阅读说明：本技术 一种螺杆涂层的喷焊方法 (Spray welding method for screw coating ) 是由 谭笛 莫健麒 陈志坤 王玉 康忠明 朱晖朝 王枫 李福球 林凯生 丘莉莉 曾良 于 2021-08-11 设计创作，主要内容包括：本发明属于注塑螺杆技术领域,具体涉及一种螺杆涂层的喷焊方法,包括S1：清洗；S2：喷砂；S3：喷涂：将螺杆预热,采用丙烷-氧气火焰喷枪,采用150/300目镍基碳化钨粉末,将粉末均匀喷涂至螺杆表面；S4：重熔：将螺杆再次预热至400～500℃,进行重熔；S5：抛光S6：磨削。本发明提供了一种两步法喷焊涂层螺杆的制备工艺,可以对螺棱、螺槽和螺根同时喷焊一层厚度均匀、硬度高、耐磨损的涂层,能大大提高螺杆的使用寿命。本发明提供了一种两步法喷焊涂层螺杆的制备工艺,可以对螺棱、螺槽和螺根同时喷焊一层厚度均匀、硬度高、耐磨损的涂层,能大大提高螺杆的使用寿命。(The invention belongs to the technical field of injection molding screws, and particularly relates to a spray welding method of a screw coating, which comprises the following steps of S1: cleaning; s2: sand blasting; s3: spraying: preheating a screw, uniformly spraying nickel-based tungsten carbide powder of 150/300 meshes to the surface of the screw by adopting a propane-oxygen flame spray gun; s4: remelting: preheating the screw to 400-500 ℃ again, and remelting; s5: polishing S6: and (6) grinding. The invention provides a preparation process of a two-step spray welding coating screw, which can spray weld a layer of coating with uniform thickness, high hardness and wear resistance on a screw ridge, a screw groove and a screw root simultaneously, and can greatly prolong the service life of the screw. The invention provides a preparation process of a two-step spray welding coating screw, which can spray weld a layer of coating with uniform thickness, high hardness and wear resistance on a screw ridge, a screw groove and a screw root simultaneously, and can greatly prolong the service life of the screw.)

1. A spray welding method of screw coating is characterized by comprising the following steps:

s1: cleaning; s2: sand blasting; s3: spraying: preheating a screw, adopting a propane-oxygen flame spray gun, adopting 150-300 mesh nickel-based tungsten carbide powder, and uniformly spraying the powder on the surface of the screw, wherein the process parameters are as follows: the oxygen pressure is 0.35MPa, the oxygen flow is 60%, the propane pressure is 0.24MPa, the propane flow is 25%, the powder feeding amount is 80g/min, the carrier gas is 6slpm, the rotating speed of a powder feeder is 2.5rpm, the rotating speed of a rotary table is 200-250 rpm, the gun walking speed is 20mm/s, the spraying distance is 250mm, and the coating thickness is 0.5-0.6 mm; s4: remelting: preheating the screw to 400-500 ℃ again, and remelting; s5: polishing S6: and (6) grinding.

2. The spray welding method for screw coating according to claim 1, wherein the nickel-based tungsten carbide in step S3 is one or more of Ni30WC, Ni25WC and Ni20 WC.

3. The spray welding method for screw coating according to claim 1, wherein in step S1, acetone is used to clean the screw ridges, grooves and screws.

4. The spray welding method for the screw coating according to claim 1, wherein in step S2, the sand blasting pressure is 0.3-0.4 MPa, the sand grains are 46# zirconium corundum, the blasting distance is 50-100 mm, the angles between the sand blasting nozzle and the screw are-67 degrees and-67 degrees, the rotating speed of the rotary table is 100-200 rpm, and the gun moving speed is 10-15 mm/S.

5. The spray welding method for screw coating according to claim 1, wherein in step S5, the screw groove and the screw root are polished by diamond abrasive belts No. 60, No. 200 and No. 400 respectively until the roughness Ra is less than or equal to 0.4.

6. The spray welding method for screw coating according to claim 1, wherein the thickness of the coating layer after grinding in step S6 is 0.2 mm.

7. The spray welding method for screw coating according to claim 1, wherein the screw is preheated to 300-350 ℃ in step S3.

