CN102825367A - Welding method for prolonging service life of high-strength metal shell - Google Patents
Welding method for prolonging service life of high-strength metal shell Download PDFInfo
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- CN102825367A CN102825367A CN2012103489114A CN201210348911A CN102825367A CN 102825367 A CN102825367 A CN 102825367A CN 2012103489114 A CN2012103489114 A CN 2012103489114A CN 201210348911 A CN201210348911 A CN 201210348911A CN 102825367 A CN102825367 A CN 102825367A
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Abstract
The invention discloses a welding method for prolonging service life of a high-strength metal shell, which adopts high-strength anti-wearing steel CiNiMo as a welding substrate. The welding method comprises the following steps of: preparing before welding, carrying out tack welding, pre-heating a welding piece, carrying out welding construction, polishing and carrying out nondestructive testing. The welding method disclosed by the invention is suitable for welding a large-sized piece of low-middle carbon alloy high-strength steel; the welding production rate is high and the anti-cracking performance is good; the welding deformation is small; the welding method has the advantages that selected materials are reasonable and have higher strength; welding current is controlled in a certain range and the occurrence possibility of crack defects is reduced; and with the adoption of the welding method disclosed by the invention, hydrogen removing treatment is carried out after the welding, residual hydrogen in a welding connector is dispersed and escaped in time, and the generation of delaying cracks is reduced.
Description
Technical field
The present invention relates to a kind of welding method, especially a kind of high duty metal housing welding method in service life that prolongs.
Background technology
Along with improving constantly of domestic performing comprehensive coal mining machineryization level, also increasingly high to the reliability requirement of high-power coal cutter, especially material and the mechanical property thereof to Coal Winning Machine and rocking arm housing proposed new requirement.Yet existing high-power housing class (rocking arm) is employed to be ZG25MnNi, ZG270-500 conventional strength steel mostly; Though the comprehensive mechanical performance of these two kinds of materials is relatively good; But the hardness of their normalizings is all lower; Intensity is not high yet, mine and abominable working condition more and more seems incompatible in existing high strength, especially the housing welding position occur crackle in the near future easily in use, leak, oil leakage phenomenon; Serious housing (rocking arm) position in addition deform, ear turns round and quality problems such as takes off, and the coal-winning machine housing is shortened service life greatly.
And the welding condition of in the past using was not good, the wlding insufficient strength, and reason such as welding current is bigger than normal often causes defectives such as bead crack, slag inclusion, undercut.
To above situation; The applicant studies the performance of high-strength abrasion-proof steel cast steel CrNiMo; Through integrating theory with practice, cast steel CrNiMo test material is carried out the engineer testing of system, confirmed that cast steel CrNiMo is fit to the material that current shell part uses; And work out comparatively perfect heat-treatment protocol and the welding procedure of a cover, make its each item performance indications that obtain can better satisfy the service condition of high-power coal casing body material.
Summary of the invention
Goal of the invention: to the deficiency of prior art, we have invented a kind of high duty metal housing welding method in service life that prolongs through long-term practical exploration.
Technical scheme: in order to realize the foregoing invention purpose; The technical scheme that the present invention adopted is: a kind of high duty metal housing welding method in service life that prolongs; Adopt high-strength abrasion-proof steel CrNiMo as the welding base material, said welding method comprises following seven procedures:
First procedure, prepare before the welding:
The welding ends that adopts method for hot cutting will weld base material cuts into monolateral double V-groove weldment, is specially at first to carry out the vertical parallel cutting, aligns, the counter-slope mouth processes again, and the franchise of the bevel angle of said monolateral double V-groove weldment is ± 5 °, root face height ± 2mm;
Careful greasy dirt, corrosion and water stain of removing welding wire and weldment surface reduces hydrogen content in the weld seam, inspection CO before the welding
2Smooth and easy situation of welding machine wire feed and gas flow situation are utilized before welding rod uses and are put oven for drying, put into heat-preserving container after taking out, and take the job site to.
Second operation work, tack welding:
To the mother metal local heat, with welding wire sheet material spot welding is fixed on the mother metal during welded blank before the weldering, position of spot welding at a certain distance, symmetrical object is therefrom entreated to cephalocaudal direction spot welding, and the spot welding of left and right directions symmetry.
