CN110744259A - Gradient repairing method for sealing surface of high-pressure main steam valve for thermal power generating unit - Google Patents
Gradient repairing method for sealing surface of high-pressure main steam valve for thermal power generating unit Download PDFInfo
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- CN110744259A CN110744259A CN201911175189.7A CN201911175189A CN110744259A CN 110744259 A CN110744259 A CN 110744259A CN 201911175189 A CN201911175189 A CN 201911175189A CN 110744259 A CN110744259 A CN 110744259A
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Abstract
The invention discloses a gradient repairing method of a sealing surface of a high-pressure main steam valve for a thermal power generating unit, wherein an original surfacing layer at the damaged sealing surface of the valve is turned off, and a double-sided smooth transition groove is formed at the bottom of a machined repairing area; preheating the repair area to a temperature not lower than 200 ℃, and performing backing TIG (tungsten inert gas) surfacing on the bottom area by using a metal repair material with low hardness and good weldability, wherein the thickness of the surfacing is 2mm less than the overall thickness of the area to be repaired; then reducing the preheating temperature to 100 ℃, replacing a metal repairing material with high hardness and good weldability to complete surfacing of a cover layer of a damaged area of the sealing surface, wherein the thickness is more than 3mm and exceeds the final machining size of the area to be repaired by at least 1 mm; then preserving heat at 620 ℃ for stress relief annealing for 2 hours; finally, according to the final machining requirement of the seal profile, turning the repaired area, and performing hardness and nondestructive testing to complete the gradient repairing process; through transition fit of different hardness materials and different preheating, the repairing efficiency is improved, the interlayer bonding strength in the sealing surface repairing process is increased, and the repairing quality is ensured.
Description
Technical Field
The invention relates to the technical field of valve sealing surface repair, in particular to a gradient repair method for a high-pressure main steam valve sealing surface for a thermal power generating unit.
Background
Along with the large-scale long-time operation of thermal power generating units in China, the operation parameters are continuously improved, the operation temperature and the pressure borne by the sealing surface of the high-pressure main steam valve in the operation process are high, and in addition, the sealing surface inevitably has the defects of block falling, pits, corrosion spots and the like along with the closing and the impacting of a valve rod in the service process, the scouring and the corrosion of working media and the like, so that the sealing effect is influenced, and the harmfulness to the units is great. Most of valves are welded on a main pipeline, so that the valves are difficult to disassemble and maintain, the traditional feasible repair method is to perform manual arc surfacing, laser cladding and other machining and repairing of a single material on a shutdown site, the period is long, the effect is general, and the economic loss is large. The repairing material has incomplete on-site repairing process for the defects of the large parts from the aspects of matching, post-welding on-site heat treatment, process quality control and the like, although a treatment mode of bottoming and hard surface layer materials is adopted recently, the whole process has not formed a complete process from the aspects of defect treatment, gradient transition requirements, different process matching, post-heat on-site treatment and the like, and has not been popularized to the repairing operation of the sealing surface of the valve in a large scale.
Disclosure of Invention
The invention aims to solve the technical problem of providing a gradient repairing method of a sealing surface of a high-pressure main steam valve for a thermal power generating unit, which adopts transition fit of materials with different hardness and different preheating temperatures, improves repairing efficiency, increases interlayer bonding strength in a sealing surface repairing process, and ensures repairing quality.
In order to solve the technical problems, the technical scheme of the invention is as follows:
a gradient repairing method for a sealing surface of a high-pressure main steam valve for a thermal power generating unit comprises the following steps:
step 1: aiming at the damage condition of the sealing surface of the high-pressure main steam valve, completely turning off the original overlaying layer damaged at the sealing surface of the high-pressure main steam valve, reserving a double-sided transition groove on the turned bottom boundary and the original sealing surface of the valve, and cleaning to form a region to be repaired;
step 2: integrally preheating the area to be repaired to be not less than 200 ℃ at the heating rate of 100 ℃/h, and preserving heat for 2 hours;
and step 3: performing priming TIG surfacing or laser cladding on the bottom of the area to be repaired by using a metal repair material with low hardness and good weldability, wherein the overlap ratio of the surfacing is 30%, the interlayer temperature is controlled at 300-350 ℃, and the thickness of the priming surfacing layer is 2mm smaller than the whole thickness of the area to be repaired;
and 4, step 4: slowly cooling, and reducing the preheating temperature to 100 ℃;
and 5: replacing a metal repairing material with high hardness and good weldability to complete surfacing of the cover layer of the area to be repaired, controlling welding repair parameters, wherein the surfacing overlap ratio is 30%, the repair thickness is greater than 3mm, and the repair thickness at least exceeds the whole thickness of the area to be repaired by 1 mm;
step 6: after welding, heating to 620 ℃, preserving heat, removing stress, annealing for 2 hours, and slowly cooling to room temperature;
and 7: and turning the repaired area according to the original drawing requirements of the sealing surface to ensure that the machined sealing surface is a high-hardness metal repairing material, and finally performing hardness test and nondestructive test on the machined sealing surface to finish the gradient repairing process.
