CN115446426A

CN115446426A - Off-line installation method for large-scale blast furnace tuyere flange

Info

Publication number: CN115446426A
Application number: CN202211263088.7A
Authority: CN
Inventors: 石建伟; 张蕾; 杨佩峰; 程永庆; 尉恒涛; 柳国志; 曹亮; 王曼; 赵凯强
Original assignee: Hebei Metallurgical Construction Group Co ltd
Current assignee: Hebei Metallurgical Construction Group Co ltd
Priority date: 2022-10-14
Filing date: 2022-10-14
Publication date: 2022-12-09

Abstract

The invention provides an off-line installation method of a large-scale blast furnace tuyere flange, which belongs to the technical field of metallurgical machinery and comprises the following steps: s1, manufacturing a furnace shell in blocks, cutting off a furnace shell plate in a tuyere area, and completing pre-assembly; s2, welding a temporary tension brace in the tuyere zone furnace shell; s3, hanging the tuyere with the furnace shell to an assembly platform, and welding the circumferential direction of the tuyere opening to adjust and position the device; s4, hoisting the tuyere flange to the tuyere area; fixing the tuyere flange in the tuyere area and welding the tuyere flange; s5, welding the furnace shell with the air port and the furnace shell below the air port, and removing the temporary tension brace. The off-line installation method of the large-scale blast furnace tuyere flange provided by the invention realizes off-line installation of the tuyere flange, so that the tuyere belt is installed in a factory, the problem of narrow construction site is solved, the welding quality and the installation precision of the tuyere flange are ensured, and the construction progress is accelerated; and the deformation is reduced by cutting the inner opening single-side groove and arranging the temporary bracing, and the welding effect is improved.

Description

Off-line installation method for large-scale blast furnace tuyere flange

Technical Field

The invention belongs to the technical field of metallurgical machinery, and particularly relates to an off-line installation method of a large-scale blast furnace tuyere flange.

Background

At present, the requirements of owners on the installation accuracy of the blast furnace tuyere flange, the center elevation of the flange and the center deviation of the blast furnace from the flange are generally improved. The existing method for installing and welding the large-volume blast furnace tuyere flange with the tuyere comprises the following steps: the tuyere zone and the tuyere flange are installed with the furnace shell in a hoisting carrying pole overhead mode, the tuyere flange is installed after the tuyere zone is welded with the upper ring seam and the lower ring seam of the tuyere zone, and after the tuyere flange is installed and accepted, a single tuyere flange is welded through a welding deformation prevention measure.

The method has the following defects: 1. the construction period is long. After the air port belt and the upper and lower belt circular seams of the air port belt are welded, a welding air port flange can be installed; 2. the preheating and heat preservation measures are inconvenient to adopt for the welding of the tuyere flange. The blast furnace tuyere flange is made of cast steel, welding stress is large, preheating and heat preservation measures are needed when the tuyere flange is welded, and the preheating and heat preservation measures are inconvenient to adopt due to high-altitude welding.

Disclosure of Invention

The invention aims to provide an off-line installation method of a large-scale blast furnace tuyere flange, and aims to solve the problem that the existing installation method is inconvenient to operate.

In order to realize the purpose, the invention adopts the technical scheme that: the method for mounting the large-scale blast furnace tuyere flange off line comprises the following steps:

s1, manufacturing a furnace shell in blocks, and completing the assembly of the furnace shell with a tuyere on an assembly platform to form a circular furnace shell;

s2, welding temporary bracing in the tuyere zone furnace shell, wherein the temporary bracing comprises an upper part bracing positioned above the tuyere opening and a lower part bracing positioned below the tuyere opening, and supporting points of the upper part bracing and the lower part bracing are positioned in a gap of the tuyere opening;

s3, cutting off a tuyere zone furnace shell plate on the tuyere zone furnace shell, and cutting an inner opening single-side groove at a tuyere opening of the tuyere zone furnace shell; welding an adjusting and positioning device in the circumferential direction of the air opening, wherein the adjusting and positioning device comprises a distance assembly and an adjusting assembly arranged on the distance assembly, and adjusting the adjusting assembly to the maximum opening;

s4, hoisting the tuyere flange to the tuyere area, and enabling the tuyere flange to abut against the distance assembly; moving the adjusting assembly, wherein the adjusting assembly abuts against the periphery and the outer side of the tuyere flange, fixes the tuyere flange in the tuyere area and welds the tuyere flange;

s5, welding the furnace shell with the air port and the furnace shell below the air port, and removing the temporary tension brace.

