SU950792A1 - Composition of steel - Google Patents

Description

one

The invention relates to metallurgy, more specifically to steels for heavy loaded parts subjected to chemical heat treatment.

Known steel 1, containing, wt. %:

0.17-0.24

Carbon

Silicon 0.17-0.37

Manganese 0.8-1.2

Chrome 0.8-1.2

Molybdenum 0.07-0.11

Bor 0.002-0.004

Iron Else

This shock is low.

bone.

Closest to the described technical essence and the achieved result is steel 2, containing, weight. % Carbon 0.14-0.19

Manganese 0.5-0.8.

Silicon0.17-0.37

Chrome0.4-0.6

Molybdenum 0.4-0.6

Nickel1,6-2,0

Vanadium 0.1-0.25

Niobium 0.05-0.10

Copper0.10-0.25

Nitrogen

0,, 016 Iron Else

The disadvantage of this steel is the low level of toughness and ductility at low temperatures, especially after prolonged chemical and thermal treatment. The presence of these shortcomings prevents the use of this steel for the manufacture of parts for machines and structures in the northern version.

The aim of the invention is to increase the toughness at low temperatures. To achieve this goal, steel containing carbon, manganese, silicon, chromium, molybdenum, nickel, vanadium, niobium, copper, nitrogen and iron, additionally contains aluminum and cerium at the following ratio of components, weight. /about:

Carbon 0.14-0.19

Manganese 0.5-0.8

Silicon0.17-0.37

Chrome0.4-0.6

Molybdenum 0.4-0.6

Nickel1,6-2,0

Vanadium 0.1-0.25

Niobium 0.03-0.10 0.10-0.25 0.01: -0.02 0.01-0.03 Aluminum 0.005-0.05 Remaining Iron In an induction furnace, several options are proposed and tested in semi-industrial conditions. become. The chemical composition of the known and proposed steel is presented in table. 1. Casting and rolling are carried out using conventional technology. Cementation was carried out in a gaseous medium at 940 ° C for 28 h, which gives the required cementation depth of at least 2.4 mm. A comparison of the mechanical properties of the proposed and known steels shows that the value of toughness at negative temperatures fully satisfies the requirements imposed on them when operating in conditions of the North. The relative elongation of the proposed steel is also somewhat higher than the corresponding properties known. The limits of strength and yield strength of both steels are the same. The mechanical properties of the investigated steels are presented in table. 2 (quenching, tempering 500 ° С). The hardness of the proposed steel after carburization, quenching and tempering is at a level of hardness known. Thus, higher toughness values at low temperatures and a rather high hardness (over 60 kg / mm) make it possible to increase the service life of parts made of the proposed steel, when used in northern conditions, by 1.5-2.0 times. . In addition, the reliability of parts made from this steel is improved. The proposed steel rolls well in hot condition, has good cementing and hardenability and satisfactory machinability. The smelting technology of the proposed steel does not vary compared with the technology used for the known.

9.8

TtZ,

162.0

Table 1

table 2

60

tS

2.7

Claims (2)

3.5 Claims of Invention Steel containing carbon, manganese, silicon, chromium, molybdenum, nickel, vanadium, niobium, copper, nitrogen and iron, characterized in that, in order to increase impact strength at low temperatures, it additionally contains aluminum and cerium in the following ratio of components, wt.%; Carbon0,14-0,19 Manganese0,5-0,8 Silicon0,17-0,37 Chrome0,4-0,6 Molybdenum0,4-0,6 Nickel 1,6-2,0 0,10-0,25 Vanadium 0.03-0.10 Niobium 0.10-0.25 0.01-0.02 Aluminum 0.01-0.03 0.005-0.050 Remaining Iron Sources of information taken into account during the examination 1. USSR author's certificate 282658, cl. C 22 C 38/32, 1971. 2. Authors certificate of the USSR 500286, cl. C 22 C 38/00, 1976.