CN114406522B

CN114406522B - Welding wire for overlaying repair of hot-rolled backup roll and preparation method thereof

Info

Publication number: CN114406522B
Application number: CN202210141825.XA
Authority: CN
Inventors: 牟淑坤; 张飞虎; 刘宏; 王凤会; 陈延清; 齐建
Original assignee: Shougang Group Co Ltd
Current assignee: Shougang Group Co Ltd
Priority date: 2022-02-16
Filing date: 2022-02-16
Publication date: 2023-08-11
Anticipated expiration: 2042-02-16
Also published as: CN114406522A

Abstract

The application particularly relates to a welding wire for overlaying repair of a hot-rolled support roller and a preparation method thereof, belonging to the technical field of welding, wherein the welding wire comprises the following chemical components in percentage by mass: c:0.18-0.35%, si:0.35-0.60%, mn:1.1-2.0%, P: < 0.015%, S: less than 0.010%, cr:4.0-8.0%, ni:2.0-5.0%, mo:1.0-3.0%, V:0.2-1.0%, and the balance of Fe and unavoidable impurities. The welding wire achieves the aim of adjusting the performance of the welding wire by adjusting the mass fraction range of the components to enable the components to be matched with each other and synergistically increase the performance of the welding wire, effectively improves the toughness and hardness uniformity of the surfacing metal, and effectively prevents cracks and chipping.

Description

Welding wire for overlaying repair of hot-rolled backup roll and preparation method thereof

Technical Field

The application belongs to the technical field of welding, and particularly relates to a welding wire for overlaying repair of a hot-rolled support roller and a preparation method thereof.

Background

The hot rolling support roller is a key metallurgical spare part on a hot rolled plate coil and medium plate steel production line, and has the advantages of large size, large weight, high performance requirement, long manufacturing period and high production cost. The traditional manufacturing process needs to be subjected to complicated procedures such as electric furnace smelting, external refining, casting, forging, multiple heat treatments, machining and the like, and needs to consume a large amount of resources to discharge a large amount of waste water, waste gas and waste residues. The hot rolling backing roll has severe service conditions, serious abrasion in the working process, easy occurrence of surface defects such as cracks, peeling and the like, and premature scrapping is caused, and the metal loss of the hot rolling backing roll is only about 15% of the total weight when the roll is scrapped. At present, most scrapped supporting rollers are used as raw materials for returning to the furnace for smelting, so that huge waste of resources and energy sources is caused.

The surfacing repair technology is a surface technology treatment process, and is a process of piling one or more layers of materials with certain performance on the surface of a part in a welding mode. The method has the advantages that the method carries out build-up welding repair on the waste large-scale supporting roller, resumes the use of the waste large-scale supporting roller, can excavate huge residual value, greatly reduces manufacturing cost, prolongs service life, and can reduce a large amount of energy consumption and save a large amount of materials. The method has the advantages of great emission reduction, energy conservation and consumption reduction, and obvious resource, environmental protection and social benefits.

The hot rolling support roller mainly has the problems that the surfacing repair roller is obviously processed and hardened in the use process, the surface hardness is uneven, and cracks and flaking blocks are easy to occur in the use process of the surfacing repair roller, so that production accidents are caused.

Disclosure of Invention

The application aims to provide a welding wire for overlaying repair of a hot-rolled support roller and a preparation method thereof, which solve the technical problems of poor toughness, uneven hardness, cracking and chipping of overlaying metal welded by the existing overlaying repair welding wire for the hot-rolled support roller.

In order to solve the technical problems, the embodiment of the application provides a welding wire for hot-rolled backup roll surfacing repair, which comprises the following chemical components in percentage by mass:

c:0.18-0.35%, si:0.35-0.60%, mn:1.1-2.0%, P: < 0.015%, S: less than 0.010%, cr:4.0-8.0%, ni:2.0-5.0%, mo:1.0-3.0%, V:0.2-1.0%, and the balance of Fe and unavoidable impurities.

