SU557117A1 - The method of obtaining nitrated ligatures - Google Patents

Description

one

The invention relates to the field of ferrous metallurgy, namely to the processing of alloys of the solid state, and can be used in the production of nitrogen-containing compositions based on iron, intended for doping constructional high-speed and other steel grades.

A known method for producing refractory inorganic compounds, the essence of which consists in grinding, briquetting a mixture of refractory nonorganic compounds, for example, metal nitrides of the IV, Y groups, followed by nitriding in the combustion mode. It is based on the use of the heat of the exothermic reaction to form the final product. The initiation of the reaction reaction of the reactants is carried out by a heated coil and the ignition mixture, which creates a temperature sufficient to initiate the process of interaction. Subsequently, the process is eliminated by the heat generated by the reaction. The temperature in the interaction zone 2 LLC-40OO ° SSh.

Essential and prosperous way

is that as the starting components for nitriding, costly powders of pure metals of groups IV-V of the Periodic System are used.

Nitrided iron alloys with metals of the IV-V1I1 groups of the Periodic Table of the Elements, for example, titanium, vanadium, chromium, manganese, etc., are widely used in the industry for alloying steels. However, it is often the nitriding of ferroalloys already in groups in the combustion mode that becomes impossible due to the high iron content in the alloy. For example, as shown by experiments, ferrovanadium is not nitrided in the combustion mode, if the content of vanadium in the alloy is less than 5%.

In addition, metals of the U1-USH groups of the Periodic System due to the WSS of the thermal effect of the formation of nitrides cannot be programed in combustion mode, let alone in the case of c5 nitriding of these elements in the alloy with iron.

The aim of the invention is to develop such conditions of interaction that would significantly expand the

tama ligatures, nitrided in combustion mode, reduce the cost of production of ligatures with a high content of nitrogen.

To this end, a method is proposed in which the initial ferroalloys (for example, ferrochrome, ferromanganese, etc.) are ground into powders and mixed for two hours with metal powders.

 groups (or their alloys with iron), the reaction of which interacts with nitrogen proceeds with a large thermal effect, for example, titanium or ferrotite poroigms, vanadium or ferrovanadium with a vanadium content of more than 5%,)

Mixed ferroshtav powders are pressed into briquettes, which then interfere with the installation of a constant pressure. The plant is filled with nitrogen. Azta pressure is 1-150 atm. On top of the briquettes, they put a tablet of igniting composition (a mixture of titanium powders with boron), which is ignited with the help of a heated crushing: from aphram or nichrome. After such an initiation of the reaction, the nitrivium-briquettes pass in the combustion mode. After the passage of the reaction front, volumetric dosage is possible, which significantly increases the degree of nitrogen absorption. The whole nitriding process, including sample cooling, takes 20-30 minutes. The temperature in the combustion zone is 1500-200 ° C.

Lit nitriding of the filthurus used highly pure nitrogen containing not more than O, 1% oxygen, and the powders of the ferroalloy composition, wt. %:

1) Ferrotitanium - Ti - 70, Those. - thirty;

2) Ferrovanadium - V - 46.81, ёt-1.70 С. - 0.56, Р - 0.12, S –0.057,

Those - the rest;

3) Ferrovanadium - V - 78.0, Te is the rest;

4) Cr 70.5 ferrochrome, Si - 0.3, C 0.1, s 0.019, P - 0.039,

6 the rest;

- SG -. 56.6,

Ferrochromoaluminium, 4- 21.0, & - 0.9, Fe - the rest.

i p and m 1, When the Te-Cr-Ti-N ligature is obtained, the initial component is oluzht-p ferrochrome, which cannot interact with nitrogen due to the low thermal effect of the reaction. The Fe-Cr-alloy is ground to a powder with a dispersion of less than 0.063 mm and mixed for two hours with ferrotitanium powder with a dispersion of 0.125 mm with a component ratio of 50.7% (Fe-Cg) 49.3% (Fe-Ti). From mixed powder Briquettes with a diameter of 20 mm, a weight of 35 g, and a relative density of 0.65 are pressed. Briquettes are loaded into a constant pressure device, an ignition tablet is placed on the briquettes, to which an electrical siiral is supplied, after which the device is closed and filled with nitrogen to a pressure of 50 atm. A spiral is applied to the coil (no more than 40 volts), after which the tablet ignites. The nitriding process lasts 2-3 seconds, after which the briquettes are kept

in nitrogen 20 min. The nitrogen content upon receipt of the alloy Fe – C p – Ti – N was 13.1% (w / w).

PRI mme R 2. When an Fe-Cp-Ti-A -N alloy is prepared, Ferrochromo-aluminum is dispersed by less than O, O63 mm as the initial component. Ferrochrome l yumknij is mixed for two hours with ferrotitanium powder with a dispersion of 0.125 mm with a ratio of components

51% ferrochromo-aluminum, 49% ferrotitanium. The prepared mixture is pressed into briquettes with a diameter of 20 mm, weight 30 g, relative density 0.56. Next, do the operation (example 1). With

The nitrogen content in the alloy after burning the mixture was 16.7% (w / w).

The same ligature can be obtained if pure titanium is introduced into the mixture instead of Fe-Ti. Then, with all the others

equal conditions, the nitrogen content in the alloy rises to 17.5%.

EXAMPLE 3 Upon receipt of an Fe V-Ti-N alloy, the starting component is ferrovanadium (vanadium content 46.81%) with a dispersion of 0.125 mm, which is mixed with ferrotitanium powder at a component ratio of 51% ferrovanadium, 49% ferrotitanium. Briquettes with a diameter of 20 mm, weight of 35 g, and relative density of 0.65 are pressed from the prepared mixture. Next, perform the operation described in example 1.

The nitrogen content in the alloy after interaction in a nitrogen atmosphere at a pressure of 50 atm was 14.3% (by weight).

Example 4. When kucheniya alloy Fe-Cr-V-N ISHODASH.1M Khomponent

ferrochrome dispersion of 0.068 mm.

The alloy is stirred for two hours with grinding to a dispersion of 0.125 mm with ferrovanadium powder (V 78%) with the following components: 4-0% ferro-

chromium, 60% ferrovanadium. The prepared mixtures are pressed into briquettes with a 20 mm tick gauge weighing 32 g, relative density 0.64. Next, the operation described in example 1 is discussed. The experiment is carried out at a pressure of 4O atm. The content of nitrogen in the prepared ligate is 10.2% (w / w). The proposed method of obtaining nitrided allows you to quickly get ligatures with a high nitrogen content when using as starting components mixtures of iron alloys with metals of the Periodic System 1 Formula of the method of obtaining nitrided ligatures, including grinding of raw materials, briquetting and nitriding 55 in the combustion mode that, in order to provide the possibility of nitriding in the combustion mode with the expansion of the mix of ligatures of noYllf group of the Periodic System ferroalloy powders are mixed - the bases are mixed with powders of metals of the IJ-V group or with ferroalloys containing metal of the IV, Y groups. Sources of information, taken into account during the examination: 1. USSR Copyright Certificate No. 255221, G01G 1/00, 1967.