RU1779515C - Method for making plate and tubular electrodes for electroslag welding and surfacing - Google Patents

Abstract

Use1 electroslag welding and surfacing, for example, for the restoration of rolls of rolling mills. The inner part of the box or tube frame of the electrode is poured with liquid metal, the chemical composition of which provides the desired composition of the weld metal. The frame is made of low-carbon sheet metal. In this case, reliable electrical contact of the cast metal with the casing is achieved by welding it by electric welding to protruding above the cast part due to underfilling of the side walls. To ensure guaranteed refilling, the side sheets of the upper part of the carcass have slots equal in height to the thickness of the carcass. The chemical composition of the cast metal, providing the specified composition of the deposited metal, is calculated according to formulas that take into account the chemical and geometric parameters of the electrode and the base metal. 2 s.p. next to

Description

The invention relates to electric welding and fusion welding and can be used in electroslag welding and surfacing. A known method of manufacturing plate electrodes by cutting from rolled stock the required thickness. In the surfacing of cylindrical surfaces, for example, to restore rolls of rolling mills, tubular electrodes are used, which are manufactured by rolling sheet metal. A disadvantage of the known method is the difficulty of producing rolled products with a high carbon content and alloying elements necessary to obtain the required strength and hardness of the deposited metal . It is impossible to make a tubular electrode from high-carbon rolled products of the thickness required for surfacing, by rolling, generally.

Known methods for manufacturing plate electrodes from packages and by casting.

The disadvantages of these methods are the presence of technological difficulties associated with the preparation of forged and cast billets from high carbon steels, as well as the high complexity of their manufacture due to the need for mechanical processing.

There is also a known method of manufacturing plate electrodes by filling a box frame of sheet metal with powder alloy material.

The disadvantage of this method of manufacturing plate electrodes is the difficulty of retaining the powder in the cage, as well as the insufficient heat generation due to the fact that the casing shell mainly serves as a current conductor. This is the limitations XI

Xi

ABOUT

cl

2

cl

The dimensions of the deposited surfaces and welded sections are given.

A known method for the manufacture of consumable electrodes for electroslag smelting of ingots of steels and alloys, when metal is formed in the cavity of the outer electrode to form the inner electrode.

The disadvantage of this method is the lack of reliable electrical contact between the cast core and the sheath. This leads to a violation of the thermal regime of melting of the electrode and the appearance of defects in the form of non-fusion.

An object of the invention is to provide a durable, high-quality weld metal for welding and surfacing large parts, such as rolls of rolling mills.

The goal is achieved by pouring the inner part of the box or tubular frame with liquid metal, the chemical composition of which provides the desired composition of the weld metal. The framework is made of low carbon sheet metal.

In this case, reliable electrical contact of the cast metal with the casing is achieved by welding it by electric welding to protruding above the cast part due to underfilling of the side walls.

To ensure guaranteed underfilling, the side sheets of the upper part of the carcass have slots equal in height to the thickness of the rolled product.

If the height of the slot, and hence the protruding part of the sheet above the cast core of electrode 1, is less than the thickness of the sheet, then the seam fastening the frame to the cast part will have an insufficient cross-section for the passage of current. The height of the slot above the thickness of the sheet will create inconvenience for applying a high-quality seam.

In order to avoid unacceptable deformations of the electrode when casting with liquid metal, the side sheets of the housing are fixed with spacers welded to the sheet, and the frame itself is fixed with stops. In order to prevent burn-in of the side sheets in the case of pouring superheated metal, the places of concentrated heating of the side walls of the body are cooled

The chemical composition of the cast metal, providing the desired composition of the weld metal, is calculated by the formulas.

In the case of plate electrode welding:

Squeeze

JCH (b + 2 g) 5 + 2 D 2 (3b + 2DK) fL-2M) a

CL 2 M (L + a) 5 a (L - 2 M);

in the case of surfacing with a cylindrical electrode:

  Cn (d + b - r) (b + r) Co (d - g) r N (d + b) b

SL -2 M

0

5

0

5

0

5

0

5

where Sn is the specified content of the chemical element in the weld metal,%;

Sg is the content of the chemical element in the cast metal of the electrode,%;

Co is the content of the chemical element in the base metal subjected to welding or surfacing,%;

Сl is the content of a chemical element in the sheet metal of the sheath of the electrode carcass,%;

B is the width of the weld deposit or weld without taking into account penetration. cm;

d is the penetration depth of the base metal, cm;

d - the thickness of the welded metal, cm:

N is the thickness of the electrode, cm;

a is the thickness of the cast part of the electrode, cm;

D, K - width and magnitude of reinforcement from the side of the forming device during electroslag welding of the butt joint, cm;

M is the thickness of the sheet sheath of the electrode, cm;

d is the diameter of the deposited cylindrical part, cm;

L is the width of the plate electrode, see

According to this method, an experimental cylindrical electrode was produced for surfacing a roll with a diameter of 100 cm, a layer 10 cm thick. Chemical composition of a liquid metal, based on the need to obtain a deposited layer, contains 0.9% carbon; chromium 0.9%; vanadium 0.15% with a penetration rate of the base metal of 2 cm. Metal roll st 40X (C 0.4%, Cr 0.5%) cast component 3.6 cm thick, the frame is made of steel 3 1.2 cm thick. Composition: carbon 0.15%; chrome 0.2%. Chemical elements calculated by the formula: carbon 1.55%; chromium 1.48%; vanadium 0.22%.