Optionally, the chemical components of the welding wire include, in mass fraction:

c:0.18-0.35%, si:0.35-0.50%, mn:1.1-1.8%, P: < 0.015%, S: less than 0.010%, cr:4.0-7.0%, ni:2.0-4.0%, mo:1.0-2.5%, V:0.2-0.8%, and the balance of Fe and unavoidable impurities.

Optionally, the metallographic structure of the deposited metal of the welding wire is as follows in volume fraction: 55-68% of medium carbon martensite and 32-45% of lower bainite.

Optionally, the diameter of the welding wire is 2.4-4.0mm.

Optionally, the diameter of the welding wire is 3.2mm.

Based on the same inventive concept, the embodiment of the application also provides a preparation method of the welding wire for hot rolling backing roll welding repair, which comprises the following steps:

carrying out converter smelting and LF refining by taking the chemical components of the welding wire for hot-rolled backup roll welding repair as end components to obtain target molten steel;

continuously casting and rolling the target molten steel to obtain a wire rod;

and sequentially carrying out shelling, acid washing, borax coating, wire drawing and copper plating on the wire rod to obtain the welding wire for hot rolling backing roll welding repair.

Optionally, top-bottom combined blowing is adopted in converter smelting.

Optionally, the rolling is carried out by adopting 22-32 passes, the rolling speed is controlled to be 650-1000mm/s, and the total rolling deformation is controlled to be 65-80%.

Optionally, the inlet temperature of the rolling is 1020-1080 ℃, and the outlet temperature of the rolling is 800-850 ℃.

Optionally, the diameter of the wire rod is 5.0-6.0mm.

One or more technical solutions in the embodiments of the present application at least have the following technical effects or advantages:

the embodiment of the application provides a welding wire for overlaying repair of a hot-rolled backup roll, which comprises the following chemical components in percentage by mass: c:0.18-0.35%, si:0.35-0.60%, mn:1.1-2.0%, P: < 0.015%, S: less than 0.010%, cr:4.0-8.0%, ni:2.0-5.0%, mo:1.0-3.0%, V:0.2-1.0%, and the balance of Fe and unavoidable impurities. The welding wire achieves the aim of adjusting the performance of the welding wire by adjusting the mass fraction range of the components to enable the components to be matched and synergistically enhanced, effectively improves the toughness and hardness uniformity of the welding wire, and effectively prevents cracks and chipping.

The foregoing description is only an overview of the present application, and is intended to be implemented in accordance with the teachings of the present application in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present application more readily apparent.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flowchart of a method for preparing a welding wire for hot-rolled backup roll welding repair, which is provided by an embodiment of the application.

Detailed Description

The advantages and various effects of the present application will be more clearly apparent from the following detailed description and examples. It will be understood by those skilled in the art that these specific embodiments and examples are intended to illustrate the application, not to limit the application.

Throughout the specification, unless specifically indicated otherwise, the terms used herein should be understood as meaning as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In case of conflict, the present specification will control. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the scope of the present application. For example, room temperature may refer to a temperature in the range of 10 to 35 ℃.

Unless otherwise specifically indicated, the various raw materials, reagents, instruments, equipment and the like used in the present application are commercially available or may be prepared by existing methods.

The technical scheme of the embodiment of the application aims to solve the technical problems, and the overall thought is as follows:

according to an exemplary embodiment of the present application, there is provided a welding wire for repairing a hot-rolled backup roll by overlaying, the welding wire comprising the chemical components in mass fraction:

Wherein the action of each component is specifically as follows:

c is a main element for ensuring the strength of the surfacing metal, but too high C element can influence the process performance of the welding wire, and can promote the formation of high-carbon martensite and influence the toughness of the surfacing metal;

si is a deoxidizing element and also plays a role in solid solution strengthening. Si can increase the hardenability and strength of the weld deposit metal, but decreases the toughness of the weld deposit metal. The Si content in the welding wire is low, the deoxidization is insufficient, and the impact toughness of the surfacing metal is affected; si content is too high, so that surfacing metal is promoted to generate grain boundary carbide, and cracks are easy to occur. The welding wire contains a proper amount of Si, so that nonmetallic inclusions in the surfacing metal can be reduced, and the impact toughness of the surfacing metal can be improved, and therefore, the mass fraction of Si in the welding wire for repairing hot-rolled backup roll surfacing provided by the application is controlled to be 0.35-0.60%;

