CN116833690A - Machining method of aviation heat-resistant bolt and bolt - Google Patents
Machining method of aviation heat-resistant bolt and bolt Download PDFInfo
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- CN116833690A CN116833690A CN202311121542.XA CN202311121542A CN116833690A CN 116833690 A CN116833690 A CN 116833690A CN 202311121542 A CN202311121542 A CN 202311121542A CN 116833690 A CN116833690 A CN 116833690A
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- coating
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- 238000000034 method Methods 0.000 title claims abstract description 23
- 238000003754 machining Methods 0.000 title claims abstract description 7
- 239000011248 coating agent Substances 0.000 claims abstract description 54
- 238000000576 coating method Methods 0.000 claims abstract description 54
- 238000005507 spraying Methods 0.000 claims abstract description 37
- 238000005096 rolling process Methods 0.000 claims abstract description 35
- 239000011253 protective coating Substances 0.000 claims abstract description 18
- 238000007689 inspection Methods 0.000 claims abstract description 9
- 238000003672 processing method Methods 0.000 claims abstract description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 33
- 239000000956 alloy Substances 0.000 claims description 22
- 239000002904 solvent Substances 0.000 claims description 20
- 229910045601 alloy Inorganic materials 0.000 claims description 19
- 229910052759 nickel Inorganic materials 0.000 claims description 15
- 239000003973 paint Substances 0.000 claims description 14
- 229910052782 aluminium Inorganic materials 0.000 claims description 12
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 9
- 230000007547 defect Effects 0.000 claims description 9
- CWQXQMHSOZUFJS-UHFFFAOYSA-N molybdenum disulfide Chemical compound S=[Mo]=S CWQXQMHSOZUFJS-UHFFFAOYSA-N 0.000 claims description 9
- 229910052982 molybdenum disulfide Inorganic materials 0.000 claims description 9
- 238000013461 design Methods 0.000 claims description 7
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical group CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 5
- SVONRAPFKPVNKG-UHFFFAOYSA-N 2-ethoxyethyl acetate Chemical group CCOCCOC(C)=O SVONRAPFKPVNKG-UHFFFAOYSA-N 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 229910052748 manganese Inorganic materials 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims 9
- 230000008569 process Effects 0.000 abstract description 7
- 230000002035 prolonged effect Effects 0.000 abstract description 4
- 230000008859 change Effects 0.000 description 6
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 230000007797 corrosion Effects 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 230000035772 mutation Effects 0.000 description 3
- 229910000531 Co alloy Inorganic materials 0.000 description 2
- 229910001069 Ti alloy Inorganic materials 0.000 description 2
- 229910000816 inconels 718 Inorganic materials 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 230000007306 turnover Effects 0.000 description 2
- 229910001247 waspaloy Inorganic materials 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 229910000601 superalloy Inorganic materials 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B33/00—Features common to bolt and nut
- F16B33/02—Shape of thread; Special thread-forms
Abstract
The application provides a processing method of an aviation heat-resistant bolt and the bolt, relating to the technical field of aviation fasteners, comprising the following steps: machining the bolt blank to form a bolt body; rolling the bolt main body in a warm rolling mode to form threads; wherein the thread crest and/or the thread root are arranged in a circular arc shape; checking the screw thread of the bolt, and judging whether the rolled screw thread is qualified or not; and spraying the bolts which are qualified in inspection, and forming a protective coating on the bolts. According to the application, the hardness of the bolt blank is reduced by adopting a warm rolling mode, so that the bolt main body is conveniently rolled by the thread rolling wheel to form threads, and cracks and folding lines on the threads in the forming process are remarkably reduced. In addition, the crests and the bottoms of the threads are arranged in the shape of the arc, so that the shapes of the threads are plump and smooth, the subsequent coating of the bolts is facilitated, the uniformity of the coating on the bolts is improved, and the service life of the bolts is prolonged.
