A process for hardfacing the surface of a milling bit used in well repair

Abstract

The application provides a process method for hard alloy surfacing on a milling bit tip surface for well repair, grooves are processed along a milling bit tip surface profile in a hard alloy surfacing position range on the milling bit tip tool surface; then the hard alloy surfacing position on the milling bit tip tool surface is preheated by using an oxygen-acetylene flame, a copper alloy layer is surfacing-welded as a transition layer; and a hard alloy surfacing layer is surfacing-welded at the hard alloy surfacing position on the milling bit tip tool surface containing the transition layer; the application optimizes the structure design and process of hard alloy particles on the milling bit tip, improves the bonding strength of the hard alloy layer and the milling bit tip base, reduces the residual stress of the hard alloy surfacing position, avoids the formation of cracks at the hard alloy surfacing position, reduces the hard alloy block falling and the milling bit tip fracture accidents, and improves the service life of the milling bit tip.

Description

Technical Field

[0001] This invention belongs to the field of well workover tool manufacturing in the oil and gas industry, and specifically relates to a process method for laying hard alloy welding rods on the surface of well workover tools. Background Technology

[0002] With the continuous development of technology, automation technology is being applied more and more widely in well workover operations. Well workover is a dangerous job due to the complex and variable downhole environment, and researchers need to pay attention to the safety performance of milling nib tips to prevent accidents. The choice of material for milling nib tips is crucial to the efficiency and durability of well workover operations. Currently, researchers are exploring new wear-resistant materials to improve the service life and performance of milling nib tips. Well workover operations typically involve cutting and grinding on high-strength rocks or downhole equipment surfaces, making the wear resistance of milling nib tips a critical issue. Insufficient wear resistance of the nib tip leads to frequent replacements, increasing well workover costs.

[0003] Furthermore, the milling function of a milling pen tip for grinding damaged tubing relies primarily on the hard alloy particles welded to its surface. Generally, milling pen tips are made with an alloy steel base, and then a layer of hard alloy particles is embedded or welded onto the milling location of the pen tip. Because hard alloy particles are hard and brittle, have weak impact resistance, and their properties differ significantly from the steel base, accidents such as particle detachment and breakage at the welded location of the milling pen tip are prone to occur during milling operations, severely affecting the service life and repair effectiveness of the milling pen tip. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a process for oxy-acetylene flame welding of hard alloy onto the surface of a well-working milling tip tool, thereby improving the bonding strength between the hard alloy and the steel substrate and reducing the occurrence of hard alloy weld layer detachment and milling tip breakage accidents.

[0005] This invention is achieved through the following technical solution:

[0006] A process for welding hard alloy onto the surface of a well-working milling pen tip, comprising,

[0007] S1, Determine the range of locations for hard alloy plating on the surface of the milling tool for pen tips;

[0008] S2, A groove is machined along the contour of the milling tool surface within the area where hard alloy is welded to the milling tool surface;

[0009] S3, after preheating the hard alloy position on the surface of the milling pen tip tool by using an oxy-acetylene flame, a copper alloy layer is then welded as a transition layer.

[0010] S4, weld a hard alloy brazing layer at the location where a hard alloy brazing layer is welded on the surface of the milling tool containing the transition layer, and complete the filling of the groove on the surface of the milling tool;

[0011] S5 involves inspecting and stress-relieving the milling pen tip tool after it has been completed with hard alloy welding, then applying anti-rust paint to the surface and marking it, thus completing the product processing of the milling pen tip tool.

[0012] Preferably, the distance between the hard alloy plating location and the tip of the milling pen is greater than 200mm; the distance between the hard alloy plating location and the disappearing thread portion of the milling pen tip connection is greater than 40mm.

[0013] Preferably, the groove has a depth of 1mm-3mm, and the groove transitions to the outer surface contour of the milled pen tip at an angle of 120°-160°.

[0014] Preferably, the preheating temperature is 200-400℃.

[0015] Preferably, the oxygen pressure in the oxygen-acetylene flame is 0.20 MPa-0.35 MPa; the acetylene pressure is 0.05-0.1 MPa, and the flow ratio of oxygen to acetylene is adjusted to 1.22-1.30:1.

[0016] Preferably, the thickness of the copper alloy layer is 0.2-1.0 mm.

[0017] Preferably, the copper alloy layer is made of copper-zinc welding wire with a diameter of 1.2mm-2mm.

