CN104625359A - Welding technique for base plate of LNG low-temperature tank - Google Patents
Welding technique for base plate of LNG low-temperature tank Download PDFInfo
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- CN104625359A CN104625359A CN201510040501.7A CN201510040501A CN104625359A CN 104625359 A CN104625359 A CN 104625359A CN 201510040501 A CN201510040501 A CN 201510040501A CN 104625359 A CN104625359 A CN 104625359A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/18—Submerged-arc welding
- B23K9/186—Submerged-arc welding making use of a consumable electrodes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/235—Preliminary treatment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2101/00—Articles made by soldering, welding or cutting
- B23K2101/04—Tubular or hollow articles
- B23K2101/12—Vessels
- B23K2101/125—Cans
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- Arc Welding In General (AREA)
- Butt Welding And Welding Of Specific Article (AREA)
Abstract
The invention discloses a welding technique for a base plate of an LNG low-temperature tank and belongs to the technical field of welding of LNG low-temperature tanks. According to the welding technique, two 9Ni steel plates with the thicknesses ranging from 6 mm to 9 mm are made to be in lap joint in the horizontal direction and overlap to form an overlap joint, the end face is cleaned, a preparation for welding is made, and then submerged-arc welding is conducted by means of alternating current, wherein the arc voltage ranges from 25 V to 29 V, the welding current ranges from 260 A to 290 A, the wire extension length ranges from 25 mm to 35 mm, the welding speed ranges from 22 in/min to 25 in/min, the welding wire angle ranges from 55 degrees to 65 degrees, and a full fillet weld with a welding foot with the length ranging from 6 mm to 9 mm is formed. By the adoption of the welding technique, submerged-arc welding of the base plate of the LNG low-temperature tank can be achieved, the problems that during submerged-arc welding, a lap fillet weld is poorly formed, hot cracks are formed during welding, and burning through occurs easily during welding are solved, the two 9Ni steel plates with the thicknesses ranging 6 mm to 9 mm can be welded in a single-pass mode at a time during actual operation, and welding efficiency is remarkably improved.
Description
Technical field
The welding procedure of LNG cryogenic tank base plate, belongs to LNG cryogenic tank welding technology field.
Background technology
LNG cryogenic tank, full name is LNG column type atmospheric low-temperature storage tank, and can be divided into single containing, double containment and entirely contain type, design pressure is generally-6mbarg ~ 140mbarg, if adopt concrete tank deck, conduct oneself with dignity heavier, the malleation of design can also be higher.Due to LNG cryogenic tank internal-external temperature difference is maximum can to 200 DEG C, in tank, temperature can reach-160 DEG C.In 9Ni steel welding technology field, the LNG cryogenic tank base plate of 9Ni steel matter girth welding is adopted to need to reach enough bearing capacities, welding arc is unstable and appearance of weld is bad, the problem of HOT CRACK FOR WELDING P as occurred for the weld seam of LNG cryogenic tank base plate, above problem will bury potential safety hazard, and serious security incident even occurs.LNG cryogenic tank base plate often adopts 9Ni steel matter.9Ni steel be nineteen forty-four exploitation Ni shared by mass percent be the medium alloy steel of 9%, it is a kind of low-carbon (LC) quenched and tempered steel, is organized as martensite and adds bainite.In prior art, there is following defect in the lap joint welding manner for LNG cryogenic tank base plate:
First, compare the welding in other regions of LNG cryogenic tank, the welding method of existing LNG cryogenic tank base plate is comparatively single, and welding efficiency is low.Its reason is: the circumferential weld being different from LNG low-temperature storage tank wallboard, LNG cryogenic tank base plate is the angle welding at horizontal lap joint, existing circular seam submerged arc welding connection technology cannot directly apply to the welding of LNG cryogenic tank base plate: existing LNG cryogenic tank base plate many employings 9Ni steel, and submerged-arc welding be applied to 9Ni steel welding often there is bias phenomenon, affect welding effect.The weldability special due to 9Ni steel and to LNG cryogenic tank base plate technological requirement, except LNG low-temperature storage tank wallboard circumferential weld adopts Lincoln weld, the welding of existing LNG low-temperature storage tank base plate lap fillet weld is all manual welding wire arc welding, 9Ni steel cored arc weldering welding efficiency is low, operating environment is poor, work situation is severe, and artificial input and cost greatly, particularly easily produce welding deformation in the welding of 9Ni steel sole plate fillet weld in the flat position.