Description
Technical Field
The application relates to the technical field of aviation fasteners, in particular to a processing method of an aviation heat-resistant bolt and the bolt.
Background
Aircraft are typically made up of thousands of parts that are joined together by fasteners to form a complete body. The fastener used on the aircraft mainly comprises a bolt, a rivet, a screw, a drawing pin and the like, wherein the screw can be quickly formed to be combined through the bolt, and the aircraft has the advantages of simple structure, reliable performance and the like. In the operation process of the aircraft, the partial area on the aircraft can possibly form an ultra-high temperature environment with the temperature exceeding 850 ℃, when the bolt is placed in the ultra-high temperature environment, the problem of adhesion seizure easily occurs at the bolt connection part, and the subsequent overhaul difficulty of the bolt is increased. In addition, under the ultra-high temperature environment, the surface of the bolt, which is in contact with the outside, is easy to oxidize, so that the defects such as hot cracks and the like are generated on the bolt.
In the prior art, a protective coating is generally coated on the bolt to increase the heat resistance or oxidation resistance of the bolt. However, in the prior art, a shape abrupt change is formed at the thread crest position of the bolt during processing. In the process of coating the coating, the coating can be influenced by the shape mutation part, so that the problems of easy accumulation, uneven thickness and discontinuity of the coating at the shape mutation part are caused, and the coating on the bolt is caused to have a weak area, so that the service life of the bolt is reduced.
Disclosure of Invention
In order to overcome the defects in the prior art, the technical problem to be solved by the embodiment of the application is to provide a processing method of an aviation heat-resistant bolt and the bolt, which are used for eliminating the shape abrupt change parts on the bolt so as to improve the coating quality of a coating.
The above purpose of the application can be achieved by adopting the following technical scheme, and the application provides a processing method of an aviation heat-resistant bolt, which comprises the following steps:
machining the bolt blank to form a bolt body;
rolling the bolt main body in a warm rolling mode to form threads; wherein the crests of the threads and/or the roots of the threads are arranged in a circular arc shape;
checking the threads of the bolts, and judging whether the rolled threads are qualified or not;
and spraying the bolt which is qualified in inspection, and forming a protective coating on the bolt.
In a preferred embodiment of the present application, the processing of the bolt blank to form the bolt body specifically comprises the steps of:
fixing the bolt blank on a lathe, and removing redundant materials on the bolt blank by using an excircle lathe tool of the lathe to form a bar stock;
and finely grinding the outer circle of the bar stock through a centerless grinder to form the bolt main body.
In a preferred embodiment of the application, the bolts are formed from a nickel-based alloy.
In a preferred embodiment of the present application, the nickel-based alloy comprises the following components in percentage by weight: cr:18% -21%, mo:3.5% -5.0%, co:12% -15%, al:1.2% -1.6%, ti:2.75% -3.25%, B:0.003% -0.01%, C:0.02% -0.1%, zr:0.02% -0.08%, fe is more than or equal to 2.0%, mn is more than or equal to 0.10%, si is more than or equal to 0.15%, P is more than or equal to 0.015%, S is more than or equal to 0.015%, cu is more than or equal to 0.10%, and the balance is Ni.
In a preferred embodiment of the present application, the nickel-based alloy comprises the following components in percentage by weight: ni:50% -55%, cr:17% -21%, mo:2.8% -3.3%, nb:4.75 to 5.50 percent, less than or equal to 0.08 percent of C, less than or equal to 0.35 percent of Mn, less than or equal to 0.35 percent of Si, less than or equal to 0.015 percent of S, less than or equal to 0.30 percent of Cu, and less than or equal to 0.30 percent of Al:0.20% -0.80%, ti:0.65% -1.15%, B is less than or equal to 0.006%, and the balance is Fe.