[0018] Preferably, in step S4, the number of hard alloy solder layers is determined based on the target thickness of the solder layer for the milling pen tip tool.

[0019] If the target thickness of the cemented carbide weld layer is 7-12mm, then an oxy-acetylene flame is used to melt cemented carbide particles with a size of 1mm-3mm and weld the first cemented carbide layer to the cemented carbide location on the surface of the milling tool. The thickness of the first cemented carbide layer is 2mm-5mm, which completes the filling of the groove on the surface of the milling tool. Then, an oxy-acetylene flame is used to melt cemented carbide particles with a size of 3mm-5mm and weld a second cemented carbide layer on the first cemented carbide layer. The thickness of the second cemented carbide layer is 4mm-7mm, so that the total thickness of the cemented carbide weld layer meets the target layer requirement. During the welding process, the heating temperature of the milling tool tip substrate must not exceed 700℃.

[0020] If the target thickness of the hard alloy weld layer is 4-7mm, then use an oxy-acetylene flame to melt a welding rod with hard alloy particles of 1mm-3mm size and weld the first hard alloy layer at the hard alloy position on the surface of the milling tool. The thickness of the first hard alloy layer is 2mm-5mm, which completes the filling of the groove on the surface of the milling tool. During the welding process, the heating temperature of the milling tool substrate must not exceed 700℃.

[0021] Preferably, in step S5, the outer diameter of the milling pen tip with hard alloy brazing is controlled, detected, and processed by using the inner hole of the detection tool. The inner diameter of the detection tool is used as the reference for controlling the outer diameter of the milling pen tip, with a lower deviation of 0 mm and an upper deviation of 1.5 mm.

[0022] Ultrasonic testing was used to perform non-destructive testing on the bottom substrate of the hard alloy brazing layer of the milling tool. The reference sample was a 3mm groove, and no cracks extending to the milling tool substrate were allowed.

[0023] Preferably, the grinding and milling pen tip tool that has completed hard alloy welding is subjected to stress relief treatment by furnace heating, with a stress relief temperature of 300±20℃ and a holding time of 60min-90min, followed by furnace cooling.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects:

[0025] This invention provides a process for welding hard alloy onto the surface of a workover nib tip. To improve the bonding performance between the hard alloy particles and the steel substrate, and to extend the service life of the hard alloy layer, a groove is machined along the contour of the workover nib tip tool surface within the area where the hard alloy is to be welded. Then, after preheating the hard alloy area on the workover nib tool surface using an oxy-acetylene flame, a copper alloy layer is welded as a transition layer. A hard alloy weld layer is then welded onto the workover nib tool surface containing the transition layer at the hard alloy area. This improves the bonding strength between the hard alloy and the steel substrate, reduces the occurrence of hard alloy weld layer detachment and workover nib tip breakage, thereby extending the service life of the workover nib tool. This invention optimizes the structural design and process of the hard alloy particles used for welding the workover nib tip, enhances the bonding strength between the hard alloy layer and the workover nib tip substrate, reduces residual stress at the hard alloy weld area, avoids the formation of cracks at the weld area, reduces the occurrence of hard alloy block detachment and workover nib tip breakage, and ultimately extends the service life of the workover nib tip.

[0026] Furthermore, the process method of the present invention determines the number of hard alloy solder layers based on the target thickness of the solder layer of the milling pen tip tool. If the target thickness of the solder layer is 7-12mm, two layers are used for soldering. If the target thickness of the solder layer is 4-7mm, one layer is used for soldering, so that the total thickness of the hard alloy solder layer meets the target layer requirements.

[0027] Furthermore, the distance between the welding range and the tip of the milling pen should be greater than 200mm, and the distance between the welding range and the point where the connecting thread of the milling pen tip disappears should be greater than 40mm, so as to reduce the impact of the heat input of the welded hard alloy on the substrate at both ends of the milling pen tip. Attached Figure Description

[0028] Figure 1 A process flow diagram for applying hard alloy to the surface of a milling tool tip for well repair;

[0029] Figure 2 This is a schematic diagram of milling a pen tip. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0031] (1) As Figure 1 and Figure 2 As shown, first determine the range 1 of the hard alloy plating position on the surface of the milling pen tip tool. The distance between the plating range and the tip 2 of the milling pen tip should be greater than 200mm, and the distance from the disappearance of the connecting thread 3 of the milling pen tip should be greater than 40mm, so as to reduce the impact of the heat input of the hard alloy plating on the substrate at both ends of the milling pen tip.