Secondly, submerged arc welding technique is used to weld LNG low-temperature storage tank wallboard circumferential weld though existed in prior art, but welding effect is unsatisfactory in actual applications, cannot meet the welding of LNG low-temperature storage tank base plate when being applied to welded lap angle welding after, weld hardness requires height.First existing submerged-arc welding process exists when actual welding that welding arc is unstable and appearance of weld is bad, HOT CRACK FOR WELDING P, and during welding, base plate easily burns, and causes the mechanical property of LNG cryogenic tank base plate weld seam poor.Obtain enough bearing capacities in order to ensure LNG cryogenic tank base plate, need the inferior weld seam of cleaning in time also again to weld when finding above problem on inspection, reduce operating efficiency.Second point LNG low-temperature storage tank base plate is thicker, and when adopting the wider Size of welds of angle welding submerged-arc welding in prior art, existing cannot the too much problem of single track forming a solder, welding line joint.It is comparatively difficult that its reason is that angle welding submerged-arc welding will obtain large fillet weld size.Production practices prove, the effective depth h1 of an angle welding single track submerged-arc welding in existing technique is only less than the weld seam of 5mm at below 4mm, leg, and when leg equals to be greater than 6mm, face of weld is spill, there is the problem that weld seam is not full.Will obtain angle welding that effective depth h1 is greater than 4mm in prior art must adopt multi-layer multi-pass welding could be shaping, and so not only efficiency is low.
Summary of the invention
The technical problem to be solved in the present invention is: overcome the deficiencies in the prior art, the welding procedure of LNG cryogenic tank base plate is provided, this welding procedure can realize the submerged arc welding of LNG cryogenic tank base plate, the problem of easily burning when solving lap fillet weld cob webbing, HOT CRACK FOR WELDING P, welding in submerged arc welding process, and once weld at two pieces of 9Ni steel plate single tracks that practical operation realizes 6 ~ 9mm thick, significantly improve welding efficiency.
Technical scheme of the present invention is, the welding procedure of LNG cryogenic tank base plate of the present invention, is characterized in that, comprise following steps:
1) lap joint is formed: by thick for 6 ~ 9mm two pieces of 9Ni steel plate level overlap joints, overlapping forms lap joint;
2) end face is cleared up: the end face using electric angle grinder cleaning polishing lap joint, until metallic luster appears in end face; The 9Ni surface of steel plate of cleaning within the scope of lap joint place 50 ~ 70mm, and remove moisture, greasy dirt and the dust within the scope of this;
3) preparation welding: by the angle welding district laid parallel of the end of welding tractor and lap joint, first welding gun alignment angle weld metal zone before weldering, spacing between wire tip and root of weld remains on 0 ~ 5mm, welding tractor is walked one time in advance along weld seam, welding tractor driving path in planning welding process;
4) weld: solder flux hopper is filled it up with solder flux, adopt diameter 1.6mm welding wire to aim at welding starting the arc position, adjustment wire feed rate 250 ~ 300 IPM, welding adopts alternating current submerged arc welding, welding current 260 ~ 350A, stem elongation degree 25 ~ 35mm, speed of welding 15 ~ 25 in/min, welding wire angle 55 ~ 65 °, using the original position of angle welding one end as welding wire, energize starts submerged arc welding, until welding wire stops welding after moving to the other end of angle welding, clears up solder flux and slag after power-off.
Preferably, step 4) adopts adjustment wire feed rate 250 ~ 300 IPM, and welding adopts alternating current submerged arc welding, welding current 260 ~ 290A, stem elongation degree 25 ~ 30mm, speed of welding 22 ~ 25 in/min, welding wire angle 55 ~ 60 °.
Preferably, step 4) adopts adjustment wire feed rate 291 ~ 300 IPM, and welding adopts alternating current submerged arc welding, welding current 310 ~ 330A, stem elongation degree 33 ~ 35mm, speed of welding 15 ~ 17in/min, welding wire angle 61 ~ 65 °.
