CN112658443A

CN112658443A - Manual argon tungsten-arc welding process method for steel-aluminum connector

Info

Publication number: CN112658443A
Application number: CN202011493804.1A
Authority: CN
Inventors: 陈杰恒; 王飞; 何仲; 沈斌强; 喜鑫; 陈益希; 方战华
Original assignee: Jiangsu Libert Inc
Current assignee: Jiangsu Libert Inc
Priority date: 2020-12-17
Filing date: 2020-12-17
Publication date: 2021-04-16
Anticipated expiration: 2040-12-17
Also published as: CN112658443B

Abstract

The invention discloses a manual argon tungsten-arc welding process method for a steel-aluminum joint and preparation before welding, which comprises the following steps: a manual argon tungsten-arc welding process method for a steel-aluminum connector comprises the following steps: B. the pipe fitting to be welded is paired with the steel-aluminum joint, and C, the groove welding seams on the two sides of the steel-aluminum joint are tack welded: D. before welding, external objective factors are checked; E. groove weld welding: firstly, welding a groove weld at the aluminum side of the steel-aluminum joint, and then welding a groove weld at the stainless steel side of the steel-aluminum joint; F. checking each objective factor of welding in the welding process; G. and (5) inspecting after welding. When the welding process method is used for welding the welding seams of the process pipelines on the two sides of the steel-aluminum joint, the welding seam is attractive in forming, uniform in welding lines, small in heat input amount, compact in structure, stable in welding seam quality, low in welding difficulty, strict in temperature control of a heat affected zone, low in heating temperature of a composite material part of the steel-aluminum joint and small in quality risk.

Description

Manual argon tungsten-arc welding process method for steel-aluminum connector

Technical Field

The invention relates to a manual argon tungsten-arc welding process method, which is used for welding stainless steel pipes and aluminum pipes with steel-aluminum joints respectively.

Background

The process pipeline containing the steel-aluminum joint has higher quality requirement on the welding seam, and has strict requirement on the welding temperature of the groove welding seams at two sides of the steel-aluminum joint. The welding seam adopts the manual arc welding single-side welding double-side forming technology, although the welding quality can be ensured, the manual arc welding spatters, the outer surface of the steel-aluminum joint and the temperature indicating band are easily damaged, and the application range is limited. The argon tungsten-arc welding has no splashing, concentrated heat, large penetration and stable welding quality, so the argon tungsten-arc welding becomes a preferred welding process method for welding the bottom layer, the filling layer and the cover surface layer of the welding seams at two sides of the steel-aluminum joint.

The manual tungsten electrode argon arc welding process for the welding seam of the stainless steel side welding seam and the welding seam of the aluminum side of the traditional steel-aluminum joint has the advantages that the assembly gap of the welding seams is small, even no gap exists, the welding operation requires a welder to keep stable arc length, the welding operation is straight-in and straight-away, the actual welding often has the defects that the staying time of electric arcs on two sides of a groove is not uniform, the electric arc length is unstable, the appearance forming is poor, the electric arcs are not fused, air holes and even roots are not welded thoroughly, the welding sequence and the welding direction are not required intentionally, the control of the temperature between channels and the temperature of a heat affected.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: when the welding process method is used for welding the welding seams of the process pipelines on the two sides of the steel-aluminum joint, the welding seam is attractive in forming, uniform in welding lines, small in heat input amount, compact in structure, stable in welding seam quality, low in welding difficulty, strict in temperature control of a heat affected zone, low in heating temperature of a composite material part of the steel-aluminum joint and small in quality risk.

In order to solve the technical problems, the technical scheme of the invention is as follows: a manual argon tungsten-arc welding process method for a steel-aluminum connector comprises the following steps:

A. preparing before welding, comprising the following steps:

A1) determining a welding execution standard;

A2) determining the specification, the mark, the specification and the mark of a welding material and a gas execution standard of the steel-aluminum connector and the connecting pipe;

A3) selecting tools and accessories;

A4) checking and accepting the pipe fittings, the steel-aluminum joints and the tool;

A5) scribing the pipe fitting and checking the size of the pipe fitting;

A6) cutting and blanking the pipe fitting, wherein the perpendicularity between the end face of the notch and the axis of the pipe fitting meets the standard requirement;

A7) processing a bevel on the end face of a cut of a pipe fitting to be welded, wherein the bevel angle is 30-32 degrees, and the truncated edge is 0.5-1 mm;

when the wall thickness of the pipe fitting is larger than 21.95, the groove machine is processed into a U-shaped step groove with the root part of R8, the thickness of the root part is 18-20mm, the groove angle is 20 degrees, the groove angle of the part above the root part is 10 degrees, and the root truncated edge is 0-2 mm;

A8) removing impurities on the inner surface and the outer surface of the groove surface within 20mm, and exposing the metallic luster;

A9) checking whether the operation of an argon filling device in the pipe fitting meets the process requirements;

B. assembling a pipe fitting to be welded with a steel-aluminum joint, and comprises the following steps:

B1) confirming that the material of the tooling fixture for pairing is the same as or the same as that of the pipe fitting, and confirming that the material of the point fixing block is the same as or the same as that of the pipe fitting when the point fixing block is required to be used;

B2) confirming that the material of the group of the aluminum material side to the gasket ring is the same as the aluminum pipe;

B3) the material specifications for the liner ring of the group were confirmed as follows:

B31) an aluminum pipe with the wall thickness delta less than or equal to 6mm is processed into a group of liner ring by adopting an aluminum plate with the width of 30mm and the thickness of 4 mm;

B32) an aluminum pipe with the wall thickness of more than 6mm and delta of less than or equal to 12mm is processed and assembled by an aluminum plate with the width of 40mm and the thickness of 4mm to form a liner ring;

B33) an aluminum pipe with the wall thickness of 12mm < delta < 18mm is processed by an aluminum plate with the width of 45mm and the thickness of 4mm to form a liner ring;

B34) an aluminum pipe with the wall thickness of more than 18mm and delta less than or equal to 26mm is processed and assembled to form a lining ring by adopting an aluminum plate with the width of 50mm and the thickness of 4 mm;

B4) respectively pairing the stainless steel pipe fitting and the aluminum pipe fitting with a stainless steel side end and an aluminum side end of a steel-aluminum joint

B5) Checking the coaxiality of the pipe sections by the group, wherein the inner misalignment is less than 10% of the wall thickness and less than or equal to 1 mm;

C. carrying out tack welding on groove welding seams on two sides of the steel-aluminum joint:

D. before welding, external objective factors are checked;

E. groove weld welding: firstly, welding a groove weld at the aluminum side of the steel-aluminum joint, and then welding a groove weld at the stainless steel side of the steel-aluminum joint;

E1) welding seam welding for aluminum side groove

E11) Determining the arc starting position, the welding position and the welding direction of backing welding:

E12) manual argon tungsten-arc welding is adopted to weld aluminum materials, and alternating current, a left welding method, linear welding beads, channel pressing welding, multilayer and multi-channel welding are carried out, and the inter-channel temperature is controlled; tracking and controlling the temperature of the aluminum side neck of the steel-aluminum joint; selecting a corresponding welding method according to the type of the welding seam for welding;

E121) determining that the welding process parameters meet the following requirements: welding current 250-; welding voltage is 33-37V; the welding speed is 12-20 cm/min; the flow of the front protective gas is 15-25L/min; the highest inter-pass temperature of the pass welding pass is less than or equal to 80 ℃; during the welding of each cladding metal, a point thermometer is used for tracking and measuring the straight-edge neck part of the edge of the groove of the molten pool, and the measuring temperature is less than or equal to 200 ℃.