Three process, the weldment preheating:
It is 30 minutes constant temperature preheating that second road step operation part is carried out duration, and the preheat temperature scope is between 300 ℃ to 400 ℃.
The 4th procedure, welding procedure:
Three process spare is adopted manual CO
2Gas shielded arc welding is walked to two along the weld seam middle part, and collar extension is welded in a mouthful back in the weldering earlier, and welding direction is welded to both sides by the centre; When running into the weld seam that intersects in length and breadth; Toe weld seam behind elder generation's weldering end weld seam when weldment length surpasses one meter, adopts balanced welding or backstep welding in the branch; When flat fillet weld on the weldment and fillet welding in the vertical position exist simultaneously, weld flat fillet weld, the long weld seam of weldering behind the short weld seam of weldering earlier after fillet welding in the vertical position should being welded earlier.If when adopting welding wire to weld, adopt welding wire CHT711 flux-cored wire.
Use CO in the welding procedure process
2Protection gas, said CO
2Protection gas is by 80% CO
2Mix with 20% Ar.Every weldering is intact cleans out welding slag together, and in the inspection weld seam pore-free, crackle is arranged, and when pore, crackle are arranged, after its thorough removing, continues following one weld seam of welding again, receives the arc operation before the welding end.
Five processes, polishing:
After welding is accomplished, carry out the rounding off polishing, remove the welding wire coating splash that produces in the welding process with grinding machine butt welded seam edge, angle and peripheral matrix, and the adjacently situated surfaces reconditioning is smooth.
The 6th procedure, the hydrogen that disappears is handled and heat treatment:
Cold crack is the subject matter of weld high strength steel, and fire check generally only accounts for 10% in high strength steel weld crack defective forms, and cold crack has accounted for 90%.The main cause that causes cold crack is the hardened structure and the hydrogen content of material, so the hydrogen that will disappear is handled and heat treatment.
After welding was accomplished, the temperature of weld seam also was in more than 100 ℃, in order to quicken the effusion of hydrogen in the welding point; Prevent that cold crack from producing; At first five processes spare is placed under 300-400 ℃ the temperature environment for high strength steel is particularly important, time range is 2-6h, and hydrogen disappears; Then workpiece being positioned over steady temperature is that time range is 4-6h, heat-treats, and slowly cools off at last in 500-600 ℃ the environment.
The 7th procedure, Non-Destructive Testing:
Weld seam to the 6th procedure spare carries out painted or magnetic powder detection, if weld seam is found defective through flaw detection, then rejected region is repaired; Adopt manual welding that rejected region is repaired, with carbon arc air gouging rejected region is criticized groove, rejected region is darker in the middle of being shaped as; The gradually shallow inside gradually surface transition in two ends is removed the carbide at groove place with the abrasive machine polishing, then after painted or magnetic particle testing are confirmed zero defect; Carry out repair welding by above-mentioned technology again, welding finishes.
Beneficial effect: the present invention compared with prior art, its beneficial effect is:
1, the present invention is applicable to the large piece welding of low, middle carbon alloy high strength steel, and its welding productivity is high, cracking resistance is good, and welding deformation is little;
2, selection of the present invention is reasonable, and intensity is higher, and welding current is controlled at certain limit, reduces the generation probability of crack defect;
3, the postwelding hydrogen that carried out disappearing is handled among the present invention, overflows when guaranteeing in the welding point residual hydrogen and diffusion, reduces the generation of delayed crack;
4, see that from the angle of implementing process engineering of the present invention is reasonable, easy to operate feasible.
The specific embodiment
Through a most preferred embodiment, the present technique scheme is elaborated, but protection scope of the present invention is not limited to said embodiment below.
A kind of high duty metal housing welding method in service life that prolongs, said high duty metal housing adopt high-strength abrasion-proof steel CrNiMo to be welded as metal shell as the welding base material, and the welding procedure flow process is following:
Preparation → tack welding before the weldering → preheating → weld → polish → hydrogen that disappears is handled and heat treatment → Non-Destructive Testing.Welding condition is selected for use:
1, wlding: the present invention considers that the cold crack tendency of high strength Cr NiMo steel is bigger; In order to obtain more toughness deposit to obtain better shock resistance, crack property, we select welding wire CHT711 flux-cored wire for use, and its deposition efficiency is high; The all-position welding processing performance is good, also can stand downward weldering.