[0032] (2) A groove with a depth of 1mm-3mm is machined along the contour of the tool surface within the range 1 of hard alloy welding on the surface of the milling pen tip tool. The groove transitions to the outer surface contour of the milling pen tip at 120°-160°.

[0033] (3) Use an oxy-acetylene flame to uniformly preheat the milling tip welding position to 200-400℃, and use copper-zinc welding wire with a diameter of 1.2mm-2mm to uniformly weld a copper alloy layer with a thickness of about 0.2-1.0mm as a transition layer;

[0034] (4) It should be further explained that the oxygen pressure is 0.20MPa-0.35MPa and the acetylene pressure is 0.05-0.1MPa. The flow ratio of oxygen and acetylene should be adjusted to about 1.22-1.30:1 to control the flame for preheating and copper wire transition layer laying.

[0035] (5) Determine the number of welding layers based on the target thickness of the welding layer of the milling pen tip tool. If the target thickness of the welding layer is 7-12mm, use the two-layer method in steps (6)-(7) to perform welding. If the target thickness of the welding layer is 4-7mm, use step (7) to perform welding.

[0036] (6) Adjust the flow ratio of oxygen and acetylene to approximately 1.12-1.16:1, control the flame for welding, select a hard alloy electrode with a particle size of 1mm-3mm, melt the electrode metal at a distance of approximately 2mm-10mm from the flame core and evenly lay a hard alloy layer, with a thickness of 2mm-5mm, to complete the filling of the machined groove on the surface of the milling tool. During the laying process, the heating temperature of the milling pen tip substrate must not exceed 700℃.

[0037] (7) Use a flame about 2mm-10mm away from the flame core to melt the hard alloy particles with a size of 3mm-5mm. Evenly lay a hard alloy layer. The thickness of the hard alloy layer with a size of 3mm-5mm is 4mm-7mm, so that the total thickness of the hard alloy layer meets the target layer requirements.

[0038] (8) For milling tips with hard alloy plating, the outer diameter of the weld layer of the milling tip with hard alloy plating is controlled and processed by means of the inner hole of the detection tool. The inner diameter of the detection tool is used as the reference for the control value of the outer diameter of the milling tip, with a lower deviation of 0mm and an upper deviation of 1.5mm.

[0039] (9) The substrate at the bottom of the hard alloy weld layer of the milled pen tip was subjected to non-destructive testing using ultrasonic testing. The reference sample for testing was a 3mm groove, and no cracks extending to the substrate of the milled pen tip were allowed.

[0040] (10) For the milled pen tip that has been completed by hard alloy welding, stress relief treatment is carried out by furnace heating. The stress relief temperature is 300±20℃, the holding time is 60min-90min, and the furnace is cooled.

[0041] (11) Apply anti-rust paint to the surface, mark it, and complete the milling and grinding of the pen tip product;

[0042] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0043] Example 1:

[0044] Using this process, a 11mm thick cemented carbide layer is welded onto the surface of a Φ60-110mm milled pen tip. The specific scheme is as follows:

[0045] (1) First, determine the location range 1 of the hard alloy plating on the surface of the milling tool tip. The plating range is 300mm away from the tip 2 of the milling tool tip and 50mm away from the point where the connecting thread 3 of the milling tool tip disappears, in order to reduce the impact of the heat input of the hard alloy plating on the substrate at both ends of the milling tool tip. Figure 1 As shown;

[0046] (2) A groove with a depth of 2mm is machined along the contour of the tool surface within the range 1 of the hard alloy welded on the surface of the milling pen tip tool. The groove transitions to the outer surface contour of the milling pen tip at 120°.

[0047] (3) Use an oxy-acetylene flame to uniformly preheat the milling tip welding position to 300°C, and use a copper-zinc welding wire with a diameter of 1.2 mm to uniformly weld a copper alloy layer with a thickness of about 0.5 mm as a transition layer.

[0048] (4) It should be further explained that the oxygen pressure is 0.20 MPa and the acetylene pressure is 0.05 MPa. The flow ratio of oxygen and acetylene is adjusted to about 1.25:1 to control the flame for preheating and copper wire transition layer welding.

