SU1585368A1 - Alloying composition for steel - Google Patents

Abstract

The invention relates to metallurgy. The purpose of the invention is to increase the wear resistance and corrosion resistance of steel. The ligature contains silicon, manganese, boron, nitrogen, molybdenum, titanium, aluminum and iron in the following ratio of components, wt.%: Silicon 17-25

manganese 15-21

molybdenum 13-17

boron 0.1-3

nitrogen 0.03-3

titanium 1.7-2.2

aluminum 9.3-15.1

iron else. Additional addition of molybdenum, titanium and aluminum to the ligatures while reducing the manganese content in it provides an increase of 1.5-2 times the wear resistance and corrosion resistance of the steel it is processed by forming the optimal composition and number of nitrides and carbonitrides, and the increased deoxidizing modifying effect of the alloy. 2 tab.

Description

This invention relates to metallurgy, in particular, to master alloys to improve the properties of corrosion resistant steels.

The purpose of the invention is to increase the wear resistance and corrosion resistance of steel.

The master alloy for steel containing silicon, manganese, boron, nitrogen and iron, additionally contains molybdenum, titanium and aluminum in the following ratio, wt.%: Silicon 17-25

Manganese 15-21 Molybdenum 13-17 Bor0.1-3

Nitro 0.03-3

Titan1,7-2,2

Aluminum 9.3-15.1 Iron Rest

The additional introduction of molybdenum is associated with a significant increase in the strength and corrosion resistance of steel, an increase in toughness and wear resistance, which ensures a reduction in corrosion-erosion wear. The upper limit of the concentration of molybdenum (17 L us) corresponds to its content, above which there is a decrease in toughness, impact-abrasive wear resistance and an increase in corrosion-wear wear. By reducing the molybdenum concentration to less than 13 wt.%, The wear resistance, corrosion erosion resistance, and resistance in the sodium chloride environment decrease.

Aluminum in the amount of 9.3–15.1 wt.% Deoxidizes steel, binds nitrogen and nitrides and increases core: l.

eo: d

:about

Ed

eo

Rosion resistance and wear resistance of steel. Its content in the ligature is limited to 15.1 masD, the concentration of non-metallic inclusions at the grain boundaries increases above this concentration, and the corrosion resistance and wear resistance are reduced. When the aluminum content to 9.3 wt. mechanical and corrosion-erosion properties of alloyed steel are insufficient, its wear resistance under conditions of impact-abrasive wear is reduced

The introduction of titanium is due to its high chemical activity in the molten metal, the tendency to nitride and carbonitride formation, which contributes to an increase in corrosion resistance both in sodium chloride and in the atmosphere, as well as to a decrease in corrosion-erosion wear. When the concentration of titanium in the ligature is up to 1.7 wt.%, Its modifying power is insufficient, and the corrosion and erosion wear is high, which reduces the reliability and durability of the parts. Increasing the concentration of titanium over 2.2 May. increases the content of non-metallic inclusions in steel and CORROSION-erosion wear. Boron contributes to the crushing of the structure, increasing wear resistance and corrosion resistance. Its content corresponds to the optimal concentration and is left unchanged.

The introduction of nitrogen ensures the formation of nitrides and carbonitrides in steel, which are evenly distributed in the matrix grain and increase the impact strength, cold resistance and corrosion resistance, dispersion of the structure and wear resistance. When the nitrogen concentration is up to 0.03 wt.%, The amount of nitrides and carbonitrides in the steel and grinding of the structure are insufficient, and the wear resistance and corrosion resistance are low, and with increasing nitrogen concentration of more than 3 wt.%, The concentration of non-metallic inclusions at the grain boundaries increases, which reduces the impact viscosity, corrosion resistance and wear resistance.

Manganese reduces the impact strength and corrosion resistance of steel, therefore its content is limited to 21 wt.%. When the concentration of manganese is less than 15 wt. reduced

Jq

J5 20 25 in

d e

five

mechanical properties and increased corrosion-erosion wear. Silicon has a deoxidizing effect, increases the corrosion resistance of steel in the atmosphere and in sodium chloride, but with increasing silicon content over 25 May L, hardness and wear resistance decrease.

The content of components in the proposed and known alloys are presented in table. one.

The following raw materials were used to melt the master alloy in induction furnaces: electro-. thermal metal manganese MPH1 and MPH2, supplied in briquettes weighing up to 5 kg, AMT-1 alloy, ground to a fraction of 0.1-5 mm; FS-75 ferrosilicon, its fraction 0.15-15 mm; boric acid in the form of powder and crushed to a fraction of 1-5 mm ferromolybdenum FMO. First, metal, manganese and ferromolyb den were melted, the melt overheated to 1510-1550 C, then AMT-1 and ferrosilicon were introduced. After deoxidation and boric acid additive, the melt is purged with nitrogen and poured into flat metal molds at a temperature of 1390-1430 ° C. The ligature in a crushed form (fraction up to 10 mm) is introduced into steel pouring ladles 5–12 minutes before casting at a steel temperature of 1580+

t I and H, g "

The following methods were used to test the steels: a test method for impact bending at room temperature on samples 55 mm long, 10 mm high and 7.5 +0.1 mm wide, type 12; Cylindrical test pieces for impact abrasive wear resistance and corrosion resistance are made according to a known technique. Methods for determining indicators of corrosion in the atmosphere, corrosion resistance in the environment of 3.5% sodium chloride were carried out on polished samples.

010 mm, using physical methods to control the depth of penetration of corrosion. Corrosion products were removed.

When tested for impact-abrasive wear, samples of 10 mm length - Noah 35 + 0.05 mm from the test material and reference samples of steel S with a hardness of 600-620 are made according to the 3rd accuracy class with a rough 5

working (face) surface

no more than 2.5 microns. When testing as an abrasive material used silicon carbide QC grain size of 0.63 mm with a relative moisture content of 0,% by weight. Corrosion-erosion wear is determined on cylindrical specimens of 010 mm on the MKF-1 installation.

Experimental melting ligatures are used in the production of corrosion-resistant steel 10ХНДЛЛ, May. chromium 14; manganese 0.5; nickel 1,3; silicon 0.3; copper 1,3; phosphorus is 0.03 and carbon is up to 0.1, iron is the rest. The ligature is introduced in the amount of 1% by weight of the melt at 1570-1590 °.

After heat treatment (quenching in air and tempering at 660 air cooling, the specimens are subjected to tests for impact strength, corrosion resistance and corrosion / erosion wear.

Properties of steel after heat treatment are presented in table. 2

0

five

From the table. 2 data shows that the proposed ligature - has compared with the known higher corrosion resistance and provides a significant reduction in corrosion-erosion wear.

Claims (1)

Invention Formula The ligature for steel containing silicon, manganese, boron, nitrogen, iron, characterized in that, in order to improve the wear resistance and corrosion resistance of steel, it additionally contains molybdenum, titanium and aluminum in the following ratio, wt.%: 0 five Silicon Manganese Boron Nitrogen Molybdenum Titanium Aluminum Iron 17-25 15-21 0.1-3 0.03-3.00 13-17 1.7-2.2 9.3-15.1 Rest table 2