CN109226934B - Build-up welding method for roller - Google Patents

Abstract

The invention discloses a welding method of a roller, wherein the roller is provided with a roller body and shaft necks arranged at two ends of the roller body, the roller is made of 50CrMo4V steel, and the welding method comprises the following steps: cutting the worn outer circle of the roller body; clamping the roller body on a special welding machine tool, and enabling the roller body to penetrate through a heating box body of an electric heating welding tool; starting the electric heating welding tool to raise the temperature in the heating box body and control the temperature to be 300-350 ℃; and (4) using special roller surfacing equipment to sequentially perform surfacing welding on the base layer and the cover wear-resistant layer on the roller body. Compared with the prior art, the invention can solve the problems that the prior roller body surfacing quality has poor stability, and the surfacing roller is easy to crack and fall blocks of an alloy layer in the using process.

Description

Build-up welding method for roller

Technical Field

The invention relates to the technical field of welding tool manufacturing, in particular to a tool for roll surfacing.

Background

The roller is one of the important parts of the roller straightening machine and is provided with a roller body and shaft necks arranged at two ends of the roller body; the roll is used for correcting shape defects of a metal plastic processing product through a roll body, and is one of important finishing processes. The rolled stock often develops various shape defects during the rolling process or during subsequent cooling and transport, such as bending of bars, profiles and pipes, bending of sheet strips, waves, buckling and the like. The defects of bending and the like can be eliminated under the action of external force through various straightening processes, so that the product reaches a qualified state. As the roller is eroded by alternating temperature and water vapor for a long time, the surface of the roller body has the defects of pockmarks, scar blocks, cracks and the like, and the axial surface of the roller body has the phenomenon of uneven wear, thereby leading the roller to be frequently replaced. The general method is to perform surfacing welding on the roller body to recover the dimensional accuracy of the roller body, but because the roller body is made of ultrahigh-strength alloy structural steel, the stability of surfacing welding quality is poor, and the problems of alloy layer cracking and block falling easily occur in the use process of the repaired roller.

Disclosure of Invention

The invention aims to solve the technical problem of providing a roller welding method to solve the problems that the stability of the surfacing quality of the roller body is poor and an alloy layer is easy to crack and drop during the use of a surfacing roller.

The technical scheme adopted by the invention for solving the technical problem is as follows: a method of welding a roll having a roll body and journals at each end of the roll body, said roll being made of 50CrMo4V steel, comprising the steps of:

A. cutting the worn outer circle of the roller body, wherein the size of the outer circle of the roller body is processed to be 18-22 mm smaller than that of the finished roller body;

B. clamping the shaft neck at one end of the roller body on a chuck of a special welding machine tool, enabling the end head of the shaft neck at the other end of the roller body to be abutted against a tailstock thimble of the special welding machine tool, and enabling the roller body to penetrate through a heating box body of an electric heating welding tool; the electric heating welding tool comprises a heating box body arranged on the rack, the heating box body is provided with a box body movably provided with an upper box cover, and two ends of the box body are provided with side openings for penetrating and installing rollers; the inner wall of the box body is provided with a refractory fiber board, and a resistance band is laid on the refractory fiber board; a thermocouple connected with a temperature controller is arranged in the box body; the box body is a rectangular box body which is provided with a bottom plate, a long side plate and a short side plate, wherein the long side plate and the short side plate are symmetrically enclosed on the bottom plate respectively; the resistance belt is laid on the refractory fiber boards on the two long side plates; the roller body penetrates through the inner cavity of the rectangular box body through the side opening on the short side plate; the distance between the roller body and the resistance belt is 48-53 mm;

C. starting the electric heating welding tool to raise the temperature in the heating box body and control the temperature to be 300-350 ℃;

