SU908923A1 - Steel composition - Google Patents

Description

(54) STEEL

This invention relates to steel metallurgy.

in particular, high-strength weldable steel for large products.

Known steel 1, which contains, wt%:

Carbon, 0.2-0.7

Silicon0.17-0.27 Manganese0.4-0.7

Chrome 1.7-2.0

Nickel1,2-1,6

Molybdenum0,51 -0,6

Vanadium, 0.01-0.1

Cerium 0.02-0.05

IronErest

The disadvantages of this steel are poor hardenability and a relatively low level of strength and ductility, which to some extent is associated with a low nickel and molybdenum content and ultimately reduces the quality of large welded products made from it.

Closest to the proposed is steel (2, containing, wt.%:

0.2-0.28

Carbon 0.4-Q, 7

Manganese 0.17-0.37

Silicon

1-1.5

Chromium 2.55-2.85

Nickel 0,66-0,75

Molybdenum 0.01-0.05

Vanadium 0.02-0.04

Aluminum 0,005-0,05

Calcium Rest

Iron

to

After normalization at 90 ° С, tempering at 650 ° С and final heat treatment consisting of quenching from 900 ° С and tempering at 645 ° С, the steel has the following mechanical properties:. Tensile strength,

kg / mm

90.5-92.6

Yield strength

kg / mm

81-83.0

20

Relative

20.0-22

elongation,%

Relative

68-70

c,% Shock viscosity at + 20 ° C kgm / cm 15.6-17.2 -80 C kgm / cm 11-11.5 The disadvantages of the known steel are relatively low ductility and toughness, which reduces the reliability of the fabricated large welded forgings from it. The purpose of the invention is to increase ductility and toughness, while maintaining strength at a high level. The goal is achieved by the fact that steel containing carbon, manganese, silicon, chromium, nickel, molybdenum, vanadium, aluminum, calcium and iron, additionally contains titanium and rare earth metals with the following ratio of components, wt.%: 0.2-0, 3 Carbon 0.4-0.8 Manganese 0.17-0.37 Silicon 1.0-1.5 2.5-3.0 0.6-0.8 Molybdenum 0.01-0.1 Vanadium 0, 01-0.05 Aluminum1 0.00 0.00-0.05 Kalydium 0.01-0.05 Rare-earth 0.005-0.08 Metals Else Additional Introduction to the composition of the steel of titanium and rare-earth metals REM is associated with their favorable influence on the structure and non-metallic include no. The introduction of titanium crushes the steel structure and neutralizes the harmful effects of free nitrogen due to the formation of nitrides. At the same time, titanium and REM, being strong deoxidizing agents, provide a decrease in the oxygen content. REM together with calcium forms the formation of complex multiphase

Known

0.27

0.5

0.02

OD) 3

0.01

O.EVDI

OD) 2OD

0.05 OyDS

0.04OgOOS

OJM "yoe 4 inclusions that are easily removed from the liquid steel. The chemical composition of the proposed steel is given in table. 1. The metal is smelted in 300 kg of an induction furnace by the method of remelting with furnace deoxidation with ferromanganese and ferrosilicon by calculation. In the process of fractional casting, the melt is modified with various additives of a complex master alloy containing calcium, rare-earth metals, aluminum, titanium, vanadium and nickel. Various experienced compositions began to pour molds. Mechanical tests are carried out on standard samples of tensile and toughness, made of blanks, forged from molds. Table 2 presents the physico-mechanical properties of steel. From the above results, it follows that the proposed steel of compositions 2-6 exceeds the known steel (composition No. 1) in ductility and toughness at a constant level of strength. Thus, the relative elongations and contractions exceed their values in the known steel by 34-40% and 17-20%, respectively. Accordingly, the impact viscosity increases by 17-30% at a normal temperature and by 32-50% at -80 ° C tests. Higher ductility and toughness allow the proposed steel to be recommended instead of the known one for making large forgings. The expected economic effect will be 6 thousand rubles. by increasing the durability of welded parts by 1.5 times and increasing plasticity by 34–40% and impact strength by 13–30%. Table}

T "ii" K "2

Mechanical Opoyepi

Claims (1)

<claim-text> Formula of the invention </ claim-text> </ td> <td> <claim-text> Molybdenum </ claim-text> <claim-text> Vanadium </ claim-text> </ td> <td> <claim-text> 0.6-0.8 </ claim-text> <claim-text> 0.01—0.1 </ claim-text> </ td> </ tr> <tr> <td> <claim-text> Steel containing carbon, manganese, cream - </ claim-text> </ td> <td> <claim-text> Aluminum </ claim-text> </ td> <td> <claim-text> 0.01-0.05 </ claim-text> </ td> </ tr> <tr> <td> <claim-text> chrome, nickel, molybdenum, vanadium, aluminum 25 </ claim-text> </ td> <td> <claim-text> Calcium </ claim-text> </ td> <td> <claim-text> 0.005-0.05 </ claim-text> </ td> </ tr> <tr> <td> <claim-text> minium, calcium and iron, I distinguish - </ claim-text> </ td> <td> <claim-text> Titan </ claim-text> </ td> <td> <claim-text> 0.01-0.05 </ claim-text> </ td> </ tr> <tr> <td> <claim-text> that, in order to increase </ claim-text> </ td> <td> <claim-text> Rare earth </ claim-text> </ td> <td> </ td> </ tr> <tr> <td> <claim-text> ductility and toughness with preserved - </ claim-text> </ td> <td> <claim-text> metals </ claim-text> </ td> <td> <claim-text> 0.005–0.08 </ claim-text> </ td> </ tr> <tr> <td> <claim-text> in strength, it additionally contains </ claim-text> </ td> <td> <claim-text> Iron </ claim-text> </ td> <td> <claim-text> Else </ claim-text> </ td> </ tr> </ table> <claim-text> titanium and rare earth metals when following · o </ claim-text> <claim-text> total ratio of components, wt.%: </ claim-text>