As another embodiment of the present application, in step S4, the distance assembly includes:

the support column is welded on the outer side of the opening of the air port;

the fixed block, the welding is in the upper end of support column, and the one end that the wind gap trompil was kept away from to the fixed block is equipped with the sideboard of outside extension, sets up the screw thread on the sideboard.

As another embodiment of the present application, an adjustment assembly includes:

the fixture block is positioned on the inner side of the side plate, an extension plate is arranged at one end of the fixture block, which is far away from the side plate, and the extension plate is abutted against the outer end face of the tuyere flange and is used for abutting the tuyere flange in the tuyere opening; the fixture block is provided with a strip hole;

the fastening bolt penetrates through the strip hole and is in threaded connection with the fixed block;

and the transverse bolt penetrates through the side plate and abuts against one end, far away from the extension plate, of the clamping block.

As another embodiment of the present application, in step S4, after all the flanges are installed, the steel wires are symmetrically pulled along the furnace shell center through the mark points of the tuyere centers on the detection frame, and the furnace mouth center is dropped through the core measuring frame, and whether the steel wires intersect with the furnace mouth center is checked.

As another embodiment of the present application, in step S5, after the flange is adjusted in place, tack welding is performed to fix the flange in place in advance by using tack welding, wherein the tack welding position includes four points where the cross center line of the tuyere flange contacts the furnace shell; after the test is qualified, the tuyere flange and the furnace shell are symmetrically welded and reinforced every 45 degrees in the circumference, and the spot welding positions are all welded at the inner opening.

As another embodiment of the present application, in step S5, during formal welding, a plurality of stiffening plates need to be uniformly arranged between the tuyere flange and the furnace shell, and the length direction of the stiffening plates is consistent with the radial direction of the tuyere flange.

As another embodiment of the application, in step S5, during formal welding, the welding tuyere flange is welded with the outer opening first and then with the inner opening, and a symmetrical layered segmented back-stepping reverse welding method is adopted; the outer opening is a fillet weld, a heating device is erected at the inner opening before the outer opening is welded, and the temperature at the welding opening is kept to be controlled at 100-150 ℃; when the inner opening is welded, backing welding is firstly carried out to fill the gap between the flange and the furnace shell, and then integral closing welding is carried out.

As another embodiment of the application, when the inner opening welding is carried out, in order to ensure the interlayer temperature during welding, a heater is needed to carry out heat tracing on a welding seam during welding of each layer, the temperature is controlled to be 120-150 ℃, the welding speed is controlled, the welding quality is finally ensured, and the welding deformation is reduced.

As another embodiment of the present application, in step S2, the upper bracing includes a plurality of welded steel pipes, and a center line of the upper bracing is spaced 200mm from an upper edge of the opening of the tuyere; the lower part bracing comprises a plurality of welded H-shaped steel, and the distance between the lower part bracing and the lower end of the tuyere belt is 150mm.

The off-line installation method of the large-scale blast furnace tuyere flange provided by the invention has the beneficial effects that: compared with the prior art, the off-line installation method of the tuyere flange of the large-scale blast furnace realizes off-line installation of the tuyere flange, enables the tuyere zone to be installed in a factory, overcomes the problem of narrow construction site, ensures the welding quality and the installation precision of the tuyere flange and accelerates the construction progress; and the deformation is reduced by cutting the inner opening single-side groove and arranging the temporary bracing, and the welding effect is improved.

Drawings

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

Fig. 1 is a schematic structural diagram of an adjusting and positioning apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a mounting base according to an embodiment of the present invention;

fig. 3 is a schematic view illustrating an installation of a stiffener according to an embodiment of the present invention;

fig. 4 is a graph of a tuyere flange welding heat treatment process provided in an embodiment of the present invention.

