SU825301A1 - Welding wire composition - Google Patents

Description

The invention relates to materials used for welded structures made of ferritic steels with 5-12% nickel, operating at temperatures up to -196 and -253®С (steel with 12% nickel).

At present, for welding cryogenic structures made of steel with 9% nickel, fillers mainly use nickel-based alloys that provide the austenitic structure of the weld metal as filler materials. There is information about the development of ferrite-class wires, similar in composition to the base metal, i.e. ’5 steel with 9% nickel. The main difficulty in obtaining high-quality welds is that the welds, identical in composition to the base metal, · have a high sensitivity of 20 to pores and hot cracks.

Known fl * J wires, recommended: for arc welding of cryogenic steels with 9% nickel, having a bare chemical composition,%: nickel

7-13; · manganese “0.45; carbon "0.9; silicon "0.15; aluminum; 0.05; titanium .to 0.1; niobium to 0.1; sulfur, "0.01; (phosphorus ί 0.01; oxygen 0 0.015;

nitrogen; 0.006; hydrogen "0.003 iron - the rest.

However, when welding in a protective gas medium and under flux with wires of the specified composition, pores and cracks are observed. At the same time, the need to obtain ferritic or ferritic-austenitic joints, combined with high strength and ductility at low temperatures, necessitates studies on the influence of alloying elements on the mechanical .. properties of welds, their technological strength and resistance to pore formation.

Known composition of the die containing nents, wt.%:

Carbon Manganese Nickel Molybdenum Vanadium Cerium Silicon Chrome Iron _: The purpose of the invention of welds, [2 J welding about the following components. 0.05-0.6 0.2-0.8 0.02-8 0.1-0.8 0.01-0.8 0.6-3.7 0.01-0.5

0.02-0.5

Rest

- obtaining heat-resistant against the formation of 3 threads.

0.01-0.08

3.2- 18 4.5-16

1.2- 5 0.001-1 0.001-1 0.001-2 '0.01-0.7 0.01-0.8 Else

No more than 0,01

- 1 '- 0.01

---- It - and

----- II

0.005

0.015

0.0003 nya of hot cracks, ductile and vih at low temperatures.

The goal is achieved that the composition additionally contains tungsten, titanium, aluminum in the following ratio of components, wt.%: Carbon Manganese Nickel Molybdenum Vanadium Cerium Tungsten Titanium Aluminum Iron

Impurities

Sulfur Phosphorus Nitrogen Oxygen Hydrogen The basis for creating the chemical composition of the wire is the principle of intense deoxidation of the weld metal by introducing manganese, titanium, cerium into the seam, as well as nitrogen binding to finely dispersed nitride.

Cerium, having a high chemical affinity for oxygen, sulfur and other harmful impurities, is effective as a modifier and deoxidizer in welding.

To increase the technological strength of the weld metal, molybdenum and tungsten are introduced into the wire. Molybdenum contributes to a more uniform distribution of oxygen in the weld metal, which also improves the crack resistance of the welds.

Manganese in selected amounts in the studied alloying system eliminates the harmful effect of sulfur, forming 40 manganese sulfide. Compared with the Fe - Fe S eutectic, manganese sulfide has a higher melting point and is located on the grain body. At the same time, manganese is a 45 intense deoxidizer, having a large affinity for oxygen, it takes it from iron. Manganese, due to its ability to bind sulfur and prevent the heat resistance of jq joints, significantly increases their crack resistance, ductility and toughness. However, alloying nickel joints only with manganese does not exclude the appearance of cracks.

Titanium is introduced into the composition of the wire as a deoxidizing agent, as well as for binding nitrogen to finely dispersed nitrides, contributing to the grinding of the primary structure of the weld metal and its increased resistance to pore formation

YES, NOAH from oxygen and nitrogen.

The introduction of cerium allows you to bind oxygen and partially sulfur. Oxides and sulfides of cerium, having a high melting point, remaining in the weld metal, have a positive effect as modifiers of the second kind or as inclusions with more favorable shapes and sizes. For example, the formation of small spherical cerium sulfides in intercrystalline zones instead of coarse precipitation of sulfides of the alloy base (Fe).

Molybdenum significantly increases the resistance of joints to cracking. The favorable effect of molybdenum on crack resistance is explained by the ability to suppress the development of physical heterogeneity in the weld metal [after crystallization is completed. Molybdenum reduces oxygen segregation over the weld metal section, which also improves crack resistance.

Tungsten, like molybdenum, contributes to the production of the initial fine grain. In addition, these elements increase the interatomic bonding forces, which prevents the formation of hot cracks. The total content of molybdenum and tungsten should not exceed 5%, as this leads to a decrease in the ductility of the seam.

'Vanadium allows you to get rid of the development of physical heterogeneity in the weld metal, binds nitrogen to nitride.' In small quantities (O, 1-0.3%), the grain is noticeably crushed.

The alloying system of the proposed compositions for the first time made it possible to obtain seams with a ferritic structure that are operable at temperatures up to minus 253 ° C, and are resistant to the formation of pores and hot cracks. At normal temperatures, high (65-70 kg / mm ² ) strength was achieved, which favorably distinguishes the specified system of existing.

Prepare 14 batches of wire. To the tab! The person presents the proposed compositions of each batch of wire.

The performed complex alloying allows to obtain high-quality seams with satisfactory ductility. viscosity and viscosity at low temperatures, as well as provide high resistance of the deposited metal against the formation of hot cracks.