E122) When the ambient temperature is-20-0 ℃, preheating the aluminum pipe fitting, wherein the preheating temperature is 40-50 ℃;

E123) the defects between welding beads need to be polished and cleaned;

E13) welding a priming bead of the aluminum side groove;

E14) welding a filling layer of the aluminum side groove;

E15) welding the cover surface layer of the aluminum side groove;

E16) in the whole welding process, the welding handle is held tightly, a left welding method is adopted, the included angle between the axis of the welding gun and the normal line is not more than 10 degrees, the welding handle is driven by the wrist to move linearly, the stable and uniform action is kept, and the arc length is controlled to be 4-7 mm; feeding wires against the welding advancing direction, wherein the included angle between the axis of the welding wire and the welding advancing direction is not more than +/-8 degrees; the included angle between the axis of the welding wire and the edge plane of the molten pool is not more than 15 degrees; when the wire feeding mode is intermittent point-like reciprocating wire feeding, the end of the welding wire does not leave the argon protection area; when the wire is continuously fed, the end of the welding wire is only fed to the edge of the molten pool;

E17) the welding mode when connecting does: starting an arc in a slope which is about 10-20 mm from the front of the joint, moving the arc backwards to the upper part of the gentle slope of the joint, heating and melting to form a molten pool, controlling the size of the molten pool to gradually supply wires, filling molten aluminum water on the edges of a fusion line at two sides of the molten pool, moving the arc forwards to move the molten pool forwards, gradually prolonging the welding line, and enabling the retention time of the arc at two sides of the slope to be longer than the middle of the welding line;

E18) tracking and measuring the temperature of the side neck of the aluminum material of the steel-aluminum joint during welding: during welding, the straight-edge neck part of the edge of the groove of the molten pool is contacted by a point thermometer, moves along with the movement of the electric arc, is tracked and measured, and the measured temperature is less than or equal to 200 ℃; stopping welding by a welder before the temperature approaches 200 ℃, and then welding when the inter-lane temperature is less than or equal to 80 ℃;

E2) stainless steel side groove weld seam welding

E21) Determining the arc starting position, the welding position and the welding direction of backing welding:

E22) manual argon tungsten-arc welding, direct-current direct connection, a left welding method, linear welding beads, channel pressing welding, multilayer multi-channel welding, inter-channel temperature control and tracking control of the temperature of the neck of the steel-aluminum joint are adopted for welding; the horizontal fixed welding mode adopts vertical upward welding; the horizontal rotation welding mode adopts anticlockwise channel pressing welding; the transverse welding position of the transverse welding mode adopts anticlockwise pressure welding;

E23) welding a priming bead of the stainless steel side groove:

E24) filling the stainless steel side groove, and welding a cover surface layer;

welding each welding seam cladding metal of the filling and covering surface layer according to the welding direction of backing welding; the linear welding bead and the pressure welding are carried out, welding is carried out from the side bevel face of the stainless steel pipe firstly, the stainless steel side bevel face of the steel-aluminum connector is welded in a step-by-step pressure welding mode, the residence time of a molten pool on two sides of the bevel face is longer than that in the middle of a welding line, the width of each welding line is not more than 3 times of the diameter of a steel core of a welding material, the cladding metal connector on the next welding line is staggered with the cladding metal connector on the previous layer (line), the arc pit is filled in the arc closing, and the defect forming of the arc closing position and the defect between the lines is cleaned in.

E25) In the whole welding process, the lower part of a magnetic nozzle of a welding gun is supported on the slope surface of the root part, the welding handle is held tightly by taking the lower part as a fulcrum, the wrist performs uniform circular motion to drive the welding handle to perform conical swing and advance in the range of 70-85 degrees of the axial direction of a tungsten wire pressure cap by taking the fulcrum of the magnetic nozzle as a vertex, the tungsten electrode pressure cap and an argon arc column perform conical swing and advance, the lower part of the magnetic nozzle rotates along with the formation of a welding seam and uses the red hot welding seam surface as a support to stably move forwards, the inner convex height of the welding seam root is controlled in the range of 0-2 mm, the end of a welding wire at an overhead welding part is sent to the root part of a groove, and the horizontal fixed welding opening is vertically inclined to the flat;

E26) the welding mode when the welding seam connects is as follows: starting an arc in a slope which is about 10-20 mm from the front of the joint, moving backwards to the upper part of the gentle slope of the joint, enabling the electric arc to stay at two sides of the slope for a longer time than the middle of a welding line to ensure that the two sides are fused, controlling the size of a molten pool to gradually feed wires after the molten pool is formed, filling molten iron on the edges of the fusion lines at the two sides of the molten pool, moving forwards to enable the molten pool to move forwards, and gradually prolonging the welding line in the forward direction;

E27) tracking and measuring the temperature of the stainless steel side neck of the steel-aluminum joint during welding: the straight edge neck part of the edge of the groove of the molten pool is contacted by a point thermometer during welding, moves along with the movement of the electric arc, is tracked and measured, and the measured temperature is less than or equal to 200 ℃; stopping welding when the temperature is close to 200 ℃, and then welding when the inter-lane temperature is less than or equal to 80 ℃;

F. checking each objective factor of welding in the welding process;

G. and (5) inspecting after welding.

Preferably, the step a3) of selecting tools and accessories specifically includes:

A31) for manual argon tungsten-arc welding of stainless steel: selecting an argon arc welding torch with an angle of 75-80 degrees and a handle wire diameter of 30-50mm²The length is 3-4m, the diameter of the cerium-tungsten electrode is 2.0mm or 2.4mm, the tip of the cerium-tungsten electrode is processed into a cone frustum with the taper of 35-45 degrees, the small diameter of the cone frustum is 0.8-1.0mm, and the protruding length of the cerium-tungsten electrode relative to a ceramic nozzle of the argon arc welding torch is 6-8 mm;

A32) for aluminum manual argon tungsten-arc welding: selecting an argon arc welding torch with an angle of 75-80 degrees and a handle wire diameter of 40-50mm²The length is 3-4m, the diameter of the cerium-tungsten electrode is 3.2mm or 4.0mm, the tip of the cerium-tungsten electrode is processed into a cone frustum with the taper of 35-45 degrees, the small diameter of the cone frustum is 1.2-2.0mm, and the extension length of the cerium-tungsten electrode relative to a ceramic nozzle of the argon arc welding torch is 5-8 mm.

Preferably, the specific acceptance and inspection modes of the pipe fitting, the steel-aluminum joint and the tool in the step A4) are as follows:

checking the grade and specification of the pipe fitting; checking whether the specification, the mark, the groove, the surface quality, the temperature control indication label and the like of the steel-aluminum joint are intact; checking whether the measuring instruments of the welding machine ammeter, the voltmeter and the argon gas flowmeter are calibrated and are in the valid period; checking whether the purity of the argon gas is 99.997%; checking whether the digital display point thermometer is calibrated and is in the valid period; checking whether the surface of the welding wire is clean; checking whether the material certificates of the pipe fittings and the welding wires quote standards and physicochemical parameters; determining that a stainless steel grinding sheet and a stainless steel cutting sheet are used for polishing and cleaning a stainless steel side weld; and determining to use the hard alloy cutting blade and the stainless steel wire brush for polishing and cleaning the side weld of the aluminum product.