In the figure: 1. a tuyere flange; 2. the air port is provided with a furnace shell; 3. a support pillar; 4. a fixed block; 5. a clamping block; 6. a transverse bolt; 7. fastening a bolt; 8. mounting a base; 9. a horizontal slide rail; 10. a slide base; 11. a lifting rod; 12. a support plate; 13. and (4) a stiffening plate.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1 to 4, an off-line installation method of a tuyere flange of a large-sized blast furnace according to the present invention will now be described. The off-line installation method of the large-scale blast furnace tuyere flange comprises the following steps:

s1, manufacturing a furnace shell in blocks, and completing pre-assembly of a tuyere zone furnace shell 2 and a furnace shell below on an assembly platform to form a circular furnace shell;

s2, welding temporary bracing in the tuyere zone furnace shell 2, wherein the temporary bracing comprises an upper part bracing positioned above the tuyere opening and a lower part bracing positioned below the tuyere opening, and supporting points of the upper part bracing and the lower part bracing are positioned in a gap of the tuyere opening;

s3, cutting off a tuyere zone furnace shell plate on the tuyere zone furnace shell 2, and cutting an inner opening single-side groove at a tuyere opening of the tuyere zone furnace shell 2; welding an adjusting and positioning device in the circumferential direction of the opening of the air port, wherein the adjusting and positioning device comprises a distance component and an adjusting component arranged on the distance component;

s4, hoisting the tuyere flange 1 to the tuyere area, and enabling the tuyere flange 1 to abut against the distance assembly; moving the adjusting assembly, wherein the adjusting assembly is abutted against the periphery and the outer side of the tuyere flange 1, fixing the tuyere flange 1 in the tuyere area and welding the tuyere flange 1;

s5, welding the tuyere belt furnace shell 2 with a furnace shell below, and removing the temporary bracing.

Compared with the prior art, the off-line installation method of the large-scale blast furnace tuyere flange provided by the invention has the advantages that the furnace shells are manufactured in a factory in a blocking manner, and a plurality of blocked furnace shells are assembled into a circular furnace shell on an assembly platform in order to ensure that the hoisting requirement is met; a temporary bracing is welded on the inner side of the tuyere zone furnace shell 2 and is used for supporting the opening of the tuyere, so that the tuyere zone furnace shell 2 is prevented from being seriously deformed during welding; and then, hanging the tuyere zone furnace shell 2 welded with the temporary bracing to an assembly platform, cutting along a pre-opening on the furnace shell, cutting a single-sided groove of an inner opening at the opening of the tuyere and welding an adjusting and positioning device at the outer side of the opening of the tuyere.

When the tuyere flange 1 is installed, firstly, the tuyere flange 1 is hoisted to a tuyere opening position of a tuyere zone furnace shell 2, the end part of the tuyere flange 1 extends into the furnace shell from the tuyere opening position, the flange surface is propped against a distance component, an adjusting component is moved, the adjusting component is propped against the edge and the outer end surface of the tuyere flange 1, and the tuyere flange 1 is fixed by means of the distance component; welding the tuyere flange 1 on the furnace shell after positioning; and welding the tuyere zone furnace shell 2 with the furnace shell below the tuyere zone furnace shell, and removing the temporary bracing to finish off-line installation of the tuyere flange 1.

The off-line installation method of the large-scale blast furnace tuyere flange provided by the invention realizes off-line installation of the tuyere flange 1, so that the installation of the tuyere zone in a factory is completed, the problem of narrow construction site is solved, the welding quality and the installation precision of the tuyere flange 1 are ensured, and the construction progress is accelerated; and the deformation is reduced by cutting the inner opening single-side groove and arranging the temporary bracing, and the welding effect is improved.

Optionally, a plurality of furnace shells are manufactured separately, the tuyere zone furnace shell 2 is a 5 th zone furnace shell, and 1-4 zone furnace shells are assembled below the tuyere zone furnace shell.

In some possible embodiments, the tuyere opening has been located and initially opened in a processing plant. The preliminary tapping is to position and tap a flat plate before the furnace shell is rolled according to the furnace shell layout pattern of the blast furnace, and a worker finds out the central line and the elevation of the air port on the furnace shell 2 of the air port zone according to the elevation of a drawing and rechecks the tapping data.

The center line of the tuyere is verified again before the furnace shell plate is cut off, the accuracy of re-measuring the opening hole by adopting a total station is used for verifying the positioning of the center of the tuyere, the total station is installed on the center of the furnace bottom on the assembly platform, and after re-measurement is correct, the center line of the tuyere is led out and marked by a marking pen or an ink line for hanging line verification when the tuyere flange 1 is installed. And cutting off the shell plate of the tuyere furnace after the central line is marked. When cutting off, the workers are working outside the furnace shell, and the cut is made according to the pre-opened radian and inclination of the processing factory. When the device is disassembled, the device is sealed by using a chain block and pushed out from the inside to the outside. And numbering the extracted furnace shell plates, and stacking the furnace shell plates to a specified place.