In a preferred embodiment of the present application, the rolling the bolt body to form the thread by warm rolling specifically includes the following steps:
heating the rolled thread blank end of the bolt main body, and controlling the temperature of the rolled thread blank end to be 300-400 ℃;
the screw thread is formed by rolling the bolt body with a thread rolling wheel.
In a preferred embodiment of the present application, the step of inspecting the bolt to determine whether the rolled bolt is acceptable includes the following steps:
comparing the bolt with a pre-stored design standard or technical pattern, and detecting whether the thread size of the bolt is qualified or not;
and checking the bolts with qualified sizes, and removing the bolts with cracks and folding defects at the thread parts.
In a preferred embodiment of the application, the defects are cracks and folds in the thread; wherein, the load bearing surface, two sides of the tooth below the pitch diameter and the root of the thread are not allowed to be folded; the non-load bearing surfaces, crests of the threads allow for a fold, but the maximum depth of the fold is no more than 0.15mm.
In a preferred embodiment of the present application, the spraying of the bolt that is qualified for inspection, and forming a protective coating on the bolt, specifically includes the following steps:
preparing a coating;
preparing spraying equipment and setting spraying parameters;
carrying out spraying operation on the bolt by utilizing the spraying equipment, and forming the protective coating on the bolt;
and randomly extracting a plurality of bolts in the spraying operation process, and checking the spraying quality.
In a preferred embodiment of the present application, the paint is prepared from an aluminum paint and a solvent, wherein the solvent is ethylene glycol monoethyl ether acetate, and the volume ratio of the aluminum paint to the solvent is 1:3.8.
in a preferred embodiment of the present application, the coating is prepared from a molybdenum disulfide coating and a solvent, wherein the solvent is acetone, and the mass ratio of the molybdenum disulfide coating to the solvent is 1:3.
in a preferred embodiment of the application, the protective coating has a thickness of 10 μm to 20. Mu.m.
The application also provides an aviation heat-resistant bolt, which comprises a bolt main body and threads arranged on the bolt main body, wherein the crests of the threads and/or the bottoms of the threads are arranged in a circular arc shape, and the bolt main body is coated with a protective coating.
The technical scheme of the application has the following remarkable beneficial effects:
according to the processing method of the aviation heat-resistant bolt, the screw thread is formed on the bolt main body in a warm rolling mode, and when the screw thread is processed in the warm rolling mode, the bolt blank can be heated, so that the hardness of the bolt blank is reduced, the fluidity of the bolt blank is increased, the bolt main body is conveniently rolled by the thread rolling wheel to form the screw thread, cracks and folds on the bolt in the forming process are remarkably reduced, and the screw thread quality of the bolt is improved. In addition, the crests and the bottoms of the threads are arranged in the shape of the circular arc, so that the thread profile of the threads is plump and smooth, the subsequent coating of the bolts is facilitated, the uniformity of the coating on the bolts is improved, the weak coating area caused by the abrupt change of the shape of the threads is eliminated, and the service life of the bolts is prolonged.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. In addition, the shapes, proportional sizes, and the like of the respective components in the drawings are merely illustrative for aiding in understanding the present application, and are not particularly limited. Those skilled in the art with access to the teachings of the present application can select a variety of possible shapes and scale sizes to practice the present application as the case may be.
FIG. 1 is a schematic view of a conventional thread structure with abrupt shape change in the prior art;
fig. 2 is a schematic view of a thread structure of the aviation heat-resistant bolt according to the present application;
FIG. 3 is a schematic view of a partially enlarged threaded construction of the aeronautical heat resistant bolt of the present application;
fig. 4 is an enlarged schematic view of a partial thread of an aeronautical heat resistant bolt according to the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
Embodiment one
Referring to fig. 1 and 2 in combination, the embodiment of the application provides a processing method of an aviation heat-resistant bolt, which comprises the following steps:
step 100: the bolt blank is processed to form a bolt body.
Step 200: rolling the bolt main body in a warm rolling mode to form threads; wherein the thread crest and/or the thread root are arranged in a circular arc shape.