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Claims (2)

The invention relates to materials used for welded structures made from ferritic steels with 5-12% nickel, working at temperatures down to -196 and -253®С (steel with 12% nickel). At present, nickel-based alloys, providing the austenitic structure of the weld metal, have been used as a filler material for swirl of cryogenic structures made of steel with 9% nickel. There is information about the development of ferritic-grade wires that are close in composition to the base metal, i.e. it became m with 9% nickel. The main difficulty in obtaining high-quality seams is that the seams, which are identical in composition to the base metal, are highly sensitive to pores and hot trescines. Known wires. Recommended: for arc welding of cryogenic steels with 9% nickel, having the desired chemical composition,%: nickel 7-13; - manganese — e 0.45; carbon "0.9 silicon 0.15;. aluminum "0.05 j titanium to 0.1; niobium to 0.1; sulfur "0.01; phosphorus 0.01; oxygen "0.015; nitrogen: "0,006; hydrogen sS 0.003; . iron - the rest. However, when welding in shielded gas and submerged-arc conditions with wires of the indicated composition, pores and cracks are observed. At the same time, the need to obtain ferritic or austenitic-ferritic joints, in combination with high strength and ductility at low temperatures, leads to research on the effect of alloying elements on the mechanical mechanism. the joint properties, their technological strength and resistance to pore formation. Known composition of 1.2 welding wire containing the following components, wt.%:. 0.05-0.6 Carbon 0.2-0.8 Manganese 0.02-8 Nickel 0.1-0.8 Molybdenum 0.01-0.8 V. Anadyy 0.6-3.7 0.01 -0.5 Silicon 0.02-0.5 Remaining Iron The purpose of the invention is to obtain welds resistant to hot cracks, ductile and hot at severe temperatures. The goal is achieved by the fact that the composition additionally contains tungsten, titanium, aluminum with the following ratio of components, wt.% 0.01-0.08 Carbon 3.2-18-18 Manganese 4.5-16 Nickel Molybdenum 0.001-1 Vanadium 0.001-1 0.001-2 Tungsten 0.01-0.7 0.01-0.8 Aluminum Rest Iron Impurities Not more than 0.01 Sulfur - - 0.01 Phosphorus - - 0.005 Nitrogen - - 0.015 Oxygen - - 0.0003 Hydrogen Base The chemical composition of the wire is based on the principle of intensive deoxidation of the weld metal due to the introduction of manganese, titanium, cerium into the weld, and also the binding of nitrogen into finely dispersed nitrides. Cerium, having a high chemical affinity for oxygen, sulfur, and other harmful impurities, is effective as a modifier and deoxidizing metal during welding. To increase the technological integrity of the weld metal, molybdenum and tungsten are introduced into the wire. Molybdenum contributes to a more uniform distribution of oxygen in the weld metal, which also improves the frictional resistance of the welds. Manganese in W: 1 selected quantities in the studied system of doping of the mouth injures the harmful effect of sulfur, the image is manganese sulphide. Compared with the eutectic Fe-Fe S, manganese sulphide has a higher melting point and is located along the grain body. At the same time, manganese is an intense deoxidizing agent, which has a greater affinity for oxygen; it takes it away from iron. Manganese, due to its ability to bind sulfur and interfere with the mountains of heave, seams noticeably increases their resistance to cracking, ductility and toughness. However, the alloying of nickel seams with manganese only does not exclude the appearance of tshchshn. Titanium is introduced into the composition of wires as a deoxidizing agent, as well as for bonding nitrogen into finely dispersed nitriles, facilitating the grinding of the primary structure of the weld metal and increasing the resistance to pore and oxygen formation. The introduction of cerium allows the binding of the isoride and partly sulfur. Cerium oxides and ulfides, having a high melting point, remaining in the metal, have a positive effect as modifiers of the second kind or as inclusions with more favorable forms and sizes. For example, the formation of fine spherical cerium sulfides in intergranular zones instead of coarse precipitates of sulfide base alloys (Fe). Molybdenum significantly increases the resistance of joints against cracking. The favorable effect of molybdenum on crack resistance is explained by its ability to suppress the development of physical inhomogeneity in the weld metal at the height of crystallization. Molybdenum reduces the segregation of oxygen over the cross section of the weld metal, which also improves crack resistance. Tungsten, like molybdenum, contributes to obtaining fine fine grains. In addition, these elements increase the interatomic bonding forces, thereby preventing the formation of hot cracks. The total content of molybdenum and tungsten should not exceed 5%, as this leads to a decrease in the ductility of the weld. Vanadium eliminates the development of physical inhomogeneity in the weld metal, binds nitrogen to nitride. In small quantities (about 1-0.3%), the grain is noticeably crushed. For the first time, the alloying system with the proposed compositions allowed to obtain welds with a ferritic structure, which are capable of working at temperatures down to minus 253 ° C and resistant to the formation of pores and hot cracks. At normal temperatures, high strength (65-70 kg / mm) was achieved, which distinguishes the specified system of av-vukntsi. Prepare 14 batches of wires. The table presents the proposed compositions of each batch of wire. The performed complex doping allows to obtain high-quality welds with satisfactory ductility and toughness at low temperatures, as well as to ensure high resistance of the weld metal to hot cracking. The invention The composition of the welding wire, mainly for welding of ferritic steels with 5-12% nickel long-lasting at temperatures up to -253®С, containing carbon, manganese, nickel, molybdenum, vanadium, | Cerium, iron, which differs from in order to obtain from seams resistant to the formation of hot cracks, ductile and viscous at low temperatures, the compound additionally contains tungsten titanium, aluminum, with the following ratio of components, wt.%: Carbon 0.01-0.08, Manganese3, 2-18 Nickel 4.5-16 Molybdenum Vanadium 0.001-1 0.001-1 Tungsten 0.001-2 0, 01-0.7 Aluminum 0.01-0.8 Iron Else Sources of information are considered in the examination 1. Patent SZNA 3902039,. B 23 K 35/22, 08.26.75. 2. USSR author's certificate 409810, cl. 23 K 35/30, 30.12,71 rototype).