SU1315508A1 - Alloy for alloy treatment of steel - Google Patents

Abstract

The invention relates to the field of ferrous metallurgy, in particular to alloys for steel alloying with manganese and nitrogen. The aim of the invention is to reduce the thermal conductivity of the alloy and increase the uptake of nitrogen by steel. The proposed alloy containing, wt.%: Manganese 70-90; nitrogen 4-8; silicon 1-5; carbon 0.5-1.5; chromium 0.01-2; calcium 0.05-2; aluminum 0.01-1; iron else. The proposed alloy has a thermal conductivity of 9, 9-13.2 W / m K and a nitrogen absorption rate of 46.0-52.0%. 2 tab. (L ate bo.

Description

1 13

The invention relates to metallurgy, in particular to alloys for steel alloying with manganese and nitrogen.

The aim of the invention is to reduce the alloying tedlop conductivity and increase nitrogen absorption by steel.

The uptake of nitrogen from nitrated ferroalloys depends on the duration of their melting in the process of melting from the unit. If the duration of the melting of a piece of ferroalloy is longer than the duration of the active period of melt production from the unit, then losses of microadditives (in this case, nitrogen) are observed in connection with incomplete melting of the pieces.

The duration of melting of the ferroalloy increases with increasing thermal conductivity of the ferroalloy due to the increase in the thickness of the metal crust on the piece of ferroalloy and increasing the duration of its subsequent melting in liquid steel. Studies show that the proposed ferroalloy has a lower thermal conductivity than the known alloying alloy and provides a higher degree of nitrogen assimilation.

An alloy for alloying steel containing manganese, nitrogen, silicon, chromium, carbon, aluminum, calcium and iron in the following ratio, wt.%:

Manganese70-90

Nitrogen4-8

Silicon 1-5

Carbon 0.5-1.5

Chrome 0,01-2

Calcium0.05-2

Aluminum 0,01-1

IronErest

The upper limit of the manganese content (90 wt.%) Is limited to a value, the excess of which leads to a sharp decrease in the degree of manganese recovery in the ferroalloy furnace, and the lower one (70 wt.%) - when the saturability of the alloy with nitrogen decreases.

The upper limit of the silicon content (5 wt.%) Is limited to the value at which the maximum manganese extraction ratio is obtained in the smelting of the alloy, and the lower one (1 wt.%) When the silicon begins to show an effect on the melt temperature. laziness alloy.

82

The lower limit of the nitrogen content (4 wt.%) Is taken from the value at which the use of the alloy becomes economically viable,

and the upper limit (8, wt.%) is limited to the value at which the rate of saturation of the ferroalloy with nitrogen with its nitriding decreases sharply.

The lower limits of the contents of carbon (0.5 wt.%) And calcium (0.05 wt.%) Are taken from the values at which their effect on the reduction of alloy strength becomes noticeable, and their upper limits (respectively 1.5 and

2 wt.%) Are limited to values, the excess of which drastically reduces the solubility of nitrogen in the alloy.

The lower limit of chromium content (0.01 wt.%) Is taken from the value

in which its effect on the degree of nitrogen absorption by the steel from an alloy becomes noticeable, and the top (2 wt.%) is limited when the strength begins to increase sharply.

alloy.

The lower limit of the aluminum content (0.01 wt.%) Is taken from the value at which its effect on the decrease in the thermal conductivity of the alloy becomes noticeable, and the upper limit (1 wt.%) Is limited by the value that allows the use of the alloy in the production of semi-quiescent steels.

Example. The alloy is produced by cp-shiko-thermal reduction of manganese-containing raw material, silicon-manganese from 0.5-1.5 wt.% Carbon, lime, aluminum alloy production waste, chrome-alloyed steel chips in ore-reducing furnaces with solid-phase nitriding of the main product of smelting in vacuum thermal furnaces. Charge consumption

materials in the smelting of the alloy in the reduction furnaces 3.1 t / t, process temperature 1470-1610 ° C. Solid nitriding of the alloy is carried out in the powder fraction

0.7 mm in an environment of gaseous nitrogen at 950 C for 53 h.

Data on the chemical composition of experimental Hb jx batches of compared steels and their thermal conductivity are given in Table. one.

The alloys are used to alloy steel containing 0.08–0.14 wt.% Carbon, 0.11–0.20 May, 7, manganese, 0.004–0.005 wt.% Nitrogen at the outlet from the steel-smelting aggregate. Temperature

3131

metal .1625-1BAO C. Doping of steel is carried out in a ladle followed by silico-manganese, 65 wt.% ferrosilicon, one of the compared alloys (Table 1) and aluminum.

In tab. Figure 2 shows the chemical composition of the obtained steels and the nitrogen uptake value of the steel from the compared alloys.

From the table. 1 and 2, it follows that the proposed alloy for alloying steel has in comparison with the known higher thermal conductivity, which provides an increase in nitrogen absorption by steel.

84,56,53,40,90,5 0,080,05, - No

90.04.01.00.52.0 0.050.01

78.35,72,51,10,01 2,00,68

70.08.05.05.01.52.0 0.91.0 .46.52.10.71.8 No No 2.8

84

Claims (1)

Invention Formula An alloy for alloying steel containing manganese, nitrogen, carbon, chromium, silicon and iron, characterized in that, in order to reduce its thermal conductivity and increase nitrogen absorption by steel, it additionally contains aluminum and calcium in the following ratio, wt.%: Manganese70-90 Nitrogen4-8 Carbon 0.5-1.5 Chrome 0,01-2 Silicon1-5 Aluminum 0,01-1 Table 1 The rest is 13.2 9.9 10.1  11.4 17.5 table 2