Preferably, welding wire described in step 4) is nickel-base alloy bare welding filler metal, and solder flux is and Ni-based submerged arc welding flux.
Preferably, welding wire described in step 4) is OK Autrod 19.82 model welding wire, and solder flux is Flux 10.90 model solder flux; Or welding wire described in step 4) is THERMANIT625 model welding wire, solder flux is MARATHON 444 model solder flux.
Preferably, step 2) described in electric angle grinder adopt cubic boron nitride or the grinding wheel that abrasive material made by black silicon carbide, rubber makes adhesive.
Preferably, in step 1), 9Ni steel plate thickness is 8 ~ 9mm.
The present invention is described as follows: for the welding tractor that the present invention is used.Preferably, welding tractor described in step 3) is the welding tractor for straight angle submerged-arc welding of indirect current, welding tractor is provided with the infrared ray pointer being used to indicate wire tip position in welding process, and welding tractor is provided with the angle of welding gun governor motion carrying out 0 ~ 90 ° of angular adjustment for welding gun.Preferably, the welding tractor described in step 3) is the model that Lincoln company produces is CRUISER
tMwelding tractor.The welding tractor welding procedure of this model have employed nickel-bass alloy material special welding program channel, meet the problem such as cob webbing and welding parameter instability when nickel-bass alloy material welds, and store and locking process welding condition in the monitoring of welding process medium-long range and record, achieve the welding of 9%Ni steel needs accurate recording and strict control and welding process dates back to heat input.
LNG low-temperature storage tank base plate of the present invention forms by organizing the 9Ni steel plate overlapped between two more, and the overlapped overlap joint welding of 9Ni steel plate often organizing two pieces of thickness 6 ~ 9mm is formed, and lap joint square groove.Because 6 ~ 9mm plate overlapping the slot submerged-arc welding is single track forming a solder, welding should ensure appearance of weld, must meet again the Size of welds requirement of lap fillet weld, and welding must have ripe welding condition.
The length that when wire feed rate refers to welding, in the unit interval, welding wire is sent to welding pool.Wire feed rate is directly proportional to welding current, the size of wire feed rate had both affected the size of welding current, also the shaping of weld seam is affected, wire feed rate is larger, and electric current is larger, and welding wire melting rate is faster, blow force of arc also increases with welding current simultaneously, molten pool metal is arranged by electric arc, is not melted the direct heating that mother metal is subject to electric arc bottom molten bath, fusion penetration increases.For the welding wire of same diameter, fusion penetration is directly proportional to wire feed rate and welding current, and the impact of welding current on pool width is less.If welding current is excessive, easily produces undercut and cob webbing, heat affected area is increased, even causes and burn; If welding current is too small, fusion penetration is reduced, easily produces that weldering meat is not full, incomplete fusion etc., and the stability of electric arc is also poor.Diameter 1.6mm welding wire is used to recommend wire feed rate to be 250 ~ 300IPM, corresponding actual welding electric current 260 ~ 350A, can make the angle welding of leg 6 ~ 9mm obtain larger fusion penetration, angle welding and closing better as melting between the LNG low-temperature storage tank base plate of mother metal and LNG low-temperature storage tank sidewall.IPM is that inches per minute is called for short, and means inch per minute preferred, and welding wire and solder flux are the diameter 1.6mm welding wire that her Sa (ESAB) wlding of Sweden is produced, and welding wire model OK Autrod 19.82, supporting solder flux model is Flux 10.90.Preferably, welding wire and solder flux are the diameter 1.6mm welding wire THERMANIT625 that the extraordinary wlding Co., Ltd of German UTP produces, and supporting solder flux model is MARATHON 444.