And after the furnace shell plate at the tuyere area is cut off, the furnace shell plate is pre-assembled with the furnace shell below, and the pre-assembly is carried out according to the standard requirement. And welding the positioning plate after the alignment meets the requirements. The ovality of the center of the tuyere, the elevation of the center of the tuyere and the eccentricity of the bottom center of the tuyere zone furnace shell are measured and recorded by workers.

And before pre-assembly, measuring the central deviation and the vertical height of a plurality of furnace shells. Because the furnace shell of the blast furnace is not installed, the vertical height of the furnace shell is easy to have larger deviation. The check measurements are therefore repeated. The first measuring method comprises the following steps: measuring the inclined length of the outer skin at the lower opening by adopting an angle square method, and then calculating the vertical height according to the inclined angle of the furnace shell; and a second measuring method comprises the following steps: and measuring the vertical height by using a method of hanging a cross wire at the upper opening and hanging a cross wire or extending a square at the lower opening. The two methods are used for measuring each time, and the measured data of the two methods can be used for determining the elevation of the tuyere after the measured data are consistent with the belt height check provided before each belt furnace shell leaves a factory.

Optionally, no cushion block is arranged at the annular gap between the belts, and the end gap is controlled within a minimum range.

When the data of the furnace shell with the 5 th zone is measured, the center measuring bridge is hung to the upper part of the 5 th zone, the temporary support is welded on the furnace shell, the center of the air outlet is determined by hanging a wire, and then the center of the air outlet is hung on the center measuring bridge to drop to the center of the furnace bottom. And measuring the furnace shell inner oblique length from the tuyere center to the 3 rd lower edge of the furnace shell by using a steel ruler, and converting into the vertical height. And accumulating the actual vertical heights of the 1-5 strips, calculating the center elevation of the pre-installed tuyere according to elevation data of a drawing, and determining the installation elevation of the tuyere flange 1.

The 5 th takes the stove outer covering to accomplish the back with the group of 4 th belt annular gap, beats interim bracing at the upper and lower position of wind gap trompil, and the bracing divides two-layerly: the bracing is all in the clearance of two wind gap trompils, and the lower part bracing is apart from the 4 th area and is gone up mouthful 150mm, and upper portion bracing is apart from about 200mm along on the wind gap trompil. The lower part is provided with 14 supporting points, and the upper part is provided with 8 supporting points. The 5 th takes the stove outer covering to accomplish the back with the group of 4 th belt annular gap, beats interim bracing at the upper and lower position of wind gap trompil, and the bracing divides two-layerly: the bracing is all in the clearance of two wind gap trompils, and the lower part bracing is apart from the 4 th area and is gone up mouthful 150mm, and upper portion bracing is apart from about 200mm along about the wind gap trompil. The lower part is provided with 14 supporting points, and the upper part is provided with 8 supporting points.

After the upper temporary bracing and the lower temporary bracing in the furnace shell with the 5 th zone are finished, hoisting the furnace shell with the 5 th zone to a ground assembly platform; the arc with the furnace shell lower opening of the 5 th zone is released according to the furnace bottom center before the furnace shell is in place, a steel wire is hung on the furnace shell upper opening after the furnace shell is in place, a center measuring bridge is arranged, and the position of the furnace shell is adjusted by using a wire to fall down to the vertical center.

And leveling the furnace shell with the 5 th belt on the assembly platform by using a jack and an oblique iron pad to ensure that the height difference between any two points of the central line of the tuyere is not more than 1mm.

As shown in fig. 2, a 5 th belt furnace shell mounting base 8 is arranged on the assembly platform, a horizontal slide rail 9 and a slide base 10 connected to the horizontal slide rail 9 in a sliding manner are arranged on the mounting base 8, a lifting rod 11 is arranged on the slide base 10, and a bearing plate 12 is arranged above the lifting rod 11. When the furnace shell with the 5 th zone is hung, horizontally moving a plurality of sliding seats 10 on a horizontal sliding rail 9 for the first time, determining the positions of the sliding seats 10 according to the size of the furnace shell with the 5 th zone, and fixing the sliding seats 10 on an installation base 8; then the 5 th furnace shell is hung on a bearing plate 12 on the base, and the leveling work is completed by adjusting a lifting rod 11 on a sliding seat 10. The lifting rod 11 can be a jack.

Optionally, there are a plurality of horizontal sliding rails 9, the plurality of horizontal sliding rails 9 are radial, and the intersection point of the plurality of horizontal sliding rails 9 is located at the center point of the furnace shell.