The subsequent heat preservation heat treatment adopts the heat preservation at 620 ℃ for 2 hours, the temperature exceeds the common working temperature of the valve sealing surface, the stress states of different gradient materials and different technological processes are eliminated and the heat stability under the service working condition is ensured.
Preferably, the bottom boundary is processed into a smooth transition form, the angle of the double-sided groove is not less than 45 degrees, and the interference of subsequent repair processing is reduced or avoided.
Preferably, the low hardness, high weldability metallic repair material is a high nickel content alloy (such as EnNiCo-3, EnNiCoMo-3 or other similar Ni based welding material), has a high temperature hardness HV of less than 200, a room temperature hardness HRC of less than 30, and has a good metallurgical bond with the base material, completely covering the area of the bottom to be repaired at the bottom and the boundary.
Preferably, the high-temperature hardness HV at 600 ℃ of the metal repair material with high hardness and good weldability is not less than 300, the room-temperature hardness HRC is not less than 40, and the interface metallurgical bonding of the metal repair material with low hardness and good weldability is good.
The preheating temperature of more than 200 ℃ is selected for the metal repairing material with low hardness and good weldability, the preheating temperature of 100 ℃ is selected for the metal repairing material with high hardness and good weldability, and the automatic surfacing repair process of different materials is matched, so that the efficiency is improved.
The nondestructive detection method comprises on-site fluorescence detection or penetration detection, and ensures that no cracks or air hole defects exist after surface processing.
The invention has the advantages that: the damage of the valve sealing surface is repaired by adopting different materials and different processes, a gradient mode is formed in the aspects of material matching and process matching, the thermal deformation in the repairing process is small, and the quality of a repairing area is controllable. Meanwhile, the bottom repairing area is made of soft materials, the service end face is made of hard materials, better repairing interface combination can be formed, repairing efficiency is improved, in addition, when the service is stressed, materials with high surface hardness improve impact resistance and corrosion resistance, materials with low internal hardness can conduct and distribute force to the base body better, and therefore the service life of the repairing sealing surface is prolonged integrally.
Drawings
Fig. 1 is a schematic diagram of a gradient repairing result of a sealing surface of a high-pressure main steam valve for a thermal power generating unit.
In the figure, 1 is a cover surface repairing material with high hardness, 2 is a priming repairing material with low hardness, and 3 is a valve base substrate.
Detailed Description
The invention is described in further detail below with reference to the figures and specific examples.
Example 1
In this embodiment, the main steam valve sealing surface is taken as an example, the material P91 is taken as an example, and the TIG automatic weld overlay repair process is taken as an example to further describe the repair method of the present invention in detail, which is explained but not limited by the present invention.
