CN105779750A - Postweld heat treatment technology for excavator bucket rod - Google Patents
Postweld heat treatment technology for excavator bucket rod Download PDFInfo
- Publication number
- CN105779750A CN105779750A CN201610369259.2A CN201610369259A CN105779750A CN 105779750 A CN105779750 A CN 105779750A CN 201610369259 A CN201610369259 A CN 201610369259A CN 105779750 A CN105779750 A CN 105779750A
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- China
- Prior art keywords
- temperature
- dipper
- heat treatment
- heat
- bucket rod
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/34—Methods of heating
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
The invention discloses a postweld heat treatment technology for an excavator bucket rod. The technology comprises the steps that firstly, the welded bucket rod is put into a heat treatment furnace; secondly, the bucket rod is heated to a first temperature at first heating rate; thirdly, the bucket rod is heated to a second temperature at second heating rate, wherein the second temperature is higher than the first temperature, and the second heating rate is smaller than the first heating rate; fourthly, heat preservation is conducted; fifthly, the bucket rod is cooled to a third temperature in the heat treatment furnace; sixthly, the bucket rod is taken out of the heat treatment furnace and cooled. According to the postweld heat treatment technology for the excavator bucket rod, distressing heat treatment is conducted after bucket rod welding, weld metal and metallographic structures in a heat affected zone can be improved, the synthesized mechanical properties of a welded joint can be improved, the residual stress of the structure can be reduced, the stability of the structure can be improved, finally, the fatigue strength of the bucket rod is improved, and the service life of the bucket rod is prolonged.
Description
Technical field
The invention belongs to technical field of heat treatment, specifically, the present invention relates to a kind of excavator boom post weld heat treatment technique.
Background technology
The dipper of excavator steel plate thickness when design is big, welding capacity is big, in structural member, higher residual stress is produced after having welded, and significantly high dynamic loading is born in dipper work, the residual stress that welding produces is concentrated in stress generating unit, cause the reduction of fatigue strength, reduce the service life of dipper.
Summary of the invention
It is contemplated that at least solve one of technical problem of existence in prior art.For this, the present invention provides a kind of excavator boom post weld heat treatment technique, it is therefore an objective to improve dipper fatigue strength.
To achieve these goals, the technical scheme that the present invention takes is: excavator boom post weld heat treatment technique, including step:
(1) dipper welded is placed in heat-treatment furnace；
(2) with first rate of heat addition by dipper heating to the first temperature；
(3) heating dipper to the second temperature with second rate of heat addition, the second temperature is more than the first temperature, and second rate of heat addition is less than first rate of heat addition；
(4) insulation；
(5) dipper is cooled to the 3rd temperature in heat-treatment furnace；
(6) dipper is taken out in heat-treatment furnace, cool down.
The cover plate of described dipper is provided with passage.
Described first rate of heat addition is 210 DEG C/h.
Described second rate of heat addition is 165 DEG C/h.
Described first temperature is 300 DEG C, in step (2), with first rate of heat addition by dipper from room temperature heating to the first temperature.
Described second temperature is 620 DEG C, in step (3), with second rate of heat addition by dipper from the first heating temperatures to the second temperature.
In step (4), by dipper at the second temperature ± 20 DEG C scope inside holding 1h.
In step (5), dipper cooldown rate to be not more than 110 DEG C/h in heat-treatment furnace is cooled to the 3rd temperature, and the maximum of the 3rd temperature is more than the first temperature.
Described 3rd temperature is not more than 315 DEG C.
Being taken out from heat-treatment furnace by dipper, air cooling is to room temperature.
The excavator boom post weld heat treatment technique of the present invention, dipper welding carries out destressing heat treatment after terminating, weld metal and heat affected area metallographic structure can be improved, improve the comprehensive mechanical performance of welding point, reduce the residual stress of structure, improve the stability of structure, finally improve the fatigue strength of dipper, improve dipper service life.
Accompanying drawing explanation
This specification includes the following drawings, it is shown that content respectively:
Fig. 1 is dipper heat treatment temperature curve chart；
Fig. 2 is the structural representation of dipper；
Figure is labeled as: 1, upper ear plate；2, rear otic placode；3, front side board；4, back side panel；5, baffle assembly；51, cover plate；52, upper bent plate；53, afterbody bent plate；54, lower bent plate；55, lower shoe；56, passage；6, front support assembly；7, rear support assembly.
Detailed description of the invention
Below against accompanying drawing, by the description to embodiment, the specific embodiment of the present invention is described in further detail, it is therefore an objective to help those skilled in the art that the design of the present invention, technical scheme are had more complete, accurate and deep understanding, and contribute to its enforcement.