And erecting a total station at the center position of the inner side of the 5 th furnace shell, and checking the vertical center lines of other air ports at intervals of 12 DEG 51 '26' by using a total station corner based on 0 DEG (0 DEG is the vertical center line of the first branch port).

And erecting a level gauge at the center of the furnace shell, checking the elevation line of the air port through the elevation line of the lower edge of the fifth furnace shell, and positioning the elevation of the center of the air port to be about 2-3mm lower than the elevation of the drawing in order to accurately control the elevation of the center of the air port during formal installation.

Air port scribing detection: and detecting whether all the air ports are converged with the center of the furnace body, wherein the detection method comprises the steps of erecting detection frames (made by using angle steel of 75 x 5) along the height centers of all the air ports, measuring all the detection frames by using an instrument until the same elevation is reached (the error is less than 2 mm), throwing the air port centers onto the detection frames, and marking. Through the mark point of each wind gap center on the test rack, draw along stove outer covering centrosymmetric and establish the steel wire to through the survey heart bridge, throw down the furnace body center, whether the inspection copper wire intersects with stove outer covering center, after the acceptance check is qualified in line with the requirement, can carry out accurate trompil to the stove outer covering side, and carry out groove treatment.

The clear sizes of the uppermost end and the lowermost end of the welding line area between the tuyere flange 1 and the furnace shell from the furnace shell are 45mm, the clear sizes of the horizontal center from the furnace shell are 70mm, grooves are formed according to the drawing requirements, and the welding line of the flange which is in butt joint with the furnace shell after being in place can not be welded. And (3) manually cutting the groove of the air port welding line, and polishing oxide skins, angular edges and the like of a cutting surface by using an angular polishing machine after cutting.

The tuyere flange 1 is marked in the installation direction of the flange before leaving the factory, namely, the flange disc edge is provided with four U-shaped grooves with the depth of 2mm, namely character marks on the flange face. Checking and confirming whether the mark is correct or not, and entering installation after confirming that the mark is correct.

Firstly, the central line of an air port at the inner side of a furnace shell is placed on the outer shell of the furnace shell by utilizing an angle square, a theodolite, a leveling instrument and the like; a distance component is arranged at a flange bolt hole on a cross center line on the outer shell of the furnace shell, wherein the distance from the outer end of the distance component on the vertical center line to the furnace shell is 45mm, and the distance from the positioning flange to the furnace shell is used for positioning; respectively placing the cross center line of the outer end surface on a cone connected with the flange and the furnace shell by using 2 square rulers as a flange mounting and positioning reference; welding a hoisting nose on the tuyere zone furnace shell 2, hoisting the tuyere flange 1 in place, and temporarily fixing by using an adjusting assembly; when the tuyere flange 1 is aligned, the inner side of the furnace shell is aligned with four central lines on a cone of the tuyere flange 1 according to a pre-drawn cross central line (the tuyere central line on the inner skin of the furnace shell is just intersected with the central line of the flange), wherein the up-down, left-right distance between the flange and the furnace shell is adjusted by an adjusting component; when the flanges are installed and adjusted, the two corresponding flange hanging lines (by using a detection frame) must be adjusted simultaneously; after the flange is adjusted in place, tack welding is performed in advance to be firm by utilizing the spot welding; after all the flanges are completely installed, the steel wires are symmetrically pulled along the center of the furnace shell through the mark points of the centers of the air ports on the detection frame, the centers of the furnace ports are thrown down through the center detection frame, whether the steel wires are intersected with the center of the furnace body is checked, and if the steel wires are not met with the requirements, the steel wires are readjusted until the requirements of drawings and acceptance standards are met. After meeting the requirements and passing the supervision and acceptance, the flange and the furnace shell are symmetrically welded and reinforced (the length is about 100 mm) at intervals of 45 degrees in the circumference, and finally the flange can be formally welded.

As shown in figure 1, the adjusting and positioning device comprises a distance assembly and an adjusting assembly arranged on the distance assembly, and the adjusting assembly is adjusted to the maximum opening. The distance assembly comprises a support column 3 and a fixed block 4; the support column 3 is welded on the outer side of the tuyere opening; fixed block 4 welding is in the upper end of support column 3, and one side that the wind gap trompil was kept away from to fixed block 4 is equipped with the sideboard that extends to the outside, sets up the screw thread on the sideboard.

