SU539976A1 - Nickel based alloy - Google Patents

Description

(54) NICKEL-BASED ALLOY

one

The invention relates to the field of metallurgy, in particular to corrosion-resistant nickel-based alloys, intended for plating the internal surfaces of special power plants

Known alloy based on Nickel ij the following chemical composition, weight. %:

Carbon 0.1 - 0.15

Silicon0.15-0.35

Manganese .0.6 - 1.0

Chrome14.0-17.0

Iron7.0 - 9.0

Nickel hard

The known alloy is not subjected to stress corrosion cracking and is used to protect the most critical nodes in power plants.

However, intercrystal corrosion in such an alloy and cracks in the welds during welding of various elements to the clad surface are possible.

Known alloy has the following mechanical properties:

Strength at

rupture

Yield strength

kg / mm

25

Relative

 about%

elongation

In the study of technical properties, it was found that when forging a known alloy, tears are observed, and prc rolling on sheets-cracking,

The aim of the invention is to improve the processability during hot working, resistance to intergranular corrosion and the formation of hot cracks during welding.

This is achieved by the fact that the alloy containing carbon, silicon, manganese, chromium, iron and nickel, additionally contains niobium, titanium, calcium and cerium in the following ratio of components, weight. %: Carbon0.015-0.04

Silicon0.15-0.30

Manganese1.0 -2.0

Chrome15.0-17.0

Iron7.0 -9.0

Niobium 1.2 -2.0

Titan0,3 -0,6

Calcium 0,015-0,04

Cerium0.01 -0.02

Nickel hard

The introduction of elements of niobium and titanium stabilizers (while reducing the carbon content) contributes to an increase in the durability of the metal of intergranular corrosion plating.

The presence of niobium in the alloy provides for joints without cracks in the places of the subsequent welding to the clad layer

The proposed alloy in the weld both in the initial state (after welding) and after tempering (660 ° С - 2 hours and 30 minutes) has a shock of 14.6 and 14.1 kg in a temperature of 2 ° C. m / cm match

In the study of the manufacturability of the proposed alloy, no defects (tears, cracks) were found during forging, and there are no defects during rolling, 40

Comparative corrosion tests of the proposed and known alloys according to the method of permanent deformation were not revealed.

various elements, such as tubes in heat exchangers.

The introduction of calcium and cerium helps to improve the processability of the metal in the process of obtaining the sheet.

The proposed alloy has the following optimal chemical composition, weight. %: carbon 0.015, silicon 0.3, manganese 1.38, chromium 15.4, iron 8.6, niobium 2.06, titanium 0.87, calcium 0.019, cerium 0.015, sulfur 0.005, phosphorus 0, O08 nickel the rest. Its mechanical properties are given in table. one.

Table 1

advantages of the proposed alloy, since the time to sample destruction in a 42% solution of Mg CBg at a temperature of 154 ° C and a solution of 25% NaCg and 0.5 at a temperature of 200 ° C and a pressure of 16 atm is 500 hours containing 200 mg / l of chlorine ions at a temperature of 300 ° C and a pressure of 115 atm - 150O hour.

The results of the tests according to the constant Hbjx stress method (INK-1) in a 42% MgCPJ solution at the boiling point are given in Table. 2,

Claims (1)

Table 2 Comparative corrosion tests showed that the proposed alloy and its welded joints in the initial state, after tempering at 650 ° C for 1 hour, 70 ° C for 1 hour and 660 ° C for 25 hours, did not undergo intercrystalline corrosion, the surface of the samples after 90 ° bend both before and after boiling there were no defects; samples from a known alloy under the same test conditions had significant etched areas on the surface. Tests of the proposed and known alloys in addition, in a solution of% HNOjnpH in the wake of 30% H 80 and 10 for 96 hours after the 90 ° bend, the mass of the proposed alloy is 18, and The invention claims Nickel-based alloy containing carbon, silicon, manganese, chromium and iron. 5 76 characterized in that, in order to improve processability during hot working, resistance against intercrystallite corrosion and the formation of hot cracks during welding, it additionally contains niobium, titanium, calcium and cerium at the following ratio of components, weight. %: 0.015-0.04 Carbon 0.15 -O, 30 Silicon 1.0 -2.0 Manganese 15.0 -17.0 7.0 -9.0 Iron 1.2 -2.0 Niobium 0.3 -0.6 Calcium 0.015-0.04 0.01 -O, O2 Nickel Else Sources of information taken into account during the examination: 1. Reference book BoiEeh Code alloy yb 163, ed. American Society of Mechanical Engineers ASM, 1965 v. 2 book 2 p. 396 (prototype).