[0049] (5) A two-layer welding method is adopted based on the target thickness of the welding layer of the milling pen tip tool;

[0050] (6) Adjust the flow ratio of oxygen and acetylene to about 1.14:1, control the flame for welding, select a welding rod with a hard alloy particle size of 2mm, use the flame to melt the welding rod metal about 5mm away from the flame core and evenly lay a hard alloy layer, the thickness of the layer is 4mm, and complete the filling of the machined groove on the surface of the milling tool. During the laying process, the heating temperature of the milling pen tip substrate shall not exceed 700℃.

[0051] (7) Use a flame about 5mm from the flame core to melt the 4mm hard alloy particles in the weld layer, and uniformly lay a hard alloy layer. The thickness of the 4mm hard alloy weld layer is 7mm, so that the total thickness of the hard alloy weld layer meets the target layer requirements.

[0052] (8) For the grinding pen tip that has completed hard alloy brazing, the outer diameter of the hard alloy brazing layer of the grinding pen tip is controlled and processed by means of the inner hole of the detection tool. The inner diameter of the detection tool is used as the reference for the control value of the outer diameter of the grinding pen tip tool, with a lower deviation of 0mm and an upper deviation of 1.5mm.

[0053] (9) The substrate at the bottom of the hard alloy weld layer of the milled pen tip was subjected to non-destructive testing using ultrasonic testing. The reference sample for testing was a 3mm groove, and no cracks extending to the substrate of the milled pen tip were allowed.

[0054] (10) For the milled pen tip that has been completed by hard alloy welding, stress relief treatment is carried out by furnace heating. The stress relief temperature is 320℃, the holding time is 90min, and it is cooled with the furnace.

[0055] (11) Apply anti-rust paint to the surface, mark it, and complete the milling and grinding of the pen tip product;

[0056] Example 2

[0057] Using this process, an 8mm thick cemented carbide layer is welded onto the surface of the Φ60-106 milled pen tip. The specific scheme is as follows:

[0058] (1) First, determine the location range 1 of the hard alloy plating on the surface of the milling pen tip tool. The plating range is 500mm away from the tip 2 of the milling pen tip and 60mm away from the point where the connecting thread 3 of the milling pen tip disappears, in order to reduce the impact of the heat input of the hard alloy plating on the substrate at both ends of the milling pen tip. Figure 1 As shown;

[0059] (2) A groove with a depth of 3mm is machined along the contour of the tool surface within the range 1 of hard alloy welding on the surface of the milling pen tip tool. The groove transitions to the outer surface contour of the milling pen tip at 160°.

[0060] (3) Use an oxy-acetylene flame to uniformly preheat the milling tip welding position to 400°C, and use a copper-zinc welding wire with a diameter of 1.6 mm to uniformly weld a copper alloy layer with a thickness of about 0.7 mm as a transition layer.

[0061] (4) It should be further explained that the oxygen pressure is 0.25 MPa and the acetylene pressure is 0.06 MPa. The flow ratio of oxygen and acetylene is adjusted to about 1.30:1 to control the flame for preheating and copper wire transition layer laying.

[0062] (5) Based on the target thickness of the solder layer for the milling tip tool, it is determined that two solder layers should be used for soldering;

[0063] (6) Adjust the flow ratio of oxygen and acetylene to about 1.16:1, control the flame for welding, select a welding rod with a hard alloy particle size of 3mm, use the flame to melt the welding rod metal at a distance of about 10mm from the flame core and evenly lay a layer of hard alloy, the thickness of the laying layer is 5mm, and complete the filling of the machined groove on the surface of the milling tool. During the laying process, the heating temperature of the milling pen tip substrate shall not exceed 700℃.

[0064] (7) Use a flame about 10mm from the flame core to melt the hard alloy particles with a size of 5mm. Then, evenly lay a hard alloy layer. The thickness of the 5mm hard alloy layer is 5mm, so that the total thickness of the hard alloy layer meets the target layer requirements.

[0065] (8) For the grinding pen tip that has completed hard alloy brazing, the outer diameter of the hard alloy brazing layer of the grinding pen tip is controlled and processed by means of the inner hole of the detection tool. The inner diameter of the detection tool is used as the reference for the control value of the outer diameter of the grinding pen tip tool, with a lower deviation of 0mm and an upper deviation of 1.5mm.

[0066] (9) The substrate at the bottom of the hard alloy weld layer of the milled pen tip was subjected to non-destructive testing using ultrasonic testing. The reference sample for testing was a 3mm groove, and no cracks extending to the substrate of the milled pen tip were allowed.

