CN114192946B - Suppression method for arc-build-up loosening defect of marine air valve sealing surface build-up welding - Google Patents
Suppression method for arc-build-up loosening defect of marine air valve sealing surface build-up welding Download PDFInfo
- Publication number
- CN114192946B CN114192946B CN202111533989.9A CN202111533989A CN114192946B CN 114192946 B CN114192946 B CN 114192946B CN 202111533989 A CN202111533989 A CN 202111533989A CN 114192946 B CN114192946 B CN 114192946B
- Authority
- CN
- China
- Prior art keywords
- arc
- alloy
- welding
- build
- air valve
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- 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
- B23K10/00—Welding or cutting by means of a plasma
- B23K10/02—Plasma welding
- B23K10/027—Welding for purposes other than joining, e.g. build-up welding
Abstract
The invention relates to a method for inhibiting arc-build-up loosening defects of a sealing surface of a marine air valve, which comprises the following steps: in the arc-receiving process, reducing the current falling time of an arc-receiving stage, and increasing the powder falling time of the arc-receiving stage to ensure that the current falling time is longer than the powder falling time; and step 2, in the surfacing process, the powder feeding amount per unit time of surfacing is increased, so that the weight of the alloy of the blank welding groove after surfacing reaches about 95 g. The method can obviously improve the qualification rate of the valve surface fluorescent flaw detection to more than 95% after the valve surface welding is machined.
Description
Technical Field
The invention relates to a build-up welding method for a marine air valve sealing surface, in particular to a plasma build-up welding arc loosening defect suppression method for the marine air valve sealing surface, and belongs to the technical field of air valve sealing surface processing.
Background
At present, a valve sealing surface of a gas valve of a medium-speed engine of a diesel engine is generally prepared by adopting a powder plasma surfacing process. The powder plasma surfacing is a high-energy density plasma arc formed between a welding gun and a workpiece, alloy powder is delivered to a plasma arc column at a certain angle through a powder delivery hole, and the alloy powder is deposited on the surface of a substrate in a cladding way under the action of the high-energy plasma arc. The existing mature alloy powder system comprises three types of iron-based, cobalt-based and nickel-based, and is mainly cobalt-based alloy powder used for surfacing the sealing surface of a marine diesel engine air valve. In order to ensure that the dilution rate of the build-up welding is controlled in a proper range and the powder is well melted, most air valves need to build up welding two layers on a welding groove continuously to obtain an alloy layer meeting the cutting quantity. Based on the technological characteristics of plasma overlaying and the structural design of an air valve alloy layer, the arc striking and arc receiving processes of the plasma overlaying are completed on the circumference of a blank welding groove.
In general, in order to prevent unstable quality of build-up welding in the arcing and arc-receiving stages from affecting the overall quality of the valve, the following modes are generally adopted for the two stages: setting delay time for the workpiece turntable during arcing, and ensuring that the turntable starts to rotate after plasma arc transfer and powder feeding are stable; and setting overlap joint amount during arc welding, and continuously welding a certain distance after welding two layers of the groove alloy, and then welding the arc.
The prior art of nickel-based alloy powder plasma surfacing valve sealing surface has the defects that: when the second layer is deposited by the alloy, the high energy density of the plasma arc column can melt the powder and simultaneously has a secondary melting effect on the upper welding layer. The second layer of penetration occupies a larger specific gravity (penetration ratio) in the whole alloy layer depth, when entering an arc-collecting stage, the energy of transferring an arc along with the attenuation of current also attenuates along with the attenuation, because the nickel-based alloy has poor heat conductivity and poor liquidity of liquid alloy, the alloy melting effect below an arc column is reduced at the moment that the plasma arc begins to attenuate, and at the moment, a Fang Yetai molten pool behind the arc column is reduced because of the reduction of the energy below the arc column, on one hand, the solidification speed is accelerated, and on the other hand, the obtained liquid alloy supplementing quantity is reduced, so that shrinkage cavity occurs in the molten pool due to insufficient feeding when solidification. And loose can be distributed in a strip shape in the alloy layer along with the arc-receiving process. After surfacing, the valve face is machined to enable the valve face alloy surface to be loosely exposed, so that the air valve is scrapped, and the valve face can become a weak ring node for abrasion and corrosion in the working condition environment of a diesel engine, so that the air valve is disabled, and the service life is shortened.