mn is a strengthening element and a deoxidizing element of the surfacing metal, the deoxidizing effect can be achieved only by enough Mn content in the welding wire, the transition coefficient of other alloy elements can be improved, the Mn element can promote the dissolution of strong carbide in austenite, the content of the alloy elements in carbide and austenite is optimized, the precipitation strengthening and solid solution strengthening capability of V, cr and Mo elements are fully exerted, in addition, the Mn/C ratio is improved, the formation of grain boundary carbide can be reduced, so that the toughness of the surfacing metal is improved, but the Mn content is not too high, otherwise the tempering brittleness of the surfacing metal can be increased, and the cracks of the surfacing layer are caused. Therefore, in the welding wire for repairing the hot-rolled backup roll welding, the mass fraction of Mn is controlled to be 1.50-2.50%, and the increase of the manganese content can improve the toughness of the weld deposit metal and the strength and the wear resistance of the weld deposit metal;

cr can reduce the decomposition speed of austenite, slow down critical cooling speed in quenching, be favorable to the formation of martensite and improve the stability of martensite, add more Cr and improve Cr/C ratio, easily form the high hardness M7C3 carbide of isolated strip form, compare the M3C carbide of net distribution, can improve the continuity of build-up welding metal, simultaneously, cr combines with Mo, can improve residual austenite content, be favorable to obtaining tiny carbide phase, improve build-up welding metal toughness. Therefore, in the welding wire for hot rolling support roller welding repair, the mass fraction of Cr is controlled to be 4.0-8.0%;

ni is an austenite stabilizing element, ni can be infinitely dissolved in gamma-Fe, and also plays a solid solution strengthening role in the surfacing metal, so that the strength and toughness of the surfacing metal can be improved. The Ni in the surfacing metal does not form any carbide, and the tempering stability of the surfacing metal can be greatly improved and the hardness and the wear resistance of the surfacing metal can be improved under the condition that the surfacing metal contains Cr element. Therefore, in the welding wire for repairing the hot-rolled backup roll welding, the mass fraction of Ni is controlled to be 2.0-5.0%, and the welding wire is matched with Cr components with the mass fraction of 4.0-8.0%, so that the hardness and the wear resistance of the metal for the welding are improved;

mo can stabilize austenitic structure, improve hardenability, refine lath size of martensite or bainite, make carbonitride precipitate more even and tiny, and then improve the toughness of the surfacing metal, in addition Mo can form intermetallic compound with Ni, play the effect of precipitation strengthening, but a large amount of Mo can increase the tendency of the decarburization of the surfacing metal. Therefore, in the welding wire for hot rolling support roller welding repair, the mass fraction of Mo is controlled to be 1.0-3.0%;

v has stronger grain refinement and solid solution strengthening capability, has super-strong binding force with C to form stable VC, is typical carbide with high melting point, high hardness and high dispersivity, is an element for strongly improving the wear resistance, and can effectively refine the grain size of the surfacing metal and improve the strength and toughness. Therefore, in the welding wire for hot rolling support roller welding repair, the mass fraction of V is controlled to be 0.2-1.0%;

s, P is a harmful element, and seriously deteriorates the performance of the surfacing metal, and is mainly characterized by reducing the toughness of an upper platform and improving the ductile-brittle transition temperature, so that hydrogen induced cracking is caused. At the same level, the detrimental effect of S is 4 times that of P. Therefore, the content of S, P, especially the content of S, in the surfacing metal is strictly controlled, and the hazard effect of the surfacing metal is limited. Therefore, in the welding wire for hot-rolled backup roll welding repair, the mass fraction of S is controlled to be less than 0.010 percent, and the mass fraction of P is controlled to be less than 0.015 percent.