The invention provides a kind of excavator boom post weld heat treatment technique, including step:
(1) dipper welded is placed in heat-treatment furnace；
(2) with first rate of heat addition by dipper heating to the first temperature；
(3) heating dipper to the second temperature with second rate of heat addition, the second temperature is more than the first temperature, and second rate of heat addition is less than first rate of heat addition；
(4) insulation；
(5) dipper is cooled to the 3rd temperature in heat-treatment furnace；
(6) dipper is taken out in heat-treatment furnace, cool down.
Specifically, the structure of excavator boom is as shown in Figure 2, it includes the front support assembly 6 that biside plate, the envelope baffle assembly 5 outside biside plate is connected and the rear support assembly 7 being connected with biside plate rear end with biside plate front end, and baffle assembly 5 is provided with two pairs of otic placodes.Side plate includes the front side board 3 being connected with front support assembly 6 and the back side panel 4 being connected with rear support assembly 7.Baffle assembly 5 includes the cover plate 51, upper bent plate 52, afterbody bent plate 53, lower bent plate 54 and the lower shoe 55 that are welded to connect successively, and the front end of front support assembly 6 and cover plate 51 and lower shoe 55 is welded to connect, and rear support assembly 7 and lower bent plate 54 are welded to connect.Cover plate 51 and lower shoe 55 are to extend from front axle initially towards front axle rear, and two front end panels are welded to connect with cover plate 51 and lower shoe 55 respectively in upper and lower side, and cover plate 51 and lower shoe 55 are long rectangular slab.Being additionally provided with a passage 56 on cover plate 51, this passage 56 is run through the circular hole that cover plate 51 is arranged, and the diameter of passage 56 is preferably 8mm, and dipper inner space can be connected by passage 56 with external environment.Owing to dipper is in heat treatment process, if dipper is in sealing state, internal can the expanding with heat and contract with cold in temperature-rise period of dipper causes deformation.And passage 56 is set on this dipper, dipper inner space can be connected by passage 56 with external environment so that because of sealing, dipper will not cause that dipper deforms in heating process in heat treatment process.
As preferably, heat-treatment furnace is combustion type heat-treatment furnace, and in stove, heating-up temperature, temperature rise speed and rate of cooling, accurately controlled by PLC system.
As preferably, first rate of heat addition is 210 DEG C/h, and the first temperature is 300 DEG C, in step (2), with first rate of heat addition by dipper from room temperature heating to the first temperature.
As preferably, second rate of heat addition is 165 DEG C/h, and the second temperature is 620 DEG C, in step (3), with second rate of heat addition by dipper from the first heating temperatures to the second temperature.
General stress relief annealing technique programming rate is about 100 DEG C, and temperature raises too fast, it is possible to can produce new additional stress because of workpiece different cross section excessive temperature differentials.The present invention construction features according to dipper, and test the programming rate drawing less than 300 DEG C and 300～620 DEG C, more general programming rate is fast, has saved production time and energy consumption.
As preferably, in step (4), by dipper at the second temperature ± 20 DEG C scope inside holding 1h.Control in the scope of lower than the second temperature 20 DEG C to higher than the second temperature 20 DEG C by heat treatment in-furnace temperature, dipper is carried out insulation 1 hour.When the second temperature is 620 DEG C, when dipper is incubated, heat treatment in-furnace temperature controls within the scope of 620 ± 20 DEG C.
Holding temperature is to determine according to dipper material, heat treatment in-furnace temperature controls when 620 ± 20 DEG C, the material yield limit of dipper has reached minimum, temperature retention time is determined according to the thickness of slab of structure, by analysis with test, temperature retention time 1 hour so that local plastic deformation and Stress Release process are accomplished.When the final residual stress of dipper is 620 DEG C, the yield strength of dipper material.
As preferably, in step (5), dipper cooldown rate to be not more than 110 DEG C/h in heat-treatment furnace is cooled to the 3rd temperature, and the maximum of the 3rd temperature is more than the first temperature.3rd temperature can be value range, and the 3rd temperature is not more than 315 DEG C.
As preferably, in step (6), by dipper from after taking out in heat-treatment furnace, air cooling is to room temperature.
When carrying out step (2), (3) and (5), dipper temperature in heat-treatment furnace raises unsuitable too fast with rate of cooling, to avoid producing new heat treatment stress.When carrying out step (4), holding temperature is typically chosen in below steel plate AC1 temperature (100～200 DEG C).The selection of temperature retention time and temperature correlation, holding temperature is more high, and required time is more short, if time fixed long, is the waste of resource.
After dipper air cooling to room temperature, heat treatment completes, and by passage set on the mode closed cover of welding, carries out dipper and can be carried out follow-up machining processes.
The principle of the Technology for Heating Processing of above-mentioned 6 steps is, steel plate material is along with the rising of temperature, yield strength reduces, when structurally internal stress is more than yield strength, the plastic deformation of local will be there is, stress is released, and after plastic deformation and Stress Release complete, namely dipper residual stress is preferably minimized (i.e. yield strength under holding temperature).
