CN110230024B - Process for nitriding metal surfaces - Google Patents
Process for nitriding metal surfaces Download PDFInfo
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- CN110230024B CN110230024B CN201811533204.6A CN201811533204A CN110230024B CN 110230024 B CN110230024 B CN 110230024B CN 201811533204 A CN201811533204 A CN 201811533204A CN 110230024 B CN110230024 B CN 110230024B
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/02—Pretreatment of the material to be coated
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/24—Nitriding
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/40—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using liquids, e.g. salt baths, liquid suspensions
- C23C8/58—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using liquids, e.g. salt baths, liquid suspensions more than one element being applied in more than one step
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- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Cleaning By Liquid Or Steam (AREA)
Abstract
The invention discloses a process for nitriding a metal surface, which comprises a metal workpiece to be processed, wherein the process for processing the workpiece comprises the following steps: washing the workpiece by water containing a detergent, washing the workpiece by water at 100 ℃ after washing by clear water; placing the workpiece without oil stain in a pool for ultrasonic cleaning, wherein the frequency of cleaning vibration is 80-160KHz, and the power density is set at 0.6-1.0W/C; preheating the workpiece to 300-385 ℃, wherein the preheating time is 6-25 min; placing the workpiece in a nitriding furnace containing base salt containing Li ions, and raising the temperature of the nitriding furnace to 520-580 ℃ for 80-100 min; adding sodium peroxide solid into the base salt, wherein the weight ratio of the solid sodium peroxide to the base salt is 1: 2.5-4.5. By adding ultrasonic cleaning, the invention can rapidly realize powerful cleaning effect on the workpiece in the process of cleaning the workpiece, so that solid dirt on the surface of the workpiece is separated from the workpiece, and the nitriding effect can be effectively improved in the nitriding process.
Description
Technical Field
The invention belongs to the technical field of surface chemical treatment, and particularly relates to a process for nitriding a metal surface.
Background
The QPQ (Quench-Polish-Quench, quenching-polishing-quenching) technology is essentially low-temperature salt bath nitriding + salt bath oxidation or low-temperature salt bath nitrocarburizing + salt bath oxidation, is a metal part surface modification technology, and has the advantages of high corrosion resistance, high wear resistance and micro deformation. The surface of the workpiece treated by the QPQ technology is an Fe3O4 oxide film, the corrosion resistance of the workpiece is far higher than the level of surface protection technologies such as chromium plating, nickel plating and the like, and medium carbon steel can replace stainless steel in many fields after being treated by the QPQ technology. Meanwhile, the QPQ process can replace the traditional corrosion-resistant processes such as blackening, phosphorization, nickel plating and the like. At present, the high corrosion resistance of the QPQ technology causes great attention to relevant industries, especially industries with serious corrosion problems such as petroleum, chemical engineering and the like.
When nitriding a workpiece, the first step is to clean the workpiece to remove oil stains on the surface of the workpiece, but in actual cleaning, because the surface of the workpiece is in an irregular state, such as an automobile engine casing, if the oil stains are removed by soaking in water only, the effect is limited, and the effect of removing the oil stains cannot be really achieved.
Disclosure of Invention
The invention provides a process for nitriding a metal surface, which saves raw materials, reduces the cost and has high utilization rate of the raw materials in order to overcome the defects of the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme: a process for nitriding a metal surface comprising a metal workpiece to be machined, the machining of the workpiece comprising the steps of:
1) cleaning the workpiece in clean water containing a cleaning agent to remove oil stains;
2) placing the workpiece without oil stain in a pool for ultrasonic cleaning, wherein the frequency of cleaning vibration is 80-160KHz, and the power density is set at 0.6-1.0W/C;
3) preheating the workpiece to 300-385 ℃, wherein the preheating time is 6-25 min;
4) placing the workpiece in a nitriding furnace containing Li ion-based salt, then pumping out air in the nitriding furnace, and refilling mixed gas in the nitriding furnace;
5) placing the workpiece in a nitriding furnace containing base salt containing Li ions, and raising the temperature of the nitriding furnace to 520-580 ℃ for 80-100 min;
6) adding sodium peroxide solid into the base salt, wherein the weight ratio of the solid sodium peroxide to the base salt is 1: 2.5-4.5;
7) after the sodium peroxide solid is added, the temperature in the nitriding furnace is increased to 520 ℃ and 580 ℃, and the nitriding time is 50-90min;
8) placing the nitrided workpiece in an oxidation furnace containing oxidation salt to carry out primary salt bath oxidation, heating the temperature of the oxidation furnace to 360-380 ℃, and oxidizing for 15-20 min;
9) polishing the workpiece subjected to the first oxidation;
10) performing secondary salt bath oxidation on the polished workpiece, wherein the temperature of an oxidation furnace is 42-450 ℃, and the oxidation time is 25-30 min;
11) and soaking the workpiece subjected to secondary oxidation in engine oil.