Step 300: and (5) checking the threads of the bolts, and judging whether the rolled threads are qualified or not.
Step 400: and spraying the bolts which are qualified in inspection, and forming a protective coating on the bolts.
In the method for processing the aviation heat-resistant bolt, the screw thread is formed on the bolt main body in a warm rolling mode, and when the screw thread is processed in the warm rolling mode, the bolt blank can be heated, so that the surface hardness of the bolt blank is reduced, the fluidity of the bolt blank is increased, the bolt main body is conveniently rolled by the thread rolling wheel to form the screw thread, cracks and folds on the bolt in the forming process are remarkably reduced, and the screw thread quality of the bolt is improved.
Fig. 1 shows a prior art bolt having a shape abrupt change in the thread crest position. The thread is enabled to be in the arc-shaped arrangement at the crests and the roots, so that the thread is enabled to be plump and smooth in profile, the subsequent coating of the bolt is facilitated, the uniformity of the coating on the bolt is improved, the weak coating area caused by the abrupt change of the shape of the thread is eliminated, and the service life of the bolt is prolonged.
In an embodiment of the present application, processing a bolt blank to form a bolt body specifically includes the steps of:
step 101: fixing the bolt blank on a lathe, and removing redundant materials on the bolt blank by using an excircle lathe tool of the lathe to form a bar stock;
step 102: and (3) finely grinding the outer circle of the bar stock through a centerless grinder to form a bolt main body.
The designer may determine the specific model of the lathe, as well as the specific model of the centerless grinder, according to design requirements, without specific limitation.
In an embodiment of the application, the bolts are formed from a nickel-based alloy. Compared with other alloys, the cobalt-based alloy still has higher strength at the high temperature of 650-1000 ℃ through the nickel-based alloy forming bolt, and the nickel-based alloy also has good oxidation resistance and corrosion resistance, can be applied to the ultra-high temperature environment on an aircraft, and ensures the connection reliability of the bolt.
In one embodiment, the nickel-based alloy comprises the following components in percentage by weight: cr:18% -21%, mo:3.5% -5.0%, co:12% -15%, al:1.2% -1.6%, ti:2.75% -3.25%, B:0.003% -0.01%, C:0.02% -0.1%, zr:0.02% -0.08%, fe is more than or equal to 2.0%, mn is more than or equal to 0.10%, si is more than or equal to 0.15%, P is more than or equal to 0.015%, S is more than or equal to 0.015%, cu is more than or equal to 0.10%, and the balance is Ni. For example, the designer may choose to use Waspaloy alloy.
In another embodiment, the nickel-based alloy comprises the following components in percentage by weight: ni:50% -55%, cr:17% -21%, mo:2.8% -3.3%, nb:4.75 to 5.50 percent, less than or equal to 0.08 percent of C, less than or equal to 0.35 percent of Mn, less than or equal to 0.35 percent of Si, less than or equal to 0.015 percent of S, less than or equal to 0.30 percent of Cu, and less than or equal to 0.30 percent of Al:0.20% -0.80%, ti:0.65% -1.15%, B is less than or equal to 0.006%, and the balance is Fe. For example, the designer may choose to use Inconel718 alloy.
The Waspaloy alloy and the Inconel718 alloy are two ultra-high temperature alloys, which are metal materials capable of keeping long-term working under the action of 600-1500 ℃ and certain stress, and have the comprehensive properties of excellent high-temperature strength, good oxidation resistance, good hot corrosion resistance, good fatigue property, good fracture toughness and the like. In the aerospace field, a common firmware material is titanium alloy, but the titanium alloy is generally applied in an environment of 150-500 ℃, and cannot meet the use requirement of higher temperature. The high-temperature alloy adopted in the application can be used in an ultra-high temperature environment of 600-1500 ℃ and keeps good performance.