According to the welding wire for repairing the hot-rolled backing roll by overlaying welding, the mass fractions of the components are strictly controlled, so that each component is in a reasonable range, meanwhile, the components, especially Cr and Ni, are matched and synergistically increased, the toughness and hardness of the welding wire are fundamentally and effectively improved, the welding wire has good wear resistance, excellent impact toughness and good weld metal toughness matching, and has excellent welding forming performance, the crack occurrence rate can be effectively reduced, and the service life of the hot-rolled backing roll for repairing the overlaying welding is prolonged.

Preferably, the chemical components of the welding wire include, in mass fraction: c:0.18-0.35%, si:0.35-0.50%, mn:1.1-1.8%, P: < 0.015%, S: less than 0.010%, cr:4.0-7.0%, ni:2.0-4.0%, mo:1.0-2.5%, V:0.2-0.8%, and the balance of Fe and unavoidable impurities.

As an optional embodiment, the metallographic structure of the deposited metal of the welding wire is as follows in volume fraction: 55-68% of medium carbon martensite and 32-45% of lower bainite.

The medium carbon martensite is a mixture of lath-shaped and lamellar martensite, and is a mixture of most dislocation substructures and a small quantity of chain grain substructures, wherein the lath-shaped martensite substructures mainly comprise high-density dislocations, and can be much better than the lamellar martensite in toughness, namely, the lath-shaped martensite has higher strength and hardness and also has quite high toughness and plasticity. The medium carbon martensite with 55-68% of the deposited metal metallographic structure of the welding wire can effectively ensure that the deposited metal has higher strength, hardness and wear resistance, can ensure excellent toughness, effectively reduce the crack occurrence rate and improve the service life of the surfacing repair hot-rolled support roller. The volume fraction value is too large, so that the strength and hardness of deposited metal are improved, but brittleness is also increased, the crack occurrence rate is increased, and the use safety of the surfacing repair hot-rolled support roller is reduced; the volume fraction is too small to reduce the strength and hardness of deposited metal, and the use requirement of the surfacing repair roller cannot be met.

The lower bainite is a mixed structure composed of bainitic ferrite and carbide, the bainitic ferrite in the deposited metal metallographic structure of the welding wire is in a sheet shape, a certain angle is formed among the sheets, the carbide is precipitated in the bainitic ferrite, is fine, dispersed and granular or short, forms an angle of 55-60 degrees with the long axis of the ferrite sheet, and has higher strength and toughness. The 32-45% lower bainite in the metallographic structure of the deposited metal of the welding wire can effectively ensure that the deposited metal has excellent toughness, effectively reduce the crack occurrence rate and improve the use safety of the surfacing repair hot-rolled support roller. The volume fraction value is too large to reduce the strength and hardness of deposited metal, and the use requirement of the surfacing repair roller cannot be met. The volume fraction is too small, so that the strength and the hardness of deposited metal are improved, the toughness is reduced, the crack occurrence rate is increased, and the use safety of the surfacing repair hot-rolled support roller is reduced.

As an alternative embodiment, the wire has a diameter of 2.4-4.0mm.

Preferably, the diameter of the welding wire is 3.2mm.

According to another exemplary embodiment of the present application, there is provided a method for preparing a welding wire for repairing a hot-rolled backup roll welding, including the steps of:

s1, carrying out converter smelting and LF refining by taking chemical components of the welding wire for hot-rolled backup roll welding repair as end components to obtain target molten steel;

s2, continuously casting and rolling the target molten steel to obtain a wire rod;

s3, sequentially carrying out shelling, acid washing, borax coating, wire drawing and copper plating on the wire rod to obtain the welding wire for hot-rolled backup roll welding repair.

As an alternative embodiment, the converter smelting adopts top-bottom combined converting.

The top-bottom combined blowing generally refers to a combined blowing process, in which oxygen is supplied from above a molten pool of a converter, namely top-blown oxygen, inert gas or oxygen is supplied from the bottom of the converter, and blowing is performed at the top and bottom simultaneously, and the combined blowing process has the advantages of both top blowing and bottom blowing. In particular, it has the advantages that:

(1) The method can obviously reduce the oxygen content in molten steel and the TFe content in slag, and the excessive oxygen content in molten steel and slag is obviously reduced because the combined blowing process strengthens the stirring of a molten pool and promotes the steel-slag section reaction so that the reaction is more similar to the equilibrium state.