Deposited metal composition is shown in table 1-1.
Table 1-1:
| The trade mark | C | Mn | Si | S | P |
| Standard value | ≤0.10 | ≤1.75 | ≤0.75 | ≤0.03 | ≤0.03 |
| Representative value | 0.06 | 1.40 | 0.40 | 0.010 | 0.017 |
The deposited metal mechanical performance is shown in table 1-2.
Table 1-2:
2, welding current: welding current is selected for use usually about 260-300A in the soldering test process; Because the excessive weld heat input that causes of welding current is excessive; To produce following two kinds of adverse consequences thus: at first weld heat input is excessive; The overheated tendency in nearly seam district is increased, and grain growth causes solidification cracking; Secondly heat input is too big, and fusion penetration is too big, and it is too much that the carbon of mother metal gets into weld seam, generates hard and crisp cementite, thus cracking.So welding current is unsuitable excessive, through test, the present invention selects current range at 160-200A crystallization control crackle preferably.
CHT711 gage of wire and reference current are shown in table 2-1.
Table 2-1:
The embodiment of the invention just is designed to example with the welding of coal-winning machine high strength rocking arm housing water-supply line cover plate; Adopt welding procedure of the present invention, not only make postwelding water channel water pressure test effect be greatly improved, stability increases; Also improve the coal-winning machine product quality, practiced thrift cost again.
Welding parameter: welding material CHT711 flux-cored wire (Φ 1.2mm);
Welding method: manual CO
2Gas shielded arc welding;
Welding current: 160-200A;
The material of backplate, cover plate: 16Mn.
Welding step is following:
1, prepares before the weldering: adopt mechanical means to process monolateral double V-groove, CO
2Smooth and easy situation of welding machine wire feed and gas flow situation conduct a survey, and with the channel plate that processes groove, be pre-bent to type by the outer shaped position of housing, water channel hole and water channel polishing are cleaned out.
2, tack welding: with housing local warming to 300 ℃-350 ℃, the spot welding of cover plate opsition dependent elder generation is fixed on the housing relevant position, position of spot welding at a certain distance, from the weldering of mediad cephalocaudal direction, and the left and right directions symmetry welds.
3, weld preheating: will put good admittedly housing and water channel cover plate, and advance stove and heat 350 ℃-400 ℃, constant temperature half an hour, the scene selects for use infrared radiation thermometer to carry out temperature control.
4, welding: use the CHT711 flux-cored wire, solid good housing of point and water channel bridge welding are expired, collar extension is welded in a mouthful back in the weldering earlier; Welding direction is welded to both sides by the centre, the left-right symmetric weldering, and plug is welding downwards; The place that welds is with asbestos insulation material protection, and when temperature is lower than 250 ℃, local warming to 350 ℃ again, it is full to continue welding; Inspection is then used carbon to shoot off and is removed if interference place is arranged.
5, polishing: after welding is accomplished; Carry out rounding off with grinding machine butt welded seam edge, angle and peripheral matrix, remove the welding wire coating splash that produces in the welding process, and smooth to the adjacently situated surfaces reconditioning; Make weld seam continuous, even, smooth, do not have crackle, slag inclusion, pore, burr and overlap etc.
6, the hydrogen that disappears of postwelding is handled and heat treatment: after welding was accomplished, weld seam also was in more than 100 ℃, in order to quicken the effusion of hydrogen in the welding point, prevented that cold crack from producing, and weldment was placed under 300-400 ℃ the environment, and the time is 2-6h.
In order to eliminate welding residual stress, the shape and size of rock-steady structure reduce distortion, prevent the embrittlement of thermal strain timeliness, and temperature commonly used in the past is 600-650 ℃ heat treatment, but so easy reduction weld seam and whole hardness cause the anti-wear performance of weldment impaired.Through overtesting, welding after-baking temperature is at 500-600 ℃, and constant temperature 4-6h cools to normal temperature with the furnace, both can reach destressing effect preferably, does not influence other performances of tissue again.
