Manufacturing method of cobalt-based alloy glass mold punch

Abstract

The invention relates to the technical field of glass mold manufacturing, in particular to a manufacturing method of a cobalt-based alloy glass mold punch, which adopts a cobalt-based alloy welding wire made of the same material as a punch body for surfacing, eliminates the material difference between a base material and a surfacing layer, and avoids the defects of insufficient interface bonding force, microcracks and the like. Interlayer stress concentration is reduced through the segmented symmetrical surfacing welding technology, the overall hardness of the punch is uniform, and the surface abrasion resistance is stable; the red copper rod serves as a built-in forming core mold, the forming space of the punch head is precisely limited, and the problem that the surfacing thickness of a complex curved surface is not uniform is solved. After surfacing, the requirement can be met by only needing a small amount of finish machining allowance, the machining cost is reduced, and the consistency of batch production is improved; the whole punch is made of a cobalt-based alloy material, the thermal expansion coefficient is uniform and consistent, and netlike cracks cannot occur under frequent hot and cold circulation. And the red copper core mold can rapidly conduct heat in the welding process, local overheating softening of a surfacing layer is avoided, and the adaptability of the punch under the ultrahigh-temperature working condition is improved.

Description

Technical Field

[0001] This invention relates to the field of glass mold manufacturing technology, and in particular to a method for manufacturing a cobalt-based alloy glass mold punch. Background Technology

[0002] Glass mold punches are essential mold components in the production of glass bottles and jars. They are mainly used in the small-mouth blow molding (NNPB) and press-blow molding (P&B) processes. They press high-temperature molten glass into the primary mold and the mouth mold to form the bottle mouth and the end face of the bottle head, and to create air cavities, providing a precise glass prototype for subsequent blow molding.

[0003] 1. Main functions

[0004] Bottle neck forming: determines key dimensions and shapes such as the inner diameter of the glass bottle neck, threads, and sealing surface.

[0005] Cavitation creation: Creating cavities inside the glass prototype to provide channels for backflow of air.

[0006] Heat transfer: By periodically contacting the high-temperature glass material at high frequencies (above 1100℃), heat is evenly removed from the glass surface, ensuring the stability of the glass prototype.

[0007] Glass distribution: The glass material is evenly distributed within the initial mold cavity to ensure uniform wall thickness of the glass product.

[0008] 2. Work Process

[0009] The initial mold closes, and the glass droplet enters the mold cavity.

[0010] The die is lifted, and the punch moves upward to press into the prototype die.

[0011] The punch presses the glass material to form the bottle neck and preform, while simultaneously creating cavities.

[0012] Compressed air enters through a cavitation chamber and blows the glass into the desired shape.

[0013] The punch retracts, the initial mold opens, and the prototype is transferred to the final mold to complete the final shaping.

[0014] 3. Main Manufacturing Process

[0015] Substrate processing: Precision CNC machining to ensure dimensional accuracy and surface roughness.

[0016] Heat treatment: tempering improves the strength and hardness of the substrate, and aging treatment eliminates internal stress.

[0017] Surface coating: Wear-resistant coatings are applied using processes such as laser cladding and plasma welding.

[0018] Precision grinding: Ensures surface precision and reduces adhesion between glass and punch.

[0019] Cooling system assembly: spiral pipe welding to ensure sealing and cooling efficiency.

[0020] Quality inspection: dimensional inspection, hardness testing, coating adhesion testing

[0021] 4. Advanced surface treatment technology

[0022] Laser cladding: cladding layer hardness HRC45-62, dilution rate ≤3%, single-pass thickness 0.8-2.0mm, suitable for complex shapes.

[0023] Plasma cladding: Ni25 nickel-based self-fluxing alloy powder, with good high-temperature stability and a service life extended by 3-5 times.

[0024] Ceramic coatings: Materials such as alumina and zirconium oxide, which are resistant to high temperatures and wear, making them suitable for high-end applications.

[0025] Carburizing / nitriding treatment: Improves surface hardness, enhances wear resistance, and has a lower cost.