(2) The Mn content of the residual molten steel at the blowing end point can be improved, so that the consumption of ferroalloy is reduced.

(3) The method can improve dephosphorization and desulfurization efficiency, has higher distribution coefficient of phosphorus and sulfur due to the reaction approaching to an equilibrium state, reduces TFe content in slag, and obviously improves desulfurization conditions.

(4) The blowing is stable, the splashing rate is reduced, and the controllability of the blowing is improved, so that the feeding strength can be improved.

As an alternative embodiment, the rolling is performed in 22-32 passes, the rolling speed is controlled to be 650-1000mm/s, and the total deformation of the rolling is controlled to be 65-80%.

As an alternative embodiment, the inlet temperature of the rolling is 1020-1080 ℃ and the outlet temperature of the rolling is 800-850 ℃.

Through the control of the deformation and the temperature in the rolling process, the uniform and uniform microstructure of the surface layer and the core of the wire rod can be realized under the condition of quicker deformation and higher temperature, the residual stress and the surface hardening generated by drawing are effectively reduced, and the wire rod has good drawing performance and is beneficial to the drawing processing of the follow-up welding wire.

As an alternative embodiment, the wire rod has a diameter of 5.0-6.0mm.

According to the preparation method, converter smelting is carried out through top-bottom combined blowing, smelting environment is optimized, deoxidization performance is remarkably improved, alloy consumption is reduced, toughness and hardness of the wire rod are effectively improved and uniform through controlling rolling pass, rolling speed, total rolling deformation, inlet temperature and outlet temperature, and then welding wires are obtained through subsequent steps, wherein room-temperature impact toughness is greater than 30J, the toughness of surfacing metal is well matched, and the preparation method has the outstanding characteristics of high strength, high hardness and high toughness.

The surface treatment liquid for a coated steel sheet, the production method and the use method of the present application will be described in detail with reference to examples, comparative examples and experimental data.

Example 1

The chemical compositions of the welding wire for hot-rolled backup roll surfacing repair are shown in a table 1 in mass fraction.

TABLE 1 chemical composition of the welding wire of example 1

Component%	C	Si	Mn	P	S	Cr	Ni	Mo	V
											0.19	0.45	1.54	0.010	0.008	4.6	4.2	2.8	0.5

The metallographic structure of deposited metal of the welding wire is calculated as volume fraction: 56% of medium carbon martensite and 44% of lower bainite.

The diameter of the welding wire is 3.2mm.

The preparation method of the welding wire for hot rolling backing roll welding repair comprises the following steps:

s1, converter smelting and LF refining are carried out by taking the chemical components as end components, and target molten steel is obtained, wherein top-bottom combined blowing is adopted in the converter smelting.

S2, continuously casting and rolling the target molten steel to obtain the wire rod.

S2.1, carrying out full-protection casting on the target molten steel by adopting a continuous casting machine to obtain a continuous casting blank.

S2.2, rolling the continuous casting blank by adopting a high-speed torsion-free rolling mill to obtain the wire rod.

The rolling is carried out by adopting 31 passes, the rolling speed is controlled to be 960mm/s, the total rolling deformation is controlled to be 89%, the inlet temperature of rolling is controlled to be 1020 ℃, and the outlet temperature is controlled to be 810 ℃; the diameter of the control wire rod is 5.0-6.0mm.

S3, sequentially carrying out shelling, acid washing, borax coating, wire drawing and copper plating on the wire rod to obtain the welding wire for hot rolling support roller welding repair.

Example 2

The chemical compositions of the welding wire for hot-rolled backup roll surfacing repair are shown in Table 2 in mass fraction.

TABLE 2 chemical compositions of the welding wire of EXAMPLE 2

Component%	C	Si	Mn	P	S	Cr	Ni	Mo	V
											0.22	0.43	1.82	0.008	0.007	6.3	3.52	2.3	0.32

The metallographic structure of deposited metal of the welding wire is calculated as volume fraction: 59% of medium carbon martensite and 41% of lower bainite.