Above in association with accompanying drawing, the present invention is exemplarily described.Obviously, the present invention implements and is not subject to the restrictions described above.As long as have employed the improvement of the various unsubstantialities that the design of the method for the present invention carries out with technical scheme；Or not improved, the above-mentioned design of the present invention and technical scheme are directly applied to other occasion, all within protection scope of the present invention.
Claims (10)
1. excavator boom post weld heat treatment technique, it is characterised in that include step:
(1) dipper welded is placed in heat-treatment furnace；
(2) with first rate of heat addition by dipper heating to the first temperature；
(3) heating dipper to the second temperature with second rate of heat addition, the second temperature is more than the first temperature, and second rate of heat addition is less than first rate of heat addition；
(4) insulation；
(5) dipper is cooled to the 3rd temperature in heat-treatment furnace；
(6) dipper is taken out in heat-treatment furnace, cool down.
2. excavator boom post weld heat treatment technique according to claim 1, it is characterised in that be provided with passage on the cover plate of described dipper.
3. excavator boom post weld heat treatment technique according to claim 1, it is characterised in that described first rate of heat addition is 210 DEG C/h.
4. excavator boom post weld heat treatment technique according to claim 1, it is characterised in that described second rate of heat addition is 165 DEG C/h.
5. excavator boom post weld heat treatment technique according to claim 1, it is characterised in that described first temperature is 300 DEG C, in step (2), with first rate of heat addition by dipper from room temperature heating to the first temperature.
6. excavator boom post weld heat treatment technique according to claim 1, it is characterised in that described second temperature is 620 DEG C, in step (3), with second rate of heat addition by dipper from the first heating temperatures to the second temperature.
7. excavator boom post weld heat treatment technique according to claim 1, it is characterised in that in step (4), by dipper at the second temperature ± 20 DEG C scope inside holding 1h.
8. excavator boom post weld heat treatment technique according to claim 1, it is characterized in that, in step (5), dipper cooldown rate to be not more than 110 DEG C/h in heat-treatment furnace is cooled to the 3rd temperature, and the maximum of the 3rd temperature is more than the first temperature.
9. the excavator boom post weld heat treatment technique according to claim 1 to 8, it is characterised in that described 3rd temperature is not more than 315 DEG C.
10. the excavator boom post weld heat treatment technique according to claim 1 to 9, it is characterised in that taken out from heat-treatment furnace by dipper, air cooling is to room temperature.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610369259.2A CN105779750B (en) | 2016-05-30 | 2016-05-30 | Excavator boom post weld heat treatment technique |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610369259.2A CN105779750B (en) | 2016-05-30 | 2016-05-30 | Excavator boom post weld heat treatment technique |
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| Publication Number | Publication Date |
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| CN105779750A true CN105779750A (en) | 2016-07-20 |
| CN105779750B CN105779750B (en) | 2018-03-16 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201610369259.2A Active CN105779750B (en) | 2016-05-30 | 2016-05-30 | Excavator boom post weld heat treatment technique |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101053930A (en) * | 2007-05-31 | 2007-10-17 | 四川东风电机厂有限公司 | Welding and hot treatment technology for bulb cross flow set main components |
| CN102127628A (en) * | 2011-03-25 | 2011-07-20 | 浙江省火电建设公司 | Overall thermal treatment process for large-sized pipeline |
| CN103320711A (en) * | 2013-06-26 | 2013-09-25 | 衡阳华菱钢管有限公司 | Seamless steel tube and manufacturing method thereof |
| CN103773931A (en) * | 2014-02-20 | 2014-05-07 | 内蒙古北方重工业集团有限公司 | Heat treatment method for eliminating residual stress of hollow long and thin parts |
| CN105463176A (en) * | 2015-12-02 | 2016-04-06 | 哈尔滨电气动力装备有限公司 | Shell flange postweld heat treatment process method |
-
2016
- 2016-05-30 CN CN201610369259.2A patent/CN105779750B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101053930A (en) * | 2007-05-31 | 2007-10-17 | 四川东风电机厂有限公司 | Welding and hot treatment technology for bulb cross flow set main components |
| CN102127628A (en) * | 2011-03-25 | 2011-07-20 | 浙江省火电建设公司 | Overall thermal treatment process for large-sized pipeline |
| CN103320711A (en) * | 2013-06-26 | 2013-09-25 | 衡阳华菱钢管有限公司 | Seamless steel tube and manufacturing method thereof |
| CN103773931A (en) * | 2014-02-20 | 2014-05-07 | 内蒙古北方重工业集团有限公司 | Heat treatment method for eliminating residual stress of hollow long and thin parts |
| CN105463176A (en) * | 2015-12-02 | 2016-04-06 | 哈尔滨电气动力装备有限公司 | Shell flange postweld heat treatment process method |
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| CN105779750B (en) | 2018-03-16 |
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