[0067] (10) For the milled pen tip that has been completed by hard alloy welding, stress relief treatment is carried out by furnace heating. The stress relief temperature is 280℃, the holding time is 60min, and it is cooled with the furnace.

[0068] (11) Apply anti-rust paint to the surface, mark it, and complete the milling and grinding of the pen tip product;

[0069] Example 3

[0070] Using this process, a 5mm thick cemented carbide layer is welded onto the surface of the Φ40-95 milled pen tip. The specific details are as follows:

[0071] (1) First, determine the location range 1 of the hard alloy plating on the surface of the milling tool tip. The plating range is 200mm away from the tip 2 of the milling tool tip and 40mm away from the disappearance of the connecting thread 3 of the milling tool tip, in order to reduce the impact of the heat input of the hard alloy plating on the substrate at both ends of the milling tool tip. Figure 1 As shown;

[0072] (2) A groove with a depth of 1 mm is machined along the contour of the tool surface within the range 1 of the hard alloy welded on the surface of the milling pen tip tool. The groove transitions to the outer surface contour of the milling pen tip at 150°.

[0073] (3) Use an oxy-acetylene flame to uniformly preheat the milling tip welding position to 200°C, and use a copper-zinc welding wire with a diameter of 2mm to uniformly weld a copper alloy layer with a thickness of about 0.6mm as a transition layer.

[0074] (4) It should be further explained that the oxygen pressure is 0.35 MPa and the acetylene pressure is 0.1 MPa. The flow ratio of oxygen and acetylene is adjusted to about 1.22:1 to control the flame for preheating and copper wire transition layer welding.

[0075] (5) Select single-layer welding based on the target thickness of the welding layer for the milling pen tip tool;

[0076] (6) Adjust the flow ratio of oxygen and acetylene to about 1.12:1, control the flame for welding, use the flame to melt the hard alloy particles with a size of 3mm within a range of about 2mm from the flame core, and evenly lay a hard alloy layer. The thickness of the 3mm hard alloy layer is 5mm, so that the total thickness of the hard alloy layer meets the target layer requirements. The heating temperature of the grinding and milling pen tip substrate during the laying process shall not exceed 700℃.

[0077] (8) For the grinding pen tip that has completed hard alloy brazing, the outer diameter of the hard alloy brazing layer of the grinding pen tip is controlled and processed by means of the inner hole of the detection tool. The inner diameter of the detection tool is used as the reference for the control value of the outer diameter of the grinding pen tip tool, with a lower deviation of 0mm and an upper deviation of 1.5mm.

[0078] (9) The substrate at the bottom of the hard alloy weld layer of the milled pen tip was subjected to non-destructive testing using ultrasonic testing. The reference sample for testing was a 3mm groove, and no cracks extending to the substrate of the milled pen tip were allowed.

[0079] (10) For the milled pen tip that has been completed by hard alloy welding, stress relief treatment is carried out by furnace heating. The stress relief temperature is 300℃, the holding time is 80min, and it is cooled with the furnace.

[0080] (11) Apply anti-rust paint to the surface, mark it, and complete the milling and grinding of the pen tip product;

[0081] Example 4

[0082] Using this process, a 4mm thick cemented carbide layer is welded onto the surface of the Φ40-95 milled pen tip. The specific details are as follows:

[0083] (1) First, determine the location range 1 of the hard alloy plating on the surface of the milling tool tip. The plating range is 200mm away from the tip 2 of the milling tool tip and 40mm away from the disappearance of the connecting thread 3 of the milling tool tip, in order to reduce the impact of the heat input of the hard alloy plating on the substrate at both ends of the milling tool tip. Figure 1 As shown;

[0084] (2) A groove with a depth of 1 mm is machined along the contour of the tool surface within the range 1 of the hard alloy welded on the surface of the milling pen tip tool. The groove transitions to the outer surface contour of the milling pen tip at 120°.

[0085] (3) Use an oxy-acetylene flame to uniformly preheat the milling tip welding position to 220°C, and use a copper-zinc welding wire with a diameter of 1.2 mm to uniformly weld a copper alloy layer with a thickness of about 0.2 mm as a transition layer;

[0086] (4) It should be further explained that the oxygen pressure is 0.20 MPa and the acetylene pressure is 0.05 MPa. The flow ratio of oxygen and acetylene is adjusted to about 1.22:1 to control the flame for preheating and copper wire transition layer laying.