The diameter of the welding wire is 2.4mm.

The rolling is carried out by 26 passes, the rolling speed is controlled to be 850mm/s, the total rolling deformation is controlled to be 71%, the inlet temperature of rolling is controlled to be 1045 ℃, and the outlet temperature is controlled to be 825 ℃; the diameter of the control wire rod is 5.0-6.0mm.

Example 3

The chemical compositions of the welding wire for hot-rolled backup roll surfacing repair are shown in Table 3 in mass percent.

TABLE 3 chemical compositions of the welding wire of EXAMPLE 3

Component%	C	Si	Mn	P	S	Cr	Ni	Mo	V
											0.32	0.48	1.88	0.012	0.009	7.8	2.26	1.9	0.87

The metallographic structure of deposited metal of the welding wire is calculated as volume fraction: 66% of medium carbon martensite and 34% of lower bainite.

The diameter of the welding wire is 4.0mm.

The rolling is carried out by adopting 24 passes, the rolling speed is controlled to be 820mm/s, the total rolling deformation is controlled to be 72%, the inlet temperature of rolling is controlled to be 1060 ℃, and the outlet temperature is controlled to be 830 ℃; the diameter of the control wire rod is 5.0-6.0mm.

Example 4

The chemical compositions of the welding wire for hot-rolled backup roll surfacing repair are shown in Table 4 in mass fraction.

TABLE 4 chemical compositions of the welding wire of EXAMPLE 4

Component%	C	Si	Mn	P	S	Cr	Ni	Mo	V
											0.27	0.39	1.25	0.006	0.007	5.56	4.32	2.0	0.56

The metallographic structure of deposited metal of the welding wire is calculated as volume fraction: 63% of medium carbon martensite and 37% of lower bainite.

The diameter of the welding wire is 3.3mm.

Wherein 27 passes are adopted for rolling, the rolling speed is controlled to 690mm/s, the total rolling deformation is controlled to 76%, the inlet temperature of rolling is controlled to 1060 ℃, and the outlet temperature is controlled to 850 ℃; the diameter of the control wire rod is 5.0-6.0mm.

Comparative example 1

TABLE 5 chemical compositions of comparative example 1 welding wire

Component%	C	Si	Mn	P	S	Cr	Ni	Mo	V
											0.47	0.31	1.45	0.006	0.007	5.51	4.15	2.1	0.46

Comparative example 2

TABLE 6 chemical compositions of comparative example 2 welding wire

Component%	C	Si	Mn	P	S	Cr	Ni	Mo	V
											0.27	0.65	1.55	0.006	0.008	6.51	3.35	1.6	0.41

Comparative example 3

TABLE 7 chemical compositions of comparative example 3 welding wire

Component%	C	Si	Mn	P	S	Cr	Ni	Mo	V
											0.29	0.45	1.51	0.007	0.008	7.51	3.15	1.45	0.31

Comparative example 4

TABLE 8 chemical compositions of comparative example 4 welding wire

Component%	C	Si	Mn	P	S	Cr	Ni	Mo	V
											0.19	0.49	1.65	0.006	0.008	5.81	4.65	2.0	0.46

Comparative example 5

TABLE 9 chemical compositions of comparative example 5 welding wire

Component%	C	Si	Mn	P	S	Cr	Ni	Mo	V	W
												0.51	0.39	1.15	0.009	0.008	12.81	1.65	2.0	0.26	1.52

Experimental example

Submerged arc surfacing is carried out by using the welding wires for repairing the surfacing of the hot-rolled support roller obtained in the examples 1-4 and the comparative examples 1-5, and then mechanical property indexes of deposited metal are detected by using GB/229-2007 and GB228-2002 standards respectively, and the detection results are shown in Table 10.

