SU1705390A1 - Alloying additive for steel - Google Patents

Abstract

The invention relates to master alloys for modifying casting steels. The aim of the invention is to improve the technological properties of the steel. Ligature contains, wt%: chromium 6-11; nickel 10-15; manganese 7-11; silicon 6-10; titanium 2-5; cerium 3-7; nitrogen 2-6; carbon 0.5-0.6; vanadium 8-12; boron 7-12; calcium 0.3-2.7; iron else. The alloying of the SOGSL steel with the proposed ligature makes it possible to increase the hot plasticity under pressure treatment up to 10–13 twists, toughness to 46.2–53.5 J / cm2, resistance to tearing to 1230–1380 cycles, to reduce the tendency to form; hot cracks in welding and a tendency to warping steel. 2 tab. s (L

Description

The invention relates to the field of metallurgy, namely to master alloys for modifying casting steels with improved technological properties.

Known ligature, containing, wt. $:

Chrome 40-50 Manganese 20-30 Silicon. 0.2-2 Carbon 0.5-3 Nitrogen 1-10 Titanium. 1-4 Calcium 0.5-2.5 Iron Else Steel treated with this ligature has low values of hot plasticity, it is difficult to handle the pressure in the hot state and have an increased tendency to hot cracks and warping.

Also known ligature of the following chemical composition, May .:

Silicon 6-85

Rare earth

metals15-70

IronErest

When modifying the steel with this ligature, the resistance to intergranular corrosion and the resistance to scuffing against friction decrease. High silicon content in the ligature leads to a decrease in technological properties

The closest technical solution, selected as a prototype, is a ligature containing

May .:

SL

GO CO

Chromium

Nickel

Silicon

Nitrogen

Manganese

40-50

20-30

6-10

1-4

3-6

Carbon 0.05-0,

Titan2-6

Cerium0,2-1,0

IronErest

The known ligature provides the following technological properties: hot plasticity during pressure treatment - 4-6 twists, the tendency to hot cracks during welding and welding 7.8-8 mm / min and resistance to scuff - 750-850 cycles.

The disadvantage is the low technological properties of the modified steel.

The purpose of the invention is to improve the technological properties of steel.

The goal is achieved by the fact that a ligature containing chromium, nickel, silicon, manganese, titanium, nitrogen, carbon, cerium and iron, additionally contains vanadium, boron and calcium in the following ratio of components, masd:

Chromium

Nickel

Manganese

Silicon

Titanium

Cerium

Nitrogen

Carbon

Vanadium

Boron

Calcium

Iron

6-11

S-15

7-11 6-10

2-s

3-7

2-6 0.5-0.8

8-12

1-M 0.3-2.7 Else

Distinctive features of the proposed ligature is the introduction of vanadium, boron and calcium, which significantly improve the technological properties of the modified steel.

In the proposed ligature, the manganese content is increased up to 7-11 May as compared with the known D. The lower limit of the manganese content is established and the need to increase the technological plasticity of steel, leveling the structure and hardness. When the concentration of manganese is more than 11 May L, the tendency of steel to buckling, bleaching and fracture of bone is reduced.

The lower limits of the concentration of carbon (0.5 masD) and silicon (6 masD) are set to prevent the formation of hot cracks during welding, a greater content in the structure of eutectic cementite, ensuring high resistance to warping and cracks

7053904

Instability Upper limits of carbon content (0.8 masD) and silicon

ten

15

20

25

thirty

35

40

., -

(10.0 masD) are due to an increase in the structure heterogeneity, a decrease in the technological plasticity and welding-technological properties at their higher concentrations.

Nickel in the amount of 10–15 masD increases the crack resistance during casting, welding and overlaying and resistance to intercrystalline corrosion, reduces the tendency to warping and increases the resistance to roughing. When the nickel concentration is up to 10 masD, the technological plasticity and jagging are insufficient, and with increasing nickel concentration above the upper limit, the resistance to hot cracks decreases and the tendency to warping increases.

Cerium and titanium increase the modifying capacity of the master alloy, grind the grain in the modified steel and increase the technological ductility. When their concentration is less than the lower limits, the modifying effect of the ligature and the technical properties of the steel are insufficient, and as their content increases above the upper limits, the content of nonmetallic inclusions increases, crack resistance, uniformity of the structure and properties of steel and its hot plasticity decrease. The nitrogen content in the amount of 2-6 May L increases the resistance of steel to bulging, without significantly reducing the welding-technological properties, but with an increase in its content above the upper limits, the plasticity properties decrease. The additional introduction of boron crushes the structure of the steel in the casting and in the weld, contributes to the improvement of hot plasticity and welding-technological properties. At a boron concentration up to May 7, resistance to the formation of hot cracks, scuffing under friction and hotness is not sufficiently plastic, while at a concentration of more than 12 masts, the homogeneity of steel and its welding-technological properties decrease.

Chromium worsens the crack resistance and technological properties of modified steels, therefore its content is reduced to 6-11 May D.

Calcium clears grain boundaries, has a deoxidizing effect and increases welding-technological failure.

properties. The upper limit of calcium (2.7 wt.%) Is due to its insufficient dissolution in steel and a decrease in its resistance to intergranular corrosion, and the lower limit (0.3 wt.%) Is due to a decrease in deoxidation ability and welding-technological properties.

The introduction of vanadium due to its high modifying and chemical activity, increases the uniformity of the structure and properties of steel. When it is contained in a ligature of up to 8 wt.%, The effect is insufficiently affected, and at a concentration of more than 12 wt.%, The crack resistance, impact strength and hot plasticity are reduced.

Experimental melting of ligatures is brought about by the use of steel scrap, the return of own production, silicomanganese in open induction furnaces with crucibles with a capacity of 150 to under fluorine flux. Silicocalcium, ferrocerium, ferrotitanium and ferroboron are introduced after melting the other components and refining the melt. Ligatures are cast in flat metal molds.

The ligature test when casting low-alloy steel ZOGSL, smelted in a DC-1.5 arc furnace, when it is released from the furnace into the ladle.

In tab. 1 shows the compositions of the alloys used to modify the steels of the experimental heats. The amount of additive ligatures - $ 0.35 by weight of the melt.

In tab. 2 shows the mechanical and technological properties of the modified steels of the experimental heats.

Properties are determined on standard samples and post normal samples.

ten

05390

870–890 ° С and tempering at 570–600 ° С. Modification of casting steels provides an increase in the technological plasticity and weld- ing and technological properties more than the ligature is known. The machinability was also higher in steels modified by the proposed ligature.

Due to the increase of the welding-technological properties of the modified steel when using the proposed alloy, the economic composition is 15.15-22 rubles. per ton of usable billets of casting steels used for the manufacture of gears, clips, rollers, gear rims and flanges.

Claims (1)

Invention Formula Steel ligature containing chromium, nickel, silicon, manganese, titanium, nitrogen, carbon, cerium and iron, characterized in that, in order to improve the technological properties of steel, it additionally contains vanadium, boron and calcium in the following ratio of components, May .: five 0 Chromium Nickel Manganese Silicon Titanium Cerium Nitrogen Carbon Vanadium Boron Calcium Iron 6-11 10-15 - 7-11 6-10 2-5 3-7 2-6 0.5-0.8 8-12 7-12 0,3-2,7 Else Table 1 table 2 five ten 13 eleven 6 eight 37.5 1.6.2 53.5 49.6 37.7 39.2 10.1, 13.8 th, 8 I., 6 10.6 12.7 7,8 Yu.5 10.8 10.6 8.1 8.7 1.0 0.8 0.7 0.75 1.0 0.9