The adjusting component is arranged at the upper end of the distance component, and the adjusting component does not need to be additionally welded, so that the welding area of the outer side of the furnace shell can be reduced, and the welding deformation is reduced.

The adjusting assembly comprises a clamping block 5, a fastening bolt 7 and a transverse bolt 6; the fixture block 5 is positioned on the inner side of the side plate, an extension plate is arranged at one end of the fixture block 5, which is far away from the side plate, the extension plate is abutted against the outer end face of the tuyere flange 1 and is used for abutting the tuyere flange 1 in the tuyere opening, and the fixture block 5 is provided with a strip hole; the fastening bolt 7 penetrates through the strip hole and is in threaded connection with the fixed block 4; the transverse bolt 6 penetrates through the side plate and abuts against one end, far away from the extension plate, of the fixture block 5.

When the fixture block 5 is installed, the fixture block is positioned on one side far away from the opening of the air opening by virtue of the strip hole and the transverse bolt 6; extending the tuyere flange 1 into the tuyere opening, wherein the end surface of the tuyere flange 1 is abutted against the fixed block 4; moving the fixture block 5 and adjusting the fastening bolt 7 to enable the extension plate on the fixture block 5 to be attached to the end face of the outer side of the tuyere flange 1; and adjusting the transverse bolt 6, driving the movable fixture block 5 to transversely move by the transverse bolt 6, enabling the end part of the fixture block 5 to abut against the side wall of the tuyere flange 1, and adjusting the position of the tuyere flange 1 in real time according to the measurement result. When the tuyere flange 1 is well positioned, the fastening bolts 7 are adjusted, and the fastening bolts 7 drive the extension plate to tightly push against the end surface of the tuyere of the flange.

The upper end of fixed block 4 is provided with the bolt hole, and fastening bolt 7 passes the rectangular hole on fixture block 5 and stretches into the bolt hole in fixed block 4 for adjust the distance between fixture block 5 and fixed block 4.

The length direction of the strip hole is consistent with the radial direction of the tuyere flange 1.

The transverse bolt 6 penetrates through the side plate and is tightly pressed against the side wall of the fixture block 5.

The welding of the tuyere flange 1 and the furnace shell plate adopts CO ₂ Gas shielded welding, wherein the welding wire is a solid welding wire ER50-6; the diameter of the flux-cored wire THY-51B (H10 Mn 2) is 1.2mm.

After the alignment of each tuyere is finished, 8 points (which are uniformly arranged along the circumference) are welded, the length of each point is about 50mm, and the positioning before the welding of the tuyere flange 1 is well performed; the positioning welding is welded at the inner opening. In the formal welding process, the tack welding is required to be planed and cleaned and then welded.

In order to ensure that the base metal has the best penetration performance, a flame heater is selected to preheat the base metal before welding, and the preheating temperature is 70-100 ℃.

Before the flange welding, an arc line is drawn on the assembly platform along the inner edge of the furnace shell, and the deformation of the ovality of the furnace shell is detected in the welding process and after the welding. Welding 20mm thick steel plate baffles on the inner side and the outer side of the furnace shell on the platform to restrain the welding deformation of the furnace shell, wherein the number of the restraint points is 8; the specific welding quantity can be increased or decreased according to the actual welding situation on site. And arc stiffening plates 13 are welded on the lower edge of the furnace shell which can not be welded with the baffle plate and returns upwards about 140mm, wherein the arc stiffening plates are arranged at the periphery of-20 multiplied by 250 multiplied by 1500.

And the inner opening welding is layered and segmented, and each welding layer is hammered by using a small electric pick to eliminate welding stress.

The welding quality of the tuyere flange 1 needs to be guaranteed firstly, the deformation in the welding process needs to be reduced secondly, and both the welding process and the welder need reasonable welding technology and higher technical level. The groove needs to be polished completely before welding, and a polishing machine and flame need to be used on the welding side of the tuyere flange 1 to clean rust, oil stain and the like on the surface.

In this embodiment, the blast furnace has 28 tuyeres, and the bevel is a single-sided bevel and is a multilayer multi-pass weld. Welding the tuyere flange 1 firstly with an outer opening and then with an inner opening; a symmetrical layered and segmented step-back reverse welding method is adopted. Every four tuyeres are a welding unit, and every tuyeres arranges two welders and carries out the welding. Backing weld 3-4 layers (about 12 mm); one stage (about 20 mm) per 7-8 layers for a total of 4 stages. And (3) polishing and polishing the welding seam and the groove to weld each layer, and then continuously welding, and checking and repairing the defects in the welding process.