Arc voltage is directly proportional to arc length.Voltage increases, and arc length increases, and molten wide increase, weld reinforcement and fusion penetration slightly reduce simultaneously, make weld seam become smooth.After arc voltage increases, solder melts increases.What in prior art, arc voltage was generally arranged is less.Applicant finds: in fact along with the increase of welding current, and arc voltage does not increase thereupon, easily occurs that cross section is mushroom weld seam, can produce overlap time serious at face of weld, and this mainly widely too littlely to cause due to molten.Angle welding in order to obtain larger leg, then needs to increase molten wide by increasing arc voltage.So along with the increase of welding current, arc voltage also will suitably increase.Diameter 1.6mm welding wire 260 ~ 350A welding current weldingvoltage is used to be 25 ~ 29V.
Be decided to be electrode extension by ignition tip end to the distance on weldment surface, be also called stem elongation degree.Stem elongation degree determines the height of ignition tip, also determines the thickness of welding flux layer, affects the size of welding current simultaneously.Stem elongation spends length, and welding wire can be made to strengthen by the pre-heat effect of current resistor heat, causes that welding arc is unstable and appearance of weld is bad, also affects the grazing of weld seam simultaneously.Somely to stretch too in short-term, easy burn-out ignition tip.Welding wire should contact well with ignition tip, otherwise can affect the stable of welding process, and ignition tip can be made time serious to melt.Attention: ignition tip is processed by red copper or brass, ignition tip fusing makes copper be transitioned in weld seam to go.Copper and iron can not mix in the liquid state mutually, and form the copper slag inclusion of bulk, and copper also can cause HOT CRACK FOR WELDING P, harmfulness is very large.So, once find ignition tip fusing in welding process, welding should be stopped immediately, root out mixed brazed seam, avoid producing weld crack and defect.Diameter 1.6mm dry extension of electrode degree is used to control at 25 ~ 35mm comparatively suitable.Speed of welding has obvious impact to molten wide and fusion penetration and appearance of weld.When speed of welding is lower, the change of speed of welding is less on fusion penetration impact.But when speed of welding is larger, because the add heat of electric arc to mother metal obviously reduces, fusion penetration significantly declines.Speed of welding is too high, can cause undercut, lack of penetration, the coarse inequality of weld seam scarce.Suitable reduction speed of welding, molten bath volume increases, and life period is elongated, is conducive to gas emersion molten bath, reduces the tendency that pore generates.But speed of welding is too low can form the mushroom-shaped weld seam that easily splits or the defect such as generation is burnt, slag inclusion, weld seam are irregular.In speed of welding 15 ~ 25 in/min, in/min means inch per minute clock.
Welding wire angle in the present invention refers to the angle becoming 55 ~ 65 ° with horizontal plane, welding wire should not lean forward or hypsokinesis, and appearance of weld can ensure that lap fillet weld top edge fuses completely, without undercut and incomplete fusion, can ensure that again weld seam lower limb is smooth, weld metal does not drop.
Compared with prior art, the beneficial effect that conduction filter bag of the present invention and preparation method thereof has is:
1, this technique can realize the submerged arc welding of LNG cryogenic tank base plate lap fillet weld, not only increases welding efficiency, and the angle welding hardness obtained is high.When applicant finds to adopt direct current to carry out submerged arc welding under study for action during 9Ni steel plate, due to the reason of the material of 9Ni steel plate own, easily there is bias phenomenon in welding process, in technique of the present invention, therefore adopt alternating current effectively can solve the magnetic bias problem of submerged arc welding.Adopt welding condition diameter 1.6mm welding wire of the present invention, wire feed rate 250 ~ 300 IPM, welding current 260 ~ 350A, stem elongation degree 25 ~ 35mm, speed of welding 15 ~ 25 in/min, welding wire angle 55 ~ 65 °, and coordinate the welding wire selected by the present invention and solder flux, the angle welding had compared with hardness can be obtained, meet the requirement to LNG low-temperature storage tank base plate bearing capacity.
2, this technique arc stability, shaping weld seam weldering meat is full, and weld seam top edge fuses completely, without undercut and incomplete fusion phenomenon.Adopt weld seam after technique of the present invention can or good mechanical property, the bearing capacity of base plate significantly improves.The present invention adopts the welding tractor used for submerged arc welding of indirect current, meets the technical requirement that the welding of 9Ni steel adopts AC welding, reduces thermal weld stress.Because thermal weld stress causes the magnetized problem of mother metal 9Ni steel plate when applicant finds to adopt direct current to weld mother metal 9Ni steel plate under study for action, adopt alternating current to weld and then can solve this problem preferably.