Disclosure of Invention
In view of the defects of the prior art, the technical problem to be solved by the invention is to provide a plasma surfacing method for inhibiting arc-collecting looseness of a sealing surface of a marine air valve, so as to overcome the looseness defect of an air valve surfacing nickel-based Colmonoy 56SPL alloy powder alloy layer at an arc-collecting position after machining, and obviously improve the flaw detection qualification rate of finished products of the valve surface to more than 95%.
In order to solve the technical problems, the invention provides a plasma surfacing method for inhibiting arc-closing looseness of a valve sealing surface of a marine air valve, which comprises the following steps: in the arc-receiving process, reducing the current falling time of an arc-receiving stage, and increasing the powder falling time of the arc-receiving stage to ensure that the current falling time is longer than the powder falling time; and step 2, in the surfacing process, the powder feeding amount per unit time of surfacing is increased, so that the weight of the alloy of the blank welding groove after surfacing reaches about 95 g.
The step 1 comprises the following steps: the current falling time in the arc receiving stage is reduced from 10s to 5s, the current falling time is the arc receiving time, the arc receiving distance is about 17mm when the current falling time is 10s, the distribution length of loose defects at the arc receiving position in the alloy circumferential direction is about 15mm through anatomy detection, the loose length of the current falling time is reduced, the loose length is about 5mm when the current falling time is 0, but the arc receiving is too fast, so that obvious step phenomenon exists at the junction between the surfacing end position and the previous surfacing layer, the damage to a cutter is larger due to the step at the arc receiving position with higher alloy hardness in the valve face alloy machining process, the current falling time is regulated to about 9mm, and the arc receiving position and the previous alloy transition are gentle. The current fall time was determined to be 5s. The powder fall time was increased from 2s to 4s. When the powder falling time is longer than the current falling time, the powder feeding hole still discharges powder to cause poor fusion, when the powder falling time is 2s, the powder feeding attenuation rate is faster than the current attenuation rate, when the powder falling time is 4s, the powder feeding end molten pool is short of alloy filling to cause larger arc pits, and when the powder falling time is 4s, the molding of the arc receiving position matched with the current falling time of 5s is optimal. Before arc-collecting, the build-up welding is in the lap joint process, which plays the role of the transition between build-up welding and arc-collecting, the build-up welding current is reduced section by section due to the temperature between build-up welding layers, the powder feeding is reduced in the lap joint process compared with the build-up welding process, and a molten pool with sufficient melting is formed by matching with the small current at the end of the build-up welding. The step 2 comprises the following steps: the powder feeding amount per unit time is increased from 18g/min to 23g/min. And determining the overlaying speed to be 100mm/min according to the disk diameter and groove design of the air valve. The thickness of the alloy layer in the finished state of the air valve is about 2.5mm, when the powder feeding amount is 18g/min, the distribution depth of arc-collecting loose defects in the alloy is in the range of 2.4-2.6mm from a fusion line, when the air valve is processed to the finished state, the loose defects are exposed on the surface of the alloy layer of the air valve, the upper part of the alloy layer of the first layer is secondarily melted when the air valve is overlaid on the second layer, the lower alloy layer is melted in the same way, when the thickness of the alloy below the arc-collecting point is increased, the distance from the bottom end of the arc-collecting fusion pool to the fusion line is also increased, the loose defects appear at the solidification part of the arc-collecting fusion pool, when the powder feeding amount is 23g/min, the loose defects of the alloy layer of the finished state of the air valve at the moment are overcome.
The gas valve is used for overlaying nickel-based Colmonoy 56SPL alloy powder, a welding gun is 10mm away from a gas valve welding groove, the overlaying linear speed is 100mm/min (the rotating speed of a rotary table is 0.46-0.48 r/min), the gas valve is used for overlaying a layer of alloy at the overlaying linear speed for 2 minutes and 5 seconds, the ion gas flow is 80L/h, the included angle between the axis direction of the gas valve and the vertical direction of the welding gun is 30 degrees, and the overlaying current is 90-110A.
Compared with the prior art, the invention has the beneficial effects that: the technical parameters of the arc receiving section are regulated to regulate the ratio of penetration in the thickness of the whole alloy layer and the distance of the arc receiving section at the beginning of arc receiving, so that the distance from the arc receiving loose to the welding line of the alloy and the matrix and the length of the arc receiving loose in the circumferential direction of the alloy layer are increased, the purpose of compactness and no defect after the machining of the alloy for the surfacing of the valve face of the air valve is achieved, and the quality of the surfacing of the air valve is stable. The method for setting the current falling time, the powder falling time and the powder feeding amount in the overlaying process is characterized in that parameter values are set through an integrated control unit of plasma overlaying equipment, and automatic overlaying is carried out after the parameter values are set. The current falling time realizes the completion time of the transfer arc power supply current of the arc receiving section to be reduced to 0 through a control signal, and the powder feeding quantity and the powder falling time control the roller rotating speed of the powder cylinder and the time for stopping rotating the roller through the control signal.