An example of calculating the carbon content in the cast metal of a cylindrical electrode for surfacing a roll of a rolling mill

The calculation is performed according to the formula:

Squeeze

  Cn (d -f b - g) (b + g) - Co (d - g) g N (d + b) b a

SL 2 M

where Sn is the specified carbon content in the weld metal, 0.9%;

Co - carbon content in the base metal, 0.4%;

Сл is the carbon content in the sheet metal of the carcass shell, 0.15%;

b - surfacing width excluding penetration, 10 cm;

d is the penetration depth of the base metal, 2 cm;

N is the thickness of the electrode, b cm;

a is the thickness of the cast part of the electrode, 3.6 cm;

M is the thickness of the sheet shell of the electrode frame, 1.2 cm;

d is the diameter of the deposited cylindrical part, 100 cm.

Sv 0.9 (100 + 10-2) (10 + 2) -0.4 (lOO-2) (100 + 10) 10 36 0.15 -2-12

3.6

1.548%.

accept 1.55%,

An example of calculating the carbon content of a cast metal of a plate electrode for welding a roll of a rolling mill.

The calculation is performed according to the formula:

Squeeze

{CH (b + 2 g) (5 + 2 D 2 rJL N (db + 2 D K) (L-2 M) a Cn 2 M (L + a)

a (L - 2 M)

where Sn is the specified carbon content in the weld metal, 0.9%;

С0 - carbon content in the base metal subjected to welding, 0.9%;

Сл - carbon content in sheet metal of the shell of the electrode carcass, 0.15%;

b - weld width excluding penetration, 12 cm;

d is the penetration depth of the base metal, 2 cm;

b - the thickness of the welded metal, 100cm;

N is the thickness of the electrode, 8 cm;

a is the thickness of the cast part of the electrode, 5 cm;

D is the gain width from the side of the forming device, 14 cm;

K is the magnitude of the gain from the side of the forming device, 1.5 cm;

M is the thickness of the sheet sheath of the electrode, 1.5 cm;

L- plate electrode width, 98

cm.

OE (12 +4) 100 +2

Sz - 14 1,, 9

0

5

0

5

0

5

0

(100 -12 + 2 0.15

14

1.5 (98-2

21.5 (98 + 51

5

0

5

5 (98-2 1.5) accept 1.28%.

Verification in laboratory conditions showed the proximity of the calculated and experimental values,

The proposed method for the manufacture of electrodes allows welding and surfacing of tool steels, in particular, the restoration of spent rolls of rolling mills, thereby obtaining a waste-free technology. In addition, it is possible to increase the operational stability of the rolls by applying a deposited layer that is more durable than the roll metal.

Claims (3)

1. A method of manufacturing plate and tubular electrodes for electroslag welding and surfacing of steel by manufacturing a box or tubular frame of low carbon steel and filling the inside with liquid metal, characterized in that, with a chain for increasing the strength and quality of the deposited metal in the manufacture of mainly rolls of rolling mills and turbine rotors, the side sheets of the carcass shell in its upper part are electrowelded to the cast part of the electrode, while the carcass is filled with underfilling. 2. The method according to claim 1, with the fact that the side sheets of the shell casing for their high-quality welding are in the upper part of the slot, providing underfilling of liquid metal to the upper edges of the side sheets of the carcass with a depth equal to the thickness of these sheets, 3. The method according to claim 1, characterized in that, in order to obtain a given chemical composition of the deposited metal, the chemical elements of the cast part of the electrode are calculated by the formulas in case of welding with a plate electrode Szh {CH (b + 2 g) d + 2 D K - Co d 2 rJL N (db +2 D K) (L-2 M) a Сл 2 M (L + a) a (L - 2 M) in the case of surfacing with a tubular electrode Sg   Cn (d + b - g) (b + g) - Cp (d - i) g N (d + b) b a SL 2M where Cm is the specified content of the chemical element in the weld metal,%; 5 Sg is the content of the chemical element in the poured metal of the electrode,%; With the content of the chemical element in the base metal subjected to welding or surfacing,%; 10 Сл is the content of a chemical element in the sheet metal of the carcass shell,%; b - width of surfacing or weld without taking into account penetration, cm; 15 cm; d is the penetration depth from the base metal, cm; d is the thickness of the welded metal, cm; L is the width of the plate electrode, N is the thickness of the electrode, cm; a is the thickness of the cast part of the electrode, cm; D. K - width and magnitude of reinforcement from the side of the forming device during electroslag welding of the butt joint, cm; M is the thickness of the sheet shell of the electrode frame, cm; d is the diameter of the deposited cylindrical part, see