3, this technique welding quality is higher, can realize flat fillet weld single track welding fabrication of 6 ~ 9mm leg.First, this effect can significantly improve welding efficiency, in a disguised form reduces the labour intensity of workman, and reduces production cost.As found undercut incomplete fusion or weld cracking phenomenon after weld seam is formed, then need trimming polishing groove face then again to weld, so not only welding efficiency declines but also weldering.Submerged-arc welding of the present invention is continuous strand welded corner joint, welding point is few, decrease cored arc to weld every root wire and receive arc and occur crater crack and the joint reconditioning that causes, avoid the weld defect caused owing to changing welding wire joint simultaneously, submerged-arc welding 6 ~ 9mm plate overlap joint only needs weldering just can meet Size of welds requirement together, and cored arc weldering 6 ~ 9mm plate overlap joint needs weldering 2 ~ 3 road to be just soldered, the operation of cleaning coating is also had between road, the speed of welding of cored arc weldering is 15 ~ 20cm/min, and the speed of welding of submerged-arc welding can reach 40 ~ 50 cm/min, welding efficiency is 3 ~ 5 times of cored arc weldering, and simplify welding sequence, alleviate the labour intensity of welder, little and the uniformity of submerged arc welding heat input simultaneously, also reduce the welding deformation of base plate thin plate, workmen is only 1/10 of cored arc weldering, the welding procedure cost-saved 30% of base plate fillet weld in the flat position.Not only alleviate the labour intensity of welder, also improve welding efficiency, calculate with 16.5 ten thousand vertical cryogenic tank, the welding of every platform tank bottom fillet weld in the flat position can be saved manually, material and equipment cost more than 20 ten thousand yuan.
Accompanying drawing explanation
Fig. 1 is the operation chart of the welding procedure of LNG cryogenic tank base plate.
Wherein: 1, top 9Ni steel plate; 2, below 9Ni steel plate; 3, ignition tip; 4, solder flux mouth; 5, welding wire; 6, angle welding; β, welding wire angle; A, wire tip and root of weld spacing; B, stem elongation degree; C, top 9Ni steel plate thickness; D, below 9Ni steel plate thickness; E, leg.
Detailed description of the invention
Embodiment 1 ~ 4 is detailed description of the invention of the welding procedure of LNG cryogenic tank base plate of the present invention, and wherein embodiment 1 is most preferred embodiment.
Ignition tip 3 internal fixtion with reference to Fig. 1 welding tractor has welding wire 5, as mother metal for welding top 9Ni steel plate 1 and the overlapped formation lap joint of below 9Ni steel plate 2 of LNG low-temperature storage tank base plate, lap joint square groove.The top 9Ni steel plate 1 that LNG low-temperature storage tank base plate is overlapped mutually by many groups and below 9Ni steel plate 2 form, and top 9Ni steel plate thickness c is 6 ~ 9mm, and below 9Ni steel plate thickness d is 6 ~ 9mm.Root of weld is the intersection of the top 9Ni steel plate 1 at angle welding 6 back side and the overlapping region of below 9Ni steel plate 2, and namely root of weld is that right angle electrical of the right angled triangle that angle welding 6 is formed.Wire tip and root of weld spacing a are 0 ~ 5mm.Stem elongation degree b refers to the distance of welding wire termination apart from ignition tip end, and stem elongation degree b is 25 ~ 35mm, and leg e is 6 ~ 9mm.Ignition tip 3 and solder flux mouth 4 are arranged on the welding gun of welding tractor, and ignition tip 3 is connected with power electric, and ignition tip 3 inside is provided with welding wire 5, are connected with the solder flux hopper on welding tractor for providing the solder flux mouth 4 of solder flux for angle welding 6.