[0087] (5) Select single-layer welding based on the target thickness of the welding layer for the milling pen tip tool;

[0088] (6) Adjust the flow ratio of oxygen and acetylene to about 1.12:1, control the flame for welding, use the flame to melt the hard alloy particles with a size of 3mm within a range of about 2mm from the flame core, and evenly lay a hard alloy layer. The thickness of the 3mm hard alloy layer is 4mm, so that the total thickness of the hard alloy layer meets the target layer requirements. The heating temperature of the grinding and milling pen tip substrate during the laying process shall not exceed 700℃.

[0089] (8) For the grinding pen tip that has completed hard alloy brazing, the outer diameter of the hard alloy brazing layer of the grinding pen tip is controlled and processed by means of the inner hole of the detection tool. The inner diameter of the detection tool is used as the reference for the control value of the outer diameter of the grinding pen tip tool, with a lower deviation of 0mm and an upper deviation of 1.5mm.

[0090] (9) The substrate at the bottom of the hard alloy weld layer of the milled pen tip was subjected to non-destructive testing using ultrasonic testing. The reference sample for testing was a 3mm groove, and no cracks extending to the substrate of the milled pen tip were allowed.

[0091] (10) For the milled pen tip that has been completed by hard alloy welding, stress relief treatment is carried out by furnace heating. The stress relief temperature is 310℃, the holding time is 60min, and it is cooled with the furnace.

[0092] (11) Apply anti-rust paint to the surface, mark it, and complete the milling and grinding of the pen tip product;

[0093] Example 5

[0094] Using this process, a 7mm thick cemented carbide layer is welded onto the surface of the Φ40-95 milled pen tip. The specific details are as follows:

[0095] (1) First, determine the location range 1 of the hard alloy plating on the surface of the milling pen tip tool. The distance from the plating range to the tip 2 of the milling pen tip is 210mm, and the distance from the point where the connecting thread 3 of the milling pen tip disappears is 45mm, in order to reduce the impact of the heat input of the hard alloy plating on the substrate at both ends of the milling pen tip. Figure 1 As shown;

[0096] (2) A groove with a depth of 1.5 mm is machined along the contour of the tool surface within the range 1 of the hard alloy welded on the surface of the milling pen tip tool. The groove transitions to the outer contour of the milling pen tip at 130°.

[0097] (3) Use an oxy-acetylene flame to uniformly preheat the milling tip welding position to 220°C, and use a copper-zinc welding wire with a diameter of 1.4 mm to uniformly weld a copper alloy layer with a thickness of about 0.4 mm as a transition layer.

[0098] (4) It should be further explained that the oxygen pressure is 0.25 MPa and the acetylene pressure is 0.80 MPa. The flow ratio of oxygen and acetylene is adjusted to about 1.26:1 to control the flame for preheating and copper wire transition layer welding.

[0099] (5) Select single-layer welding based on the target thickness of the welding layer for the milling pen tip tool;

[0100] (6) Adjust the flow ratio of oxygen and acetylene to about 1.13:1, control the flame for welding, use the flame to melt the hard alloy particles with a size of 5mm within a range of about 4mm from the flame core, and evenly lay the first hard alloy layer. The thickness of the 5mm hard alloy layer is 7mm, so that the total thickness of the hard alloy layer meets the target layer requirements. The heating temperature of the grinding and milling pen tip substrate during the laying process shall not exceed 700℃.

[0101] (8) For the grinding pen tip that has completed hard alloy brazing, the outer diameter of the hard alloy brazing layer of the grinding pen tip is controlled and processed by means of the inner hole of the detection tool. The inner diameter of the detection tool is used as the reference for the control value of the outer diameter of the grinding pen tip tool, with a lower deviation of 0mm and an upper deviation of 1.5mm.

[0102] (9) The substrate at the bottom of the hard alloy weld layer of the milled pen tip was subjected to non-destructive testing using ultrasonic testing. The reference sample for testing was a 3mm groove, and no cracks extending to the substrate of the milled pen tip were allowed.

[0103] (10) For the milled pen tip that has been completed by hard alloy welding, stress relief treatment is carried out by furnace heating. The stress relief temperature is 320℃, the holding time is 70min, and it is cooled with the furnace.