D. using special roller surfacing equipment, welding a ring plate at both ends of the roller body, and surfacing a priming layer and a cover wear-resistant layer on the roller body in sequence; when the priming layer is subjected to surfacing welding, a high-nickel welding wire is adopted to carry out continuous spiral submerged arc surfacing welding on the roller body in the circumferential direction of the monofilament, the width of a surfacing welding seam of the priming layer is 18-20 mm, and the lap joint amount of the welding seam is controlled at 45-50%; the thickness of the priming layer is 3 mm, the thickness of each monofilament in the circumferential direction of continuous spiral submerged arc surfacing is 2 mm-3 mm, and overlaying is sequentially carried out until the thickness of the priming layer is reached;

when the facing wear-resistant layer is subjected to surfacing welding, a medium-carbon alloy welding wire is adopted to carry out continuous spiral submerged arc surfacing welding on the roller body in the circumferential direction of a single wire, the width of a surfacing welding seam of the facing wear-resistant layer is controlled to be 16-18 mm, and the lap joint quantity between the welding seam and the welding seam is controlled to be 50%; the thickness of the facing wear-resistant layer is 9 mm, the thickness of each monofilament in the circumferential direction of continuous spiral submerged arc surfacing is 2 mm-3 mm, and the rollers can be dismounted from the special welding machine tool after the surfacing is sequentially overlapped and surfacing until the thickness of the facing wear-resistant layer is reached;

E. putting the roller subjected to surfacing into a heat treatment furnace, heating to 560 ℃ at a heating rate of 50 ℃/h, preserving heat for 5 hours, and cooling to room temperature along with the furnace;

and F, grinding the outer circle of the roller body to the size of the outer circle of the finished roller body, and then finishing the welding of the roller.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following beneficial effects: 1. because the roller base is made of 50CrMo4V medium carbon low alloy forged steel, the high nickel welding wire and the medium carbon alloy welding wire are respectively deposited on the surface of the roller body base body through continuous spiral submerged arc surfacing in the circumferential direction of a continuous uniform temperature, so that the roller body has a tough roller core hard surface, the stability of roller body surfacing quality is improved, the problems that an alloy layer is easy to crack and fall off during the use process of the roller body after surfacing are solved, the welding seam has the performances of high hardness, large lightness and good wear resistance, the cost of tooling equipment can be greatly reduced, the labor operation intensity is reduced, and low price and high efficiency are realized; 2. fig. 1 is a schematic structural view of a roll according to an embodiment of the present invention. The electric heating welding tool is adopted to carry out uniform temperature protection on the roller body of the roller, so that the temperature compensation process required by welding temperature loss can be reduced, the construction period of build-up welding is effectively shortened, and the welding method is innovative in process, low in cost and high in welding quality.

Drawings

Fig. 1 is a schematic structural view of a roll according to an embodiment of the present invention.

Fig. 2 is a schematic structural view of an electrical heating welding tool according to an embodiment of the invention.

Fig. 3 is a top view of fig. 2.

Detailed Description

The invention is described in further detail below with reference to the accompanying drawings:

example 1:

a method for welding a roll, the roll 1 shown in FIG. 1 having a roll body 1-2 and journals 1-1 and 1-3 provided at both ends of the roll body 1-2, respectively, the roll being made of 50CrMo4V steel, comprising the steps of:

A. cutting the worn outer circle of the roller body 1-2, and processing the outer circle size of the roller body 1-2 to be 18 mm smaller than that of the finished roller body 1-2;