embodiment 1
The present embodiment comprises following steps:
1) lap joint is formed: by thick for 6mm two pieces of 9Ni steel plate level overlap joints, overlapping forms lap joint;
2) end face is cleared up: the end face using electric angle grinder cleaning polishing lap joint, until metallic luster appears in end face; The 9Ni surface of steel plate of cleaning within the scope of lap joint place 50mm, and remove moisture, greasy dirt and the dust within the scope of this; Sanding machine adopts the grinding wheel that abrasive material made by black silicon carbide, rubber makes adhesive;
3) preparation welding: the angle welding district laid parallel that the end of welding tractor and lap joint is reserved, first welding gun alignment angle weld metal zone before weldering, spacing between wire tip and root of weld remains on 0 ~ 5mm, welding tractor is walked one time in advance along weld seam, welding tractor driving path in planning welding process;
4) weld: solder flux hopper is filled it up with solder flux, adopt diameter 1.6mm welding wire to aim at welding starting the arc position, adjustment wire feed rate 250 ~ 300 IPM, welding adopts alternating current submerged arc welding, welding current 260 ~ 290A, stem elongation degree 25 ~ 27mm, speed of welding 22 ~ 25 in/min, welding wire angle 55 ~ 60 °, using the original position of angle welding one end as welding wire, energize starts submerged arc welding, until welding wire stops welding after moving to the other end of angle welding, clears up solder flux and slag after power-off; Described welding wire is OK Autrod 19.82 model welding wire, and solder flux is Flux 10.90 model solder flux.
embodiment 2
The present embodiment comprises following steps:
1) lap joint is formed: by thick for 7mm two pieces of 9Ni steel plate level overlap joints, overlapping forms lap joint;
2) end face is cleared up: the end face using electric angle grinder cleaning polishing lap joint, until metallic luster appears in end face; The 9Ni surface of steel plate of cleaning within the scope of lap joint place 60mm, and remove moisture, greasy dirt and the dust within the scope of this; Sanding machine adopts the grinding wheel that abrasive material made by black silicon carbide, rubber makes adhesive;
3) preparation welding: the angle welding district laid parallel that the end of welding tractor and lap joint is reserved, first welding gun alignment angle weld metal zone before weldering, spacing between wire tip and root of weld remains on 0 ~ 5mm, welding tractor is walked one time in advance along weld seam, welding tractor driving path in planning welding process;
4) weld: solder flux hopper is filled it up with solder flux, adopt diameter 1.6mm welding wire to aim at welding starting the arc position, adjustment wire feed rate 250 ~ 300 IPM, welding adopts alternating current submerged arc welding, welding current 260 ~ 350A, stem elongation degree 28 ~ 30mm, speed of welding 20 ~ 22 in/min, welding wire angle 60 ~ 65 °, using the original position of angle welding one end as welding wire, energize starts submerged arc welding, until welding wire stops welding after moving to the other end of angle welding, clears up solder flux and slag after power-off; Described welding wire is THERMANIT625 model welding wire, and solder flux is MARATHON 444 model solder flux.
embodiment 3
The present embodiment comprises following steps:
1) lap joint is formed: by thick for 8mm two pieces of 9Ni steel plate level overlap joints, overlapping forms lap joint;
2) end face is cleared up: the end face using electric angle grinder cleaning polishing lap joint, until metallic luster appears in end face; The 9Ni surface of steel plate of cleaning within the scope of lap joint place 60mm, and remove moisture, greasy dirt and the dust within the scope of this;
Sanding machine adopts the grinding wheel that abrasive material made by black silicon carbide, rubber makes adhesive;
3) preparation welding: the angle welding district laid parallel that the end of welding tractor and lap joint is reserved, first welding gun alignment angle weld metal zone before weldering, spacing between wire tip and root of weld remains on 0 ~ 5mm, welding tractor is walked one time in advance along weld seam, welding tractor driving path in planning welding process;
4) weld: solder flux hopper is filled it up with solder flux, diameter 1.6mm welding wire is adopted to aim at welding starting the arc position, adjustment wire feed rate 250 ~ 300 IPM, welding adopts alternating current submerged arc welding, whole wire feed rate 250 ~ 300 IPM, welding adopts alternating current submerged arc welding, welding current 260 ~ 290A, stem elongation degree 25 ~ 30mm, speed of welding 22 ~ 25 in/min, welding wire angle 55 ~ 60 °, using the original position of angle welding one end as welding wire, energize starts submerged arc welding, until welding wire stops welding after moving to the other end of angle welding, clears up solder flux and slag after power-off; Described welding wire is THERMANIT625 model welding wire, and solder flux is MARATHON 444 model solder flux.