The outer opening is a fillet weld, and because the gap between the end face of the welding flange and the furnace shell is too small, a 500A welding machine 350A welding gun is adopted for welding, and a solid welding wire is selected. A heating device is erected at the inner opening before welding; preheating to a set temperature, adjusting the flame intensity, and keeping the temperature at the welding position to be controlled between 100 and 150 ℃ for heat tracing. Firstly, welding along the circumference of the tuyere in sections, staggering a positioning welding line, and simultaneously welding by two persons, wherein the welding length is not less than 100 mm. And after the broken welding is finished, the positioning welding meat is planed and simultaneously the broken welding arc striking and arc extinguishing points are subjected to back chipping treatment. And then, carrying out teasel root welding to carry out backing welding on the whole outer opening to finish a circle. And starting welding according to the welding principle after backing welding is finished. The welding speed is controlled, the welding speed is not required to be fast, and the interlayer temperature is ensured (30-40 mm/min) until the welding is finished. The height of the solder meat is about 20mm.

And after the outer opening is welded, planing the inner opening, and back chipping by using an inner grinder. Uneven gaps are reserved on the contact surface of each flange and the furnace shell, the upper gaps are small, the lower gaps are large, and the maximum gap is about 10mm; backing welding is required first. Because the gaps between each flange and the furnace shell are different, the end gaps need 2-4 welding passes to be filled, and the thickness of the welding meat after the end gaps are filled is about 5mm, namely the first layer. Bottoming and arcing are carried out by filling meat in layers from the furnace shell plate; after the gap of the whole circle of meat is basically even, the temperature of the circle is detected, and then the whole closed welding is carried out. And after the gap is filled, carrying out integral back gouging treatment, and continuously welding for 2-4 layers, wherein the thickness of the final welding meat is about 12mm. This scheme compiles backing welding and 2-4 layer welding as the first stage of welding. Because the depth of the groove is larger, backing welding is carried out by using a 300A secondary shielded welding nozzle, and a flux-cored wire is selected.

The length of the welding seam can be adjusted according to the actual situation on site by the sectional step-back welding, the position of the arc starting point can be properly adjusted, but the welding principle is unchanged.

And after the 28 tuyere backing welds are finished, replacing the welding gun with 500A, and selecting a flux-cored wire. Returning to the 1 st welding unit, 5-11 layers are welded, and the thickness of the welding seam is about 20-25mm. The second stage of welding is carried out, and heat treatment can be carried out after the welding is finished. And similarly, after the second stage welding is finished, welding the third stage, namely 12-19 layers. The fourth stage is 20-24 layers (including cover surface), the 13 th layer and later are welded according to the principle of multi-layer and multi-pass welding, at least 3 passes of welding are needed for each layer, and about 37 passes of welding are completed for each tuyere. Each stage is completed by welding 28 tuyeres.

In order to ensure the interlayer temperature during welding, a heater is needed to carry out heat tracing on the welding seam during welding of each layer, the temperature is controlled to be 120-150 ℃, the welding speed is controlled, the welding quality is finally ensured, and the welding deformation is reduced.

And (3) performing postweld heat treatment at each stage in the same way as the postweld heat treatment after all welding seams are welded, namely performing flame heating on each layer of welded seam, and heating to 250-300 ℃. Heating for 1 hour, maintaining the temperature at about 300 ℃ for 1.5 hours, and slowly cooling. When the temperature is lower than the preheating temperature during the secondary welding, the lower layer welding operation can be carried out by preheating again.

Attention is required during welding: a. each layer must be welded from bottom to top; b. the starting end and the ending end of each layer of welding bead need to be staggered by at least 50mm; c. after each welding is finished, removing the original fixed-position welding points by using an air plane and polishing the points to be bright; d. the interlayer temperature must be ensured not to be lower than the preheating temperature; e. hammering is adopted to eliminate welding stress in the welding process; f. in the welding process, the width-depth ratio of each welding line is more than 1.1; g. each layer is welded without allowing for discontinuities.

The fillet weld of the tuyere flange 1 and the furnace shell requires to be welded through. Except for the visual inspection, the welding seams are inspected by ultrasonic waves of 100 percent, and the internal defects are inspected.