Technical Field

The invention belongs to the technical field of injection molding screws, and particularly relates to a spray welding method of a screw coating.

Background

The screw is a core component on the injection molding machine, the use condition of the screw is very bad, and the abrasion is a main cause of failure. Therefore, the screw is required to have the advantages of high temperature resistance, corrosion resistance, high strength, good cutting processing performance and the like. At present, 45# steel, 40Cr, 38CrMoAl and the like are commonly used screw materials, and in order to improve the wear resistance of the surface of the screw, the chromium plating and nitriding are commonly used on the surface of the screw. But the chromium plating process has serious environmental pollution. After nitriding of the screw, the screw is poor in hydrogen chloride corrosion resistance and high in cost. As the additives in the extruded materials increase, the abrasion of the screw edges, the screw grooves and the screw roots of the screws becomes more and more serious. Most of the prior screws mainly adopt a one-step spray welding coating, and only spray welding the screw ridge part can not spray weld the screw groove and the screw root. When the screw is used for processing plastics containing additives such as glass fiber and the like, the screw groove and the screw root can seriously cause screw failure due to abrasion.

Therefore, the existing screw needs to be improved, not only the wear resistance of the screw ridge needs to be improved, but also the wear resistance of the screw groove and the screw root needs to be improved, and the service life of the screw is prolonged.

Disclosure of Invention

The invention provides a preparation process of a two-step spray welding coating screw, which can spray weld a layer of coating with uniform thickness, high hardness and wear resistance on a screw ridge, a screw groove and a screw root simultaneously, and can greatly prolong the service life of the screw.

In order to achieve the purpose, the invention adopts the technical scheme that:

a spray welding method for screw coating comprises the following steps:

s1: cleaning; s2: sand blasting; s3: spraying: preheating a screw, adopting a propane-oxygen flame spray gun, adopting 150-300 mesh nickel-based tungsten carbide powder, and uniformly spraying the powder on the surface of the screw, wherein the process parameters are as follows: the oxygen pressure is 0.35MPa, the oxygen flow is 60%, the propane pressure is 0.24MPa, the propane flow is 25%, the powder feeding amount is 80g/min, the carrier gas is 6slpm, the rotating speed of a powder feeder is 2.5rpm, the rotating speed of a rotary table is 200-250 rpm, the gun walking speed is 20mm/s, the spraying distance is 250mm, and the coating thickness is 0.5-0.6 mm; s4: remelting: preheating the screw to 400-500 ℃ again, and remelting; s5: polishing S6: and (6) grinding.

As a preferable technical solution, in the step S3, the nickel-based tungsten carbide is one or more of Ni30WC, Ni25WC, and Ni20 WC.

As a preferable technical solution, in step S1, the screw flight, screw groove, and screw of the screw are cleaned with acetone.

As a preferable technical scheme, in the step S2, the sand blasting pressure is 0.3-0.4 MPa, the sand grains are 46# zirconium corundum, the blasting distance is 50-100 mm, the angles between a sand blasting nozzle and a screw are-67 degrees and 67 degrees, the rotating speed of a rotary table is 100-200 rpm, and the gun moving speed is 10-15 mm/S.

As a preferable technical scheme, in the step S5, diamond abrasive belts with the number 60#, 200#, 400# are respectively used for polishing the screw groove and the screw root until the roughness Ra is less than or equal to 0.4.

As a preferable technical scheme, the thickness of the coating after grinding in the step S6 is 0.2 mm.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a preparation process of a two-step spray welding coating screw, which can spray weld a layer of coating with uniform thickness, high hardness and wear resistance on a screw ridge, a screw groove and a screw root simultaneously, and can greatly prolong the service life of the screw.

Drawings

FIG. 1 is a metallographic structure of a spray welded coating according to example 1.

FIG. 2 is a metallographic structure of a spray welded coating according to example 2.

FIG. 3 is a metallographic structure of a spray welded coating according to example 3.

Fig. 4 is a schematic view of a screw structure. 1-a spiral groove; 2-a helical edge; 3-root of Chinese snail.

Detailed Description

The following further describes the embodiments of the present invention. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The test methods used in the following experimental examples are all conventional methods unless otherwise specified; the materials, reagents and the like used are, unless otherwise specified, commercially available reagents and materials.