embodiment 4
The present embodiment comprises following steps:
1) lap joint is formed: by thick for 9mm two pieces of 9Ni steel plate level overlap joints, overlapping forms lap joint;
2) end face is cleared up: the end face of use electric angle grinder cleaning polishing lap joint, until metallic luster appears in end face; The 9Ni surface of steel plate of cleaning within the scope of lap joint place 70mm, and remove moisture, greasy dirt and the dust within the scope of this; Sanding machine adopts the grinding wheel that abrasive material made by cubic boron nitride, rubber makes adhesive;
3) preparation welding: the angle welding district laid parallel that the end of welding tractor and lap joint is reserved, first welding gun alignment angle weld metal zone before weldering, spacing between wire tip and root of weld remains on 0 ~ 5mm, welding tractor is walked one time in advance along weld seam, welding tractor driving path in planning welding process;
4) weld: solder flux hopper is filled it up with solder flux, adopt diameter 1.6mm welding wire to aim at welding starting the arc position, adjustment wire feed rate 291 ~ 300 IPM, welding adopts alternating current submerged arc welding, welding current 310 ~ 330A, stem elongation degree 33 ~ 35mm, speed of welding 15 ~ 17in/min, welding wire angle 61 ~ 65 °, using the original position of angle welding one end as welding wire, energize starts submerged arc welding, until welding wire stops welding after moving to the other end of angle welding, clears up solder flux and slag after power-off; Welding wire described in step 4) is THERMANIT625 model welding wire, and solder flux is MARATHON 444 model solder flux.
performance test
In the angle welding 6 that random selecting embodiment 1 ~ 4 obtains, fusion length is that 10cm scope detects, each embodiment random selecting 3 times, calculates and detects mean value typing following table 1.Use angle welding reinforcement, leg that mortgage detection ruler measurement embodiment 1 ~ 4 obtains.Angle welding weld reinforcement refers to the maximum height of the part weld metal exceeded above the line of mother metal surface.Whether visual observations has undercut situation, and the mode estimated by inspector is carried out outward appearance and detected in embodiment 1 ~ 4 with or without HOT CRACK FOR WELDING P, incomplete fusion phenomenon.The width of angle welding 6 is molten wide.Liquid penetrant testing standard No. JB/T4730.5-2005, macroscopical metallographic examination criteria NB/T47014-2011, Vickers hardness examination criteria GB/T4340.1-2009.
Table 1 embodiment 1 ~ 4 performance test
。
Can find out that embodiment 1 ~ 4 is all that larger 6 ~ 9mm angle welding can realize the one-time formed submerged arc welding of alternating current single track for Size of welds by table 1, bonding speed can remain on 15 ~ 25in/min, compare existing multilayer welding and arc welding welding efficiency of the present invention be significantly improved.Angle welding weld reinforcement refers to the maximum height of the part weld metal exceeded above the line of mother metal surface.And by table 1 can find out angle welding reinforcement that embodiment 1 ~ 4 obtains on the occasion of and higher, illustrates that angle welding weldering meat is full, after testing without undercut, incomplete fusion phenomenon and the generation of HOT CRACK FOR WELDING P phenomenon, illustrates that the one-time formed weld seam welding effect of this single track is good.Vickers hardness number is lower, shows that the hardness of weld seam is higher, and the bearing capacity of the LNG low-temperature storage tank base plate formed after overlap joint welding is better.Industry code requirements Vickers hardness number is 360 HV10, and the Vickers hardness number of the angle welding that embodiment 1 ~ 4 is obtained is significantly less than Industry code requirements Vickers hardness number 360 HV10, illustrate that technique of the present invention not only can realize the submerged arc welding to LNG low-temperature storage tank base plate, and the bearing capacity of the LNG low-temperature storage tank base plate obtained.