[0104] (11) Apply anti-rust paint to the surface, mark it, and complete the milling and grinding of the pen tip product;

[0105] Example 6

[0106] Using this process, a 14mm thick cemented carbide layer is welded onto the surface of the Φ60-106 milled pen tip. The specific scheme is as follows:

[0107] (1) First, determine the location range 1 of the hard alloy plating on the surface of the milling pen tip tool. The distance from the plating range to the tip 2 of the milling pen tip is 450mm, and the distance from the point where the connecting thread 3 of the milling pen tip disappears is 55mm, in order to reduce the impact of the heat input of the hard alloy plating on the substrate at both ends of the milling pen tip. Figure 1 As shown;

[0108] (2) A groove with a depth of 2.5 mm is machined along the contour of the tool surface within the range 1 of the hard alloy welded on the surface of the milling pen tip tool. The groove transitions to the outer contour of the milling pen tip at 140°.

[0109] (3) Use an oxy-acetylene flame to preheat the milling tip welding position to 350°C. Use a copper-zinc welding wire with a diameter of 2mm to evenly weld a copper alloy layer with a thickness of about 1.0mm as a transition layer.

[0110] (4) It should be further explained that the oxygen pressure is 0.35 MPa and the acetylene pressure is 0.1 MPa. The flow ratio of oxygen and acetylene is adjusted to about 1.30:1 to control the flame for preheating and copper wire transition layer welding.

[0111] (5) Based on the target thickness of the solder layer for the milling tip tool, it is determined that two solder layers should be used for soldering;

[0112] (6) Adjust the flow ratio of oxygen and acetylene to about 1.16:1, control the flame for welding, select a welding rod with a hard alloy particle size of 3mm, use the flame to melt the welding rod metal about 8mm away from the flame core and evenly lay the first hard alloy layer, the thickness of the laying layer is 4mm, and complete the filling of the machined groove on the surface of the milling tool. During the laying process, the heating temperature of the milling pen tip substrate must not exceed 700℃.

[0113] (7) Use a flame about 8mm from the flame core to melt the 4mm hard alloy particles in the weld layer, and uniformly lay the second hard alloy layer. The thickness of the 4mm hard alloy weld layer is 7mm, so that the total thickness of the hard alloy weld layer meets the target layer requirements.

[0114] (8) For the grinding pen tip that has completed hard alloy brazing, the outer diameter of the hard alloy brazing layer of the grinding pen tip is controlled and processed by means of the inner hole of the detection tool. The inner diameter of the detection tool is used as the reference for the control value of the outer diameter of the grinding pen tip tool, with a lower deviation of 0mm and an upper deviation of 1.5mm.

[0115] (9) The substrate at the bottom of the hard alloy weld layer of the milled pen tip was subjected to non-destructive testing using ultrasonic testing. The reference sample for testing was a 3mm groove, and no cracks extending to the substrate of the milled pen tip were allowed.

[0116] (10) For the milled pen tip that has been completed by hard alloy welding, stress relief treatment is carried out by furnace heating. The stress relief temperature is 300℃, the holding time is 90min, and it is cooled with the furnace.

[0117] (11) Apply anti-rust paint to the surface, mark it, and complete the milling and grinding of the pen tip product;

[0118] The inner hole of the inspection tool can ensure that the outer diameter of the weld layer meets the requirements, thereby guaranteeing the quality and performance of the milling pen tip.

[0119] The following are the steps to perform this detection method:

[0120] 1. Prepare the testing tools: First, you need to prepare a suitable testing tool. This tool is usually an internal bore gauge or caliper with precise measuring scale. Ensure the accuracy and stability of the tool to guarantee the accuracy of the measurement results.

[0121] 2. Insert the milling tip into the inner hole of the testing tool: Place the milling tip to be tested into the inner hole of the testing tool. Ensure that the tip is in full contact with the tool's inner hole and that there is no looseness or rotation.

[0122] 3. Perform measurement: Use a suitable handheld measuring tool (such as a vernier caliper) or digital measuring instrument to measure the outer diameter of the weld layer on the milling tip. In the method of internal hole inspection, the outer diameter of the weld layer can be indirectly obtained by measuring the diameter of the internal hole.

[0123] 4. Check the measurement results: Compare the measurement results with the design requirements or specifications. If the outer diameter of the weld layer is within the allowable range, the milled pen tip is considered to have passed the inspection and can continue with subsequent processes; if it exceeds the specified allowable range, appropriate handling measures are required.

[0124] 5. Handling Non-conforming Products: If the outer diameter of the weld layer on the milled pen tip is found to be non-compliant, measures should be taken promptly to address the issue. Possible solutions include re-welding, re-grinding, or discarding the non-conforming product to ensure product quality.