[0026] The shortcomings of existing technology are as follows:

[0027] The weld overlay and the substrate (such as hot work die steel or cast iron) have a metallurgical interface. If the welding parameters are not appropriate, defects such as insufficient bonding strength, microcracks, and porosity are likely to occur. Under high-temperature cycling, the interface is prone to peeling. Multi-layer weld overlay is prone to uneven hardness between layers, resulting in large fluctuations in surface wear resistance.

[0028] Stress concentration zones easily form at the overlap of weld overlays, leading to preferential cracking under thermal fatigue. Welding deformation occurs after overlay, especially with thin-walled and irregularly shaped punches, making deformation difficult to control and requiring increased machining allowances in subsequent finishing processes. The thickness of the weld overlay is limited by process constraints (typically 0.5–3 mm), failing to meet the requirements for ultra-thick wear-resistant layers. When overlaying complex curved surfaces of punches (such as the threaded area at the bottle neck), uneven coating thickness is prone to occur, affecting the bottle neck forming accuracy. The thermal expansion coefficients of the substrate and the weld overlay are mismatched (e.g., the linear expansion coefficient of steel substrate is approximately 12 × 10⁻⁻⁻⁴). 6 / ℃, cobalt-based alloy approximately 14×10⁻ 6 Under frequent hot and cold cycles (temperatures around ℃), the weld overlay is prone to network cracks. If the cooling system is poorly designed, the heat from the weld overlay cannot be quickly conducted to the substrate, causing the surface to overheat and soften, accelerating the adhesion of molten glass. After the weld overlay is worn or cracked, it can be repaired by secondary welding, but the dimensional accuracy decreases after repair, requiring re-grinding, which is time-consuming. The weld overlay process requires high operator skill, labor costs account for a large proportion, and consistency is difficult to guarantee in mass production. High quality cooling water is also crucial; impurities in the cooling water can easily lead to substrate corrosion, indirectly affecting the adhesion of the weld overlay.

[0029] Therefore, there is an urgent need to design a method for manufacturing cobalt-based alloy glass mold punches to solve the above problems. Summary of the Invention

[0030] The purpose of this invention is to solve the technical problems existing in the prior art and to provide a method for manufacturing a cobalt-based alloy glass mold punch.

[0031] This invention provides a method for manufacturing a cobalt-based alloy glass mold punch, comprising the following steps:

[0032] Step S100: The punch body is made of cobalt-based alloy material through precision casting process. The head of the punch body has a reserved inner hole structure, and the inner hole size is determined according to the design parameters of the finished punch head.

[0033] Step S200: Select a copper rod and process one end into a ball head. The diameter of the ball head is smaller than the inner diameter of the punch body head. Coat the surface of the ball head with an inorganic high-temperature resistant coating of 0.05-0.1 mm. After coating, place it in a ventilated environment to dry naturally.

[0034] Step S300: Place the precision-cast punch body into a heat treatment furnace and heat it to 200°C at a heating rate of 5-8°C / min. Hold it at that temperature for at least 30 minutes. Remove the punch from the furnace after holding it at that temperature.

[0035] Step S400: Insert the dried copper rod into the bottom of the punch body until the ball of the copper rod is completely exposed from the inner hole of the punch body, and the exposed length is consistent with the height of the protrusion of the finished punch head.

[0036] Step S500: Using cobalt-based alloy welding wire of the same material as the punch body, adjust the tungsten inert gas (TIG) welding process parameters: welding current 100-140A, arc voltage 10-15V, welding speed 80-200mm / min, shielding gas argon with purity ≥99.99%, and gas flow rate 15-20L / min; perform overlay welding along the inner hole of the punch head and the outer side of the ball head.

[0037] Step S600: After the welding is completed, remove the copper rod and immediately place the punch workpiece into the heat preservation furnace to cool it to room temperature at a cooling rate of 2-3℃ / min.

[0038] Step S700: The punch workpiece after slow cooling is subjected to CNC turning and grinding to ensure that the dimensional accuracy and surface roughness of the punch meet the requirements of the finished product.

