SU1759954A1 - Compound for diffusion saturation of iron-carbon alloys - Google Patents

Abstract

The invention: the composition contains, May. %: chromium 20-30; waste of enrichment production of tin ores containing tourmaline and quartz, 66-78; ammonium chloride 2-4. 1 tab.

Description

The invention relates to the chemical heat treatment of metals and alloys and can be used for products in the metallurgical, engineering and other sectors of the national economy.

A known composition for the diffusion chromium plating of cast iron with the following content of components, May. %:

Ferrochrome 50

Alumina 45

Ammonium Chloride5

At parts of modified ductile iron with the use of this composition at 1050–1150 ° C and an exposure time of 4–8 h, a diffusion layer with a thickness of 130-160 µm is formed.

The disadvantage of this composition is its relatively low saturation ability. In addition, the chromium plating of articles made of cast iron at temperatures above 1050 ° C is impractical because of the possible surface melting.

The closest in technical essence to the proposed is the composition for

diffusion chromium plating of steel parts (steel 45) with the following composition of components, May. %:

Chrome25

Alumina 70

Ammonium Chloride5

A disadvantage of the known composition is the relatively low saturability, the need to carry out the process at high temperatures and long exposures to obtain the desired thickness of the doped layer.

The aim of the invention is to increase the saturability of the composition while lowering the saturation temperature.

For this, the composition for diffusion chromium containing chromium, ammonium chloride and a filler contains as a filler a waste product from the enrichment of tin ores containing tourmaline and quartz in the following ratio, wt.%:

Hrom20-30

Production waste

VI

about you

enrichment of tin

ores containing

tourmaline and quartz66-78

Ammonium Chloride2-4

A comparative analysis with the prototype allows us to conclude that the claimed composition differs from the well-known introduction of a new component, namely, the tailings production of tin ores containing tourmaline and quartz. Thus, the claimed technical solution meets the criterion of novelty.

Comparison of the proposed solution not only with the prototype, but also with other technical solutions in the field of technology did not allow identifying in them the signs that distinguish the proposed solution from the prototype, which allows to conclude that the criterion meets significant differences.

The functional purpose of each of the components, GOST of supplies and chemical formulas are as follows.

Chromium grade PCM1 (TU 14-1-1474-75) is a supplier of chromium atoms.

NH4CI ammonium chloride (GOST 3773-72) is an activator of the process, promotes the formation of active gaseous chromium compounds, and accelerates diffusion processes.

Waste from the enrichment of tin ore is a product of the processing of tin ore, which is carried out in accordance with the Technological Instruction for the Solar Processing Plant Solar GOK and the Apparatus Chain Scheme. Specifications for the equipment of GS-761 from 01.24.89 of the Solar Mining Plant and agreed with the head organization Gipronikel (Leningrad). The chemical composition of this product contains 39 elements of the periodic system and 20 mineralogical elements, which are based on quartz (SiOa) 36.1% and tournaline based on iron type Sherl in the form of intergrowth with quartz and rock, the thinnest (first microns) needles, grains and their aggregates in the amount of 39.1%,

The chemical composition of the tourmaline product,%: 35.25: 02; 30, 10.5V; 9.1 FeO-.4.6Rv20z; 4.4MgO; 2.1 CaO; 1, SNU2; 1, ONa20; 0.5MnO; OJfeP; 0.1 F; OJH20 + (see Geologists, Mineralogy, and Geochemistry of the Komsomolsky District. Edited by EB Radkevich. M., Nauka, 1971, p. 63-67).

The waste from the production of the enrichment of tin ore in a hammer form with a grain size of 5–10 µm was used, which, due to the characteristics of its composition, increases the saturating ability of the mixture, reduces the process needed

the temperature in the furnace is up to 800-900 ° C and reduces the duration of exposure, thus increasing the surface hardness and wear resistance of the processed products.

For experimental verification of the claimed composition, five mixtures of components were prepared, three of which showed optimal results (see table).

0 All components of powder mixes were carefully ground, sieved, dried and mixed before use. Powder materials that have passed during screening are used.

5 through a sieve with cells 0.05 X 0.05 mm. Drying was carried out at 120-140 ° C for 2 hours with occasional stirring. The powders were mixed in a drum-type mixer for 4 hours with loading.

0 working volume of 60-70%.

- Products before chemical heat treatment were degreased with a solvent, dried, placed in a container, poured in layers with a mixture of the specified

5 composition. In conjunction with the products, witness samples from the same alloys, which determine the thickness of the diffusion layer and its hardness, are subjected to processing. After the chrome plating is completed, the containers are unloaded from the furnace, cooled to room temperature, and depressurized.

Chromium plating of products from gray cast iron of the SCOOO brand and steel 45 in the proposed powder composition was carried out in a hermetic container in an electric furnace at a temperature of 900 + 5 ° C for 3 hours. The results obtained are presented in the table.

From the data presented in the table it follows that the proposed composition has a significantly greater saturability, which allows to significantly improve the performance characteristics of hardened products: the depth of the diffusion layer is 4-6

5 times, the surface hardness of 1-5 GPA and, consequently, the service life of products, while you can significantly reduce the temperature of the furnace and the duration of the process of chemical-thermal processing.

The use of the claimed invention will increase:

the quality of processing products by increasing the depth of the diffusion layer and the surface hardness;

5 process performance due to the greater activity of the composition;

the possibility of using the diffusion chromium plating process;

the possibility of using low temperature furnaces.

The optimum composition is for chrome plating within the limits. When deviating from the indicated limits, the saturability of the composition and surface hardness monotonously decrease.

Claims (1)

Composition for diffusion saturation of iron-carbon alloys containing chromium, ammonium chloride and a filler, 0 characterized in that, in order to increase the saturability with decreasing saturation temperature, it contains as a filler a waste product from the enrichment of tin ores containing tourmaline and quartz in the following ratio of components, wt.% chromium - 20-30; production waste is enriched with tin ores containing turmalm and quartz - 66-78; ammonium chloride - 2-4.