CN115609188A

CN115609188A - Surfacing flux-cored wire and preparation method and welding method thereof

Info

Publication number: CN115609188A
Application number: CN202211409196.0A
Authority: CN
Inventors: 冯素英; 刘晓茹; 杨平; 马永琪; 李东军
Original assignee: Cohesive New Materials Technology Rizhao Co ltd; Shandong Lianli Automatic Welding Engineering Technology Research Center; Shandong Juli Welding Co Ltd
Current assignee: Cohesive New Materials Technology Rizhao Co ltd; Shandong Lianli Automatic Welding Engineering Technology Research Center; Shandong Juli Welding Co Ltd
Priority date: 2022-11-11
Filing date: 2022-11-11
Publication date: 2023-01-17

Abstract

The invention provides a surfacing flux-cored wire, a preparation method and a welding method thereof, and particularly relates to the field of welding materials. The surfacing flux-cored wire comprises a steel strip and a flux core filled in the steel strip, wherein the flux core comprises the following components in percentage by mass: 40-55% of medium carbon ferrochrome, 9-17% of metal chromium, 3-5% of metal manganese, 5-8% of ferrosilicon, 2-3% of nickel powder and the balance of iron powder. The surfacing flux-cored wire has excellent wear resistance, and the deposited metal has high hardness, strength and toughness, so that the generation of cracks of the deposited metal of the surfacing layer can be effectively controlled, the falling-off is prevented, and the surfacing flux-cored wire is suitable for repairing cold rolls.

Description

Surfacing flux-cored wire and preparation method and welding method thereof

Technical Field

The invention relates to the field of welding materials, in particular to a surfacing flux-cored wire and a preparation method and a welding method thereof.

Background

The cold roll is a key part of a cold rolling mill, and has strict performance requirements on the working surface due to the extremely harsh working environment of the cold roll, and the surface of the cold roll is required to have ultrahigh hardness, good toughness and wear resistance under huge variable pressure. The cold roll is repaired by surfacing mainly, but most of the cold rolls are cast by adopting a high-chromium cast iron alloy system, and the high-chromium cast iron alloy system has high carbon and alloy element contents, so that the surfacing layer is easy to crack when the rolls are subjected to surfacing. Therefore, the surfacing repair of the cold roll requires high hardness and good uniformity of the surfacing metal, and also requires high crack resistance, good toughness and strong fatigue resistance. The high-hardness surfacing materials at home and abroad mainly adopt a high-chromium cast iron alloy system, and the cost is high; the maintenance of a plurality of parts in domestic market is mainly completed by the wear-resistant welding rod, which is time-consuming and labor-consuming, has long repair period, and the maintenance quality of the wear-resistant welding rod is inferior to that of the welding wire, so that a plurality of maintenance processes cannot be realized or are difficult to realize.

At present, the international production of surfacing flux-cored wires has been developed to a certain scale, and various series industrial roads corresponding to the performance of surfacing welding electrodes are developed. Most of the prior domestic flux-cored wires consumed at present are imported products, so that the domestic flux-cored wires for hardfacing are few and single in variety, the market requirements cannot be met far away, the price of the foreign flux-cored wires is high, and the ordering period is long. The development of the cold roll surfacing flux-cored wire has wide market prospect and great significance.

Disclosure of Invention

In view of the defects of the prior art, the invention provides a surfacing flux-cored wire, a preparation method and a welding method thereof, so as to improve the welding manufacturability of the welding wire, and the mechanical property and corrosion resistance of weld metal.

In order to achieve the above and other related objects, the present invention provides a surfacing flux-cored welding wire, which comprises a steel strip and a flux core filled in the steel strip, wherein the flux core comprises the following components by mass: 40-55% of medium carbon ferrochrome, 9-17% of metal chromium, 3-5% of metal manganese, 5-8% of ferrosilicon, 2-3% of nickel powder and the balance of iron powder.

In an example of the present invention, the carbon content of the medium carbon ferrochrome is 1 to 1.5wt%, and the chromium content is 78 to 85wt%.

In an example of the present invention, the ferrosilicon is 75# ferrosilicon, and the content of silicon in the ferrosilicon is 72 to 75wt%.

In one example of the invention, the steel strip is an HS1 steel strip, the width of the steel strip is 14-18 mm, and the thickness of the steel strip is 0.3-0.6 mm.

In an example of the present invention, the weight of the flux core in the overlay welding flux-cored wire is 20 to 30% of the total weight of the overlay welding flux-cored wire.