Table 10 test example test results

As can be seen from Table 10, compared with the welding wires for hot-rolled backup roll repair welding of comparative examples 1-5, the welding wires for hot-rolled backup roll repair welding provided by examples 1-4 have higher strength and hardness and excellent impact toughness, the room-temperature impact toughness of the surfacing metal can be more than 30J, the toughness of the surfacing metal is well matched, the hardness of the hot-rolled roll after repair is uniform, the on-site use requirement of the roll is met, the defects of cracks, peeling off and blocking and the like of the surfacing repair roll in the use process are prevented, and the use safety and the service life of the surfacing repair hot-rolled backup roll are greatly improved. Therefore, the welding wire for repairing the hot-rolled backup roll pile-up welding can effectively solve the technical problems of poor toughness, uneven hardness, cracking and chipping of the existing welding wire for repairing the hot-rolled backup roll pile-up welding.

(1) The welding wire for overlaying repair of the hot-rolled support roller is a high-strength high-hardness high-toughness solid welding wire, has high strength and hardness and excellent impact toughness through reasonable composition and proportion, has the room-temperature impact toughness of overlaying metal of more than 30J, has good overlaying metal toughness matching, has the outstanding characteristics of high strength, high hardness and high toughness, and has excellent welding process performance.

(2) According to the welding wire for hot-rolled backup roll surfacing repair, the content of Ni, cr, mo, V is optimized in the components, the tempering stability of surfacing metal is greatly improved, the hardness and wear resistance of surfacing metal are improved, and a proper amount of Mo and Ni form intermetallic compounds to achieve the effect of precipitation strengthening. The binding force of V and C is super strong, so that stable carbide VC with high melting point, high hardness and high dispersity is formed, the grain size of the surfacing metal is effectively thinned, and the strength, toughness and wear resistance of the surfacing metal are improved.

(3) The welding repair is carried out by adopting the welding wire for the surfacing repair of the hot-rolled support roller, the welding process performance of the welding wire is excellent, the arc stability is good, the welding bead is formed attractive, the hardness of the repaired hot-rolled roller is uniform, the defects of cracks, peeling off blocks and the like do not occur in the use process of the surfacing repair roller, the service life of the surfacing repair hot-rolled support roller is greatly prolonged, and compared with the surfacing repair by adopting other welding wires, the welding wire for the surfacing repair of the hot-rolled support roller has better market competitiveness.

Finally, it is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

While preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the application.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. The welding wire for hot-rolled backup roll surfacing repair is characterized by comprising the following chemical components in percentage by mass:

c:0.18-0.35%, si:0.35-0.60%, mn:1.1-2.0%, P: < 0.015%, S: less than 0.010%, cr:4.0-8.0%, ni:2.0-5.0%, mo:1.0-3.0%, V:0.2-1.0%, and the balance of Fe and unavoidable impurities;

the metallographic structure of deposited metal of the welding wire is calculated as volume fraction: 55-68% of medium carbon martensite, 32-45% of lower bainite;

carrying out converter smelting and LF refining by taking chemical components of the welding wire for hot rolling support roller welding repair as end components to obtain target molten steel;

continuously casting and rolling the target molten steel to obtain a wire rod;

2. The welding wire for hot-rolled backup roll welding repair according to claim 1, wherein the chemical composition of the welding wire comprises, in mass fraction:

3. The welding wire for repairing a hot-rolled backup roll overlay welding according to claim 1, wherein the diameter of the welding wire is 2.4-4.0mm.

4. A hot rolled backup roll weld overlay repair welding wire according to claim 3, wherein the wire has a diameter of 3.2mm.

5. The welding wire for hot-rolled backup roll welding repair according to claim 1, wherein the converter smelting adopts top-bottom composite blowing.

6. The welding wire for hot-rolled backup roll repair according to claim 1, wherein the rolling is performed in 22-32 passes, the rolling speed is controlled to be 650-1000mm/s, and the total rolling deformation is controlled to be 65-80%.

7. The welding wire for hot rolled backup roll repair of claim 1 wherein the inlet temperature of the rolling is 1020-1080 ℃ and the outlet temperature of the rolling is 800-850 ℃.

8. The welding wire for hot-rolled backup roll repair welding according to claim 1, wherein the wire rod has a diameter of 5.0-6.0mm.