RU2250927C2 - Special bridge steel - Google Patents

Abstract

FIELD: metallurgy, in particular steels for bridge engineering.

SUBSTANCE: claimed steel contains (mass %): carbon 0.09-0.12; manganese 0.70-1.0; nickel 1.50-2.0; silicium 0.20-0.35; aluminum 0.015-0.045; copper 0.30-0.50; sulfur 0.001-0.010; phosphorus 0.001-0.010; and balance: iron.

EFFECT: steel with increased corrosion resistance in wet environment.

1tbl, 1 ex

Description

The invention relates to the field of metallurgy, and more particularly to steels used in bridge construction.

Steel is known (see the catalog “Shahlschlüssel”, A 350 LF5, 1986, p. 169, No. 51, ed. MVND-7142), trace. composition, wt.%:

Carbon no more than 0.30

Manganese no more than 1.35

Nickel 1.0-2.0

Silicon 0.20-0.35

Sulfur no more than 0,040

Phosphorus no more than 0,035

Iron rest

The closest in composition, adopted as a prototype, is steel grade 10GN2 (RF patent No. 2049146, C 22 C 38/38), used in the energy industry of the following composition, wt.%:

Carbon 0.09-0.12

Manganese 0.90-1.35

Nickel 1.50-2.0

Silicon 0.20-0.35

Vanadium 0.005-0.02

Niobium 0.005-0.02

Aluminum 0.015-0.045

Calcium 0.005-0.010

Chrome 0.05-0.2

Molybdenum 0.01-0.12

provided that Cr + Mo≤0.32

Iron and impurities rest

This steel does not provide corrosion resistance in a humid atmosphere.

The objective of the invention is to provide increased corrosion resistance in a humid atmosphere.

The solution to this problem is achieved by the fact that in the steel containing C, Mn, Ni, Si, Al, Cu, P, S are additionally introduced, with the following ratio of components, wt.%:

Carbon 0.09-0.12

Manganese 0.70-1.0

Nickel 1.50-2.0

Silicon 0.20-0.35

Aluminum 0.015-0.045

Copper 0.30-0.50

Sulfur 0.001-0.010

Phosphorus 0.001-0.010

Iron rest

The choice of elements for alloying the selected steel grade was determined by the required properties and cost.

Carbon in steel in an amount of C = 0.09-0.12% was selected in order to ensure high ductility, reduce the brittleness of the heat-affected zone and eliminate the likelihood of the formation of cold cracks.

Manganese in steel in the amount of Mn = 0.70-1.0% is selected from the condition of ensuring full deoxidation of the steel, increasing hardenability and lowering the temperature of the cold brittleness threshold.

Nickel in steel in an amount of Ni = 1.50-2.0% provides an increase in ductility, toughness and corrosion resistance.

Silicon in steel in the amount of Si = 0.20-0.35% is an active deoxidizer of steel and reduces the sensitivity to overheating.

Aluminum in steel in an amount of Al = 0.015-0.045% ensures complete deoxidation of the steel and contributes to the production of a fine-grained structure.

Copper in an amount of 0.30-0.50% is selected to increase corrosion resistance in a humid atmosphere.

Sulfur in an amount of 0.001-0.010% helps to improve the cold resistance and ensure a given level of toughness.

Phosphorus in an amount of 0.001-0.010% also helps to ensure a given level of corrosion resistance.

Example.

Known and proposed compositions of steels were smelted in induction furnaces IST-16 and cast into molds of 50 kg.

Table 1 shows the chemical compositions of the proposed steel and known, as well as data on the corrosion resistance of the material.

The data presented show that the introduction of new components into the steel composition together with components of known composition can increase the corrosion resistance of the material.

Table 1 steel grade Chemical composition, wt.% Job
Bump
main met
J * Job
Bump
HAZ
J
at t - 50 ° С Speed
corrosion FROM Mn Ni Si Al Cr V Mo Nb Sa Cu S R Famous 0.12 1.35 2.0 0.35 0,045 0.2 ** 0.02 0,12 ** 0.02 0.010 - - - 120 100 4 Suggested 1 0.08 0.65 1.3 0.18 0.010 - - - - - 0.25 0,0005 0,0005 60 80 2 Suggested 2 0.09 0.70 1.5 0.20 0.015 - - - - - 0.30 0.001 0.001 140 120 2 Suggested 3 0.11 0.95 1.7 0.30 0,030 - - - - - 0.40 0.004 0.004 160 140 2 Offered 4 0.12 1.00 2.0 0.35 0,045 - - - - - 0.50 0.010 0.010 140 160 1 Offered 5 0.13 1.05 2.1 0.40 0.05 - - - - - 0.55 0.011 0.011 90 100 2 *) On Charpy type specimens with a sharp notch.
**) Cr + Mo≤0.32

Claims (1)

Steel containing carbon, manganese, nickel, silicon, aluminum, characterized in that it is additionally introduced copper, phosphorus, sulfur in the following ratio, wt.%: Carbon 0.09-0.12 Manganese 0.70-1.0 Nickel 1.50-2.0 Silicon 0.20-0.35 Aluminum 0.015-0.045 Copper 0.30-0.50 Sulfur 0.001-0.010 Phosphorus 0.001-0.010 Iron Else