The invention provides a preparation method of a surfacing flux-cored wire, which is characterized by comprising the following steps of: mixing the above components uniformly to prepare a drug core; longitudinally shearing, winding and cleaning a steel strip, and then rolling the steel strip into a U-shaped groove; filling the medicine core into the U-shaped groove; and (4) closing, reducing, drawing and taking up the steel strip filled with the flux core to obtain the surfacing flux-cored wire.

The invention provides a welding method of a surfacing flux-cored wire, which comprises the following steps: preheating a workpiece; backing welding the workpiece by using a backing welding wire; performing single-side surfacing welding, tempering and cooling on the bottomed and welded workpiece under a welding flux layer; repeating the surfacing operation, and after the surfacing operation is completely finished, integrally tempering; and (6) cooling and discharging.

In an example of the present invention, the preheating temperature when preheating the workpiece is 250 to 300 ℃.

In an example of the present invention, the thickness of the primer layer at the time of primer welding is less than 4mm.

In one example of the invention, the welding current during overlaying is 450-550A, the welding voltage is 28-32V, and the temperature of a workpiece is 200-250 ℃ during welding; the tempering temperature during tempering is 480-510 ℃, and the heat preservation time is 8-12 h.

The surfacing flux-cored wire disclosed by the invention is used for converting alloy elements such as chromium, manganese, silicon, nickel and the like into deposited metal, the hardness and the strength of the deposited metal can be improved by adjusting the proportion of the alloy elements, the surfacing flux-cored wire is good in wear resistance and has certain toughness, the generation of deposited metal cracks of a surfacing layer can be effectively controlled, the surfacing flux-cored wire is prevented from falling off, and the surfacing flux-cored wire is suitable for repairing cold rolls in the steel industry.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 shows: the invention discloses a preparation flow chart of a surfacing flux-cored wire;

FIG. 2 is a diagram: the invention relates to a welding flow chart of a surfacing flux-cored wire.

Detailed Description

The following embodiments of the present invention are provided by specific examples, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure of the present invention. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict. It is also to be understood that the terminology used in the examples is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. Test methods in which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under conditions recommended by the respective manufacturers.

In the present specification, "%" and "% by weight" each represent a mass percentage, and "part" represents a part by weight.

The invention provides a surfacing flux-cored wire which comprises a steel strip and a flux core filled in the steel strip, wherein the flux core comprises the following components in percentage by mass: 40-55% of medium carbon ferrochrome, 9-17% of metal chromium, 3-5% of metal manganese, 5-8% of ferrosilicon, 2-3% of nickel powder and the balance of iron powder.

The flux core of the surfacing flux-cored wire has the following functions:

medium carbon ferrochrome: transition of alloying elements to the weld overlay; the ferrochrome has strong oxidizability and can release heat to accelerate reaction. In the surfacing flux core, the mass percent of the medium carbon ferrochrome is 40-55%, for example, the mass percent of the medium carbon ferrochrome can be any value in the range of 40-55%, such as 40%, 45% or 55%.

Metallic chromium: alloy elements are transited to the overlaying layer, so that the hardenability of the deposited metal is increased, a secondary hardening effect is achieved, and the hardness and the wear resistance of the deposited metal can be improved without making the deposited metal brittle; increasing the chromium content of the metal can improve the resistance of the deposited metal to corrosion by oxidizing media; however, if the amount of chromium metal added is too large, the hardness and strength of the deposited metal will be reduced. In the surfacing flux core, the mass percent of the metal chromium is 9-17%, for example, the mass percent of the medium carbon ferrochrome can be any value in the range of 9-17%, such as 9%, 13% or 17%.

Metal manganese: and (3) alloy elements are subjected to metal transition on the surfacing layer, deoxidation and desulfurization are carried out, a protective atmosphere is formed, heat is released, and the welding reaction speed is accelerated. Manganese can increase the strength and hardness of the deposited metal, but if the amount of manganese metal added is too large, the ductility, toughness and weldability of the deposited metal deteriorate. In the surfacing flux core, the mass percent of the metal manganese is 3-5%, for example, the mass percent of the metal manganese can be any value in the range of 3-5%, such as 3%, 4% or 5%.

Silicon iron: and (4) carrying out metal transition on alloy elements to the overlaying layer, and deoxidizing. The heat is released in the welding process, the welding wire is accelerated to melt, the slag fluidity is improved, the pore sensitivity of the overlaying layer is reduced, the welding wave is fine, the hardness and the strength of deposited metal are improved, but the toughness of the deposited metal is reduced when the ferrosilicon is excessively added. In the surfacing flux core, the ferrosilicon accounts for 5-8% by mass, for example, the ferrosilicon can account for 5%, 7% or 8% by mass or any value in the range of 5-8%.