B. a shaft neck 1-1 at one end of a roller body 1-2 is clamped on a chuck 2-1 of a special welding machine tool 2, the end of the shaft neck 1-3 at the other end of the roller body is abutted with a tailstock thimble 2-2 of the special welding machine tool 2, and an upper box cover is covered on a box body after the roller body 1-2 passes through the box body of a heating box body 4 of an electric heating welding tool; the electric heating welding tool shown in fig. 2 and 3 comprises a heating box body 4 arranged between a chuck 2-1 and a tailstock thimble 2-2 of a special welding machine tool 2, wherein the heating box body 4 is provided with a box body arranged on a machine frame 4-1, the box body of the embodiment is a rectangular box body, and the rectangular box body is provided with a bottom plate 4-2, a long side plate 4-3 and a short side plate 4-4 which are symmetrically enclosed on the bottom plate 4-2 respectively; the two ends of the box body are provided with side openings for penetrating and installing the rollers, and the side openings of the box body of the embodiment are arranged on the short side plates 4-4 at the two sides; a fire-resistant layer is arranged on the inner wall of the box body, the fire-resistant layer in the embodiment is a fire-resistant fiber board, fire-resistant fibers are respectively paved on the long side plate and the short side plate, and the fire-resistant fiber board on the long side plate is 4-5; resistance bands 4-6 are laid on the fire-resistant layer, and the resistance bands 4-6 of the embodiment are respectively laid on the fire-resistant fiber boards 4-5 on the two long side boards 4-3; a temperature sensor connected with a temperature controller is arranged in the box body, the temperature controller in the embodiment is a thermocouple temperature controller (not shown in the figure), and the temperature sensor is a thermocouple (not shown in the figure); a movable upper box cover is arranged on the box body; when the roller body 1-2 passes through the inner cavity of the rectangular box body through the side opening on the short side plate, the distance between the excircle of the roller body and the resistance band is 48 mm;

C. starting the electric heating welding tool to raise the temperature in the heating box body and control the temperature to be 300-350 ℃;

D. opening an upper box cover, welding a ring plate at each of two ends of the roller body 1-2, and then sequentially overlaying a priming layer and a cover wear-resistant layer on the roller body 1-2 by using a long dynamic welding head 3-1 of special roller overlaying equipment 3; surfacing a priming coat, namely performing continuous spiral submerged arc surfacing on the roller body by adopting a high-nickel welding wire in the circumferential direction of a single wire, wherein the width of a surfacing welding seam of the priming coat is 18-20 mm, and the overlapping amount of the welding seam is controlled at 45-50%; the thickness of the bottom layer is 3 mm, the thickness of continuous spiral submerged arc surfacing in the circumferential direction of each monofilament is 2 mm-3 mm, and overlaying is sequentially carried out until the thickness of the bottom layer is reached;

surfacing a facing wear-resistant layer, wherein a medium carbon alloy welding wire is adopted for continuous spiral submerged arc surfacing of the roller body in the circumferential direction of a single wire, the width of a surfacing welding seam of the facing wear-resistant layer is controlled to be 16-18 mm, and the lap joint quantity between the welding seam and the welding seam is controlled to be 50%; the thickness of the wear-resistant layer of the cover surface is 9 mm, the thickness of continuous spiral submerged arc surfacing welding in the circumferential direction of each monofilament is 2 mm-3 mm, and the roller 1 can be dismounted from the special welding machine tool after the surfacing welding is sequentially overlapped until the thickness size of the wear-resistant layer of the cover surface is reached;

D. putting the roller 1 subjected to surfacing welding into a heat treatment furnace, heating to 560 ℃ at a heating rate of 50 ℃/h, preserving heat for 5 hours, and cooling to room temperature along with the furnace;

and E, grinding the outer circle of the roller body 1-2 to the outer circle size of the finished roller body, and then finishing the welding of the roller.

Example 2:

A. cutting the worn outer circle of the roller body 1-2, and processing the outer circle size of the roller body 1-2 to be 22 mm smaller than that of the finished roller body 1-2;

B. when the roller body 1-2 penetrates through the inner cavity of the rectangular box body through the side opening on the short side plate, the distance between the excircle of the roller body 1-2 and the resistance band is 53 mm;

the rest is the same as in example 1.