In other embodiments, the designer may adjust the composition of the nickel-base alloy according to the needs of the application, without specific limitation.
In the embodiment of the application, the method for forming the screw thread by rolling the bolt main body in a warm rolling mode specifically comprises the following steps:
step 201: heating the rolled thread blank end of the bolt main body, and controlling the temperature of the rolled thread blank end to be 300-400 ℃;
step 202: rolling the bolt main body by using a thread rolling wheel to form threads; wherein, the crest of the thread and the root of the thread are both circular arc-shaped.
The heating temperature has a great influence on the size and performance of the threads, and when the temperature is lower than 300 ℃, the fluidity of the nickel-based alloy material is reduced, so that the size of the processed threads is not satisfactory, and the threads are easy to generate defects. And when the temperature is higher than 400 ℃, the nickel-based alloy material is easy to overheat, so that the nickel-based alloy material has over-strong fluidity, and the stability of the size of the machined thread is easy to influence. Therefore, the application can well control the size of the screw thread by controlling the heating temperature between 300 ℃ and 400 ℃, and the rebound quantity of the cooled screw thread is smaller, thereby being beneficial to processing control.
In addition, the temperature of the rolled thread blank end of the bolt main body is controlled to be 300-400 ℃, the nickel-based superalloy cannot be softened, certain surface layer work hardening is eliminated through heating, the surface layer material performance is improved, the thread forming is facilitated, defects in the thread such as cracks or folds are eliminated, and meanwhile, a metal streamline structure in the thread is guaranteed.
Specifically, as shown in the embodiments of fig. 2, 3 and 4, the design of the thread in the present application is based on the conventional thread, and the crest of the thread is designed in an arc shape under the condition of constant thread angle, wide thread diameter range and the like. The conventional thread profile and dimensions are shown in fig. 2, wherein the upper profile is the maximum solid tooth shape, the lower profile is the minimum solid tooth shape, d1max corresponding to the maximum solid tooth shape is the maximum value of the major diameter of the thread, and d1min corresponding to the minimum solid tooth shape is the minimum value of the major diameter of the thread. Taking the large diameter of the thread as a reference, taking two sides of the tooth shape as inscribed circles, and changing the shape of the large diameter of the thread into circular arc shape.
In the embodiment of the application, the bolts are inspected to judge whether the rolled bolts are qualified or not, and the method specifically comprises the following steps:
step 301: comparing the bolt with a pre-stored design standard or technical pattern, and detecting whether the thread size of the bolt is qualified or not;
step 302: and (5) checking the bolts with qualified sizes, and eliminating bolts with cracks and folding defects at the threaded parts.
Further, the defects are cracks and folds on the bolts. Wherein, the load bearing surface, two sides of the tooth below the pitch diameter and the root of the tooth are not allowed to be folded; the non-load bearing surfaces, crests of the threads allow for folds, but the maximum depth of the folds is no more than 0.15mm.
The structural stability and the service life of the bolt are ensured by eliminating the bolt with cracks and folds at the thread part.
An operator can compare the bolt with a pre-stored design standard and a pre-stored technical sample through a manual measurement mode so as to judge whether the screw thread size of the bolt is qualified or not. The qualified size ranges corresponding to threads with different sizes are recorded in the design standard and the technical pattern in advance, so that operators can quickly compare and calculate whether the threads are qualified.
For example, an operator can use a micrometer to measure the major diameter of the thread, detect the intermediate diameter of the thread by a go-no-go gauge, and detect the arc sizes of the root and the crest by a projection measuring instrument to judge whether the rolled thread size is qualified. Taking 7/16-20UNJF as an example, a thread size standard is designed, and the thread is formed by rolling. And detecting the sizes of the threads, and judging that each size meets the standard tolerance requirement.