Nickel powder: and alloy elements are transited to the overlaying layer, so that the toughness of the overlaying layer is improved. In the surfacing flux core of the present invention, the nickel powder may be present in an amount of 2 to 3% by mass, for example, the nickel powder may be present in an amount of 2 to 3% by mass, such as 2%, 2.5% or 3%.

Iron powder: the deficiency of alloy powder in the flux core is supplemented, and the welding efficiency is improved.

In one embodiment, the content of carbon in the medium carbon ferrochrome is 1-1.5 wt%, the content of chromium is 78-85 wt%, and the granularity of the medium carbon ferrochrome is preferably 60 meshes.

In one embodiment, the ferrosilicon is 75# ferrosilicon, the content of silicon in the ferrosilicon is 72 to 75wt%, and the grain size of the ferrosilicon is preferably 60 meshes.

In one embodiment, the steel strip is a HS1 steel strip, the width of the steel strip is 14 mm-18 mm, and the thickness of the steel strip is 0.3 mm-0.6 mm. For example, the width of the steel strip may be any value in the range of 14 to 18mm, such as 14mm, 16mm or 18 mm; the thickness of the steel strip may be any value in the range of 0.3 to 0.6mm, such as 0.3mm, 0.5mm or 0.6mm.

Referring to fig. 1, the invention provides a method for preparing a surfacing flux-cored wire, which comprises the following steps:

s11, uniformly mixing the components to prepare a medicine core;

s12, longitudinally cutting, winding and cleaning a steel strip, and then rolling the steel strip into a U-shaped groove;

s13, filling the medicine core into the U-shaped groove;

s14, closing, reducing, drawing and taking up the steel strip filled with the flux core to obtain the surfacing flux core welding wire. .

In step S11, the components in the drug core are as follows: 40-55% of medium carbon ferrochrome, 9-17% of metal chromium, 3-5% of metal manganese, 5-8% of ferrosilicon, 2-3% of nickel powder and the balance of iron powder.

In step S12, the steel strip is longitudinally cut to a proper size, then the steel strip is wound and cleaned to remove impurities on the surface of the steel strip, and then the steel strip is rolled into a U-shaped groove. The steel strip used in the invention is an HS1 steel strip, and the steel strip contains 0.03wt% of carbon, 0.03wt% of silicon, 0.1-0.3 wt% of manganese, 0.02wt% of phosphorus and 0.02wt% of sulfur.

In step S13, the filling rate of the flux core, that is, the weight of the flux core in the overlay welding flux-cored wire is 20 to 30% of the total weight of the overlay welding flux-cored wire, for example, the filling rate of the flux core may be any value in the range of 20 to 30%, such as 20%, 25%, or 30%.

In step S14, a lubricant powder may be used to increase the lubricity during the drawing process. The diameter of the surfacing flux-cored wire is preferably 2.4mm.

Referring to fig. 2, the invention provides a welding method of a build-up welding flux-cored wire, comprising the following steps:

s21, preheating a workpiece;

s22, backing welding is carried out on the workpiece by adopting a backing welding wire;

s23, performing single-side surfacing on the workpiece subjected to backing welding under the flux layer, tempering and cooling;

s24, repeating the surfacing operation, and performing integral tempering after surfacing is completely finished;

s25, cooling and discharging.

In one embodiment, the thickness of the backing weld is less than 4mm.

In step S21, the preheating temperature when preheating the workpiece is 250 to 300 ℃. For example, the preheating temperature may be 250 to 300 ℃ such as 250 ℃, 280 ℃ or 300 ℃.

In step S22, the thickness of the priming layer during priming welding is less than 4mm; the backing wire used in backing welding can be selected conventionally in the field, and is not described herein.

In step S23, tempering is performed to eliminate welding stress when the thickness of the one-side bead welding is about 30 mm.

In step S24, after the welding of the workpiece is completed according to the welding requirements, tempering is performed to eliminate the welding stress.