The above is only preferred embodiment of the present invention, and be not restriction invention being made to other form, any those skilled in the art may utilize the technology contents of above-mentioned announcement to be changed or be modified as the Equivalent embodiments of equivalent variations; But everyly do not depart from technical solution of the present invention content, any simple modification, equivalent variations and the remodeling done above embodiment according to technical spirit of the present invention, still belong to the protection domain of technical solution of the present invention.
Claims (7)
- The welding procedure of 1.LNG cryogenic tank base plate, is characterized in that, comprise following steps:1) lap joint is formed: by thick for 6 ~ 9mm two pieces of 9Ni steel plate level overlap joints, overlapping forms lap joint;2) end face is cleared up: the end face using electric angle grinder cleaning polishing lap joint, until metallic luster appears in end face; The 9Ni surface of steel plate of cleaning within the scope of lap joint place 50 ~ 70mm, and remove moisture, greasy dirt and the dust within the scope of this;3) preparation welding: by the angle welding district laid parallel of the end of welding tractor and lap joint, first welding gun alignment angle weld metal zone before weldering, spacing between wire tip and root of weld remains on 0 ~ 5mm, welding tractor is walked one time in advance along weld seam, welding tractor driving path in planning welding process;4) weld: solder flux hopper is filled it up with solder flux, adopt diameter 1.6mm welding wire to aim at welding starting the arc position, adjustment wire feed rate 250 ~ 300 IPM, welding adopts alternating current submerged arc welding, welding current 260 ~ 350A, stem elongation degree 25 ~ 35mm, speed of welding 15 ~ 25 in/min, welding wire angle 55 ~ 65 °, using the original position of angle welding one end as welding wire, energize starts submerged arc welding, until welding wire stops welding after moving to the other end of angle welding, clears up solder flux and slag after power-off.
- 2. the welding procedure of LNG cryogenic tank base plate according to claim 1, is characterized in that: adopt adjustment wire feed rate 250 ~ 300 IPM, welding adopts alternating current submerged arc welding, welding current 260 ~ 290A, stem elongation degree 25 ~ 30mm, speed of welding 22 ~ 25 in/min, welding wire angle 55 ~ 60 °.
- 3. the welding procedure of LNG cryogenic tank base plate according to claim 1, it is characterized in that: step 4) adopts adjustment wire feed rate 291 ~ 300 IPM, welding adopts alternating current submerged arc welding, welding current 310 ~ 330A, stem elongation degree 33 ~ 35mm, speed of welding 15 ~ 17in/min, welding wire angle 61 ~ 65 °.
- 4. the welding procedure of LNG cryogenic tank base plate according to claim 1, is characterized in that: welding wire described in step 4) is nickel-base alloy bare welding filler metal, and solder flux is and Ni-based submerged arc welding flux.
- 5. the welding procedure of LNG cryogenic tank base plate according to claim 1, is characterized in that: welding wire described in step 4) is OK Autrod 19.82 model welding wire, and solder flux is Flux 10.90 model solder flux; Or welding wire described in step 4) is THERMANIT625 model welding wire, solder flux is MARATHON 444 model solder flux.
- 6. the welding procedure of LNG cryogenic tank base plate according to claim 1, is characterized in that: step 2) described in electric angle grinder adopt cubic boron nitride or the grinding wheel that abrasive material made by black silicon carbide, rubber makes adhesive.
- 7. the welding procedure of LNG cryogenic tank base plate according to claim 1, is characterized in that: in step 1), 9Ni steel plate thickness is 8 ~ 9mm.
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| CN105269175A (en) * | 2015-11-11 | 2016-01-27 | 武汉一冶钢结构有限责任公司 | Shielded metal arc welding method used for phase welding of X7Ni9 steel and S30408 steel |
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| CN115351396A (en) * | 2022-08-23 | 2022-11-18 | 武汉钢铁有限公司 | Welding method for improving plane bending fatigue performance of lap joint |
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| CN114433842B (en) * | 2022-03-03 | 2024-05-28 | 宁波江丰热等静压技术有限公司 | Sheath for hot isostatic pressing |
| CN115351396A (en) * | 2022-08-23 | 2022-11-18 | 武汉钢铁有限公司 | Welding method for improving plane bending fatigue performance of lap joint |
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