Drawings
The invention is further described below with reference to the accompanying drawings.
FIG. 1 shows the dimensions of a marine gas valve prior to weld overlay and the weld pool configuration.
FIG. 2 is a timing diagram of a plasma build-up welding process for a marine gas valve according to the present invention.
FIG. 3 is a schematic diagram of the alloy layer position of the marine valve product according to an embodiment of the present invention.
Detailed Description
As shown in fig. 1 and 2, the embodiment of the invention provides a method for inhibiting arc-closing and loosening of a valve surface of a gas valve plasma surfacing, which comprises the following steps: step 1, reducing the current falling time in the arc-receiving stage from 10s to 5s, increasing the powder falling time from 2s to 4s, and immediately finishing the attenuation of the current when the powder attenuation is finished, so that the arc-receiving process time is reduced. Step 2, increasing the powder feeding amount per unit time in the surfacing process from 18g/min to 23g/min.
The arc-receiving process is changed by changing the current and the powder feeding reduction time in the arc-receiving stage, the arc-receiving distance is reduced, the distribution length of the looseness in the alloy layer along the circumferential direction is regulated and controlled, and the distance between the looseness in the alloy layer and the welding line of the matrix and the alloy layer in the arc-receiving process is regulated and controlled by changing the powder feeding amount in unit time in the overlaying process, so that the purpose of improving the qualification rate of finished products is achieved.
The implementation method of the arc defect suppression technology of the valve surface of the gas valve plasma surfacing valve is combined, and the whole process flow of the gas valve of the model is as follows: 1. preheating for 1h at 300 ℃ after alcohol wiping of a gas valve welding groove; 2. the equipment adjusts and inputs parameters, such as figure 2, wherein (1) represents non-transferred arc current, (2) represents powder feeding per unit time, (3) represents transferred arc current, (4) represents rotating speed of a rotary table, (5) represents rotating angle of the rotary table, (6) represents welding gun height (distance from the lower end surface of the welding gun to the bottom of a gas valve welding groove), and (7) represents ion gas flow; the 0-1 section is an arc starting stage of overlaying, the 1-2 section is a first section of overlaying, the section of turntable rotates 10 degrees, the 2-3 section is a second section of overlaying, namely a first layer of alloy, the section of turntable rotates 360 degrees, the 3-4 section is a third section of overlaying, namely a second layer of alloy, the section of turntable rotates 360 degrees, the 4-5 section is a fourth section of overlaying, the section of turntable rotates 10 degrees, and the 5-6 section is an arc collecting section of overlaying; 21-22 powder feeding 10g/min,22-23 powder feeding 23g/min,23-24 powder feeding 14.5g/min,31-32 current 110A,32-33 current 100A,33-34 current 90A; (5) the whole process of overlaying is kept unchanged, (4) the whole process of overlaying is kept unchanged in the process of 1-6, and the whole process of overlaying is kept unchanged in the process of 5-6, (2) the time is 4s from 24 points to 0, and (3) the time is 5s from 34 points to 0. Wherein (5) and (6) adopt a mechanical regulation mode, and (1), (2), (3) and (4) are controlled by a device PLC through parameter input. 3. And performing overlaying welding according to the set technological parameters. It should be noted that the plasma overlaying according to the embodiment of the present invention is directed to nickel-based Colmonoy 56SPL alloy powder for inhibiting arc-loosening defects of a valve surface.
The powder feeding amount per unit time in the process of overlaying is increased, so that the re-smelting effect of the two-layer molten pool on the first-layer molten pool is reduced when the overlaying is carried out on the second layer, namely the height of the bottom of the two-layer molten pool from the welding line of the matrix and the alloy is increased, and the distance between the molten pool and the welding line is kept consistent with that in the process of overlaying when the overlaying enters an arc-collecting stage. The time of the arc-receiving process is reduced, the depth of a molten pool in the arc-receiving stage is gradually reduced, and the defect length is not controlled due to overlong arc-receiving time.