The ultrasonic cleaning device has the advantages that through the addition of ultrasonic cleaning, ultrasonic waves can penetrate into all places of a workpiece in the process of cleaning the workpiece, and the workpiece can be rapidly and powerfully cleanedThe cleaning effect of the cleaning agent enables solid dirt on the surface of the workpiece to be separated from the workpiece, so that the nitriding effect can be effectively improved in the nitriding process; the mixed gas is added into the nitriding furnace, so that the inside of the whole nitriding furnace is realized, on one hand, the air pressure in the nitriding furnace can be ensured, the effect during nitriding can be ensured, and on the other hand, the nitriding efficiency can be improved by adding nitrogen into the mixed gas; by using sodium peroxide as the solid, the oxidation of sodium peroxide during nitrogen permeation of the workpiece by the basic salt will reduce CN-Reduction to CNO-Therefore, in the whole process, the flow is guaranteed to reuse the basic salt, and the stability of cyanate is guaranteed; in addition, sodium ions exist in the sodium peroxide, and the sodium ions can ensure that the sodium ions can react with other ions in the base salt in the using process to generate sodium carbonate, so that the generation of impurities is reduced, the raw materials after reaction can continue to react, and the reaction efficiency is high.
Preferably, the mixed gas is formed by mixing nitrogen and carbon dioxide; nitrogen can supplement nitrogen element in a trace amount in the nitriding process, and is inert gas which can be used as protective gas, while carbon dioxide gas can improve carbon element entering the metal surface in the nitriding process, so that the carbon content of the metal surface can be improved, and the strength of the metal is further improved.
Preferably, the molar mass ratio of the nitrogen gas to the carbon dioxide gas is 6-10: 1.
Preferably, the ultrasonic cleaning time in the step 2) is 8-15 min; the long-time ultrasonic cleaning has the best cleaning effect and can save energy to the maximum extent.
Preferably, the raw materials of the base salt in the step 4) by weight ratio comprise: 3-5 parts of lithium carbonate, 8-15 parts of potassium chloride, 5-8 parts of sodium carbonate and 2-4 parts of carbamide; the utilization ratio of each raw material can be effectively improved by the proportioning mode, and the raw materials can be effectively used.
Preferably, the raw materials of the oxide salt in the step 8) by weight ratio comprise: 2-5 parts of potassium hydroxide, 5-8 parts of sodium nitrate, 12-15 parts of sodium carbonate and 5-7 parts of ammonium tetrachloride.
Preferably, the nitriding furnace in the step 4) comprises
A furnace body;
the furnace pot is used for containing base salt and placing a workpiece;
the heating element is used for heating the interior of the furnace tank to 520-580 ℃, and is sleeved on the outer wall of the furnace tank;
a cooling member for blowing cold air into the furnace body;
the furnace cover structure is matched with the furnace body in a sealing way, at least two layers of the furnace body are sealed by the furnace cover structure, and the reaction in the furnace body can be directly observed through the furnace cover structure.
By arranging the furnace cover structure, the furnace cover structure can keep the temperature inside the furnace tank in the process of nitriding a workpiece, so that a heat insulation effect is realized, the furnace cover structure is divided into two layers, the sealing effect of the furnace cover structure on a furnace body can be guaranteed, the phenomenon that the nitriding reaction of the furnace tank on the workpiece is influenced due to the gas leakage in the furnace tank in the nitriding reaction process is avoided, the nitriding effect on the workpiece is improved, and the internal condition can be directly observed through the furnace cover structure; and establish into two-layer through the bell, it can directly look over, can judge the condition of internal reaction like this, and gas and temperature in the nitriding furnace can not outdiffusion again, guarantee the security of operation at the in-process of nitrogenize, and the same waste that reduces the raw materials reduces the heat and loses.
Preferably, the furnace cover structure comprises a first cover body, a second cover body movably connected with the first cover body, and an opening and closing part for opening the first cover body and the second cover body, wherein the first cover body is arranged above the second cover body, and the interior of the furnace tank can be observed through the second cover body; through setting up first lid and second lid, on the one hand it can realize two-layer sealed, improves sealed effect, and on the other hand, first lid is located the top of second lid, it can protect the second lid, avoids the second lid because of receiving external force striking and breakage.
Preferably, the second cover body comprises a fixing piece and a lens, wherein the fixing piece is annularly arranged, the lens is transparently arranged, the fixing piece is connected with the lens, and the fixing piece is connected with the fixing piece through a connecting part; by providing the lens, the gas and heat can be blocked, and the lens has good light transmittance, so that the condition inside the nitriding furnace can be accurately observed.
In conclusion, the ultrasonic cleaning is added, so that the workpiece can be rapidly cleaned powerfully in the process of cleaning the workpiece, solid dirt on the surface of the workpiece is separated from the workpiece, and the nitriding effect can be effectively improved in the nitriding process.
Drawings
FIG. 1 is a schematic structural diagram of the present invention.
Fig. 2 is a cross-sectional view of the present invention.
Fig. 3 is an enlarged view of a in fig. 2.
Fig. 4 is a partial exploded view of the present invention.
Fig. 5 is a schematic structural diagram of a second cover according to the present invention.
Fig. 6 is a cross-sectional view of fig. 5.
Fig. 7 is a schematic structural view of the first cover according to the present invention.
Fig. 8 is a cross-sectional view of fig. 7.
Fig. 9 is an enlarged view of B in fig. 8.
Fig. 10 is an enlarged view of C in fig. 8.
Fig. 11 is an exploded view of fig. 8.
Fig. 12 is a partial structural schematic diagram of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.
Example one
A process for nitriding a metal surface comprising a metal workpiece to be machined, the machining of the workpiece comprising the steps of:
1) washing the workpiece by water containing a detergent, washing the workpiece by water at 100 ℃ after washing by clear water;
2) placing the workpiece without oil stains in a pool for ultrasonic cleaning, wherein the frequency of cleaning vibration is 80KHz, the power density is set at 0.6W/C, and the ultrasonic cleaning time is 8 min;
3) preheating the workpiece to 300 ℃ for 6min;
4) placing the workpiece in a nitriding furnace containing Li ion-based salt, then pumping out air in the nitriding furnace, and refilling mixed gas in the nitriding furnace;
5) placing the workpiece in a nitriding furnace containing base salt containing Li ions, and raising the temperature of the nitriding furnace to 520 ℃ for 80min;
6) adding sodium peroxide solid into the base salt, wherein the weight ratio of the solid sodium peroxide to the base salt is 1: 2.5;
7) after the sodium peroxide solid is added, the temperature in the nitriding furnace is increased to 520 ℃, and the nitriding time is 50min;
8) placing the nitrided workpiece in an oxidation furnace containing oxidation salt for primary salt bath oxidation, heating the oxidation furnace to 360 ℃, and oxidizing for 15min
9) Polishing the workpiece after the first oxidation
10) Performing secondary salt bath oxidation on the polished workpiece, wherein the temperature of an oxidation furnace is 420 ℃, and the oxidation time is 25min;
11) and cooling the workpiece subjected to secondary oxidation to 70 ℃, and soaking the workpiece in machine oil at the temperature of 20 ℃.
Further, the mixed gas is formed by mixing nitrogen and carbon dioxide, and the molar mass ratio of the nitrogen to the nitrogen is 6: 1;
further, the raw materials of the base salt in the step 4) by weight ratio comprise: 3 parts of lithium carbonate, 8 parts of potassium chloride, 5 parts of sodium carbonate and 2 parts of carbamide; the raw materials of the oxide salt in the step 8) by weight ratio comprise: 2 parts of potassium hydroxide, 5 parts of sodium nitrate, 12 parts of sodium carbonate and 5 parts of ammonium tetrachloride.
Further, the polishing treatment method in step 9):
s1, polishing for 1 time by using fine sand paper;
s2, rubbing the workpiece for 2 times by using coarse linen;
s3, rubbing the workpiece for 5 times by using cotton cloth until the surface is smooth;
s4, placing the workpiece which is rubbed smoothly in the step S3 in water of 100 ℃ for cleaning.
Example two
A process for nitriding a metal surface comprising a metal workpiece to be machined, the machining of the workpiece comprising the steps of:
1) washing the workpiece by water containing a detergent, washing the workpiece by water at 100 ℃ after washing by clear water;
2) placing the workpiece without oil stains in a pool for ultrasonic cleaning, wherein the frequency of cleaning vibration is 120KHz, the power density is set at 0.8W/C, and the time of ultrasonic cleaning is 12 min;
3) preheating the workpiece to 355 ℃ for 15min;
4) putting the workpiece into a nitriding furnace containing Li-ion-based salt, then pumping out air in the nitriding furnace, and refilling mixed gas into the nitriding furnace
5) Placing the workpiece in a nitriding furnace containing base salt containing Li ions, and raising the temperature of the nitriding furnace to 550 ℃ for nitriding time of 93 min;
6) adding sodium peroxide solid into the base salt, wherein the weight ratio of the solid sodium peroxide to the base salt is 1: 3.2;
7) after the sodium peroxide solid is added, the temperature in the nitriding furnace is increased to 550 ℃, and the nitriding time is 72min;
8) placing the nitrided workpiece in an oxidation furnace containing oxidation salt to carry out primary salt bath oxidation, heating the temperature of the oxidation furnace to 372 ℃, and oxidizing for 18 min;
9) polishing the workpiece subjected to the first oxidation;
10) performing secondary salt bath oxidation on the polished workpiece, wherein the temperature of an oxidation furnace is 433 ℃, and the oxidation time is 28 min;
11) and cooling the workpiece subjected to secondary oxidation to 75 ℃, and soaking the workpiece in machine oil at the temperature of 28 ℃.
Further, the mixed gas is formed by mixing nitrogen and carbon dioxide, and the molar mass ratio of the nitrogen to the nitrogen is 8: 1.
Further, the raw materials of the base salt in the step 4) by weight ratio comprise: 4 parts of lithium carbonate, 12 parts of potassium chloride, 7 parts of sodium carbonate and 3 parts of carbamide; the raw materials of the oxide salt in the step 8) by weight ratio comprise: 3 parts of potassium hydroxide, 6 parts of sodium nitrate, 13 parts of sodium carbonate and 6 parts of ammonium tetrachloride.
Further, the polishing treatment method in step 9):
s1, polishing for 2 times by using fine sand paper;
s2, rubbing the workpiece for 3 times by using coarse linen;
s3, rubbing the workpiece for 5 times by using cotton cloth until the surface is smooth;
s4, placing the workpiece which is rubbed smoothly in the step S3 in water of 100 ℃ for cleaning.
EXAMPLE III
A process for nitriding a metal surface comprising a metal workpiece to be machined, the machining of the workpiece comprising the steps of:
1) washing the workpiece by water containing a detergent, washing the workpiece by water at 100 ℃ after washing by clear water;
2) placing the workpiece without oil stains in a pool for ultrasonic cleaning, wherein the frequency of cleaning vibration is 160KHz, the power density is set at 1.0W/C, and the time of ultrasonic cleaning is 15min;
3) preheating the workpiece to 385 ℃ for 25min;
4) placing the workpiece in a nitriding furnace containing Li ion-based salt, then pumping out air in the nitriding furnace, and refilling mixed gas in the nitriding furnace;
5) placing the workpiece in a nitriding furnace containing base salt containing Li ions, and raising the temperature of the nitriding furnace to 580 ℃ for 100min;
6) adding sodium peroxide solid into the base salt, wherein the weight ratio of the solid sodium peroxide to the base salt is 1: 4.5;
7) after the sodium peroxide solid is added, the temperature in the nitriding furnace is increased to 580 ℃, and the nitriding time is 90min;
8) placing the nitrided workpiece in an oxidation furnace containing oxidation salt to carry out primary salt bath oxidation, heating the temperature of the oxidation furnace to 380 ℃, and oxidizing for 20 min;
9) polishing the workpiece subjected to the first oxidation;
10) performing secondary salt bath oxidation on the polished workpiece, wherein the temperature of an oxidation furnace is 450 ℃, and the oxidation time is 30 min;
11) and cooling the workpiece subjected to secondary oxidation to 80 ℃, and soaking the workpiece in engine oil at the temperature of 35 ℃.
Further, the mixed gas is formed by mixing nitrogen and carbon dioxide, and the molar mass ratio of the nitrogen to the nitrogen is 6-10: 1.
Further, the raw materials of the base salt in the step 4) by weight ratio comprise: 5 parts of lithium carbonate, 15 parts of potassium chloride, 8 parts of sodium carbonate and 4 parts of carbamide; the raw materials of the oxide salt in the step 8) by weight ratio comprise: 5 parts of potassium hydroxide, 8 parts of sodium nitrate, 15 parts of sodium carbonate and 7 parts of ammonium tetrachloride.
Further, the polishing treatment method in step 9):
s1, polishing for 3 times by using fine sand paper;
s2, rubbing the workpiece for 3 times by using coarse linen;
s3, rubbing the workpiece for 6 times by using cotton cloth until the surface is smooth;
s4, placing the workpiece which is rubbed smoothly in the step S3 in water of 100 ℃ for cleaning.
As shown in fig. 1 to 12, the present invention further discloses a specific structure of the nitriding kettle in embodiments 1 to 3, wherein the nitriding kettle comprises a furnace body 1, a furnace tank 2, a heating element 3, a cooling element 4 and a furnace cover structure 5, wherein the furnace body 1 is a metal tank, an insulating layer 11 is arranged on an inner wall of the furnace body 1, the insulating layer 11 is an asbestos layer, the furnace tank 2 is arranged in the furnace body 1, the furnace tank 2 is a crucible, and the base salt and the workpiece are both placed in the furnace tank 2; the heating element 3 is a spiral resistance wire, and the heating element 3 is sleeved on the outer wall of the furnace pot 2, so that the heating element 3 heats the furnace pot 2 when heating, and the temperature in the furnace pot 2 reaches 520 ℃ and 580 ℃; the cooling part 4 comprises a fan 41 and a ventilation pipeline 42, and after the fan 41 is started, cold air is conveyed to the interior of the furnace body through the ventilation pipeline 42.
Further, the furnace cover structure 5 is used for closing an opening at the upper end of the furnace body 1, the furnace cover structure 5 realizes two-layer sealing for the furnace body 1, and the conditions of base salt and workpieces in the furnace tank 2 can be directly observed through the furnace cover structure 5; specifically, the furnace cover structure 5 includes a first cover 51, a second cover 52, and an opening and closing member 53; the first cover body 51 is a circular metal cover, a first seal ring 511 arranged annularly is arranged at the edge of the first cover body 51, the first seal ring 511 is a metal ring connected with the lower end face of the first cover body 51, the first seal ring 511 is hollow, a saturated sodium acetate solution is filled in the first seal ring 511, and a first seal groove 101 is arranged on the furnace body 1; when the first cover body 51 is covered, the first sealing ring 511 is inserted into the first sealing groove 101, and in the process of preheating the nitriding furnace, the saturated sodium acetate solution in the first sealing ring 511 is heated, and changes from a solid state to a liquid state, so that the volume of the first sealing ring 511 is increased, and each wall of the first sealing ring 511 is extruded, so that the side wall of the first sealing ring 511 and the inner wall of the first sealing groove 101 can be tightly attached together, and a good sealing effect is achieved; moreover, because the first sealing ring is made of metal, the first sealing ring can resist high temperature, and compared with the traditional rubber sealing ring, the first sealing ring can not be melted even if the temperature in the furnace body 1 rises.
Specifically, the second cover 52 is disposed below the first cover 51, the second cover 52 includes a fixing member 521 and a lens 522, the fixing member 521 is a metal ring, the lens 522 is a high temperature resistant glass lens, and the lens 522 is connected to the fixing member 521; the fixing member 521 is connected to the first cover 51 by a hinge; at a position opposite to the hinge, the fixing member 521 is connected to the first cover 51 by two connecting members 54; meanwhile, a supporting part 109 is arranged on the inner wall of the furnace body 1, a second sealing ring 108 is arranged on the supporting part 109, the second sealing ring 108 is the same as the first sealing ring 511, the interior of the second sealing ring 108 is also hollow, and saturated sodium acetate is filled in the second sealing ring 108; the fixing member 521 is provided with a second seal groove 509, and the second seal ring 108 is inserted into the second seal groove 509 when the second cover 52 is closed.
Further, the connecting component 54 includes a connecting component 541, an elastic component 542, and a sealing component 543, where the connecting component 541 is a metal rod, the connecting component 541 passes through the second cover 52, and the connecting component 541 is connected to the first cover 51 through a bearing; a first limiting portion 501 is arranged below the connecting member 541, the first limiting portion 501 is a fan-shaped metal block having a plurality of positioning protrusions 591, the fixing member 521 is provided with a limiting member 544, the limiting member 544 is a metal block, a second limiting portion 502 is arranged at an end of the limiting member 544, the second limiting portion 502 is a fan-shaped metal block, the second limiting portion 502 is provided with a positioning recess 581, and when the connecting member 541 is matched with the limiting member 544, the positioning protrusions 591 are inserted into the positioning recess 581; through setting up location convex part and location concave part, it is when first lid and second lid link to each other, the lateral wall of location convex part with can be spacing each other between the inner wall of location concave part, this process realizes only needing two adapting unit can stable connection first lid and second lid, has reduced the required cost of nitriding furnace manufacturing on the one hand, and on the other hand has reduced the volume of nitriding furnace, is difficult for following bad.
Specifically, the elastic member 542 is a spring, the elastic member 542 is sleeved on the connecting member, one end of the elastic member 542 is connected to the connecting member 541, and the other end of the elastic member 542 is connected to the first cover 51, so that the elastic member 541 always pulls the connecting member 541 upwards, the sealing member 543 is a ring of metal ring sleeved on the connecting member 541, the sealing member 543 is hollow, and solid sodium acetate is filled inside the sealing member 543; meanwhile, the upper end surface of the sealing member 543 is relatively thin, so that when the sealing member 543 is contacted with the first cover 51, the upper end surface of the sealing member 543 is deformed and recessed inwards; the first cover 51 is provided with a ring groove 517 formed in a flared shape, and the sealing member 543 is inserted into the ring groove 517.
Further, the opening and closing member 53 includes a support frame 531, a screw rod 532 and a driving motor 533 which are arranged in an L shape, the driving motor 533 is a servo motor, the screw rod 532 is a metal screw rod, and the driving motor 533 is connected with the lower end of the screw rod 532 through a bevel gear, so that the driving motor 533 drives the screw rod 532 to rotate; the support frame 531 is provided with internal threads, the support frame 531 is sleeved on the screw rod 532, and the support frame 531 moves up and down when the screw rod 532 rotates forwards and backwards; the supporting frame 531 is provided with a plurality of pull rods 551, and the first cover 51 is provided with a plurality of socket joint members 552 matched with the pull rods 551. Specifically, the socket 552 is a metal sleeve, the pulling member 551 penetrates into the socket 552, the bottom of the pulling member 551 is connected with an anti-falling block 553, and the socket 552 is provided with an extending block 554 in anti-falling fit with the anti-falling block 553; the anti-falling block 553 is spaced apart from the extension block 554; therefore, when the support 531 is started to move upwards, the pull rod 551 needs to move a certain distance before contacting the anti-falling block 553, so as to pull the first cover 51 to move upwards, and the pull rod 551 is a screw rod.
Specifically, the socket 552 is connected with a rotating gear 561 through a bearing, the upper end of the connecting piece 541 is connected with a rotating gear 549, and the rotating gear 561 is meshed with the rotating gear 549; the inner wall of the rotating gear 561 is provided with internal threads, and the rotating gear 561 is meshed with the external threads on the outer wall of the pull rod 551; therefore, when the supporting frame 531 moves upward, the pull rod 551 moves upward to drive the rotating gear 561 to rotate, so as to drive the rotating gear 549 to rotate, and further the first limiting portion 501 disengages from the second limiting portion 502, so that the first cover 51 can be opened first; it should be noted that before the first cover 51 is opened alone, the elastic member 542 is released from the opening of the first cover 51, i.e., the connecting member 542 is moved downward for a certain distance.
