SU1216246A1 - Steel - Google Patents

Description

The invention relates to metallurgy and can be used for the manufacture of cast parts subjected to hardening heat treatment (quenching and low temperature tempering), in particular for the manufacture of track tracks machines.

The purpose of the invention is to increase the toughness of steel at low temperatures and reduce cost.

The introduction of titanium and nitrogen into the steel with an elevated chromium content allows the average content of nickel, copper and silicon to be reduced without reducing the strength properties of steel, and molybdenum is excluded from the composition of steel without the risk of its embrittlement during heat treatment. The latter is also associated with a decrease in the silicon content.

All this is achieved with the presence of a very small amount of titanium (0.005-0.02%) and nitrogen (0.002-0.02%) in cast steel. The higher content of these elements leads to a significant dispersion, strengthening, hardening of ferrite and the formation of precipitates along the grain boundaries, which reduces the ductility and toughness of steel, especially at low temperatures 10, 16 1,111,000,651,12

20.22 1,001,020,721,23

30, 18 1,250,900,700,10

40.24 0.800.880.850.60

50.24 1,400,850,850,57

60.15 1,320,401,500,33

/

70.12 1,340,651,100,41

) 0

16246

tours. The proposed combination of titanium and nitrogen in low carbon steel provides for the formation of titanium carbonitrides in a quantity that is sufficient to preserve the fine grain structure during heating of the steel for quenching.

The composition of steel is given in table. one.

The mechanical properties of the compared - steels after quenching from 930 C and tempering at 200 C are presented in table. 2

As can be seen from the table. 2 data, in its heat-treated state, it possesses a combination of high strength properties, ductility and toughness, moreover, in terms of toughness at negative temperatures, it surpasses the known steels. This ensures high reliability and durability of cast parts under operating conditions. Testing an experimental batch of links 25 tracked chain tractor T-140, made; From the proposed steel, it was shown that the experienced parts are not inferior to serial ones in terms of wear resistance of friction pairs (eyelets and links of links) (Table 3).

15

20

thirty

Table 1

0.40 0.10 - 0.54 0.11

0,005

0,005

0.02

0.02

0,017

0,002

0,004

0.02

0,007

0.015

T 4 blitz 3

Editor S.Patrusheva

Order 964/31 Circulation 567 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d, 4/5

Branch PPP Patent, Uzhgorod, st. Project, 4

.Table 2

Continued table. 3

e

1 2 3

four

The average ,

2.5 2.6

2.5 2.8

2.6

3.0 3.0

3.3

3.4

3.2

Compiled by S. Derkachev

Tehred S. Migunova Corrector T. Kolb

Claims (1)

STEEL is mainly for castings containing carbon, manganese, silicon, chromium, nickel, copper and iron, characterized in that, in order to increase the toughness at low temperatures and reduce cost, it additionally contains titanium and nitrogen in the following ratio of components , wt.%: Carbon 0.12-0.24 Manganese 0.8-1.4 Silicon 0.4-0.9 Chromium 0.7-1.5 Nickel 0.1-0.6 Copper 0.1-0.4 Titanium 0.005-0.02 Nitrogen 0.002-0.02 Iron Rest > I