From the above description, it can be seen that the following technical effects are achieved in the embodiments of the present invention: the arc collecting process of the plasma overlaying is regulated and controlled by reducing the current falling time and increasing the powder falling time in the arc collecting stage; the penetration ratio during arc collection is regulated and controlled by changing the powder feeding amount in the overlaying process, so that the distance from loosening to a welding line is increased, the problem of loosening defects of a valve face after machining of an overlaying alloy layer is solved, the quality qualification rate of products produced by batch operation is prevented from being unstable, and the primary flaw detection qualification rate of the valve face is stably kept above 95%.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.
Claims (5)
1. A method for inhibiting arc-build-up loosening defects of a sealing surface of a marine air valve is characterized by comprising the following steps of: in the process of plasma surfacing of the sealing surface of the marine air valve, the method comprises the following steps:
step 1, in the arc-collecting process of plasma overlaying, reducing the current falling time of an arc-collecting stage, and increasing the powder falling time of the arc-collecting stage, so that the current falling time is longer than the powder falling time;
the current falling time in the arc receiving stage is 5s, namely the arc receiving time, when the current falling time is 10s, the arc receiving distance is 17mm, the distribution length of loose defects at the arc receiving position in the circumferential direction of the alloy is 15mm through anatomy detection, and the current falling time is reduced, so that the loose length tends to be reduced;
when the current drop time is 0, the loosening length is 5mm, the arc is quickly received at the moment, so that a step phenomenon exists at the junction of the surfacing end position and the previous surfacing layer, and the step at the arc receiving position causes damage to a cutter in the machining process of the valve face alloy because the alloy hardness is between 56 and 59HRC, the current drop time is regulated to 5s, the loosening length is 9mm at the moment, and the arc receiving position and the previous alloy are smoothly transited;
the powder falling time of the arc receiving stage is 4s, namely the time for the powder feeding to decay to zero in the arc receiving stage, when the powder falling time is longer than the current falling time, the powder feeding hole still feeds powder to cause poor fusion, when the powder falling time is 2s, the powder feeding decay rate is too fast compared with the current decay rate, when the powder feeding at the rear end of the arc receiving stage ends, the molten pool is lack of alloy filling to cause arc pits with the diameter of 5-6mm and the depth of 1-2mm, and when the powder falling time is 4s, the molding of the arc receiving position with the matching current falling time of 5s is optimal;
step 2, in the plasma surfacing process, increasing the powder feeding amount in a surfacing unit time, so that the alloy weight of a blank welding groove reaches 90-100 g after surfacing; the arc-receiving process is changed by changing the current and the powder feeding reduction time in the arc-receiving stage, the arc-receiving distance is reduced, the distribution length of the looseness in the alloy layer along the circumferential direction is regulated and controlled, and the distance between the looseness in the alloy layer and the welding line of the matrix and the alloy layer in the arc-receiving process is regulated and controlled by changing the powder feeding amount in unit time in the overlaying process, so that the purpose of improving the yield of finished products is achieved; the powder feeding amount per unit time is increased from 18g/min to 23g/min.
2. The method for inhibiting arc build-up loosening defects of marine air valve sealing surface build-up welding according to claim 1, wherein the method comprises the following steps: the current for starting attenuation in the step 1 is 90A, and the powder feeding amount for starting attenuation is 14.5g/min.
3. The method for inhibiting arc build-up loosening defects of marine air valve sealing surface build-up welding according to claim 1, wherein the method comprises the following steps: in the step 2, the thickness of an alloy layer in a finished product state of the air valve is 2.5mm, when the powder feeding amount is 18g/min, the distribution depth of arc-collecting loose defects in the alloy is within the range of 2.4-2.6mm from a fusion line, when the air valve is processed to a finished product state, the loose defects are exposed on the surface of the alloy layer of the air valve, the upper part of the alloy layer of the first layer is secondarily melted when the air valve is overlaid on a second layer, the alloy layer of the first layer is melted in the same way, the lower alloy layer is melted in the arc-collecting process, when the thickness of the alloy below the arc-collecting point is increased, the distance from the bottom end of the arc-collecting fusion pool to the fusion line is increased, the loose defects appear at the solidification part of the arc-collecting fusion pool, and when the powder feeding amount is 23g/min, the loose defects are overcome at the depth of the alloy layer of more than 2.7mm, and the alloy in the finished product state of the air valve at the moment.
4. The method for inhibiting arc deposition loosening defect of marine air valve sealing surface build-up welding according to claim 1, wherein the plasma build-up welding material uses nickel-based Colmonoy 56SPL alloy powder, a welding gun is 10mm away from an air valve welding groove, the build-up welding linear speed is 100mm/min, the rotating speed of a turntable is 0.46-0.48r/min, the air valve is 2 minutes and 5 seconds when being built-up welding is carried out at the build-up welding linear speed, the ion air flow is 80L/h, the air valve axis direction forms an included angle of 30 degrees with the welding gun vertical direction, and the build-up welding current is 90-110A.