Preferably, the specific manner of pairing the stainless steel pipe fitting and the aluminum pipe fitting with the stainless steel side end and the aluminum side end of the steel-aluminum joint respectively by B4) is as follows:

B41) and (3) for the pairing of the side groove welds of the aluminum material:

B411) assembling the gasket ring: processing the aluminum strip into a pairing gasket ring slightly smaller than the inner diameter of the pipe, and then installing the pairing gasket ring into a pipe head at the bevel end, wherein the gap between the pairing gasket ring and the inner wall of the pipe is 0-1.5 mm, and the width center line of the pairing gasket ring is superposed with the center line of the pairing gap; for the condition that the stainless steel pipe fitting and the aluminum pipe fitting are not equal in thickness, machining the inner wall of the thicker pipe fitting with a gradient smaller than 1: 4;

B412) when the welding position selects a horizontal fixed welding position for groove weld assembly, when the pipe diameter phi is more than 13mm and less than or equal to phi 168.3mm, the assembly gap at six points of the clock point position of the pipe fitting is 3-4 mm, and the assembly gap at twelve points is more than 4-5 mm; when D is larger than phi 168.3mm, the pairing gap at six points of the clock point position of the pipe fitting is 4-6 mm, and the pairing gap at twelve points is larger than 4-6 mm;

when the welding position selects a horizontal rotation welding position and a transverse welding position, performing groove weld assembly, wherein the horizontal rotation groove weld assembly gap and the transverse welding position groove weld assembly gap are both uniform and are 4-6 mm;

B42) for the pairing of stainless steel side groove welds:

B421) assembling an argon chamber: and installing one air inlet blocking plate and one air outlet blocking plate on the inner wall of the pipe at the distance of 300-400 mm from the welding line on two sides of the welding line. The air inlet blocking plate is connected with the air outlet blocking plate through a steel wire, the air inlet blocking plate is also connected with a steel wire and an argon inlet pipe and extends out of the pipe orifice, the argon inlet pipe is arranged at the low point position near the 6 point of the air inlet blocking plate, the air outlet blocking plate is provided with an argon outlet pipe, and the argon outlet pipe is arranged at the high point position near the 12 point of the air outlet blocking plate;

B422) when the welding position selects a horizontal fixed welding position for groove weld assembly, when the pipe diameter phi is more than 13mm and less than or equal to phi 168.3mm, the assembly gap at six points of the clock point position of the pipe fitting is 2.4-3.2 mm, and the assembly gap at twelve points is more than 3.2-4.0 mm; when D is larger than phi 168.3mm, the pairing gap at six points of the clock point position of the pipe fitting is 3.2-4.0 mm, and the pairing gap at twelve points is larger than 3.2-4.0 mm;

and when the welding position selects the horizontal rotation welding position and the transverse welding position to carry out groove weld assembly, the horizontal rotation groove weld assembly gap and the transverse welding position groove weld assembly gap are both uniform 3.2-4.0 mm.

Preferably, in the step C, performing tack welding on groove welds on two sides of the steel-aluminum joint, the method comprises the following steps:

C1) spot welding for aluminum side groove weld joint

C11) Determining a fixing mode, and selecting group-to-liner ring group pair spot welding;

C12) the tack welding seam is tack-welded on two circular intersecting lines between the truncated edge of the groove and the outer surface of the pairing gasket ring respectively by avoiding three, six, nine and twelve points of the clock point position of the pipe fitting, and when the pipe diameter phi is more than 13mm and less than or equal to 168.3mm, 2-3 tack welding spots are uniformly distributed on each circular intersecting line; when the pipe diameter D is larger than phi 168.3mm, more than or equal to 3 point welding spots are uniformly distributed on each circular intersection line; fully welding a fillet weld between the lining ring and the inner wall of the aluminum pipe fitting on the upstream side of the medium flow direction;

C13) quality of a welding point of the inspection point: the thickness of the tack welding seam is 3-5mm, the length is 10-35mm, if the tack welding seam is defective, the tack welding seam must be polished and removed, then the tack welding seam is tack welded again, and two ends of the tack welding seam are polished into a gentle slope shape;

C2) tack welding of stainless steel side groove weld

C21) Determining a pairing mode: when the pipe diameter is less than 13mm and less than or equal to 168.3mm, selecting a spot welding group to fix or a spot fixing group to fix; when D is larger than phi 168.3mm, the point fixing block group pair is selected for fixing;

C22) when a tack weld joint pair is selected, the gap of the groove is blocked by an adhesive tape without halogen pollution, before tack welding spots are welded at the root part of the groove, a small opening is torn by the adhesive tape, tack welding is started after the argon filling purity of the back side meets the welding requirement, and the tack welding spots at the root part of the groove are melted into the weld joint;

C23) when a tack weld pairing is selected, tack welds are required to avoid the positions of three, six, nine and twelve clock points of the pipe fitting, the number of the tack welds is 1-3, and the tack welds are uniformly distributed at the root of the groove of the pipe fitting; when the point fixing block group pair is selected, point fixing welding points fall between the bevel face and the point fixing blocks, the point fixing blocks are required to avoid the positions of three, six, nine and twelve points of the clock point position of the pipe fitting, and the number of the point fixing blocks is 1-3 when the pipe diameter is phi 13mm and D is less than or equal to phi 168.3mm, and the point fixing blocks are uniformly distributed on the circumferential bevel face of the pipe fitting except the avoiding points; when the pipe diameter D is larger than phi 168.3mm, dividing the circumference of the welding line into 2(n +2) sections which are symmetrical, wherein the number of the point fixing blocks is 2(n +2), and the point fixing blocks are uniformly distributed on the circumferential slope opening surface of the pipe fitting except the avoidance points;

C24) quality of a fixed weld at an inspection point: when the point-fixing weld joint pair is selected, the thickness of the point-fixing weld joint is 3-5mm, the length of the point-fixing weld joint is 10-35mm, and if the point-fixing weld joint is defective, the point-fixing weld joint must be polished and removed and then is subjected to point-fixing welding again. Polishing two ends of the point-fixed welding seam into a gentle slope shape; when the point fixing block group pair is selected, the thickness of point fixing welding lines on two sides of the point fixing block is 4-8mm, the length of the point fixing welding lines is 10-45mm, and the point fixing welding lines fall between the bevel face and the point fixing block.

Preferably, the specific manner of welding the backing weld bead in the step E13) is as follows:

E131) the handle line of the welding tongs crosses the arm and then is held by the right hand, the arc is started from the arc starting position, and the welding tongs move backwards to the initial welding position to start welding;

E132) when welding with horizontal fixed position

When the pipe diameter phi is more than 13mm and less than or equal to phi 168.3mm, the welding seam of the bottom layer only needs to be divided into two symmetrical circular arcs, one of the two circular arcs is symmetrically welded in the moving direction of 6 points → 3 points → 12 points, and the other circular arc is symmetrically welded in the moving direction of 6 points → 9 points → 12 points; dissolving the spot welding spots into the backing welding cladding metal layer; finally, connecting the backing weld bead near 12 points to form a whole backing weld deposited metal weld bead; before the welding bead end joint is connected, oxide impurities need to be removed by polishing, and the surface of the end is polished into a gentle slope shape;

when the pipe diameter D is larger than phi 168.3mm, the welding seam of the bottoming layer is a symmetrical 2(n +2) section according to the distribution of clocks; each pair of symmetrical welding beads are symmetrically welded according to the moving direction of 6 points → 3 points → 12 points or 6 points → 9 points → 12 points;

starting an arc from an arc starting position close to 6 points, moving an electric arc backwards to a position 10-20 mm away from the rear side of the 6 point position, moving the electric arc forwards by 5-10 mm after the electric arc is stably combusted, starting welding, and moving a molten pool to a9 point position to form a first section of backing welding deposited metal weld bead;

then, in the same welding mode, arc striking is carried out near the position which is centrosymmetric with the arc striking end of the first section of backing weld cladding metal weld bead, and after welding is started, arc striking is carried out near the position which is centrosymmetric with the arc striking end of the first section of backing weld cladding metal weld bead, so as to form a second section of backing weld cladding metal weld bead; the first section of backing welding deposited metal bead is symmetrical to the second section of backing welding deposited metal bead;

then, in the same welding mode, arcing is carried out from the position 10-20 mm before the first section of backing welding deposited metal bead starting point near 6 points, after the arc is stably burnt, the arc moves backwards to weld a spot starting joint with the first section of backing welding deposited metal bead, and then moves towards the position of 3 points to form a third section of backing welding deposited metal bead;

then, arc striking is carried out near the position which is centrosymmetric with the arc striking end of the third backing weld cladding metal weld bead in the same welding mode, and after welding is started, arc striking is carried out near the position which is centrosymmetric with the arc striking end of the third backing weld cladding metal weld bead to form a fourth backing weld cladding metal weld bead; the third section of backing welding deposited metal bead is symmetrical to the fourth section of backing welding deposited metal bead;

and so on and finally form the finished backing weld;