7, postwelding check: the operator is to welding the back quality and examine voluntarily or specially inspection of the person of accepting inspection (before weldering, weld in will check equally); The postwelding inspection content comprises: actual welding record, the size of weldment, weld appearance and size and flaw detection crackle etc.
8, the water pressure test: the pipeline that butt welding connects carries out the water pressure test, and hydraulic pressure keeps 12MPa, and the time is 5-10min; Do not leak if having, weldquality is intact, if leak; Then to the timely repair welding of leakages (repair welding follow procedures 3 and 4), and once more according to step 8 test to do not have leak into and the site clearing.
The inventive method the welding of high strength rocking arm housing water-supply line cover plate, is applicable to that also other high strength operates the welding of mechanical metal shell or mechanical arm in being suitable for the foregoing description.
Claims (4)
1. one kind prolongs the high duty metal housing welding method in service life; Said high duty metal housing adopts high-strength abrasion-proof steel CrNiMo to be welded as metal shell as the welding base material, it is characterized in that: said a kind of welding method that prolongs high duty metal housing service life comprises following operation:
First procedure, prepare before the welding:
The welding ends that adopts method for hot cutting will weld base material cuts into monolateral double V-groove weldment, is specially at first to carry out the vertical parallel cutting, aligns, the counter-slope mouth processes again;
Careful greasy dirt, corrosion and water stain of removing welding wire and weldment surface reduces hydrogen content in the weld seam before the welding, and inspection CO2 smooth and easy situation of welding machine wire feed and gas flow situation are utilized before welding rod uses and put oven for drying, put into heat-preserving container after taking out, and take the job site to;
Second operation work, tack welding:
To the mother metal local heat, with welding wire sheet material spot welding is fixed on the mother metal during welded blank before the weldering, position of spot welding at a certain distance, symmetrical object is therefrom entreated to cephalocaudal direction spot welding, and the spot welding of left and right directions symmetry;
Three process, the weldment preheating:
It is 30 minutes constant temperature preheating that second road step operation part is carried out duration, and the preheat temperature scope is between 300 ℃ to 400 ℃;
The 4th procedure, welding procedure:
Three process spare is adopted manual CO
2Gas shielded arc welding is walked to two along the weld seam middle part, and collar extension is welded in a mouthful back in the weldering earlier, and welding direction is welded to both sides by the centre; When running into the weld seam that intersects in length and breadth; Toe weld seam behind elder generation's weldering end weld seam when weldment length surpasses one meter, adopts balanced welding or backstep welding in the branch; When flat fillet weld on the weldment and fillet welding in the vertical position exist simultaneously, weld flat fillet weld, the long weld seam of weldering behind the short weld seam of weldering earlier after fillet welding in the vertical position should being welded earlier;
Every weldering is intact cleans out welding slag together, and in the inspection weld seam pore-free, crackle is arranged, and when pore, crackle are arranged, after its thorough removing, continues following one weld seam of welding again, receives the arc operation before the welding end;
Five processes, polishing:
After welding is accomplished, carry out the rounding off polishing, remove the welding wire coating splash that produces in the welding process with grinding machine butt welded seam edge, angle and peripheral matrix, and the adjacently situated surfaces reconditioning is smooth;
The 6th procedure, the hydrogen that disappears is handled and heat treatment:
After welding is accomplished, at first five processes spare is placed under 300-400 ℃ the temperature environment, time range is 2-6h; The hydrogen that disappears, then workpiece being positioned over steady temperature is that time range is 4-6h in 500-600 ℃ the environment; Heat-treat last slowly cooling;
The 7th procedure, Non-Destructive Testing:
Weld seam to the 6th procedure spare carries out painted or magnetic powder detection, if weld seam is found defective through flaw detection, then rejected region is repaired; Adopt manual welding that rejected region is repaired, with carbon arc air gouging rejected region is criticized groove, rejected region is darker in the middle of being shaped as; The gradually shallow inside gradually surface transition in two ends is removed the carbide at groove place with the abrasive machine polishing, then after painted or magnetic particle testing are confirmed zero defect; Carry out repair welding by above-mentioned technology again, welding finishes.