Example 1:

the spray welding screw rod of the invention has the following preparation process:

1, cleaning: cleaning the spraying areas of the screw, such as the screw edge, the screw groove, the screw and the like by using clean cloth dipped in acetone, wherein the surface of the cleaned screw is free from water, oil, grease, dust, water scale, paint and other foreign matters.

2, sand blasting: protecting the non-spraying area by using an iron sheet, clamping a screw (shown in figure 4) on a sand blasting turntable, wherein the sand blasting pressure is 0.3MPa, the sand grain is 46# zirconium corundum, the spraying distance is 50mm, the angles between a sand blasting nozzle and the screw are-67 degrees and 67 degrees, the rotating speed of the turntable is 100rpm, and the gun moving speed is 10 mm/s. The surface after sand blasting should be uniform, have no bright spots, no pollution, no depression and the like.

3, clamping the sand-blasted screw on a spraying turntable, starting the turntable, and uniformly preheating the screw to 300 ℃ by using an oxyacetylene remelting gun. Using a propane-oxygen flame spray gun, powder: 150/300 mesh Ni20WC, Ni20WC was sprayed uniformly onto the screw surface. The technological parameters are as follows: the oxygen pressure is 0.35MPa, the oxygen flow is 60%, the propane pressure is 0.24MPa, the propane flow is 25%, the powder feeding amount is 80g/min, the carrier gas is 6slpm, the rotating speed of a powder feeder is 2.5rpm, the rotating speed of a rotary table is 200rpm, the gun walking speed is 20mm/s, the spraying distance is 250mm, the coating thickness is 0.5mm, the angle between a spray gun and a screw is 90 degrees, -67 degrees and 67 degrees, and the coating is uniformly sprayed on the front and the back of the screw root 3 by adjusting the angle of the spray gun.

4, adopting neutral flame or slight carbonized flame of an oxyacetylene remelting gun to preheat the whole screw rod to 400-500 ℃, remelting the spray welding coating by using another remelting gun, moving the spray gun after the liquid metal is in mirror reflection, remelting the screw rod screw root 3 uniformly in front and back by adjusting the angle between the remelting gun and the screw rod, and immediately preserving heat and slowly cooling the workpiece after remelting.

And 5, polishing, namely clamping the remelted screw rod to a polishing turntable, and polishing the screw groove and the screw root of the screw rod by using a 60#, 200#, 400# diamond abrasive belt respectively until the roughness Ra is less than or equal to 0.4.

And 6, grinding, namely clamping the polished screw rod on a grinding machine, and grinding the screw edge to the required size. The thickness of the coating after grinding is 0.2 mm. As shown in fig. 1, the metallographic structure of the sprayed layer after spraying was shown.

Example 2:

the spray welding screw rod of the invention has the following preparation process:

1, cleaning: cleaning the spraying areas of the screw, such as the screw edge, the screw groove, the screw and the like by using clean cloth dipped in acetone, wherein the surface of the cleaned screw is free from water, oil, grease, dust, water scale, paint and other foreign matters.

2, sand blasting: protecting the non-spraying area by using an iron sheet, clamping the screw on a sand blasting turntable, wherein the sand blasting pressure is 0.4MPa, the sand grain is 46# zirconium corundum, the spraying distance is 100mm, the angles between a sand blasting nozzle and the screw are-67 degrees and 67 degrees, the rotating speed of the turntable is 200rpm, and the gun moving speed is 15 mm/s. The surface after sand blasting should be uniform, have no bright spots, no pollution, no depression and the like.

3, clamping the sand-blasted screw on a spraying turntable, starting the turntable, and uniformly preheating the screw to 350 ℃ by using an oxyacetylene remelting gun. Using a propane-oxygen flame spray gun, powder: 150/300 mesh Ni25WC, Ni25WC was sprayed uniformly onto the screw surface. The technological parameters are as follows: the oxygen pressure is 0.35MPa, the oxygen flow is 60%, the propane pressure is 0.24MPa, the propane flow is 25%, the powder feeding amount is 80g/min, the carrier gas is 6slpm, the rotating speed of a powder feeder is 2.5rpm, the rotating speed of a rotary table is 250rpm, the gun walking speed is 20mm/s, the spraying distance is 250mm, the coating thickness is 0.6mm, the angle between a spray gun and a screw is 90 degrees, -67 degrees and 67 degrees, and the coating is uniformly sprayed on the front and the back of a screw root 3 by adjusting the angle of the spray gun.

4, adopting neutral flame or slight carbonized flame of an oxyacetylene remelting gun to preheat the whole screw rod to 400-500 ℃, remelting the spray welding coating by using another remelting gun, moving the spray gun after the liquid metal is in mirror reflection, remelting the screw rod screw root 3 uniformly in front and back by adjusting the angle between the remelting gun and the screw rod, and immediately preserving heat and slowly cooling the workpiece after remelting.

And 5, polishing, namely clamping the remelted screw rod to a polishing turntable, and polishing the screw groove and the screw root of the screw rod by using a 60#, 200#, 400# diamond abrasive belt respectively until the roughness Ra is less than or equal to 0.4.

And 6, grinding, namely clamping the polished screw rod on a grinding machine, and grinding the screw edge to the required size. The thickness of the coating after grinding is 0.3 mm. As shown in fig. 2, the metallographic structure of the sprayed layer after spraying was shown.

Example 3:

the spray welding screw rod of the invention has the following preparation process:

1, cleaning: cleaning the spraying areas of the screw, such as the screw edge, the screw groove, the screw and the like by using clean cloth dipped in acetone, wherein the surface of the cleaned screw is free from water, oil, grease, dust, water scale, paint and other foreign matters.

2, sand blasting: protecting the non-spraying area by using an iron sheet, clamping the screw on a sand blasting turntable, wherein the sand blasting pressure is 0.4MPa, the sand grain is 46# zirconium corundum, the spraying distance is 100mm, the angles between a sand blasting nozzle and the screw are-67 degrees and 67 degrees, the rotating speed of the turntable is 200rpm, and the gun moving speed is 15 mm/s. The surface after sand blasting should be uniform, have no bright spots, no pollution, no depression and the like.

3, clamping the sand-blasted screw on a spraying turntable, starting the turntable, and uniformly preheating the screw to 350 ℃ by using an oxyacetylene remelting gun. Using a propane-oxygen flame spray gun, powder: 150/300 mesh Ni30WC, Ni30WC is evenly sprayed on the surface of the screw. The technological parameters are as follows: the oxygen pressure is 0.35MPa, the oxygen flow is 60%, the propane pressure is 0.24MPa, the propane flow is 25%, the powder feeding amount is 80g/min, the carrier gas is 6slpm, the rotating speed of a powder feeder is 2.5rpm, the rotating speed of a rotary table is 250rpm, the gun walking speed is 20mm/s, the spraying distance is 250mm, the coating thickness is 0.6mm, the angle between a spray gun and a screw is 90 degrees, -67 degrees and 67 degrees, and the coating is uniformly sprayed on the front and the back of a screw root 3 by adjusting the angle of the spray gun.

4, adopting neutral flame or slight carbonized flame of an oxyacetylene remelting gun to preheat the whole screw rod to 400-500 ℃, remelting the spray welding coating by using another remelting gun, moving the spray gun after the liquid metal is in mirror reflection, remelting the screw rod screw root 3 uniformly in front and back by adjusting the angle between the remelting gun and the screw rod, and immediately preserving heat and slowly cooling the workpiece after remelting.

And 5, polishing, namely clamping the remelted screw rod to a polishing turntable, and polishing the screw groove and the screw root of the screw rod by using a 60#, 200#, 400# diamond abrasive belt respectively until the roughness Ra is less than or equal to 0.4.

And 6, grinding, namely clamping the polished screw rod on a grinding machine, and grinding the screw edge to the required size. The thickness of the coating after grinding is 0.3 mm. As shown in fig. 3, the metallographic structure of the sprayed layer after spraying was shown.

The following table shows the comparison of the performance of the spray-welded coated screw rod and the common screw rod in the embodiment

	Hardness HV0.3	Porosity of coating	Thickness of coating	Service life of screw/month
					Example 1	940	2.7％	0.5	6
Example 2	930	2.8％	0.6	6
					Example 3	950	2.6％	0.6	6
38CrMoAl screw rod	285	/	/	3

The embodiments of the present invention have been described in detail, but the present invention is not limited to the described embodiments. It will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, and the scope of protection is still within the scope of the invention.