E133) when using the horizontal rotational position for backing welding

Welding in the anticlockwise direction, linearly welding a bead and pressing the bead, starting arc at the position of 10-20 mm behind 0.5 point between the positions of 1 point → 12 point, then moving the arc forward by 10mm to start welding, when a point welding point is met, lengthening the arc to increase preheating, ensuring penetration, and dissolving the point welding point into a backing welding cladding metal layer; after rotating for one circle, an electric arc and a backing weld joint start welding end joint to form a whole backing weld deposited metal weld bead, before the weld bead end joint is connected, oxide impurities need to be polished to remove, and the surface of the end is polished to be in a gentle slope shape;

E134) when transverse welding is carried out at the transverse welding position

Welding in the anticlockwise direction, linearly welding a bead and pressing the bead, moving the electric arc backwards by 20mm after starting the arc from the position with the minimum gap, then moving the electric arc forwards by 10mm to start welding, lengthening the electric arc to increase preheating when a point welding spot is met, ensuring penetration, and dissolving the point welding spot into a backing welding cladding metal layer; and finally, the electric arc and the backing weld joint start welding an end joint to form a whole backing weld deposited metal weld bead, before the weld bead end joint is connected, oxide impurities need to be polished to remove, and the surface of the end is in a gentle slope shape.

Preferably, in the step E21), the arc starting position, the welding position and the welding direction of the backing weld are determined, and the specific determination contents are as follows:

E211) when welding with horizontal fixed position

Dividing according to the circumference section of the pipe fitting, defining the bottom position as 6 point positions, defining the top position as 12 point positions, dividing the pipe fitting section according to the clock scale, and welding the direction: 6 points → 3 points → 12 points; point 6 → point 9 → point 12, and defines the advancing direction of the weld as forward; the initial welding position is 10-20 mm away from the rear side of the position 6 of the arcing position;

E212) when backing welding is carried out at a horizontal rotating position, dividing according to the circumferential section of the pipe fitting, defining the bottom position as the position of 6 points, defining the top position as the position of 12 points, dividing the section of the pipe fitting according to the scale of a clock, defining the advancing direction of a welding line as the front, welding in the anticlockwise direction, and taking the initial welding position as the position 10-20 mm behind the 1.5 point of an arc starting position between the positions of 2 points → 12 points;

E213) when the transverse welding position is adopted for transverse welding, the advancing direction of a welding seam is defined as the front direction, the welding is carried out in the anticlockwise direction, the arc is started at the position with the minimum assembly gap, and the initial welding position is taken at the position 10-20 mm behind the arc starting point.

Preferably, the substeps of step E22) are:

E221) determining that the welding process parameters meet the following requirements: welding current is 60-160A; welding 10-14V; the welding speed is 5-10 cm/min; the flow of the front protective gas is 10-25L/min; the flow of the back side protective gas is 10-15L/min; the highest inter-pass temperature of each welding pass is less than or equal to 80 ℃;

E222) preheating at the ambient temperature of-20-0 ℃, wherein the preheating temperature is 40-50 ℃;

E223) during each welding period of the cladding metal, a point thermometer is used for tracking and measuring the straight-edge neck part of the edge of the groove of the molten pool, and the measuring temperature is less than or equal to 200 ℃.

E224) Defects between the weld beads require grinding for cleaning.

Preferably, the specific welding mode of the backing weld of the E23) stainless steel side groove is as follows:

E231) the handle line of the welding tongs crosses the arm and then is held by the right hand, the arc is started from the arc starting position, and the welding tongs move backwards to the initial welding position to start welding;

E232) for horizontal fixed position welds:

e2321) For the pipe diameter phi 13mm < D < phi 168.3mm, and when spot welding groups are adopted to weld the welding seams, the welding seams of the bottom layer are divided into two symmetrical circular arcs, namely one arc is symmetrically welded in the moving direction shown by 6 points → 3 points → 12 points, and the other arc is symmetrically welded in the moving direction shown by 6 points → 9 points → 12 points; when welding is carried out in the moving direction of 6 points → 3 points → 12 points, an electric arc is used for penetrating through the blunt edge from the middle position of the gap to form a molten hole at the position 10-20 mm behind the 6 points, molten iron is filled at the lower part of the molten hole, the molten hole moves upwards, the molten iron is cooled to form a backing weld bead with one-side welding and two-side forming, the backing weld bead dissolves a point welding point into a backing weld pool, the weld bead cladding metal continues to extend towards the 12 point direction, and an arc is closed near the 12 point to form a first section of backing weld cladding metal weld bead;

welding in the same welding mode in the moving direction of 6 points → 9 points → 12 points, starting arcing from the position 10-20 mm before the starting end point of the first section of backing weld deposited metal weld bead, moving the electric arc to the gentle slope position joint of the starting end point, moving the electric arc forward, punching a truncated edge from the middle position of the gap to form a fusion hole, filling molten iron at the lower part of the fusion hole, moving the fusion hole upwards, cooling the molten iron to form a single-side welding double-sided formed backing weld, dissolving a point welding point into a backing weld pool by the backing weld, and finally closing the backing weld bead near 12 points with the first section of backing weld deposited metal arc closing point joint to form the whole backing weld deposited metal weld bead;

e2322) For the pipe diameter phi 13mm < D < phi 168.3mm, and when the spot-solid block group is adopted for butt welding, the welding seam of the bottom layer only needs to be divided into two symmetrical circular arcs, namely one arc is symmetrically welded in the moving direction shown by 6 points → 3 points → 12 points, and the other arc is symmetrically welded in the moving direction shown by 6 points → 9 points → 12 points; when welding is carried out in the moving direction of 6 points → 3 points → 12 points, an electric arc is used for penetrating through a truncated edge from the middle position of a gap to form a molten hole at the position 10-20 mm behind the 6 points, molten iron is filled at the lower part of the molten hole, the molten hole moves upwards, molten iron is cooled to form a backing weld bead with a single-side welding and double-side forming, the backing weld bead extends forwards to meet the front arc-closing of the point fixing block, the point fixing block is polished and removed, the end of the weld bead is polished to be in a gentle slope shape, the arc starts at the position 10-20 mm in front of the end of the weld bead, then the electric arc moves to a gentle slope joint at the end, the weld cladding metal continues to extend towards the 12 points, the arc is closed near the 12 points, and a first backing welding.