2. a kind of high duty metal housing welding method in service life that prolongs according to claim 1, it is characterized in that: the franchise of the bevel angle of said monolateral double V-groove weldment is ± 5 °, root face height ± 2mm.
3. a kind of high duty metal housing welding method in service life that prolongs according to claim 1 is characterized in that: use CO in the said welding procedure process
2Protection gas, said CO
2CO in the protection gas
2With the volume ratio of Ar be 4:1.
4. a kind of high duty metal housing welding method in service life that prolongs according to claim 1 is characterized in that: when adopting welding wire to weld, adopt welding wire CHT711 flux-cored wire.
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104227180A (en) * | 2014-09-23 | 2014-12-24 | 重庆舸海机电有限公司 | Welding method for NM400 wear-resistant steel |
| CN104259632A (en) * | 2014-07-10 | 2015-01-07 | 扬帆集团股份有限公司 | Tail fin welding process of 10000-ton level bulk cargo ship |
| CN105738468A (en) * | 2014-12-10 | 2016-07-06 | 西安航空动力控制科技有限公司 | Nondestructive test method of gear component subjected to laser repair welding |
| CN106180981A (en) * | 2016-08-05 | 2016-12-07 | 中铁十八局集团第四工程有限公司 | The CO of super large caliber steel pipe2gas protection welding process |
| CN106624288A (en) * | 2016-10-19 | 2017-05-10 | 杭州锅炉集团股份有限公司 | Welding method for header pipelines |
| CN107081506A (en) * | 2017-07-04 | 2017-08-22 | 合肥市大卓电力有限责任公司 | A kind of welding procedure of high-strength alloy steel plate |
| CN108057963A (en) * | 2017-12-15 | 2018-05-22 | 重庆友拓汽车零部件有限公司 | Neutral column reinforcement plate welds cooling means |
| CN108480912A (en) * | 2018-05-31 | 2018-09-04 | 广州中船文冲船坞有限公司 | Welding repair method is changed in the digging of ironcasting |
| CN111545988A (en) * | 2020-03-31 | 2020-08-18 | 广州文冲船舶修造有限公司 | Repair method for prolonging service life of brake hub of marine anchor cable machine |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104259632A (en) * | 2014-07-10 | 2015-01-07 | 扬帆集团股份有限公司 | Tail fin welding process of 10000-ton level bulk cargo ship |
| CN104227180A (en) * | 2014-09-23 | 2014-12-24 | 重庆舸海机电有限公司 | Welding method for NM400 wear-resistant steel |
| CN105738468A (en) * | 2014-12-10 | 2016-07-06 | 西安航空动力控制科技有限公司 | Nondestructive test method of gear component subjected to laser repair welding |
| CN106180981A (en) * | 2016-08-05 | 2016-12-07 | 中铁十八局集团第四工程有限公司 | The CO of super large caliber steel pipe2gas protection welding process |
| CN106624288A (en) * | 2016-10-19 | 2017-05-10 | 杭州锅炉集团股份有限公司 | Welding method for header pipelines |
| CN107081506A (en) * | 2017-07-04 | 2017-08-22 | 合肥市大卓电力有限责任公司 | A kind of welding procedure of high-strength alloy steel plate |
| CN108057963A (en) * | 2017-12-15 | 2018-05-22 | 重庆友拓汽车零部件有限公司 | Neutral column reinforcement plate welds cooling means |
| CN108480912A (en) * | 2018-05-31 | 2018-09-04 | 广州中船文冲船坞有限公司 | Welding repair method is changed in the digging of ironcasting |
| CN111545988A (en) * | 2020-03-31 | 2020-08-18 | 广州文冲船舶修造有限公司 | Repair method for prolonging service life of brake hub of marine anchor cable machine |
| CN111545988B (en) * | 2020-03-31 | 2021-03-16 | 广州文冲船舶修造有限公司 | Repair method for prolonging service life of brake hub of marine anchor cable machine |
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Application publication date: 20121219 |