5. The method for suppressing arc build-up porosity defect on a sealing surface of a marine air valve according to claim 1, wherein the sealing surface is formed by two layers of alloy build-up welding.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111533989.9A CN114192946B (en) | 2021-12-15 | 2021-12-15 | Suppression method for arc-build-up loosening defect of marine air valve sealing surface build-up welding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111533989.9A CN114192946B (en) | 2021-12-15 | 2021-12-15 | Suppression method for arc-build-up loosening defect of marine air valve sealing surface build-up welding |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114192946A CN114192946A (en) | 2022-03-18 |
| CN114192946B true CN114192946B (en) | 2023-04-28 |
Family
ID=80654019
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111533989.9A Active CN114192946B (en) | 2021-12-15 | 2021-12-15 | Suppression method for arc-build-up loosening defect of marine air valve sealing surface build-up welding |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114192946B (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4104505A (en) * | 1976-10-28 | 1978-08-01 | Eaton Corporation | Method of hard surfacing by plasma torch |
| CN2083766U (en) * | 1990-12-26 | 1991-08-28 | 机械电子工业部哈尔滨焊接研究所 | Welding current attenuation controlling device |
| CN105643069A (en) * | 2014-12-03 | 2016-06-08 | 重庆远煌机械制造有限公司 | Valve sealing surface overlaying process |
| CN106112204A (en) * | 2016-07-15 | 2016-11-16 | 南京国际船舶设备配件有限公司 | A kind of marine low-speed machine air valve sealing surface build-up welding Nickel-based Alloy Welding technique |
| CN110102923B (en) * | 2019-05-28 | 2021-04-30 | 昆山华恒焊接股份有限公司 | Arc-closing control method for applying plasma-TIG double welding guns to welding of circular weld joint |
-
2021
- 2021-12-15 CN CN202111533989.9A patent/CN114192946B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN114192946A (en) | 2022-03-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105755464B (en) | Double-deck gradient laser gain material manufacture method | |
| CN105734560B (en) | The eight road coaxial powder-feeding nozzles for the manufacture of double-deck gradient laser gain material | |
| CN102015194A (en) | Process for building up an edge of a machine component, and machine component remanufacturing strategy | |
| CN108746959B (en) | Preparation method of ceramic powder reinforced metal base welding layer and powder feeding device thereof | |
| CN104816093B (en) | Manufacturing method for deep hole bottom sealing surface laser cladding of valve body part | |
| CN110052728A (en) | A kind of online welding repair method of Ball Milling Machine End Cover cracking | |
| CN110923700A (en) | Steel surface coating, preparation method and device | |
| CN110919135B (en) | Preparation method for Babbitt metal composite welding on surface of curved surface bearing bush | |
| CN111058036A (en) | Method for preparing wear-resistant corrosion-resistant temperature-sensitive coating by double-laser synergistic ultrahigh-speed laser cladding | |
| CN108165987A (en) | A kind of prosthetic device and restorative procedure of machine tool chief axis endoporus | |
| CN114192946B (en) | Suppression method for arc-build-up loosening defect of marine air valve sealing surface build-up welding | |
| CN113529005A (en) | Spraying manufacturing method of continuous casting roller | |
| CN107805809A (en) | A kind of automobile die surface coating renovation technique | |
| CN102615395A (en) | Method for welding single-arc double-wire pipelines | |
| JPH1034360A (en) | Built up welding by laser beam | |
| CN111843146B (en) | Welding method for wear-resistant materials | |
| Kong et al. | High-rate laser metal deposition of Inconel 718 component using low heat-input approach | |
| CN114082962A (en) | Online repairing and annealing process for nodular cast pipe | |
| CN112935549A (en) | Narrow-gap laser wire filling welding equipment and method thereof | |
| CN107116338A (en) | A kind of method for laser compound treating of sealing surface | |
| CN111014901A (en) | Automatic self-melting TIG welding method for thin-wall stainless steel pipe | |
| CN215469320U (en) | Roller way roller remanufacturing device for laser cladding composite rolling | |
| CN109570764A (en) | A kind of laser overlaying welding method of the engine valve conical surface | |
| CN103949750A (en) | Method for preventing bead welding copper alloy from generating air holes | |
| EP0129402A1 (en) | Spray welding of metals |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |