CN111843384B - Composite manufacturing method of impeller nut of sea water pump - Google Patents
Composite manufacturing method of impeller nut of sea water pump Download PDFInfo
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Abstract
The invention relates to the technical field of seawater pumps, and provides a composite manufacturing method of a seawater pump impeller nut, which comprises the following steps: casting a mother material to be surfacing welded by cast steel, and after the mother material is cleaned, depositing a layer of 316L stainless steel on the outer surface of the mother material by adopting a strip electrode electroslag surfacing welding method; depositing martensitic stainless steel on the inner cavity wall of the parent metal by adopting a shielded metal arc welding method; processing and milling the outer surface of the nut; tapping threads on the inner cavity of the base material. Through the process, the corrosion-resistant alloy shell layer can be sleeved on the outer surface of the cast steel, the threaded layer with the inner cavity formed by the martensitic stainless steel has excellent wear resistance, the manufactured finished product has the advantages of wear resistance and corrosion resistance, and the service life of the impeller nut is greatly prolonged compared with that of the impeller nut manufactured by the traditional single material.
Description
Technical Field
The invention relates to the technical field of seawater pumps, in particular to a composite manufacturing method of a seawater pump impeller nut.
Background
A sea water pump is a machine for transferring mechanical energy of a motor to sea water, and is widely applied to occasions such as seaside fire fighting, sea water desalination, tidal power generation and the like. The overflowing part of the sea water pump mainly comprises: a suction chamber, a discharge chamber, an impeller nut, and a pump housing. As a part for limiting the axial translation of the impeller, the impeller nut bears the flowing and scouring of seawater in the working state and is easy to corrode and lose efficacy. The prior art mainly solves the problem that the impeller nut is easy to corrode by two methods: firstly, the outer surface of the nut is sleeved with a macromolecule anti-rust shell layer, and the method mainly has the defects that: the shell layer and the internal metal do not form the connection of an atomic layer, once the shell has cracks, the structure is helpful for seawater to be retained between the metal and the shell, and the corrosion of the metal is accelerated; the other process is to integrally adopt a high-alloy stainless steel precision casting impeller nut, and the main defects are as follows: the hardness of stainless steel materials generally used for casting nuts is not large, generally is less than 20HRC, and impeller nuts made of single materials are easy to generate thread abrasion and even clamping faults in use.
The basic idea of composite manufacturing is to organically combine materials with different properties together, so that various materials fully exert the inherent properties of the components when the components work, the overall performance of the components is improved, and the service life of the components is prolonged. In the field of metal part manufacturing, a fusion welding method is often adopted, and a layer of alloy with different properties from the base metal is deposited on the surface of the part, so that the properties of corrosion resistance, wear resistance and the like of a working end face are improved. In order to improve the corrosion resistance of the impeller nut, the surface of the cast parent metal can be deposited with corrosion-resistant stainless steel by adopting a strip electrode electroslag surfacing process. Because the dilution rate of the strip electrode electroslag surfacing is low (less than 15 percent), the deposition efficiency is high. However, the research on the strip electrode electroslag surfacing in China is just started, the variety of the commercially available welding flux is limited, the welding flux is imported from countries such as Japan, Germany and the like, the research on the process parameters is also limited, and the application of the process in the composite manufacturing field is hindered to a certain extent.
To improve the wear resistance of the threaded layer of the impeller nut, the threaded layer on the inner cavity of the nut can be made of martensitic stainless steel. The hardness of the overlaying layer is improved by adopting a method of increasing the content of solid-solution carbon in the common martensite welding core, so that the problems of poor corrosion resistance and toughness are caused, and the common martensite welding core cannot be directly applied to the manufacture of the impeller nut of the sea water pump.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides the composite manufacturing method for manufacturing the seawater pump impeller nut with excellent performance and high appearance precision, which can solve the problems in the background technology, the manufactured finished product has the advantages of wear resistance and corrosion resistance, and the service life of the impeller nut is greatly prolonged compared with the impeller nut manufactured by the traditional single material.
In order to achieve the purpose, the invention is realized by the following technical scheme:
a composite manufacturing method of a sea water pump impeller nut comprises the following steps:
casting a mother material to be surfacing welded by cast steel, and after the mother material is cleaned, depositing a layer of 316L stainless steel on the outer surface of the mother material by adopting a strip electrode electroslag surfacing welding method; depositing martensitic stainless steel on the inner cavity wall of the parent metal by adopting a shielded metal arc welding method; processing and milling the outer surface of the nut; tapping threads on the inner cavity of the base material.
Further, the cleaning of the base material comprises the steps of channel trimming, sand paper polishing to remove oxide skin and clamp sand, cleaning, dedusting and decontamination.
Further, the method also comprises the steps of finish milling and polishing.
Furthermore, a surfacing material adopted by strip electrode electroslag surfacing consists of a welding strip and a welding flux; the solder strip is 316L stainless steel with the cross section size of 10mm multiplied by 0.5mm, and the flux comprises the following components in parts by mass: 50-70 parts of fluorite, 15-35 parts of bauxite, 10-25 parts of magnesia, 15-35 parts of clay and 5-10 parts of zircon; the welding flux also comprises rutile, ferrosilicon and ferromanganese, and the total mass of the rutile, the ferrosilicon and the ferromanganese is not more than 3 parts.
Further, the preparation method of the flux comprises the following steps: (1) accurately taking powder raw materials after the required mineral and alloy powder quality is converted; (2) pouring various raw materials into a closed container, and uniformly stirring to obtain powder with uniform color; (3) adding sodium silicate accounting for 20 percent of the mass of the powder into the dry powder as a binder, and uniformly stirring, wherein the sodium potassium ratio of the sodium silicate is 1: 1, and the modulus is 3.0; (4) manually kneading the wet powder to obtain granules; screening by using a 20-mesh screen, and re-kneading particles which do not pass through the screen to ensure that at least 90 percent of the welding flux passes through the 20-mesh screen; then sieving particles with undersize diameter by using a 40-mesh sieve, and leaving the particles above the sieve to enter the next link; (5) and (3) putting the particles into an oven to be dried for 1-2 hours at the temperature of 100-200 ℃, then heating to 600 ℃, preserving heat for 1 hour, cooling to room temperature along with the oven, taking out, and screening by using a screen again to ensure that the particle diameter of the sintered flux is 0.38-0.83 mm.
Furthermore, the welding rod adopted by the shielded metal arc welding consists of a welding core and an external coating; the core wire is 1Cr13 martensitic stainless steel with the diameter of 4mm, and the coating comprises the following components in parts by mass: 40-50 parts of marble, 20-30 parts of fluorite, 3-6 parts of titanium dioxide, 3-5 parts of zircon sand, 3-5 parts of potassium feldspar, 5-7 parts of ferroniobium, 5-8 parts of ferrotitanium, 3-5 parts of ferromolybdenum, 2-5 parts of ferromanganese, 2-6 parts of ferrosilicon and 4-5 parts of chromium nitride.
Further, the preparation method of the welding rod comprises the following steps: (1) straightening the core wires, polishing with sand paper to remove rust, cleaning and removing dirt; (2) after the required raw materials are converted according to the formula proportion, accurately weighing mineral and alloy powder, pouring the powder into a mortar, and simultaneously grinding and dry-mixing until the powder is uniform in texture and consistent in color; (3) adding water glass into the dry powder for a small number of times, and stirring at a constant speed until the wet powder has moderate viscosity and uniform texture; the modulus of the water glass is 2.9, and the Baume degree is 47-48; (4) coating the wet powder on the surface of the welding core centripetally, controlling the thickness to be 2-3mm, and keeping good concentricity; (5) at room temperature, the welding rod is vertically placed and aired for at least 24 hours, and the welding rod is dried after the coating is shaped; heating to 100 deg.C, holding for 1 hr, heating to 380 deg.C, oven drying for 2 hr, cooling to room temperature, and storing in shade.
Further, the technological parameters of strip electrode electroslag surfacing are as follows: the welding current 338-380A, the welding voltage 25-28V, the welding speed 8m/h, the dry extension of the welding strip 25mm, the coverage thickness of the welding flux 30mm, and the polarity of the power source adopts a direct current reverse connection mode.
Further, the welding parameters of the manual shielded metal arc welding are as follows: welding current 120A, welding voltage 35-45V, welding speed 18-23m/h, and power supply polarity direct current reverse connection.
The invention also provides a seawater pump impeller nut which is prepared by any one of the methods.
Advantageous effects
The invention provides a composite manufacturing method of a sea water pump impeller nut, which has the following beneficial effects:
(1) the invention overcomes the defect of the process of coating the metal parent metal with the macromolecular shell layer, and adopts the strip electrode electroslag surfacing welding method to melt 316L stainless steel on the outer surface of the cast steel parent metal to form the corrosion-resistant metal shell layer.
(2) The invention overcomes the defects that the impeller nut made of a single stainless steel material has insufficient hardness and the thread is easy to wear, and uses the wear-resistant welding rod to deposit the martensitic stainless steel in the inner cavity of the base metal, so that the manufactured thread has the advantages of wear resistance and difficult locking.
(3) The invention overcomes the defect of insufficient carbon toughness of common martensitic stainless steel. By adding a proper amount of chromium nitride into the coating of the welding rod and replacing carbon with nitrogen, the toughness and the corrosion resistance of the alloy of the overlaying layer are improved.
(4) In summary, the welding material and method provided by the present invention can be used to manufacture an impeller nut with cast steel as the inner matrix, 316L stainless steel as the outer anti-rust shell, and martensitic stainless steel as the threaded material. The nut has excellent performance in all aspects, and the process scheme is simple and easy to understand and is convenient to popularize and apply.
(5) According to the invention, the corrosion-resistant alloy shell layer can be sleeved on the outer surface of the cast steel, the threaded layer with the inner cavity formed by the martensitic stainless steel has excellent wear resistance, the manufactured finished product has the advantages of wear resistance and corrosion resistance, and the service life of the impeller nut is greatly prolonged compared with that of the impeller nut manufactured by the traditional single material.
Drawings
FIG. 1 is a schematic process flow diagram of the present invention;
FIG. 2 is a schematic view of a strip electroslag surfacing process;
FIG. 3 is a schematic view of a manual shielded metal arc welding process;
fig. 4 is a schematic axial cross-section of the finished product.
1. A flat welding trolley; 2. welding a strip; 3. a tape feeding mechanism; 4. a contact tip; 5. depositing alloy; 6. a nut to be welded; 7. a conductive platform; 8. surfacing welding flux; 9. a power source; 11. welding rods; 12. welding direction; 13. an inner cavity of the parent metal; 14. a power source; 15. a 316L stainless steel corrosion resistant shell layer; 16. a martensitic stainless steel wear-resistant thread layer; 17. and casting a mother blank by cast steel.
Detailed Description
The embodiment of the composite manufacturing method of the impeller nut of the sea water pump provided by the invention is further explained by referring to fig. 1-4. It should be noted that the following examples are only for the purpose of more clearly describing the technical solutions provided by the present invention, and are not used to limit the protection scope of the present invention.
Example 1
A composite manufacturing method of a sea water pump impeller nut comprises the following steps:
(1) casting a base material to be built-up welded by using cast steel, and cleaning the surface of the base material;
(2) depositing a layer of 316L stainless steel on the outer surface of the parent metal by using the surfacing material provided by the invention
(3) The martensite stainless steel is deposited on the inner cavity wall of the parent metal by using the wear-resistant welding rod provided by the invention;
(4) setting a moving path and technological parameters of the milling cutter according to the shape and surface material characteristics of the finished nut;
(5) processing and milling the outer surface of the nut;
(6) tapping threads on the inner cavity of the base metal;
(7) further processing as required, such as finish milling, polishing, etc.
Further, the process of cleaning the surface of the base metal in the step (1) mainly comprises the steps of channel trimming, sand paper polishing to remove oxide skin and sand inclusion, cleaning, dedusting and decontamination.
Further, the step (2) mainly adopts a strip electrode electroslag surfacing method, and the surfacing material consists of a welding strip and a welding flux. The solder strip is 316L stainless steel with a cross-sectional dimension of 10mm × 0.5mm, and the flux composition and preparation method are as follows.
Flux composition (mass fraction Zt%): 50-70 parts of fluorite, 15-35 parts of bauxite, 10-25 parts of magnesia, 15-35 parts of clay and 5-10 parts of zircon. In addition, a small amount of rutile, ferrosilicon and ferromanganese can be added, and the mass fraction is not more than 3%.
The preparation method of the welding flux comprises the following steps: (1) accurately taking powder raw materials after the required mineral and alloy powder quality is converted; (2) pouring various raw materials into a closed container, and uniformly stirring to obtain powder with uniform color; (3) adding water glass with the powder mass of 20% into the dry powder as a binder, and uniformly stirring, wherein the sodium potassium ratio of the water glass is 1: 1, modulus 3.0; (4) manually kneading the wet powder to obtain granules. The screening was carried out using a 20 mesh (0.83mm) screen and particles having a diameter significantly greater than 0.83mm were re-kneaded so that at least 90% of the flux passed through the 20 mesh screen. Sieving with 40 mesh (0.38mm) sieve to remove particles with small diameter, and leaving above the sieve for the next step; (5) and (3) drying the particles in an oven at 100-200 ℃ for 1-2 hours, heating to 600 ℃, preserving heat for 1 hour, cooling to room temperature along with the oven, taking out, and screening by using a screen again to ensure that the particle diameter of most of the sintered flux is 0.38-0.83 mm.
Further, the technological parameters of the strip electrode electroslag surfacing in the step (2) are selected as follows: the welding current 338-380A, the welding voltage 25-28V, the welding speed 8m/h, the dry extension of the welding strip 25mm, the coverage thickness of the welding flux 30mm, and the polarity of the power source adopts a direct current reverse connection mode.
Further, step (3) adopts a manual shielded metal arc welding method, wherein the welding rod consists of a core wire and an outer coating. The core wire is 1Cr13 martensite stainless steel with the diameter of 4mm, and the coating formulation and the preparation method of the welding rod are as follows.
The formula of the coating (mass fraction Zt%): 40-50 parts of marble, 20-30 parts of fluorite, 3-6 parts of titanium dioxide, 3-5 parts of zircon sand, 3-5 parts of potash feldspar, 5-7 parts of ferroniobium, 5-8 parts of ferrotitanium, 3-5 parts of ferromolybdenum, 2-5 parts of ferromanganese, 2-6 parts of ferrosilicon and 4-5 parts of chromium nitride.
The preparation method of the welding rod comprises the following steps: (1) straightening the core wires, polishing with sand paper to remove rust, cleaning and removing dirt; (2) after the required raw materials are converted according to the formula proportion, accurately weighing mineral and alloy powder, pouring the powder into a mortar, and simultaneously grinding and dry-mixing until the powder is uniform in texture and consistent in color; (3) adding water glass into the dry powder for a few times and stirring at a constant speed until the wet powder has moderate viscosity and uniform texture. The modulus of the water glass is 2.9, and the Baume degree is 47-48. (4) The wet powder is centripetally coated on the surface of the welding core, the thickness is controlled to be 2-3mm, and good concentricity is kept. (5) And (3) standing the welding rod vertically at room temperature, airing for at least 24 hours, and drying after the coating is shaped. Heating to 100 deg.C, holding for 1 hr, heating to 380 deg.C, oven drying for 2 hr, cooling to room temperature, and storing in shade.
Further, the welding parameters of the manual shielded metal arc welding are selected as follows: welding current 120A, welding voltage 35-45V, welding speed 18-23m/h, and power supply polarity direct current reverse connection.
Example 2
In order to obtain the hexagonal prism-shaped impeller nut shown in fig. 4, the composite manufacturing method provided by the invention is adopted for manufacturing, and the process is as follows:
(1) casting a base material to be subjected to surfacing welding by using cast steel, and cleaning the surface of the base material. The present embodiment preferably uses ZG275-485H as the casting material. The method for cleaning the surface of the base metal comprises the steps of trimming a runner, polishing by abrasive paper to remove oxide skin and clamp sand, and cleaning, dedusting and decontaminating.
(2) The corrosion-resistant shell layer is deposited on the outer surface of the parent metal by using the surfacing material provided by the invention through a strip electrode electroslag surfacing method. The surfacing material consists of a welding strip and a welding flux. The solder ribbon is 316L stainless steel having a cross-sectional dimension of 10mm by 0.5mm, and a preferred method of preparing the solder is as follows.
The preparation method of the welding flux comprises the following steps:
the method comprises the following steps: the required mineral and alloy powder mass is converted according to the table 1, and the powder raw materials are accurately taken;
table 1 sample mass fraction (Zt%) examples
| Name of raw materials | Fluorite | Bauxite | Clay clay | Magnesite clinker | Zircon stone | Rutile type | Silicon iron | Ferromanganese |
| Mass fraction | 50 | 15 | 15 | 10 | 5.3 | 1.7 | 1 | 2 |
Step two: pouring various raw materials into a closed container, and uniformly stirring to obtain powder with uniform color;
step three: adding water glass with the mass of 20% of the powder into the dry powder as a binder and uniformly stirring. In the embodiment, the ratio of sodium to potassium in water glass is 1: 1, and the modulus is 3.0;
step four: manually kneading the wet powder to obtain granules. The screening was carried out using a 20 mesh (0.83mm) screen and particles having a diameter significantly greater than 0.83mm were re-kneaded so that at least 90% of the flux passed through the 20 mesh screen. Sieving with 40 mesh (0.38mm) sieve to remove particles with small diameter, and leaving above the sieve for the next step;
step five: and (3) putting the particles into an oven, drying for 1-2 hours at 100-200 ℃, heating to 600 ℃, preserving heat for 1 hour, cooling to room temperature along with the oven, and taking out. The sintering temperature is screened again by using a screen to ensure that the particle diameter of most sintered flux is 0.38 mm-0.83 mm.
The preferred welding parameters of this example during strip electroslag surfacing are: the welding current 338-380A, the welding voltage 25-28V, the welding speed 8m/h, the dry extension of the welding strip 25mm, the coverage thickness of the welding flux 30mm, and the polarity of the power source adopts a direct current reverse connection mode.
The schematic diagram of the strip electrode electroslag surfacing process is shown in figure 2; the process is described as follows: (1) before starting welding, the nut 6 mother blank to be welded is fixed on a conductive platform 7, the end face to be welded is upward, and a 30mm surfacing flux 8 is uniformly spread on the end face. Mounting the welding strip 2 on a flat welding trolley 1 by adopting a strip conveying mechanism 3, and keeping the distance from a contact tip 4 to the tail end of the welding strip to be 25 mm; (2) at the beginning of welding, adjusting voltage to be 25-28V, current to be 338-380A, carrying out mode direct current reverse connection on a power supply 9, carrying out arc discharge between a welding strip 2 and a base metal, and melting a welding flux to form a slag pool; (3) after the slag bath has enough depth, the welding strip 2 is inserted into the slag bath, the electric arc is extinguished, and the electroslag process is carried out; (4) the flat welding trolley 1 moves forward at 8m/h, and one welding is finished stably; (5) and (4) removing slag, adjusting the position of the base metal facing the welding strip, and keeping 1/2 the overlapping area between the roads. The above process is repeated.
The general sequence of the strip electrode electroslag surfacing welding is as follows: the corrosion-resistant alloy is deposited on the side surface, and then the two end surfaces are subjected to overlaying welding.
(3) The martensite stainless steel is deposited on the inner cavity wall of the parent metal by using the wear-resistant welding rod provided by the invention. The welding rod consists of martensitic stainless steel with the inner diameter of 4mm and 1Cr13 and an outer coating, and the preparation process of the welding rod is as follows:
the method comprises the following steps: the required mineral and alloy powder mass is converted according to table 2, and the raw materials are accurately taken. Pouring the mixture into a mortar for grinding and dry mixing at the same time until the powder is uniform in texture and consistent in color;
table 2: sampling mass fraction (Zt%) examples
Step two: adding water glass into the dry powder for a few times and stirring at a constant speed until the wet powder has moderate viscosity and uniform texture. The water glass modulus of the water glass is 2.9, and the Baume degree is 47-48.
Step three: the wet powder is centripetally coated on the surface of the straightened and smooth welding core, the thickness is controlled to be 2-3mm, and good concentricity is kept.
Step four: and (3) vertically placing the welding rod at room temperature, airing for at least 24 hours, and drying after the coating is shaped. Heating to 100 deg.C, holding for 1 hr, heating to 380 deg.C, oven drying for 2 hr, cooling to room temperature, and storing in shade.
In the manual electrode arc surfacing process, the preferred welding parameters of the embodiment are as follows: welding current 120A, welding voltage 35-45V, welding speed 18-23m/h, and power supply polarity direct current reverse connection.
FIG. 3 is a schematic diagram of a stick electrode arc build-up process; the process is described as follows: (1) fixing a nut semi-finished product on a conductive platform before welding, wherein 13 holes of a base metal inner cavity of the nut semi-finished product are upward; (2) the voltage is regulated to 35-45V, the current is 120A, and the power supply is in 14-mode direct current reverse connection. The welding rod 11 provided by the invention is used for cladding the wear-resistant alloy (3) by knocking out a slag shell by a vertical welding method from bottom to top, the overlapping area between the channels is kept about 1/3, and the process is repeated until the inner surface is fully coated with the wear-resistant alloy.
(4) Setting a moving path and technological parameters of the milling cutter according to the shape and surface material characteristics of the finished nut;
(5) processing and milling the outer surface of the nut;
(6) tapping threads on the inner cavity of the base material to obtain the axial section appearance of the manufactured finished product as shown in FIG. 4;
(7) further processing according to requirements, such as finish milling, polishing and the like, and obtaining the axial section appearance of a finished product.
As shown in fig. 4, the seawater pump impeller nut comprises a cast mother blank 17, a martensitic stainless steel wear thread layer 16 and a 316L stainless steel corrosion shell layer 15. The cast steel casting mother blank 17 is positioned at the innermost layer of the nut finished product, takes ZG275-485H as a material, and has the characteristics of excellent casting performance and excellent welding performance. The 316L stainless steel corrosion-resistant shell layer 15 is positioned on the outer side of the cast steel mother blank, the 316L stainless steel is widely applied to an easily corroded part in seawater engineering machinery, and the method provided by the invention only needs to melt the corrosion-resistant shell layer outside the mother blank, so that the using amount of the 316L stainless steel is reduced. The martensite stainless steel wear-resistant thread layer 16 is positioned on the inner side of the cast steel mother blank, and the welding rod provided by the invention strengthens common martensite stainless steel by using a nitrogen alloying method and enhances the wear resistance of the common martensite stainless steel.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (4)
1. A composite manufacturing method of a sea water pump impeller nut is characterized by comprising the following steps:
casting a base material to be built-up welded by using cast steel, and cleaning the surface of the base material;
depositing a layer of 316L stainless steel on the outer surface of the parent metal by adopting a strip electrode electroslag surfacing method;
depositing martensitic stainless steel on the inner cavity wall of the parent metal by adopting a shielded metal arc welding method;
setting a moving path and technological parameters of the milling cutter according to the shape and surface material characteristics of the finished nut;
processing and milling the outer surface of the nut;
tapping threads on the inner cavity of the base metal; the surfacing material adopted by the strip electrode electroslag surfacing consists of a welding strip and a welding flux; the solder strip is 316L stainless steel with the cross section size of 10mm multiplied by 0.5mm, and the flux comprises the following components in parts by mass: 50-70 parts of fluorite, 15-35 parts of bauxite, 10-25 parts of magnesia, 15-35 parts of clay and 5-10 parts of zircon; the flux also comprises rutile, ferrosilicon and ferromanganese, and the total mass of the rutile, the ferrosilicon and the ferromanganese is not more than 3 parts;
the technological parameters of the strip electrode electroslag surfacing welding are as follows: the welding current is 338-380A, the welding voltage is 25-28V, the welding speed is 8m/h, the dry extension of the welding strip is 25mm, the coverage thickness of the welding flux is 30mm, and the polarity of the power supply adopts a direct current reverse connection mode;
the preparation method of the flux comprises the following steps: (1) accurately taking powder raw materials after the required mineral and alloy powder quality is converted; (2) pouring various raw materials into a closed container, and uniformly stirring to obtain powder with uniform color; (3) adding water glass with the powder mass of 20% into the dry powder as a binder, and uniformly stirring, wherein the sodium potassium ratio of the water glass is 1: 1, modulus 3.0; (4) manually kneading the wet powder to obtain granules; screening by using a 20-mesh screen, and re-kneading particles which do not pass through the screen to ensure that at least 90 percent of the welding flux passes through the 20-mesh screen; then sieving particles with undersize diameter by using a 40-mesh sieve, and leaving the particles above the sieve to enter the next link; (5) drying the particles in an oven at 100-200 ℃ for 1-2 hours, heating to 600 ℃, preserving heat for 1 hour, cooling to room temperature along with the oven, taking out, and screening by using a screen again to ensure that the particle diameter of the sintered flux is 0.38-0.83 mm;
the welding rod adopted by the shielded metal arc welding consists of a welding core and an external coating; the core wire is 1Cr13 martensitic stainless steel with the diameter of 4mm, and the coating comprises the following components in parts by mass: 40-50 parts of marble, 20-30 parts of fluorite, 3-6 parts of titanium dioxide, 3-5 parts of zircon sand, 3-5 parts of potassium feldspar, 5-7 parts of ferroniobium, 5-8 parts of ferrotitanium, 3-5 parts of ferromolybdenum, 2-5 parts of ferromanganese, 2-6 parts of ferrosilicon and 4-5 parts of chromium nitride;
the welding parameters of the manual shielded metal arc welding are as follows: welding current is 120A, welding voltage is 35-45V, welding speed is 18-23m/h, and power supply polarity direct current is reversely connected;
the preparation method of the welding rod comprises the following steps: (1) straightening the core wires, polishing with sand paper to remove rust, cleaning and removing dirt; (2) after the required raw materials are converted according to the formula proportion, accurately weighing mineral and alloy powder, pouring the powder into a mortar, and simultaneously grinding and dry-mixing until the powder is uniform in texture and consistent in color; (3) adding water glass into the dry powder for a small number of times, and stirring at a constant speed until the wet powder has moderate viscosity and uniform texture; the modulus of the water glass is 2.9, and the Baume degree is 47-48; (4) coating the wet powder on the surface of the welding core centripetally, controlling the thickness to be 2-3mm, and keeping good concentricity; (5) at room temperature, the welding rod is vertically placed and aired for at least 24 hours, and the welding rod is dried after the coating is shaped; heating to 100 ℃, preserving heat for 1 hour, heating to 380 ℃, drying for 2 hours, cooling to room temperature along with the furnace, and storing the finished welding rod in a cool and dry place.
2. The composite manufacturing method of the seawater pump impeller nut as claimed in claim 1, wherein the base material cleaning comprises channel trimming, sand sanding to remove oxide scale and sand inclusion, cleaning to remove dust and dirt.
3. The composite manufacturing method of the seawater pump impeller nut as claimed in claim 1, further comprising the steps of finish milling and polishing.
4. A seawater pump impeller nut is characterized by being prepared by the method of any one of claims 1-3.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6086953A (en) * | 1997-07-01 | 2000-07-11 | Raghavan; Srimathy | Ceramic-coated metal guide pin |
| DE102008051712A1 (en) * | 2008-10-16 | 2009-06-10 | Daimler Ag | Contact arrangement for vehicle body, has metallic threaded bolt and threaded nut comprising external and/or internal threads with protection coating, and varnish layer formed on protection coating |
| CN201344237Y (en) * | 2008-12-25 | 2009-11-11 | 李京孝 | Double-metal valve rod nut for gate valve |
| CN102069325A (en) * | 2010-12-30 | 2011-05-25 | 河海大学常州校区 | Sintered flux for austenitic stainless steel strip electrode electro-slag surfacing |
| CN102528309A (en) * | 2010-12-17 | 2012-07-04 | 天津重型装备工程研究有限公司 | Welding fluid for overlaying welding of strip-shaped electrode electroslag and preparation method thereof |
| CN209953500U (en) * | 2019-01-30 | 2020-01-17 | 烟台蓝鲸增材有限公司 | Screw-down nut manufactured by additive composite |
| CN110877170A (en) * | 2019-12-04 | 2020-03-13 | 河海大学常州校区 | Surfacing electrode, preparation method and dredging reamer abrasion repair surfacing method |
-
2020
- 2020-07-20 CN CN202010698621.7A patent/CN111843384B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6086953A (en) * | 1997-07-01 | 2000-07-11 | Raghavan; Srimathy | Ceramic-coated metal guide pin |
| DE102008051712A1 (en) * | 2008-10-16 | 2009-06-10 | Daimler Ag | Contact arrangement for vehicle body, has metallic threaded bolt and threaded nut comprising external and/or internal threads with protection coating, and varnish layer formed on protection coating |
| CN201344237Y (en) * | 2008-12-25 | 2009-11-11 | 李京孝 | Double-metal valve rod nut for gate valve |
| CN102528309A (en) * | 2010-12-17 | 2012-07-04 | 天津重型装备工程研究有限公司 | Welding fluid for overlaying welding of strip-shaped electrode electroslag and preparation method thereof |
| CN102069325A (en) * | 2010-12-30 | 2011-05-25 | 河海大学常州校区 | Sintered flux for austenitic stainless steel strip electrode electro-slag surfacing |
| CN209953500U (en) * | 2019-01-30 | 2020-01-17 | 烟台蓝鲸增材有限公司 | Screw-down nut manufactured by additive composite |
| CN110877170A (en) * | 2019-12-04 | 2020-03-13 | 河海大学常州校区 | Surfacing electrode, preparation method and dredging reamer abrasion repair surfacing method |
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| CN111843384A (en) | 2020-10-30 |
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