In order to realize that the connecting member 542 moves downwards by an external force for a certain distance, the pull rod 551 is provided with two segments, the pull rod 551 comprises a first rod 571 and a second rod 572, the first rod 571 is a metal rod connected with the supporting frame 531, the second rod 572 is a lead screw provided with an anti-falling block 553, an insertion cavity 573 is provided at the upper end of the second rod 572, an insertion convex part 574 is provided at the lower end of the first rod 571, the insertion convex part 574 is inserted into the insertion cavity 573, the section of the insertion cavity 573 is a T-shaped cavity, and the insertion convex part 574 is an inverted T-shaped convex part, so that when the supporting frame 531 moves upwards, the first rod 571 moves for a certain segment relative to the second rod 572, and then the second rod 572 is pulled to move; the first cover body 51 is provided with a connecting pressing rod 575, one end of the pressing rod 575 is connected with the first rod body 571, the other end of the pressing rod 575 is movably connected with the upper end of the connecting piece 542, the middle part of the pressing rod 575 is connected with the first cover body 51 through a hanging rod 576, therefore, when the supporting frame 531 moves upwards, the first rod body 571 moves upwards, the other end of the pressing rod 575 presses the connecting piece 541 to move downwards, the lever principle is utilized, and the first limiting part 501 and the second limiting part 502 are separated from contact with each other, so that in the subsequent operation process, the rotating gear can smoothly drive the rotating gear to rotate, and the first limiting part and the second limiting part are connected and contacted with each other.
Meanwhile, the first rod 571 is provided with a first bolt hole 578, the first rod 571 is provided with a detachable bolt 579, the bolt 579 is used for limiting the downward movement of the end of the pressure lever 575, so that if the pressure lever 575 is not needed to press and pull out the bolt 579 downwards for the connecting piece 541, the end of the pressure lever 575 cannot move, and the process that the pressure lever 575 presses the connecting piece 542 is also released; the socket also has a through hole as the second latch hole 580 formed in the second rod 572, and the second latch hole 580 is aligned with the through hole, so that when the connector 541 does not need to move downward, that is, the first cover 51 and the second cover 52 need to be lifted at the same time, the latch 579 is inserted into the through hole and the second latch hole 580, and the first cover 51 and the second cover 52 can be lifted synchronously.
The furnace cover is characterized in that a plurality of guide pipes and stirring paddles are arranged on the existing furnace cover, because the observable second cover body is additionally arranged on one traditional cover body, each guide pipe is divided into two parts in the production process, one part is connected with the first cover body, the other part is connected with the second cover body, and when the first cover body is connected with the second cover body, the guide pipes of the two parts are mutually connected in a sealing way; similarly, for the arrangement of the stirring paddle and the like, the traditional stirring shaft can be divided into two parts, one part is connected with the motor, the other part is positioned on the second cover body, and when the first cover body is connected with the second cover body, the two parts of the stirring shaft are connected together in a rotation stopping way; which is a problem that can be easily solved by a person skilled in the art after viewing this document, and therefore will not be described in detail herein.
It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Claims (5)
1. A process for nitriding a metal surface, comprising a metal workpiece to be machined, characterized in that: the processing of the workpiece comprises the following steps:
1) cleaning the workpiece in clean water containing a cleaning agent to remove oil stains;
2) placing the workpiece without oil stain in a pool for ultrasonic cleaning, wherein the frequency of cleaning vibration is 80-160KHz, and the power density is set at 0.6-1.0W/C;
3) preheating the workpiece to 300-385 ℃, wherein the preheating time is 6-25 min;
4) placing the workpiece in a nitriding furnace containing Li ion-based salt, then pumping out air in the nitriding furnace, and refilling mixed gas in the nitriding furnace;
5) placing the workpiece in a nitriding furnace containing base salt containing Li ions, and raising the temperature of the nitriding furnace to 520-580 ℃ for 80-100 min;
6) adding sodium peroxide solid into the base salt, wherein the weight ratio of the solid sodium peroxide to the base salt is 1: 2.5-4.5;
7) after the sodium peroxide solid is added, the temperature in the nitriding furnace is increased to 520 ℃ and 580 ℃, and the nitriding time is 50-90min;
8) placing the nitrided workpiece in an oxidation furnace containing oxidation salt to carry out primary salt bath oxidation, heating the temperature of the oxidation furnace to 360-380 ℃, and oxidizing for 15-20 min;