[0125] 6. Record test results: Accurate records must be kept for the test results of each milling pen tip. These records will help track product quality and conduct quality control analysis.

[0126] Using internal bore inspection to control the outer diameter of the weld layer in milled pen tips is a commonly used non-destructive testing method. This allows for real-time monitoring of product quality during production, enabling timely detection and resolution of problems. Ensuring that the outer diameter of the weld layer in milled pen tips meets requirements helps improve product quality and lifespan.

[0127] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0128] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A process for welding hard alloy onto the surface of a well-working milling pen tip, characterized in that, include, S1, Determine the range of locations for hard alloy plating on the surface of the milling tool for pen tips; S2, A groove is machined along the contour of the milling tool surface within the area where hard alloy is welded to the milling tool surface; S3, after preheating the hard alloy position on the surface of the milling pen tip tool by using an oxy-acetylene flame, a copper alloy layer is then welded as a transition layer. S4, weld a hard alloy layer at the location where a hard alloy layer is welded on the surface of the milling tool containing the transition layer, and complete the filling of the groove on the surface of the milling tool; S5. After inspecting and stress-relieving the milling pen tip tool that has completed hard alloy welding, apply anti-rust paint to the surface and mark it to complete the product processing of the milling pen tip tool. In S4, the number of hard alloy solder layers is determined based on the target thickness of the solder layer for the milling pen tip tool. If the target thickness of the cemented carbide weld layer is 7-12mm, then an oxy-acetylene flame is used to melt cemented carbide particles with a size of 1mm-3mm and weld the first cemented carbide layer to the cemented carbide location on the surface of the milling tool. The thickness of the first cemented carbide layer is 2mm-5mm, which completes the filling of the groove on the surface of the milling tool. Then, an oxy-acetylene flame is used to melt cemented carbide particles with a size of 3mm-5mm and weld a second cemented carbide layer on the first cemented carbide layer. The thickness of the second cemented carbide layer is 4mm-7mm, so that the total thickness of the cemented carbide weld layer meets the target layer requirement. During the welding process, the heating temperature of the milling tool tip substrate must not exceed 700℃. If the target thickness of the hard alloy weld layer is 4-7mm, then use an oxy-acetylene flame to melt a welding rod with hard alloy particles of 3mm-5mm in size, and weld a hard alloy layer at the location where the hard alloy is to be welded on the surface of the milling tool. The thickness of the hard alloy layer is 4mm-7mm, so that the total thickness of the hard alloy weld layer meets the target layer requirements; and the heating temperature of the milling tool substrate during the welding process must not exceed 700℃. The distance between the location of the hard alloy plating and the tip of the milling pen is greater than 200mm; the distance between the location of the hard alloy plating and the disappearing part of the connecting thread of the milling pen tip is greater than 40mm; The groove has a depth of 1mm-3mm and transitions to the outer surface contour of the milled pen tip at an angle of 120°-160°. The preheating temperature is 200-400℃; The grinding pen tip tool with hard alloy brazing was subjected to stress relief treatment by furnace heating. The stress relief temperature was 300±20℃, the holding time was 60min-90min, and it was cooled in the furnace.

2. The process for welding hard alloy onto the surface of a well-working milling pen tip according to claim 1, characterized in that, The oxygen pressure in the oxygen-acetylene flame is 0.20 MPa-0.35 MPa; the acetylene pressure is 0.05-0.1 MPa, and the flow ratio of oxygen to acetylene is adjusted to 1.22-1.30:

1.

3. The process for welding hard alloy onto the surface of a well-working milling pen tip according to claim 1, characterized in that, The thickness of the copper alloy layer is 0.2-1.0 mm.

4. The process for welding hard alloy onto the surface of a well-working milling pen tip according to claim 1, characterized in that, The copper alloy layer is laid using copper-zinc welding wire with a diameter of 1.2mm-2mm.

5. The process for welding hard alloy onto the surface of a well-working milling pen tip according to claim 1, characterized in that, In S5, the outer diameter of the milling pen tip with hard alloy brazing is controlled, detected, and processed by using the inner hole of the detection tool. The inner diameter of the detection tool is used as the reference for controlling the outer diameter of the milling pen tip, with a lower deviation of 0 mm and an upper deviation of 1.5 mm. The bottom substrate of the hard alloy brazing layer of the milling tool was non-destructively tested using ultrasonic testing. The reference sample was a 3mm groove, and no cracks extending to the milling tool substrate were allowed.

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