In the embodiment of the application, the bolts which are qualified in inspection are sprayed, and a protective coating is formed on the bolts, and the method specifically comprises the following steps:
step 401: preparing a coating;
step 402: preparing spraying equipment and setting spraying parameters;
step 403: spraying the bolts by using spraying equipment to form a protective coating on the bolts;
step 404: during the spraying operation, a plurality of bolts are randomly extracted, and the spraying quality is checked.
In one embodiment, the coating is prepared from an aluminum coating and a solvent, wherein the solvent is ethylene glycol monoethyl ether acetate, and the volume ratio of the aluminum coating to the solvent is 1:3.8. for example, the aluminum paint is identified as HI-KOTE1 or HI-KOTE4.
The aluminum coating has the advantages of wear resistance, corrosion resistance, oxidation resistance, capability of eliminating potential difference between the fastener and the connected piece, prolonged service life of the fastener and the structure, and the like.
Further, the spraying equipment may include coaters, high temperature test boxes, air compressors, magnetic stirrers, electronic scales (precision grade g), manual spray guns, and the like. The usage amount of the paint can be measured through the electronic scale.
Wherein, setting the spraying parameters comprises: the spraying amount of the coating machine is about 4g/min to 6g/min, the interior of the coating machine cabin is in a negative pressure state, the negative pressure is between 0.8 KPa and 0.95KPa, and the temperature in the coating machine cabin is set to be about 55 ℃. The rotating speed of a main machine of the coating machine is 8 r-10 r/min so as to ensure that the bolts can freely turn over in a roller of the coating machine.
Before the spraying operation, the set spraying parameters are checked, the bolts to be sprayed are put into the roller of the coater, the cabin door of the coater is closed, the coater is started, and the spraying timing is started.
After spraying for about 1 hour, a plurality of bolts are randomly taken out, and the thread go-no-go gauge and the appearance inspection are carried out. Then, the inspection was performed every 30 minutes until the spraying was completed.
And closing the spraying equipment after the spraying is finished, opening a cabin door of the coating machine, taking out the sprayed bolt, putting the sprayed bolt on a stainless steel tray, uniformly tiling the sprayed bolt in a single layer, putting the tray in a high-temperature test box, closing the cabin door, and finally curing the coating.
In another specific embodiment, the coating is prepared from a molybdenum disulfide coating and a solvent, wherein the solvent is acetone, and the mass ratio of the molybdenum disulfide coating to the solvent is 1:3. for example, molybdenum disulfide paint is identified by the HM-102 designation. The molybdenum disulfide coating has the advantages of improving lubrication, preventing seizure, preventing occlusion, rust and corrosion, resisting oxidation and the like.
Further, the spraying equipment may include a coater, a high temperature test box, an air compressor, a magnetic stirrer, an electronic scale (precision grade g). The coater can be used for coating the surface of a part and uniformly spraying the coating on the surface of the part. The high-temperature test chamber is used for curing the surface of the part so as to improve the binding force of the coating. The air compressor is used for providing stable compressed air for the coating machine. The magnetic stirrer is used to stir the paint sufficiently to prevent the paint from settling out in layers during the spraying process. The usage amount of the paint can be measured through the electronic scale.
Wherein, setting the spraying parameters comprises: the spraying amount of the coating machine is about 6g/min to 11g/min, the interior of the coating machine cabin is in a negative pressure state, the negative pressure is between 0.8 KPa and 0.95KPa, and the temperature in the coating machine cabin is set to be about 35 ℃. The rotating speed of a main machine of the coating machine is 11-r r/min to 15r/min so as to ensure that the bolts can freely turn over in a roller of the coating machine.
In a possible embodiment, such as the one shown in FIG. 2, the major diameter d1 ranges from phi 10.820mm to phi 10.947mm and the inscribed circle radius R ranges from 0.22mm to 0.245mm at a thread gauge of 7/16-20 UNJF. The small diameter shape and the size of the thread are the same as those of the traditional UNJF thread, the radius r of the thread is 0.19mm-0.23mm without modification.
The above mentioned are the coated dimensions of the thread, the thickness of the coating ranges from 10 μm to 20 μm, the dimensions of the thread before coating need to be determined. The thread size ranges are shown in table 1 by analysis of thread shape and coating thickness.
TABLE 1
The circular arcs of the upper and lower tooth shapes of the thread rolling wheel of the 7/16-20UNJF circular arc thread are designed according to the thread size, and the tolerance range is narrowed, so that the dimensional accuracy of the rolled thread is ensured. Wherein, the R 'range of the thread rolling wheel is 0.22mm-0.235mm, and the R' range of the thread rolling wheel is 0.19mm-0.215mm. Through a rolling process test, the reasonable rolling thread blank size is determined to be phi 10.23-10.24mm, and the reasonable rolling temperature is determined to be 350 ℃.
The bolt is required to be used for a long time in an ultra-high temperature environment, and the uniformity, the continuity and the non-falling-off of the surface coating are greatly determined. As shown in fig. 1, the thread crests of the conventional bolt have abrupt shape changes, which often cause uneven or even falling-off of the coating, so that the conventional bolt cannot play a good role in protection, and the conventional bolt cannot be used in an ultra-high temperature environment for a long time; the method optimizes the traditional thread crest structure, changes the traditional thread crest structure into a circular arc structure, and the circular arc crest has no shape mutation part and smooth transition profile, thereby being more beneficial to the uniform and continuous attachment and difficult falling of the coating. The method improves the service performance of the bolt in the ultra-high temperature environment by the improvement mode.
Second embodiment
In an embodiment of the present application, there is further provided an aviation heat-resistant bolt, as in the embodiment shown in fig. 3, the aviation heat-resistant bolt includes a bolt body and a thread provided on the bolt body, wherein a crest of the thread and/or a root of the thread are provided in a circular arc shape, and a protective coating is coated on the bolt body.
Specifically, the bolts are formed by cobalt-based alloy. The protective coating is prepared from aluminum paint and solvent, or the protective coating is prepared from molybdenum disulfide paint and solvent.
All articles and references, including patent applications and publications, disclosed herein are incorporated by reference for all purposes. The term "consisting essentially of …" describing a combination shall include the identified element, ingredient, component or step as well as other elements, ingredients, components or steps that do not substantially affect the essential novel features of the combination. The use of the terms "comprises" or "comprising" to describe combinations of elements, components, or steps herein also contemplates embodiments consisting essentially of such elements, components, or steps. By using the term "may" herein, it is intended that any attribute described as "may" be included is optional. Multiple elements, components, parts or steps can be provided by a single integrated element, component, part or step. Alternatively, a single integrated element, component, part or step may be divided into separate plural elements, components, parts or steps. The disclosure of "a" or "an" to describe an element, component, section or step is not intended to exclude other elements, components, sections or steps.
In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described by differences from other embodiments, and identical and similar parts between the embodiments are all enough to be referred to each other. The above embodiments are provided to illustrate the technical concept and features of the present application and are intended to enable those skilled in the art to understand the content of the present application and implement the same, and are not intended to limit the scope of the present application. All equivalent changes or modifications made in accordance with the spirit of the present application should be construed to be included in the scope of the present application.
Claims (12)
1. The processing method of the aviation heat-resistant bolt is characterized by comprising the following steps of:
machining the bolt blank to form a bolt body;
rolling the bolt main body in a warm rolling mode to form threads; wherein the crests of the threads and/or the roots of the threads are arranged in a circular arc shape;
checking the threads of the bolts, and judging whether the rolled threads are qualified or not;
and spraying the bolt which is qualified in inspection, and forming a protective coating on the bolt.
2. The method of machining an aircraft heat resistant bolt according to claim 1, wherein the machining the bolt blank to form the bolt body comprises the steps of:
fixing the bolt blank on a lathe, and removing redundant materials on the bolt blank by using an excircle lathe tool of the lathe to form a bar stock;
and finely grinding the outer circle of the bar stock through a centerless grinder to form the bolt main body.
3. The method of manufacturing an aircraft heat resistant bolt of claim 1 wherein said bolt is formed from a nickel based alloy.
4. The method for manufacturing an aircraft heat resistant bolt according to claim 3, wherein the nickel base alloy comprises the following components in percentage by weight: cr:18% -21%, mo:3.5% -5.0%, co:12% -15%, al:1.2% -1.6%, ti:2.75% -3.25%, B:0.003% -0.01%, C:0.02% -0.1%, zr:0.02% -0.08%, fe is more than or equal to 2.0%, mn is more than or equal to 0.10%, si is more than or equal to 0.15%, P is more than or equal to 0.015%, S is more than or equal to 0.015%, cu is more than or equal to 0.10%, and the balance is Ni.
5. The method for manufacturing an aircraft heat resistant bolt according to claim 3, wherein the nickel base alloy comprises the following components in percentage by weight: ni:50% -55%, cr:17% -21%, mo:2.8% -3.3%, nb:4.75 to 5.50 percent, less than or equal to 0.08 percent of C, less than or equal to 0.35 percent of Mn, less than or equal to 0.35 percent of Si, less than or equal to 0.015 percent of S, less than or equal to 0.30 percent of Cu, and less than or equal to 0.30 percent of Al:0.20% -0.80%, ti:0.65% -1.15%, B is less than or equal to 0.006%, and the balance is Fe.
6. The method for manufacturing an aeronautical heat-resistant bolt according to claim 3, wherein the rolling the bolt body to form the thread by warm rolling comprises the following steps:
heating the rolled thread blank end of the bolt main body, and controlling the temperature of the rolled thread blank end to be 300-400 ℃;
the screw thread is formed by rolling the bolt body with a thread rolling wheel.
7. The method for manufacturing an aeronautical heat-resistant bolt according to claim 1, wherein the step of inspecting the bolt to determine whether the rolled bolt is acceptable comprises the steps of:
comparing the bolt with a pre-stored design standard or technical pattern, and detecting whether the thread size of the bolt is qualified or not;
and checking the bolts with qualified sizes, and removing the bolts with cracks and folding defects at the thread parts.
8. The method for manufacturing an aircraft heat resistant bolt according to claim 5, wherein said spraying of said bolt that is acceptable for inspection forms a protective coating on said bolt, comprising the steps of:
preparing a coating;
preparing spraying equipment and setting spraying parameters;
and spraying the bolt by using the spraying equipment to form the protective coating on the bolt.
9. The method for manufacturing an aircraft heat-resistant bolt according to claim 8, wherein the paint is prepared from an aluminum paint and a solvent, the solvent is ethylene glycol ethyl ether acetate, and the volume ratio of the aluminum paint to the solvent is 1:3.8.
10. the method for manufacturing an aircraft heat-resistant bolt according to claim 8, wherein the coating is prepared from a molybdenum disulfide coating and a solvent, wherein the solvent is acetone, and the mass ratio of the molybdenum disulfide coating to the solvent is 1:3.
11. the method of manufacturing an aircraft heat resistant bolt according to claim 8, wherein the protective coating has a thickness of 10 μm to 20 μm.
12. The aviation heat-resistant bolt is characterized by comprising a bolt main body and threads arranged on the bolt main body, wherein crests of the threads and/or roots of the threads are arranged in a circular arc shape, and the bolt main body is coated with a protective coating.
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| CN202311121542.XA CN116833690A (en) | 2023-09-01 | 2023-09-01 | Machining method of aviation heat-resistant bolt and bolt |
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| CN202311121542.XA CN116833690A (en) | 2023-09-01 | 2023-09-01 | Machining method of aviation heat-resistant bolt and bolt |
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