[0039] Preferably, the chemical composition of the cobalt-based alloy in step S100 is as follows (by mass percentage): C 0.9-1.8%, Cr 20-30%, W 3.5-15%, Ni ≤ 3%, Fe ≤ 3%, with the balance being Co.

[0040] Preferably, the inorganic high-temperature resistant coating in step S200 is an alumina-zirconia composite coating with a temperature resistance of ≥1500℃.

[0041] Preferably, in step S500, during the welding process, a segmented symmetrical welding method is adopted, with each segment having a welding length of 20-30mm, or a continuous welding method is adopted, wherein the interlayer temperature is controlled below 800℃ during continuous welding to avoid local overheating of the punch body.

[0042] Preferably, after step S700, a quality inspection step is also included, and the inspection items include dimensional accuracy inspection, hardness inspection, coating adhesion inspection and thermal fatigue performance test; among which, the hardness inspection requires the surface hardness of the punch to reach HRC40-55, and the adhesion test adopts the tensile method, with a adhesion strength ≥450MPa.

[0043] Preferably, the precision casting process in step S100 is vacuum lost-wax casting, the shell is a silica sol shell, the shell baking temperature is 900-1050℃, the baking time is 1-2h; the alloy melting vacuum degree is ≤5Pa, and the casting temperature is 1550-1600℃, to avoid the generation of porosity and inclusion defects during the casting process.

[0044] Preferably, after the preheating treatment described in step S300 is completed, the punch body is protected with an inert gas when it exits the furnace. The protective gas is nitrogen, and the gas flow rate is 10-15 L / min, to prevent the punch body from oxidizing and discoloring at room temperature.

[0045] Preferably, during the heat preservation and slow cooling process described in step S600, alumina insulation cotton with a thickness of 50-80mm is filled into the heat preservation furnace to cover the punch workpiece; at the same time, when the temperature is slowly cooled to 100°C, dry nitrogen gas is introduced into the heat preservation furnace to remove moisture from the furnace and prevent oxidation and corrosion of the punch surface.

[0046] Preferably, the diameter of the cobalt-based alloy welding wire in step S500 is 1.0-3.2 mm; the welding wire is pretreated before welding. The pretreatment step is to put the welding wire into an ultrasonic cleaner and clean it with anhydrous ethanol for 10-15 minutes to remove surface oil and oxide scale, and then put it into a 120°C oven to dry for 30 minutes.

[0047] Beneficial effects:

[0048] This invention employs cobalt-based alloy welding wire of the same material as the punch body for surfacing, eliminating material differences between the substrate and the surfacing layer and avoiding defects such as insufficient interfacial bonding and microcracks. The segmented symmetrical surfacing process reduces interlayer stress concentration, resulting in uniform overall punch hardness and stable surface wear resistance. A copper rod, acting as an internal forming core mold, precisely defines the forming space of the punch head, solving the problem of uneven surfacing thickness on complex curved surfaces. Only a small amount of finishing allowance is required after surfacing, reducing processing costs and improving consistency in mass production. The punch is made entirely of cobalt-based alloy, with a uniform coefficient of thermal expansion, preventing network cracks under frequent thermal cycling. The copper core mold rapidly conducts heat during welding, preventing localized overheating and softening of the surfacing layer, and improving the punch's adaptability to ultra-high temperature conditions. The punch produced by this invention has no risk of interfacial peeling and its service life is more than twice that of traditional methods. After the punch wears out, it can be directly repaired by welding without extensive rework, which greatly shortens the customer's downtime for replacement. In practical applications, this method has been used to complete the delivery of 10 batches, totaling about 2,000 punches, achieving sales of about one million RMB. The time for customers to replace punches has been greatly reduced, and the service life has been increased by 2 times compared to the original solution. Attached Figure Description

[0049] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0050] Figure 1 This is a schematic diagram of the punch blank in this invention;

[0051] Figure 2 This is a schematic diagram of the punch welding copper rod in this invention;

[0052] Figure 3 This is a schematic diagram of the punch after welding in this invention;

[0053] Figure 4 This is a flowchart of the method of the present invention. Detailed Implementation

[0054] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0055] Example 1: Operating temperature 800℃.