Because the roller base is made of 50CrMo4V medium carbon low alloy forged steel, the high nickel welding wire and the medium carbon alloy welding wire are respectively deposited on the surface of the roller body base body through continuous spiral submerged arc overlaying in the circumferential direction of a continuous uniform temperature, so that the roller body has a tough roller core hard surface, the problems of alloy layer cracking and block dropping in the using process are eliminated, the welding seam has the performances of high hardness, large lightness and good wear resistance, the cost of tooling equipment can be greatly reduced, the labor operation intensity is reduced, and low price and high efficiency are realized; in addition, the electric heating welding tool is adopted to carry out uniform temperature protection on the roller body of the roller, so that the temperature compensation process required by welding temperature loss can be reduced, the surfacing construction period is effectively shortened, and the method is a welding method with innovative process, low cost and high welding quality.

Claims (1)

1. A method of welding a roll having a roll body and journals at each end of the roll body, said roll being made of 50CrMo4V steel, comprising the steps of:

A. cutting the worn outer circle of the roller body, wherein the size of the outer circle of the roller body is processed to be 18-22 mm smaller than that of the finished roller body;

B. clamping the shaft neck at one end of the roller body on a chuck of a special welding machine tool, enabling the end head of the shaft neck at the other end of the roller body to be abutted against a tailstock thimble of the special welding machine tool, and enabling the roller body to penetrate through a heating box body of an electric heating welding tool; the electric heating welding tool comprises a heating box body arranged on the rack, the heating box body is provided with a box body movably provided with an upper box cover, and two ends of the box body are provided with side openings for penetrating and installing rollers; the inner wall of the box body is provided with a refractory fiber board, and a resistance band is laid on the refractory fiber board; a thermocouple connected with a temperature controller is arranged in the box body; the box body is a rectangular box body which is provided with a bottom plate, a long side plate and a short side plate, wherein the long side plate and the short side plate are symmetrically enclosed on the bottom plate respectively; the resistance belt is laid on the refractory fiber boards on the two long side plates; the roller body penetrates through the inner cavity of the rectangular box body through the side opening on the short side plate; the distance between the roller body and the resistance belt is 48-53 mm;

C. starting the electric heating welding tool to raise the temperature in the heating box body and control the temperature to be 300-350 ℃;

D. using special roller surfacing equipment, welding a ring plate at both ends of the roller body, and surfacing a priming layer and a cover wear-resistant layer on the roller body in sequence; when the priming layer is subjected to surfacing welding, a high-nickel welding wire is adopted to carry out continuous spiral submerged arc surfacing welding on the roller body in the circumferential direction of the monofilament, the width of a surfacing welding seam of the priming layer is 18-20 mm, and the lap joint amount of the welding seam is controlled at 45-50%; the thickness of the priming layer is 3 mm, the thickness of each monofilament in the circumferential direction of continuous spiral submerged arc surfacing is 2 mm-3 mm, and overlaying is sequentially carried out until the thickness of the priming layer is reached;

when the facing wear-resistant layer is subjected to surfacing welding, a medium-carbon alloy welding wire is adopted to carry out continuous spiral submerged arc surfacing welding on the roller body in the circumferential direction of a single wire, the width of a surfacing welding seam of the facing wear-resistant layer is controlled to be 16-18 mm, and the lap joint quantity between the welding seam and the welding seam is controlled to be 50%; the thickness of the facing wear-resistant layer is 9 mm, the thickness of each monofilament in the circumferential direction of continuous spiral submerged arc surfacing is 2 mm-3 mm, and the rollers can be dismounted from the special welding machine tool after the surfacing is sequentially overlapped and surfacing until the thickness of the facing wear-resistant layer is reached;

E. putting the roller subjected to surfacing into a heat treatment furnace, heating to 560 ℃ at a heating rate of 50 ℃/h, preserving heat for 5 hours, and cooling to room temperature along with the furnace;

and F, grinding the outer circle of the roller body to the size of the outer circle of the finished roller body, and then finishing the welding of the roller.

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