9) polishing the workpiece subjected to the first oxidation;
10) performing secondary salt bath oxidation on the polished workpiece, wherein the temperature of the oxidation furnace is 420-450 ℃, and the oxidation time is 25-30 min;
11) soaking the workpiece subjected to secondary oxidation in engine oil;
the mixed gas is formed by mixing nitrogen and carbon dioxide;
the nitriding furnace in the step 4) comprises:
a furnace body (1);
a furnace pot (2) used for containing base salt and placing workpieces;
the heating element (3) is used for heating the interior of the furnace tank (2) to 520-580 ℃, and the heating element (3) is sleeved on the outer wall of the furnace tank (2);
a cooling member (4) for blowing cold air into the furnace body (1);
the furnace cover structure (5) is matched with the furnace body (1) in a sealing way, at least two layers of the furnace body (1) are sealed by the furnace cover structure (5), and the internal reaction of the furnace body (1) can be directly observed through the furnace cover structure (5);
the furnace cover structure (5) comprises a first cover body (51), a second cover body (52) movably connected with the first cover body (51) and an opening and closing part (53) used for opening the first cover body (51) and the second cover body (52), the first cover body (51) is arranged above the second cover body (52), and the interior of the furnace tank (2) can be observed through the second cover body (52);
the second cover body (52) comprises a fixing piece (521) and a lens (522), wherein the fixing piece (521) is arranged in a ring shape, the lens (522) is arranged in a transparent mode, the fixing piece (521) is connected with the lens (522), and the fixing piece (521) is connected with the first cover body (51) through a connecting component (54);
a first seal ring (511) arranged annularly is arranged at the edge of the first cover body (51), the first seal ring (511) is a metal ring connected with the lower end face of the first cover body (51), the first seal ring (511) is hollow, a saturated sodium acetate solution is filled in the first seal ring (511), and a first seal groove (101) is arranged on the furnace body (1); a supporting part (109) is arranged on the inner wall of the furnace body (1), a second sealing ring (108) is arranged on the supporting part (109), the interior of the second sealing ring (108) is hollow, and saturated sodium acetate is filled in the second sealing ring (108); a second sealing groove (509) is formed in the fixing piece (521);
the connecting part (54) comprises a connecting piece (541), an elastic piece (542) and a sealing piece (543), a first limiting part (501) is arranged below the connecting piece (541), the first limiting part (501) is a fan-shaped metal block with a plurality of positioning convex parts (591), a limiting part (544) is arranged on the fixing piece (521), a second limiting part (502) is arranged at the end part of the limiting part (544), the second limiting part 502 is a fan-shaped metal block, and a positioning concave part (581) is arranged on the second limiting part (502).
2. A process for nitriding a metal surface according to claim 1, characterized in that: the molar mass ratio of the nitrogen to the carbon dioxide is 6-10: 1.
3. A process for nitriding a metal surface according to claim 1, characterized in that: the ultrasonic cleaning time in the step 2) is 8-15 min.
4. A process for nitriding a metal surface according to claim 1, characterized in that: the base salt in the step 4) comprises the following raw materials in parts by weight: 3-5 parts of lithium carbonate, 8-15 parts of potassium chloride, 5-8 parts of sodium carbonate and 2-4 parts of carbamide.
5. A process for nitriding a metal surface according to claim 1, characterized in that: the raw materials of the oxide salt in the step 8) by weight ratio comprise: 2-5 parts of potassium hydroxide, 5-8 parts of sodium nitrate, 12-15 parts of sodium carbonate and 5-7 parts of ammonium chloride.
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| CN110512168B (en) * | 2019-09-20 | 2024-04-19 | 长兴凯越机械科技有限公司 | Ion nitriding furnace for automobile part production |
| CN112458397B (en) * | 2021-02-02 | 2021-04-13 | 湖南机电职业技术学院 | Stainless steel surface siliconizing device |
| CN115233150B (en) * | 2022-07-27 | 2023-06-09 | 桂林理工大学 | Formula of rare earth carbonitriding compound salt of Q235 and 9Cr18Mo and QPQ gas carbonitriding salt bath process thereof |
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| US6645566B2 (en) * | 1999-06-01 | 2003-11-11 | Jong Ho Ko | Process for heat treatment nitriding in the presence of titanium and products produced thereby |
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| CN1394982A (en) * | 2002-06-20 | 2003-02-05 | 烟台海德机床厂 | Vacuum well type tank-free ion carburizing multipurpose furnace |
| CN103215539A (en) * | 2006-04-18 | 2013-07-24 | 菲洛斯·琼贺·高 | Process for diffusing titanium and nitride into a material having a coating thereon |
| CN105349942A (en) * | 2015-12-02 | 2016-02-24 | 成都锦汇科技有限公司 | QPQ (quench-polish-quench) salt bath treatment method |
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