The method comprises the following steps:
step 1: aiming at the damage condition of the sealing surface of the high-pressure main steam valve, completely turning off the damaged original overlaying layer at the sealing surface of the high-pressure main steam valve, reserving a double-sided transition groove on the turned bottom boundary and the original sealing surface of the valve, and cleaning the two-sided transition groove as shown in figure 1;
step 2: preheating the area to be repaired to be not less than 200 ℃ at the heating rate of 100 ℃/h, and preserving heat for 2 hours;
and step 3: performing backing TIG automatic surfacing on the bottom of the area to be repaired by using a metal repairing material with low hardness and good weldability, wherein the lapping rate of surfacing is 30%, the interlayer temperature is controlled at 300-;
and 4, step 4: slowly cooling, and reducing the preheating temperature to 100 ℃;
and 5: replacing a metal repairing material with high hardness and good weldability to finish automatic surfacing of the cover surface layer of the area to be repaired finally, controlling welding repair parameters, wherein the surfacing lap joint rate is 30%, the thickness is more than 3mm, and the allowance of the surfacing lap joint rate exceeds the sealing surface of the area to be repaired by at least 1 mm;
step 6: after welding, heating to 620 ℃, preserving heat, removing stress, annealing for 2 hours, and slowly cooling to room temperature;
and 7: according to the original drawing requirements of the sealing surface, turning the repaired area to ensure that the machined sealing surface is a high-hardness metal repairing material to form a high-hardness cover surface repairing material 1 in the drawing 1; and finally, performing hardness test on the processed sealing surface, and performing nondestructive testing by adopting a fluorescence or permeation method to finish the gradient repairing process.
Example 2
In this embodiment, the sealing surface of the main steam valve is taken as an example, the material P91 and the CMT automatic surfacing repair process are taken as examples to further describe the repair method of the present invention in detail, and the description is for explanation and not for limitation of the present invention.
The method comprises the following steps:
step 1: aiming at the damage condition of the sealing surface of the high-pressure main steam valve, completely turning off the damaged original overlaying layer at the sealing surface of the high-pressure main steam valve, reserving a double-sided transition groove on the turned bottom boundary and the original sealing surface of the valve, and cleaning the two-sided transition groove as shown in figure 1;
step 2: preheating the area to be repaired to be not less than 200 ℃ at the heating rate of 100 ℃/h, and preserving heat for 2 hours;
and step 3: utilizing a metal repair material with low hardness and good weldability, calling a CMT automatic surfacing optimization program, including current, pulse, frequency and the like, performing bottom surfacing on the bottom of the area to be repaired, wherein the surfacing overlap ratio is 30%, the interlayer temperature is controlled at 300-;
and 4, step 4: slowly cooling, and reducing the preheating temperature to 100 ℃;
and 5: replacing a metal repairing material with high hardness and good weldability to complete surfacing of the cover surface layer of the area to be repaired finally, and controlling welding repair parameters, wherein the surfacing lap joint rate is 30%, the thickness is more than 3mm, and the allowance of the surfacing lap joint rate exceeds the sealing surface of the area to be repaired by at least 1 mm;
step 6: after welding, heating to 620 ℃, preserving heat, removing stress, annealing for 2 hours, and slowly cooling to room temperature;
and 7: according to the original drawing requirements of the sealing surface, turning the repaired area to ensure that the machined sealing surface is a high-hardness metal repairing material to form a high-hardness cover surface repairing material 1 in the drawing 1; and finally, performing hardness test on the processed sealing surface, and performing nondestructive testing by adopting a fluorescence or permeation method to finish the gradient repairing process.
Claims (6)
1. A gradient repairing method for a sealing surface of a high-pressure main steam valve for a thermal power generating unit is characterized by comprising the following steps of: the method comprises the following steps:
step 1: aiming at the damage condition of the sealing surface of the high-pressure main steam valve, completely turning off the original overlaying layer damaged at the sealing surface of the high-pressure main steam valve, reserving a double-sided transition groove on the turned bottom boundary and the original sealing surface of the valve, and cleaning to form a region to be repaired;
step 2: integrally preheating the area to be repaired to be not less than 200 ℃ at the heating rate of 100 ℃/h, and preserving heat for 2 hours;
and step 3: performing priming TIG surfacing or laser cladding on the bottom of the area to be repaired by using a metal repair material with low hardness and good weldability, wherein the overlap ratio of the surfacing is 30%, the interlayer temperature is controlled at 300-350 ℃, and the thickness of the priming surfacing layer is 2mm smaller than the whole thickness of the area to be repaired;
and 4, step 4: slowly cooling, and reducing the preheating temperature to 100 ℃;
and 5: replacing a metal repairing material with high hardness and good weldability to complete surfacing of the cover layer of the area to be repaired, controlling welding repair parameters, wherein the surfacing overlap ratio is 30%, the repair thickness is greater than 3mm, and the repair thickness at least exceeds the whole thickness of the area to be repaired by 1 mm;
step 6: after welding, heating to 620 ℃, preserving heat, removing stress, annealing for 2 hours, and slowly cooling to room temperature;
and 7: and turning the repaired area according to the original drawing requirements of the sealing surface to ensure that the machined sealing surface is a high-hardness metal repairing material, and finally performing hardness test and nondestructive test on the machined sealing surface to finish the gradient repairing process.