Welding in the same welding mode in the moving direction of 6 points → 9 points → 12 points, starting arc at the position 10-20 mm before the starting end of the first section of backing welding deposited metal bead, moving the arc to the gentle slope of the starting end to perform joint, then welding in the direction of 12 points, and performing joint with the arc closing point of the first section of backing welding deposited metal bead to form a second section of backing welding deposited metal bead;

e2323) For the pipe diameter D larger than phi 168.3mm, adopting the welding seam welding of point-fixed block pairing and adopting a sectional symmetrical welding method;

starting welding from an initial welding position of an arc starting position, moving backwards to a position 10-20 mm away from the rear side of the position of 6 points, penetrating a truncated edge from the middle position of a gap by using an electric arc to form a molten hole, filling molten iron on the lower part of the molten hole, moving the molten hole upwards, cooling the molten iron to form a single-side welding double-sided forming backing weld, extending a weld cladding metal to the direction of 9 points, closing the arc when meeting a point solid block in the process, polishing and removing the point solid block, continuing welding, closing the arc at 8 points to form a first section of backing welding deposited metal weld bead, and polishing two ends of the first section of backing welding deposited metal weld bead into a gentle slope shape;

then, in the same welding mode, welding is started 10-20 mm before the point fixing block at the position of 2 points of the pipe fitting, and the weld cladding metal extends towards the direction of 12 points until the arc is closed to form a second section of backing welding cladding metal weld bead near 12 points; polishing two ends of the second backing weld deposited metal bead into a gentle slope shape;

moving backwards from a 6-point arc starting position in the same welding mode, moving the electric arc to a 3-point position after starting a welding point joint with the first backing weld deposited metal weld bead until the electric arc is closed to form a third backing weld deposited metal weld bead near 4 points, and polishing the arc closing part of the third backing weld deposited metal weld bead into a gentle slope shape;

then, in the same welding mode, starting welding at a position 10-20 mm before the point fixing block is positioned at the position of 10 points of the pipe fitting until the arc is closed at a joint close to 12 with the end of the second section of backing weld to form a fourth section of backing weld deposited metal weld bead, and polishing the welding starting end of the fourth section of backing weld deposited metal weld bead into a gentle slope shape;

then, in the same welding mode, arcing is carried out at the position 10-20 mm before the third section of backing weld cladding metal end near the position 4 of the pipe fitting, the electric arc is moved to the gentle slope joint of the third section of backing weld cladding metal end to start welding, and the gentle slope joint of the third section of backing weld cladding metal end and the gentle slope joint of the second section of backing weld cladding metal end is arched to form a fifth section of backing weld cladding metal weld bead near 2;

then, in the same welding mode, arcing is carried out at the position 10-20 mm before the first-section backing weld cladding metal end near the position of 8 points of the pipe fitting, the electric arc is moved to the gentle slope joint of the first-section backing weld cladding metal end to start welding, and the arc is closed to form a sixth-section backing weld cladding metal weld bead with the gentle slope joint of the fourth-section backing weld cladding metal end near 10 points;

e2324) The priming coat is welded with two layers, one for each layer.

After the technical scheme is adopted, the invention has the effects that: when the welding process method is used for welding the welding seam process pipelines on the two sides of the steel-aluminum joint, the welding seam is attractive in forming, uniform in welding lines, small in heat input amount, compact in structure, stable in welding seam quality, low in welding difficulty, small in welding seam heat affected zone, low in temperature, the color of the temperature indicating label is changed in a qualified area, and the influence of welding heat on thermal expansion damage of a steel-aluminum joint composite material is small.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a partial axial structural section of a groove after steel-aluminum joint assembly of an embodiment of the invention;

FIG. 2 is a circumferential uniform split schematic of a steel aluminum joint weld of an embodiment of the invention;

FIG. 3 is a schematic view of spot welding of an aluminum material side groove of a steel-aluminum joint according to an embodiment of the invention;

FIG. 4 is a schematic diagram of a point thermometer tracking measurement during welding of a steel aluminum joint according to an embodiment of the invention;

FIG. 5 is a schematic view of a metal bead distribution of an aluminum side weld cladding of a steel aluminum joint of an embodiment of the invention;

FIG. 6 is a schematic illustration of a stainless steel side weld clad metal bead distribution for a steel aluminum joint according to an embodiment of the invention;

in the drawings: 1. an aluminum pipe fitting; 101. blunt edges of aluminum pipe fittings; 2. aluminum side beveling; 3. assembling a liner ring; 4. coating bottom cladding metal on the side of the aluminum material; 5. solidifying the blocks; 6. fixing welding spots; 7. stainless steel pipe fittings; 701. stainless steel pipe fitting blunt edges; 8. a stainless steel side bevel; 9. fillet welding; D. a point thermometer D; J. a steel-aluminum joint;

Detailed Description

The present invention is described in further detail below with reference to specific examples.

As shown in fig. 1 to 6, a manual argon tungsten-arc welding process method for a steel-aluminum joint comprises the following steps:

A. preparing before welding, comprising the following steps:

A1) determining a welding execution standard; the execution criteria in this embodiment are: ASME boiler and pressure vessel code "welding and brazing process, welder, brazier and welding and brazing operator evaluation Standard" volume IX 2015; ASME boiler and pressure vessel code pressure vessel construction rules volume VIII-1, volume 2015; ASME pressure pipeline Specification "Process pipeline" ASME B31.3-2014;

A2) determining the specification, the mark, the specification and the mark of a welding material and the gas execution standard of the steel-aluminum joint J and the connecting pipe;

table 1 records the technological parameters of the steel-aluminum joint J, the pipe and the welding material for welding in the embodiment;

type (B)	Number plate	Specification of	Execution criteria
				Steel-aluminum joint J	MPS-275	φ219.1×12.7	MPS-275 Enterprise Standard
Aluminum pipe fitting	5083-O	φ219.1×12.7	SAME SB-210
				Aluminum flat steel	5083	45×4	SAME SB-209
Stainless steel pipe fitting	304	φ219.1×12.7	SAME SA-240
				Aluminum welding wire	ER5183	φ3.2	AWS A5.10
Stainless steel welding wire	ER308	φ2.4	AWS A5.9
				Argon gas	Ar	99.997％	GB/T 4842-2006

TABLE 1

A3) Selecting tools and accessories;

A4) Checking and accepting the pipe fitting, the steel-aluminum joint J and the tool;

the specific mode of checking and accepting the pipe fitting, the steel-aluminum joint J and the tool in the step A4) is as follows:

checking the grade and specification of the pipe fitting; checking whether the J specification, the mark, the groove, the surface quality, the temperature control indication label and the like of the steel-aluminum joint are intact; checking whether the measuring instruments of the welding machine ammeter, the voltmeter and the argon gas flowmeter are calibrated and are in the valid period; checking whether the purity of the argon gas is 99.997%; checking whether the digital display point thermometer D is calibrated and is in the valid period; checking whether the surface of the welding wire is clean; checking whether the material certificates of the pipe fittings and the welding wires quote standards and physicochemical parameters; determining that a stainless steel grinding sheet and a stainless steel cutting sheet are used for polishing and cleaning a stainless steel side weld; and determining to use the hard alloy cutting blade and the stainless steel wire brush for polishing and cleaning the side weld of the aluminum product.

A5) Scribing the pipe fitting and checking the size of the pipe fitting;

B. assembling a pipe fitting to be welded with a steel-aluminum joint J, and comprising the following steps:

B1) confirming that the tooling fixture for pairing is the same as or the same as the pipe fitting in material, and confirming that the point fixing block 5 is the same as or the same as the pipe fitting in material when the point fixing block 5 is needed;

B2) confirming that the material of the pairing gasket ring 3 on the aluminum material side is the same as the quality of the aluminum pipe fitting 1;

B3) the material specifications of the set for the gasket ring 3 were confirmed as follows:

B31) an aluminum pipe with the wall thickness delta less than or equal to 6mm is processed into a group by an aluminum plate with the width of 30mm and the thickness of 4mm to form a lining gasket ring 3;

B32) an aluminum pipe with the wall thickness of more than 6mm and delta of less than or equal to 12mm is processed and assembled by an aluminum plate with the width of 40mm and the thickness of 4mm to form a lining ring 3;

B33) an aluminum pipe with the wall thickness of 12mm < delta < 18mm is processed and assembled by an aluminum plate with the width of 45mm and the thickness of 4mm to form a lining ring 3;

B34) an aluminum pipe with the wall thickness of more than 18mm and delta less than or equal to 26mm is processed and assembled by an aluminum plate with the width of 50mm and the thickness of 4mm to form a lining ring 3;

B4) respectively pairing the stainless steel pipe fitting 7 and the aluminum pipe fitting 1 with a stainless steel side end and an aluminum side end of a steel-aluminum joint J; as shown in figure 1 of the drawings, in which,

the B4) is characterized in that the specific mode that the stainless steel pipe fitting 7 and the aluminum pipe fitting 1 are respectively paired with the stainless steel side end and the aluminum side end of the steel-aluminum joint J is as follows:

B41) for the pair of the aluminum material side groove 2 welding seams:

B411) assembly of the gasket ring 3: processing the aluminum strip into a fitting gasket ring 3 ring slightly smaller than the inner diameter of the pipe, and then installing the fitting gasket ring 3 ring into a pipe head at the bevel end, wherein the gap between the fitting gasket ring 3 and the inner wall of the pipe is 0-1.5 mm, and the width center line of the fitting gasket ring 3 is superposed with the fitting gap center line; for the condition that the stainless steel pipe fitting 7 and the aluminum pipe fitting 1 are not equal in thickness, the inner wall of the thicker pipe fitting is processed with a gradient smaller than 1: 4;

B42) for the pair of stainless steel side groove 8 welds:

B421) assembling an argon chamber: and installing one air inlet blocking plate and one air outlet blocking plate on the inner wall of the pipe at the distance of 300-400 mm from the welding line on two sides of the welding line. The air inlet blocking plate is connected with the air outlet blocking plate through a steel wire, the air inlet blocking plate is also connected with a steel wire and an argon inlet pipe and extends out of the pipe orifice, the argon inlet pipe is arranged at the low point position near the 6 point of the air inlet blocking plate, the air outlet blocking plate is provided with an argon outlet pipe, and the argon outlet pipe is arranged at the high point position near the 12 point of the air outlet blocking plate; therefore, the gas flow which is convenient for filling argon gas into the interior is in a low-in and high-out mode, and is beneficial to exhausting all impurity gas. In addition, an argon outlet pipe is arranged for pressure relief, so that the defect that the arc-closing position of the bottom layer is concave can be effectively avoided.

C. spot welding is carried out on groove welding seams on two sides of a steel-aluminum joint J, as shown in figures 2 and 3:

preferably, in the step C, the tack welding of groove welds on two sides of the steel-aluminum joint J includes the following steps:

C1) tack welding for aluminum side groove 2 weld joint

C11) Determining a fixing mode, and selecting a pair of group-to-group gasket rings 3 for point welding;

C12) the tack welding seam is tack welded on two circular intersecting lines between the truncated edge of the groove and the outer surface of the pairing gasket ring 3 respectively by avoiding three, six, nine and twelve points of the clock point position of the pipe fitting, and when the pipe diameter phi is less than 13mm and less than or equal to 168.3mm, 2-3 tack welding spots 6 are uniformly distributed on each circular intersecting line; when the pipe diameter D is larger than phi 168.3mm, more than or equal to 3 point welding points 6 are uniformly distributed on each circular intersection line; fully welding fillet welds 9 between the gasket ring 3 and the inner wall of the aluminum pipe fitting 1 by the assembly on the upstream side of the medium flowing direction;

C13) quality of the inspection point weld points 6: the thickness of the tack welding seam is 3-5mm, the length is 10-35mm, if the tack welding seam is defective, the tack welding seam must be polished and removed, then the tack welding seam is tack welded again, and two ends of the tack welding seam are polished into a gentle slope shape;

C2) tack welding of stainless steel side groove 8 weld

C21) Determining a pairing mode: when the pipe diameter is less than 13mm and less than or equal to 168.3mm, selecting a spot welding group to fix or a spot fixing block 5 to fix; when D is larger than phi 168.3mm, selecting and fixing 5 point-fixing blocks to be paired and fixed;

C22) when a tack weld joint pair is selected, the gap of the groove is blocked by an adhesive tape without halogen pollution, before tack welding spots 6 at the root part of the groove are welded, a small opening is torn by the adhesive tape, tack welding is started after the argon filling purity of the back side meets the welding requirement, and the tack welding spots 6 at the root part of the groove are melted into the weld joint;

C23) when a tack weld pairing is selected, tack welds are required to avoid the positions of three, six, nine and twelve clock points of the pipe fitting, the number of the tack welds is 1-3, and the tack welds are uniformly distributed at the root of the groove of the pipe fitting; when 5 groups of the point fixing blocks are selected, the point fixing welding points 6 fall between the bevel surface and the point fixing blocks 5, the point fixing blocks 5 are required to avoid the positions of three, six, nine and twelve points of the clock point position of the pipe fitting, and the number of the point fixing blocks 5 is 1-3 when the pipe diameter phi 13mm is more than D and less than or equal to phi 168.3mm, and the point fixing blocks are uniformly distributed on the circumferential bevel surface of the pipe fitting except the avoidance points; when the pipe diameter D is larger than phi 168.3mm, the circumference of the welding line is divided into 2(n +2) sections which are symmetrical, the number of the point fixing blocks 5 is 2(n +2), and the point fixing blocks are uniformly distributed on the circumferential groove surface of the pipe fitting except the avoidance point;

C24) quality of a fixed weld at an inspection point: when the point-fixing weld joint pair is selected, the thickness of the point-fixing weld joint is 3-5mm, the length of the point-fixing weld joint is 10-35mm, and if the point-fixing weld joint is defective, the point-fixing weld joint must be polished and removed and then is subjected to point-fixing welding again. Polishing two ends of the point-fixed welding seam into a gentle slope shape; when the point fixing blocks 5 are selected for pairing, the thickness of point fixing welding seams on two sides of the point fixing blocks 5 is 4-8mm, the length of the point fixing welding seams is 10-45mm, and the point fixing welding seams fall between the bevel face and the point fixing blocks 5.

D. Before welding, external objective factors are checked;

E. groove weld welding: firstly, welding a groove weld at the aluminum material side of the steel-aluminum joint J, and then welding a groove weld at the stainless steel side of the steel-aluminum joint J;

E1) aluminum side bevel 2 weld joint welding

E12) manual argon tungsten-arc welding is adopted to weld aluminum materials, and alternating current, a left welding method, linear welding beads, channel pressing welding, multilayer and multi-channel welding are carried out, and the inter-channel temperature is controlled; tracking and controlling the temperature of the aluminum material side neck part of the steel-aluminum joint J; selecting a corresponding welding method according to the type of the welding seam for welding;

E121) determining that the welding process parameters meet the following requirements: welding current 250-; welding voltage is 33-37V; the welding speed is 12-20 cm/min; the flow of the front protective gas is 15-25L/min; the highest inter-pass temperature of the pass welding pass is less than or equal to 80 ℃; during the welding of each cladding metal, a point thermometer D is used for tracking and measuring the straight-edge neck part of the edge of the groove of the molten pool, and the measuring temperature is less than or equal to 200 ℃.

E122) When the ambient temperature is-20 ℃ to 0 ℃, preheating the aluminum pipe fitting 1 at the preheating temperature of 40 ℃ to 50 ℃;

E123) the defects between welding beads need to be polished and cleaned;

table 2 is a welding process parameter table of the steel aluminum joint JJ aluminum material side 1 groove weld 2 priming coat and the filling cover coat:

TABLE 2

E13) Welding a priming bead of the aluminum side groove;

E132) when welding with horizontal fixed position

When the pipe diameter phi is more than 13mm and less than or equal to phi 168.3mm, the welding seam of the bottom layer only needs to be divided into two symmetrical circular arcs, one of the two circular arcs is symmetrically welded in the moving direction of 6 points → 3 points → 12 points, and the other circular arc is symmetrically welded in the moving direction of 6 points → 9 points → 12 points; dissolving the spot welding spots 6 into the backing welding cladding metal layer; finally, connecting the backing weld bead near 12 points to form a whole backing weld deposited metal weld bead; before the welding bead end joint is connected, oxide impurities need to be removed by polishing, and the surface of the end is polished into a gentle slope shape;

and so on and finally form the finished backing weld;

E133) when using the horizontal rotational position for backing welding

Welding in the anticlockwise direction, linearly welding a bead and pressing the bead, starting arc at the position of 10-20 mm behind 0.5 point between the positions of 1 point → 12 point, then moving the arc forward by 10mm to start welding, when a tack welding point 6 is met, lengthening the arc to increase preheating, ensuring penetration, and dissolving the tack welding point 6 into a backing welding cladding metal layer; after rotating for one circle, an electric arc and a backing weld joint start welding end joint to form a whole backing weld deposited metal weld bead, before the weld bead end joint is connected, oxide impurities need to be polished to remove, and the surface of the end is polished to be in a gentle slope shape;

E134) when transverse welding is carried out at the transverse welding position

Welding in the anticlockwise direction, linearly welding a bead and pressing the bead, moving the electric arc backwards by 20mm after starting the arc from the position with the minimum gap, then moving the electric arc forwards by 10mm to start welding, stretching the electric arc to increase preheating when a point welding spot 6 is met, ensuring penetration, and dissolving the point welding spot 6 into a backing welding cladding metal layer; and finally, the electric arc and the backing weld joint start welding an end joint to form a whole backing weld deposited metal weld bead, before the weld bead end joint is connected, oxide impurities need to be polished to remove, and the surface of the end is in a gentle slope shape.

E14) Welding a filling layer of the aluminum side groove;

E15) welding the cover surface layer of the aluminum side groove;

E18) tracking and measuring the temperature of the side neck part of the J aluminum material of the steel aluminum joint during welding: during welding, the straight-edge neck part of the edge of the groove of the molten pool is contacted with a point thermometer D, moves along with the movement of the electric arc, is tracked and measured, and the measured temperature is less than or equal to 200 ℃; stopping welding by a welder before the temperature approaches 200 ℃, and then welding when the inter-lane temperature is less than or equal to 80 ℃;

E2) stainless steel side bevel 8 weld joint weld

E211) when welding with horizontal fixed position

E22) Manual argon tungsten-arc welding, direct-current positive welding, a left welding method, linear welding beads, channel pressing welding, multilayer multi-channel welding, inter-channel temperature control and tracking control of the J neck temperature of the steel-aluminum joint; the horizontal fixed welding position adopts vertical upward welding; the horizontal rotation welding position adopts anticlockwise channel welding; the transverse welding position which is vertically fixed adopts anticlockwise channel welding;

E23) welding of the priming bead of the stainless steel side groove 8:

preferably, the substeps of step E22) are:

E223) during each welding period of the cladding metal, a point thermometer D is used for tracking and measuring the straight-edge neck part of the edge of the groove of the molten pool, and the measuring temperature is less than or equal to 200 ℃.

E224) Defects between the weld beads require grinding for cleaning.

Table 3 is a welding process parameter table of the steel-aluminum joint JJ stainless steel side 11 groove weld 22 priming layer and the filling cap layer:

TABLE 3

Preferably, the specific welding mode of the backing weld of the E23) stainless steel side groove 8 is as follows:

E232) for horizontal fixed position welds:

e2321) For the pipe diameter phi 13mm < D < phi 168.3mm, and when spot welding groups are adopted to weld the welding seams, the welding seams of the bottom layer are divided into two symmetrical circular arcs, namely one arc is symmetrically welded in the moving direction shown by 6 points → 3 points → 12 points, and the other arc is symmetrically welded in the moving direction shown by 6 points → 9 points → 12 points; when welding is carried out in the moving direction of 6 points → 3 points → 12 points, an electric arc is used for penetrating through the blunt edge from the middle position of the gap to form a molten hole at the position 10-20 mm behind the 6 points, molten iron is filled at the lower part of the molten hole, the molten hole moves upwards, the molten iron is cooled to form a backing weld bead with one-side welding and two-side forming, the backing weld bead dissolves the point welding spot 6 into a backing weld pool, the weld bead cladding metal continues to extend towards the 12 point direction, and an arc is closed near the 12 points to form a first section of backing weld cladding metal weld bead;

welding in the same welding mode in the moving direction of 6 points → 9 points → 12 points, starting arcing from the position 10-20 mm before the starting end point of the first section of backing weld deposited metal weld bead, moving the electric arc to the gentle slope position joint of the starting end point, moving the electric arc forward, punching a truncated edge from the middle position of the gap to form a fusion hole, filling molten iron at the lower part of the fusion hole, moving the fusion hole upwards, cooling the molten iron to form a single-side welding double-sided formed backing weld, dissolving the point welding point 6 into a backing weld pool by the backing weld, and finally closing the backing weld bead near 12 points with the first section of backing weld deposited metal weld bead arc-closing point joint to form the whole backing weld deposited metal weld bead;

e2322) When the pipe diameter phi 13mm is larger than D and is not larger than phi 168.3mm and the spot-fixing block 5 group is adopted to weld the welding seam, the welding seam of the bottom layer only needs to be divided into two symmetrical circular arcs, namely one arc is symmetrically welded in the moving direction shown by 6 points → 3 points → 12 points, and the other arc is symmetrically welded in the moving direction shown by 6 points → 9 points → 12 points; when welding is carried out in the moving direction of 6 points → 3 points → 12 points, an electric arc is used for penetrating through a truncated edge from the middle position of a gap to form a molten hole at the position 10-20 mm behind the 6 points, molten iron is filled at the lower part of the molten hole, the molten hole moves upwards, the molten iron is cooled to form a backing weld bead with a single-side welding and double-side forming, the backing weld bead extends forwards to meet the front arc-closing of the point fixing block 5, the point fixing block 5 is polished and removed, the end of the weld bead is polished to be in a gentle slope shape, the arc starts at the position 10-20 mm in front of the end of the weld bead, then the electric arc moves to a gentle slope joint at the end, the weld bead cladding metal continues to extend towards the 12 points, the arc-closing is carried out near the 12 points.

e2323) For the pipe diameter D larger than phi 168.3mm, adopting the welding seam welding of the point fixing block 5 group pair, and adopting a sectional symmetrical welding method;

starting welding from an initial welding position of an arc starting position, moving backwards to a position 10-20 mm away from the rear side of the position of 6 points, penetrating a truncated edge from the middle position of a gap by using an electric arc to form a molten hole, filling molten iron at the lower part of the molten hole, moving the molten hole upwards, cooling the molten iron to form a single-side welding double-sided formed backing weld, extending a weld cladding metal to the direction of 9 points, continuing welding after meeting a point fixing block 5 in the process, finally performing arc closing at 8 points to form a first section of backing welding deposited metal weld bead, and polishing two ends of the first section of backing welding deposited metal weld bead into a gentle slope shape;

then, in the same welding mode, welding is started 10-20 mm before the point fixing block 5 is positioned at the position of 2 points of the pipe fitting, and the weld cladding metal extends towards the direction of 12 points until the arc is closed to form a second section of backing welding cladding metal weld bead near 12 points; removing the point fixing block 5 at the position of 2 points, and polishing two ends of the second backing welding deposited metal welding bead into a gentle slope shape;

then, in the same welding mode, starting welding at the position 10mm before the fixed block 5 at the position of 10 points of the pipe fitting until the arc is closed at the position close to 12 and the joint of the end of the second section of backing weld joint, forming a fourth section of backing weld deposited metal weld bead, removing the fixed block 5 at the position of 10 points, and polishing the welding starting end of the fourth section of backing weld deposited metal weld bead into a gentle slope shape;

e2324) The priming coat is welded with two layers, one for each layer.

E24) Filling and cover surface layer welding of the stainless steel side groove 8;

welding each welding seam cladding metal of the filling and covering surface layer according to the welding direction of backing welding; the linear welding bead and the pressure welding are firstly welded from the side bevel face of the stainless steel pipe, the welding bead is gradually welded to the 8 faces of the stainless steel side bevel of the steel-aluminum joint J, the residence time of a molten pool on the two sides of the bevel face is longer than that in the middle of a welding bead, the width of each welding bead is not more than 3 times of the diameter of a steel core of a welding material, the cladding metal joint on the next step is staggered with the joint of the cladding metal on the previous layer (step), the arc-closing is filled in the arc pit, and the poor forming of the arc-closing part and the defects between the steps is timely cleaned.

E25) In the whole welding process, at first the welder magnetic nozzle lower part supports on the root bevel face to this is the fulcrum, holds the handle of a welder, and the even circular motion is made to the wrist, drives to weld the handle of a welder and presses the axial 70 ~ 85 within range of cap at the tungsten filament, uses the magnetic nozzle fulcrum to be the summit, and the tungsten electrode presses cap and argon arc post to do the circular cone swing and advance. With the formation of a welding seam, the lower part of the magnetic nozzle is changed to stably move forwards by taking the surface of the red hot welding seam as a support, the inward convex height of the root of the welding seam is controlled within the range of 0-2 mm, the end of a welding wire at the overhead welding part is sent to the root of a groove, and the end of the welding wire at the horizontal fixed welding port is only fed to the edge of a molten pool after being lifted up to the flat welding position;

E27) tracking and measuring the temperature of the stainless steel side neck of the steel-aluminum joint J during welding: the straight edge neck part of the edge of the groove of the molten pool is contacted with a point thermometer D during welding, moves along with the movement of the electric arc, is tracked and measured, and the measured temperature is less than or equal to 200 ℃; stopping welding when the temperature is close to 200 ℃, and then welding when the inter-lane temperature is less than or equal to 80 ℃;

E3) temperature indicating color code

E31) The temperature indication color code is pasted on the aluminum side of the steel-aluminum joint J by a manufacturer. The position can not be moved before welding, and the welding machine can not be damaged or damaged and can not be soaked in water or oil.

E32) And checking the color of the temperature indication color scale. After the welding was completed, the color change of the temperature indicating color scale was checked. And if the color changes in the safe area, the welding quality of the steel-aluminum joint J is qualified. And if the color change exceeds the safe area, the welding quality of the steel-aluminum joint J is unqualified, and the steel-aluminum joint J is scrapped.

This temperature indication color mark generally leaves the factory along with steel aluminium joint J and just sets up, all need monitor temperature indication color mark when welding the aluminium pipe side and when welding stainless steel pipe side, convenient better control temperature.

F. Checking each objective factor of welding in the welding process;

G. and (5) inspecting after welding.

G1) Appearance inspection, namely 100% appearance self-inspection is carried out after welding seams are finished;

G2) checking whether scars are polished to be flat when the point fixing blocks 5 are removed, and performing PT (potential transformer) checking if necessary to eliminate surface defects;

G3) and carrying out ray detection according to the design requirements of the process pipeline.

The above-mentioned embodiments are merely descriptions of the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, and various modifications and alterations made to the technical solution of the present invention without departing from the spirit of the present invention are intended to fall within the scope of the present invention defined by the claims.

Claims

1. A manual argon tungsten-arc welding process method for a steel-aluminum joint is characterized by comprising the following steps: the method comprises the following steps:

A. preparing before welding, comprising the following steps:

A1) determining a welding execution standard;

A3) selecting tools and accessories;

A5) scribing the pipe fitting and checking the size of the pipe fitting;

D. before welding, external objective factors are checked;

E1) welding seam welding for aluminum side groove

E123) the defects between welding beads need to be polished and cleaned;

E13) welding a priming bead of the aluminum side groove;

E14) welding a filling layer of the aluminum side groove;

E15) welding the cover surface layer of the aluminum side groove;

E2) stainless steel side groove weld seam welding

E23) welding a priming bead of the stainless steel side groove:

F. checking each objective factor of welding in the welding process;

G. and (5) inspecting after welding.

2. The manual argon tungsten-arc welding process method for the steel-aluminum joint as claimed in claim 1, wherein the argon tungsten-arc welding process method comprises the following steps: the step A3) of selecting tools and accessories specifically comprises the following steps:

3. The manual argon tungsten-arc welding process method for the steel-aluminum joint as claimed in claim 2, wherein the argon tungsten-arc welding process method comprises the following steps: the specific mode of checking and accepting the pipe fitting, the steel-aluminum joint and the tool in the step A4) is as follows:

4. The manual argon tungsten-arc welding process method for the steel-aluminum joint as claimed in claim 3, wherein the argon tungsten-arc welding process method comprises the following steps: the B4) is characterized in that the specific mode of respectively pairing the stainless steel pipe fitting and the aluminum pipe fitting with the stainless steel side end and the aluminum side end of the steel-aluminum joint is as follows:

B41) and (3) for the pairing of the side groove welds of the aluminum material:

B42) for the pairing of stainless steel side groove welds:

5. The manual argon tungsten-arc welding process method for the steel-aluminum connector as claimed in claim 4, wherein the argon tungsten-arc welding process method comprises the following steps: and step C, performing tack welding on groove welding seams on two sides of the steel-aluminum joint, wherein the tack welding method comprises the following steps:

C1) spot welding for aluminum side groove weld joint

C2) tack welding of stainless steel side groove weld

6. The manual argon tungsten-arc welding process method for the steel-aluminum joint as claimed in claim 5, wherein the argon tungsten-arc welding process method comprises the following steps: the specific mode for welding the backing weld bead in the step E13) is as follows:

E132) when welding with horizontal fixed position

and so on and finally form the finished backing weld;

E133) when using the horizontal rotational position for backing welding

E134) when transverse welding is carried out at the transverse welding position

7. The manual argon tungsten-arc welding process method for the steel-aluminum joint as claimed in claim 6, wherein the argon tungsten-arc welding process method comprises the following steps: step E21) determining the arc starting position, the welding position and the welding direction of the backing weld, wherein the specific determination contents are as follows:

E211) when welding with horizontal fixed position

8. The manual argon tungsten-arc welding process method for the steel-aluminum joint as claimed in claim 7, wherein the argon tungsten-arc welding process method comprises the following steps: the step E22) comprises the following steps:

E224) Defects between the weld beads require grinding for cleaning.

9. The manual argon tungsten-arc welding process method for the steel-aluminum joint as claimed in claim 8, wherein the argon tungsten-arc welding process method comprises the following steps: e23) the specific mode of welding the priming weld bead of the stainless steel side groove is as follows:

E232) for horizontal fixed position welds:

e2322) For the pipe diameter phi 13mm < D < phi 168.3mm, and when the spot-solid block group is adopted for butt welding, the welding seam of the bottom layer only needs to be divided into two symmetrical circular arcs, namely one arc is symmetrically welded in the moving direction shown by 6 points → 3 points → 12 points, and the other arc is symmetrically welded in the moving direction shown by 6 points → 9 points → 12 points; when welding is carried out in the moving direction of 6 points → 3 points → 12 points, an electric arc is used for penetrating a truncated edge from the middle position of a gap to form a molten hole at the position 10-20 mm behind the 6 points, molten iron is filled at the lower part of the molten hole, the molten iron moves upwards, a single-side welding double-side forming backing weld is formed by cooling the molten iron, the backing weld extends forwards and is subjected to arc withdrawing before meeting a point fixed block, the point fixed block is polished and removed, the end of the weld is polished to be in a gentle slope shape, the arc is started at the position 10-20 mm before the end of the weld, then the electric arc moves to a gentle slope joint at the end, the weld cladding metal continues to extend towards the 12 points, the arc is withdrawn near the 12 points, and a first section of backing welding deposited metal weld bead is formed;

e2324) The priming coat is welded with two layers, one for each layer.