In the steps S23 and S24, the welding current is 450-550A during overlaying, the welding voltage is 28-32V, the workpiece temperature is kept at 200-250 ℃ during welding, the tempering temperature is 480-510 ℃ during tempering, and the heat preservation time is 8-12 h. For example, the temperature of the workpiece may be any value within the range of 200 to 250 ℃, such as 200 ℃, 220 ℃, or 250 ℃; the welding current may be any value in the range of 450 to 550A, such as 450A, 500A or 550A; the welding voltage may be any value in the range of 28 to 32V, such as 28V, 30V, or 32V; the tempering temperature can be any value in the range of 480-510 ℃, such as 480 ℃, 490 ℃ or 510 ℃; the heat preservation time can be any value within the range of 8-12 h, such as 8h, 10h or 12h.

And in the step S25, after the integral tempering, cooling the workpiece to below 50 ℃ along with the furnace, and taking out the workpiece.

It should be noted that the parameters not described in detail in the welding process can be set according to the welding process conventional in the art.

The invention is described in detail below with reference to specific examples. The drugs used in the following examples are commercially available in general.

Example 1

The surfacing flux-cored wire comprises a steel strip and a flux core filled in the steel strip, wherein the surfacing flux-cored wire comprises the following components in percentage by mass: 55% of medium carbon ferrochrome, 10% of metal chromium, 5% of metal manganese, 6% of ferrosilicon, 2% of nickel powder and the balance of iron powder. The steel belt is made of HS1 steel belt, the steel belt is rolled into a U-shaped groove, and then the uniformly mixed drug core is filled into the U-shaped groove, wherein the filling rate of the drug core is 28%; and then closing, reducing the diameter, drawing and taking up the wire to obtain the welding wire.

During welding, a workpiece is preheated to 268 ℃, then backing welding is carried out on the workpiece by using a backing welding wire, the thickness of a backing layer is 3.7mm, the backing-welded workpiece is subjected to single-side surfacing under a welding flux layer, tempering is carried out when the thickness of the single-side surfacing is about 30mm, so as to eliminate welding stress, wherein the tempering temperature is 489 ℃, and the tempering time is 10 hours; and (3) after the furnace is cooled to 280 ℃, continuing the surfacing operation, integrally tempering at 503 ℃ for 10h after surfacing is completely finished, and then cooling the workpiece to 46 ℃ along with the furnace and taking out. In the embodiment, the current is controlled to be 450-510A during welding, and the interlayer temperature is controlled to be 200-250 ℃. (ii) a

Example 2

The surfacing flux-cored wire comprises a steel strip and a flux core filled in the steel strip, wherein the surfacing flux-cored wire comprises the following components in percentage by mass: 45% of medium carbon ferrochrome, 15% of metal chromium, 5% of metal manganese, 7% of ferrosilicon, 2.5% of nickel powder and the balance of iron powder. The steel belt is made of HS1 steel belt, the steel belt is rolled into a U-shaped groove, and then the uniformly mixed medicine core is filled into the U-shaped groove, wherein the filling rate of the medicine core is 24%; and then closing, reducing the diameter, drawing and taking up the wire to obtain the welding wire.

In the embodiment, the welding method is the same as that in the first embodiment, except that the preheating temperature of the workpiece is 277 ℃, the thickness of the priming layer for priming welding is 3.8mm, the current during welding is controlled to be 460-495A, the interlayer temperature is controlled to be 230-245 ℃, the partial tempering temperature is 495 ℃, and the tempering time is 8h; the integral tempering temperature is 485 ℃, the tempering time is 8 hours, and the tapping temperature is 48 ℃.

Example 3

The surfacing flux-cored wire comprises a steel strip and a flux core filled in the steel strip, wherein the surfacing flux-cored wire comprises the following components in percentage by mass: 55% of medium carbon ferrochrome, 13% of metal chromium, 4% of metal manganese, 5% of ferrosilicon, 2% of nickel powder and the balance of iron powder. The steel belt is made of HS1 steel belt, the steel belt is rolled into a U-shaped groove, and then the uniformly mixed medicine core is filled into the U-shaped groove, wherein the filling rate of the medicine core is 26%; and then closing, reducing the diameter, drawing and taking up the wire to obtain the welding wire.

In the embodiment, the welding method is the same as that in the first embodiment, except that the preheating temperature of the workpiece is 296 ℃, the thickness of the priming layer for priming welding is 3.8mm, the current during welding is controlled to be 520-540A, the interlayer temperature is controlled to be 236-248 ℃, the partial tempering temperature is 492 ℃, and the tempering time is 8.5h; the whole tempering temperature is 496 ℃, the tempering time is 8h, and the tapping temperature is 48 ℃.

Example 4

The surfacing flux-cored wire comprises a steel strip and a flux core filled in the steel strip, wherein the surfacing flux-cored wire comprises the following components in percentage by mass: 43% of medium carbon ferrochrome, 12% of metal chromium, 3.5% of metal manganese, 5% of ferrosilicon, 2% of nickel powder and the balance of iron powder. The steel belt is made of HS1 steel belt, the steel belt is rolled into a U-shaped groove, and then the uniformly mixed medicine core is filled into the U-shaped groove, wherein the filling rate of the medicine core is 30%; and then closing, reducing the diameter, drawing and taking up the wire to obtain the welding wire.

In the embodiment, the welding method is the same as that in the first embodiment, except that the preheating temperature of the workpiece is 258 ℃, the thickness of the priming layer for priming welding is 3.6mm, the current during welding is controlled to be 530-550A, the interlayer temperature is controlled to be 235-250 ℃, the partial tempering temperature is 488 ℃, and the tempering time is 8.5h; the integral tempering temperature is 486 ℃, the tempering time is 10 hours, and the tapping temperature is 45 ℃.

According to the welding process, various welding tests are carried out on the welding wires provided by the above examples 1, 2, 3 and 4, the welding process and the heat treatment parameters are as shown in the following table 1, and the deposited metal chemical compositions and properties are as shown in the following table 2:

TABLE 1 welding process parameters (submerged arc welding \ HJ260 welding flux)

TABLE 2 deposited metal chemistry (%) and Properties

The test results of examples 1 to 4 show that the surfacing flux-cored wire provided by the invention has excellent wear resistance, and deposited metal has high strength and hardness and good surface formability.

The surfacing flux-cored wire disclosed by the invention is used for converting alloy elements such as chromium, manganese, silicon, nickel and the like into deposited metal, the hardness and the strength of the deposited metal can be improved by adjusting the proportion of the alloy elements, the surfacing flux-cored wire is good in wear resistance and has certain toughness, the generation of deposited metal cracks of a surfacing layer can be effectively controlled, the surfacing flux-cored wire is prevented from falling off, and the surfacing flux-cored wire is suitable for repairing cold rolls in the steel industry. Therefore, the invention effectively overcomes some practical problems in the prior art, thereby having high utilization value and use significance.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Those skilled in the art can modify or change the above-described embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. The surfacing flux-cored wire is characterized by comprising a steel strip and a flux core filled in the steel strip, wherein the flux core comprises the following components in percentage by mass: 40-55% of medium carbon ferrochrome, 9-17% of metal chromium, 3-5% of metal manganese, 5-8% of ferrosilicon, 2-3% of nickel powder and the balance of iron powder.

2. The flux-cored welding wire for build-up welding according to claim 1, wherein the carbon content in the medium carbon ferrochrome is 1 to 1.5wt%, and the chromium content is 78 to 85wt%.

3. The surfacing flux-cored wire according to claim 1, wherein the ferrosilicon is 75# ferrosilicon, and the content of silicon in the ferrosilicon is 72-75 wt%.

4. The overlaying flux cored welding wire according to claim 1, wherein the steel strip is an HS1 steel strip, the width of the steel strip is 14mm to 18mm, and the thickness of the steel strip is 0.3mm to 0.6mm.

5. The flux-cored welding wire of claim 1, wherein the weight of the flux core in the flux-cored welding wire is 20 to 30% of the total weight of the flux-cored welding wire.

6. A preparation method of a surfacing flux-cored wire is characterized by comprising the following steps:

mixing the components of claim 1 to form a core;

longitudinally cutting, winding and cleaning a steel strip, and then rolling the steel strip into a U-shaped groove;

filling the medicine core into the U-shaped groove;

and (4) closing, reducing, drawing and taking up the steel strip filled with the flux core to obtain the surfacing flux-cored wire.

7. A welding method of a build-up welding flux cored wire according to claim 1, characterized by comprising the steps of:

preheating a workpiece;

backing welding the workpiece by using a backing welding wire;

performing single-side surfacing welding, tempering and cooling on the bottomed and welded workpiece under a welding flux layer;

repeating the surfacing operation, and after the surfacing operation is completely finished, integrally tempering;

and (6) cooling and discharging.

8. The welding method according to claim 7, wherein the preheating temperature at the time of preheating the workpiece is 250 to 300 ℃.

9. The welding method of claim 7, wherein the primer layer thickness during primer welding is less than 4mm.

10. The welding method according to claim 7, wherein the welding current during overlaying is 450-550A, the welding voltage is 28-32V, and the temperature of a workpiece in the welding process is 200-250 ℃; the tempering temperature during tempering is 480-510 ℃, and the heat preservation time is 8-12 h.