2. The gradient repairing method for the sealing surface of the high-pressure main steam valve for the thermal power generating unit according to claim 1, characterized by comprising the following steps of: the bottom boundary is processed into a smooth transition form, and the angle of a double-sided groove is not less than 45 degrees.
3. The gradient repairing method for the sealing surface of the high-pressure main steam valve for the thermal power generating unit according to claim 1, characterized by comprising the following steps of: the metal repairing material with low hardness and good weldability is high-nickel-content alloy, the high-temperature hardness HV is less than 200, the room-temperature hardness HRC is less than 30, the metal repairing material and a base material to be repaired are well metallurgically bonded, and the bottom area to be repaired is completely covered at the bottom and the boundary.
4. The gradient repairing method for the sealing surface of the high-pressure main steam valve for the thermal power generating unit according to claim 1, characterized by comprising the following steps of: the high-temperature hardness HV at 600 ℃ of the metal repair material with high hardness and good weldability is not less than 300, the room-temperature hardness HRC is not less than 40, and the interface metallurgical bonding of the metal repair material with low hardness and good weldability is good.
5. The gradient repairing method for the sealing surface of the high-pressure main steam valve for the thermal power generating unit according to claim 1, characterized by comprising the following steps of: the preheating temperature of more than 200 ℃ is selected for the metal repairing material with low hardness and good weldability, the preheating temperature of 100 ℃ is selected for the metal repairing material with high hardness and good weldability, and the automatic surfacing repair process of different materials is matched, so that the efficiency is improved.
6. The gradient repairing method for the sealing surface of the high-pressure main steam valve for the thermal power generating unit according to claim 1, characterized by comprising the following steps of: the nondestructive detection method comprises on-site fluorescence detection or penetration detection, and ensures that no cracks or air hole defects exist after surface processing.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113231788A (en) * | 2021-06-03 | 2021-08-10 | 上海电力股份有限公司吴泾热电厂 | On-site repairing method for sealing surface of valve seat of in-service safety valve |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101181764A (en) * | 2007-12-12 | 2008-05-21 | 湖南珠华机械有限公司 | Build-up welding process for low-alloy cast iron valve body sealing surface |
| CN101367148A (en) * | 2007-08-15 | 2009-02-18 | 南通龙源电站阀门有限公司 | F92 base metal weld deposit cobalt based hard alloy process |
| CN104690482A (en) * | 2015-02-10 | 2015-06-10 | 上海平安高压调节阀门有限公司 | Repairing process of sealing surface of valve seat of high-pressure bypass main valve for ultra-supercritical thermal power generating unit |
| CN106891131A (en) * | 2016-12-29 | 2017-06-27 | 常熟市常轴轴承有限公司 | The surface repairing technique of high abrasion seal |
| EP3441180A1 (en) * | 2017-08-11 | 2019-02-13 | General Electric Company | Method of repairing superalloys |
-
2019
- 2019-11-26 CN CN201911175189.7A patent/CN110744259A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101367148A (en) * | 2007-08-15 | 2009-02-18 | 南通龙源电站阀门有限公司 | F92 base metal weld deposit cobalt based hard alloy process |
| CN101181764A (en) * | 2007-12-12 | 2008-05-21 | 湖南珠华机械有限公司 | Build-up welding process for low-alloy cast iron valve body sealing surface |
| CN104690482A (en) * | 2015-02-10 | 2015-06-10 | 上海平安高压调节阀门有限公司 | Repairing process of sealing surface of valve seat of high-pressure bypass main valve for ultra-supercritical thermal power generating unit |
| CN106891131A (en) * | 2016-12-29 | 2017-06-27 | 常熟市常轴轴承有限公司 | The surface repairing technique of high abrasion seal |
| EP3441180A1 (en) * | 2017-08-11 | 2019-02-13 | General Electric Company | Method of repairing superalloys |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113231788A (en) * | 2021-06-03 | 2021-08-10 | 上海电力股份有限公司吴泾热电厂 | On-site repairing method for sealing surface of valve seat of in-service safety valve |
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