The preheating and heating of the welding seam are carried out on the opposite side of the welding surface, and the temperature measurement is carried out by the same principle. If the heat treatment time after welding is not enough in each stage, the temperature needs to be measured and controlled to be about 150 ℃ when the welding in the next stage is carried out, and the temperature needs to be kept until the welding in each stage is finished.

And finally, after the inner and outer welding openings of the 28 air ports on the ground assembly platform are welded, installing the air port belt in place by using a 500-ton crawler crane. The elevation of the 4 th belt upper opening is measured before installation, and the elevation of the center of the tuyere is ensured by adjusting the end part clearance of the circular seam.

After the tuyere belt is installed in place, steel wires are hung at the centers of 28 tuyeres. And hanging a line pendant on the center measuring bridge to coincide with the intersection point of the tuyere center, and checking the deviation of the tuyere center to the center of the furnace bottom. And the installation data of other air ports are checked and accepted according to the specifications.

And after the air port installation data are accepted, handing over the follow-up work to a Jinjie team, and welding 4+5 with a circular seam. And continuously installing a 6+7 belt, and adjusting the ovality welding 5+6 belt circular seam. And cutting off the bracing of the tuyere area after the welding of the upper circular seam and the lower circular seam is finished. And finishing the installation work of the whole tuyere.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. The off-line installation method of the large-scale blast furnace tuyere flange is characterized by comprising the following steps of:

s3, cutting off a tuyere zone furnace shell plate on the tuyere zone furnace shell, and cutting an inner-opening single-side groove at the tuyere opening position of the tuyere zone furnace shell; welding an adjusting and positioning device in the circumferential direction of the air opening, wherein the adjusting and positioning device comprises a distance assembly and an adjusting assembly arranged on the distance assembly, and adjusting the adjusting assembly to the maximum opening;

2. The off-line installation method of the large-sized blast furnace tuyere flange of claim 1, wherein in step S4, the distance assembly comprises:

the supporting column is welded on the outer side of the opening of the air port;

3. A large blast furnace tuyere flange off-line installation method according to claim 2, wherein the adjusting assembly includes:

4. The off-line installation method of the tuyere flange of the large-scale blast furnace according to claim 1, wherein in step S4, after all flanges are installed, steel wires are symmetrically pulled along the center of the furnace shell through the mark points of the centers of the tuyeres on the detection frame, and the center of the tuyere is dropped through the center detection frame to check whether the steel wires meet the center of the tuyere.

5. The off-line installation method of the tuyere flange of the large-scale blast furnace according to claim 4, wherein in step S5, after the flange is adjusted in place, tack welding is previously performed for firmness by using tack welding, wherein the tack welding positions include four points where the cross center line of the tuyere flange contacts the furnace shell; after the test and acceptance are qualified, spot welding is symmetrically carried out between the tuyere flange and the furnace shell at intervals of 45 degrees in the circumference for reinforcement, and the spot welding positions are all welded at the inner opening.

6. The off-line installation method of the tuyere flange of the large-scale blast furnace according to claim 5, wherein in step S5, a plurality of stiffening plates are required to be uniformly arranged between the tuyere flange and the furnace shell during formal welding, and the length direction of the stiffening plates is consistent with the radial direction of the tuyere flange.

7. The off-line installation method of the tuyere flange of the large-scale blast furnace as claimed in claim 6, wherein in step S5, during formal welding, the tuyere flange is welded with the outer opening first and then with the inner opening, and a symmetrical layered step-by-step backward reverse welding method is adopted; the outer opening is a fillet weld, a heating device is erected at the inner opening before the outer opening is welded, and the temperature at the welding opening is kept to be controlled at 100-150 ℃; when the inner opening is welded, backing welding is firstly carried out to fill the gap between the flange and the furnace shell, and then integral closing welding is carried out.

8. The off-line installation method of the tuyere flange of the large-sized blast furnace according to claim 7, wherein in the process of inner port welding, in order to ensure the interlayer temperature in welding, a heater is required to carry out heat tracing on the welding seam in each layer of welding, the temperature is controlled to be 120-150 ℃, the welding speed is controlled to finally ensure the welding quality, and the welding deformation is reduced.

9. The off-line installation method of the tuyere flange of the large-scale blast furnace as claimed in claim 1, wherein in step S2, the upper bracing comprises a plurality of welded steel pipes, and a center line of the upper bracing is spaced 200mm from an upper edge of the tuyere opening; the lower part bracing includes a plurality of welded H shaped steel, and the lower part bracing is apart from tuyere belt lower extreme 150mm.