 intake of the Zündmisehung attached and the Up to 50 percent by weight of finely powdered calcium carbide ignition mixture made from technical calcium carbide and with a grain size below 0.5 mm and from 10 to calcium nitrate (weight ratio 1: 1) in one 50 percent by weight of crushed steel refiner with an amount of about 2 to 3 kg per ignition hole Grain size below 0.5 mm under nitrogen atmosphere. After the ignition, the car was in privacy to homogenize, in a reaction vessel continuously through a tunnel furnace in which a Fill in and use an ignition nitrogen pressure of about 200 mm of water mixture locally prevails inside the mixture.

Bring reaction temperature. The reaction after several days of being in the oven

The mixture in the vessel becomes, after ignition 65, a solidly sintered block with a weight of in an oven exposed to a nitrogen atmosphere obtained 2515 kg, which was roughly crushed. Of the and the reaction product thus embroidered up to the nitrogen content averaged 17.8%, the Leave sintering there. Manganese content 19.6%.

Claims (4)

Patent claims: 1. A method for producing a sintered nitrogen-containing steel finisher, in particular a ferro alloy with a high nitrogen content, characterized in that a Mixture of 90 to 50 percent by weight of finely powdered calcium carbide with a grain size less than 0.5 mm and from 10 to 50 percent by weight of crushed steel refiner with a grain size is homogenized under 0.5 mm under a nitrogen atmosphere, poured into a reaction vessel and locally to reaction temperature using an ignition mixture inside the mixture is brought, and that the mixture located in the reaction vessel after ignition exposed to a nitrogen atmosphere in a furnace and the reaction product embroidered in this way is left there until sintering. 2. The method according to claim 1, characterized in that the mixture is used in a composition of 30 to 40 percent by weight steel refiner, the remainder technical calcium carbide, with at least 65%, preferably 72 to 74% CaC ₂ . 3. The method according to claim 1 to 2, characterized in that for the homogeneous mixture Calcium carbide with a grain size below 0.1 mm and a steel refiner with a grain size below 0.25 mm can be used. 4. The method according to claim 1 to 3, characterized in that the mixture is brought to the reaction temperature at 3 to 5 points ^{per m 2 of cross-sectional area.}