[0056] Reference Figure 1-4 An embodiment of the present invention discloses a method for manufacturing a cobalt-based alloy glass mold punch, comprising the following steps:

[0057] Step S100: The punch body is manufactured using a cobalt-based alloy material through precision casting. The punch body has a pre-drilled inner hole at its head, the size of which is determined based on the design parameters of the finished punch head. Specifically:

[0058] A cobalt-based alloy suitable for ultra-high temperature operating conditions is selected, with the following chemical composition by mass percentage: C 1.3%, Cr 30%, W 8%, Ni 2%, Fe 2%, Si 0.8%, Mn 0.5%, and the balance being Co. The precision casting process is vacuum lost-wax casting, using a silica sol shell mold. The shell is fired at 900-1050℃ for 1-2 hours. The alloy melting vacuum degree is ≤5Pa, and the casting temperature is 1550-1600℃ to avoid porosity and inclusion defects during casting. The wax pattern accuracy is controlled within ±0.05mm. The cobalt-based alloy is melted to 1550-1600℃ and vacuum-cast into a ceramic shell. The shell preheating temperature is 800℃, and after casting, it cools to room temperature along with the shell to avoid casting cracks caused by rapid cooling. The head of the punch body after casting has a pre-reserved cylindrical inner hole with a diameter of 22mm and a depth of 15mm. The roughness of the inner hole wall Ra≤3.2μm, and the dimensions of the rest of the body meet the requirements of semi-finishing.

[0059] Step S200: Select a copper rod and process one end into a ball head. The diameter of the ball head is smaller than the inner diameter of the punch body head. Coat the surface of the ball head with an inorganic high-temperature resistant coating of 0.05-0.1 mm. After coating, place it in a ventilated environment to dry naturally.

[0060] Specifically, a T2 copper rod with a diameter of 21.8 mm and a length matching the total length of the punch body is selected. Copper has excellent thermal conductivity, which can quickly dissipate heat during the welding process, preventing local overheating and deformation of the punch body. One end of the copper rod is machined into a ball head with a radius of 11 mm using CNC turning, consistent with the curved surface of the finished punch head, and the surface roughness Ra of the ball head is ≤1.6 μm. The diameter of the ball head is 0.2 mm smaller than the inner hole of the punch head to allow space for coating and welding. An alumina-zirconia composite inorganic high-temperature resistant coating is selected, with a solid content percentage of 60% alumina, 30% zirconia, and 10% binder. The coating is uniformly applied to the surface of the copper ball head by spraying, with a coating thickness of 0.08 mm. After coating, it is placed in a ventilated environment at 25℃ for natural drying for 4 hours to ensure complete curing. The coating has a temperature resistance of ≥1500℃ to prevent the copper rod from sticking to the welding wire during welding.

[0061] Step S300: Place the precision-cast punch body into a heat treatment furnace and heat it to 200℃ at a heating rate of 5-8℃ / min, hold it at that temperature for at least 30 minutes, and then remove it from the furnace. Specifically:

[0062] A box-type resistance heat treatment furnace with a precise temperature control system is selected, achieving a temperature control accuracy of ±5℃. The punch body is placed inside the furnace and heated to 200℃ at a heating rate of 6℃ / min. During the heating process, excessively rapid heating should be avoided to prevent uneven thermal stress on the body. After reaching the target temperature, it is held at that temperature for 40 minutes to ensure uniform temperature distribution and reduce thermal stress during subsequent welding. After holding at that temperature, the punch body is quickly removed to prevent excessive cooling. The surface temperature of the punch body after removing it from the furnace should not be lower than 180℃.

[0063] Step S400: Insert the dried copper rod through the bottom of the punch body until the ball end of the copper rod is completely exposed inside the punch head hole, with the exposed length matching the height of the protrusion at the finished punch head. Specifically:

[0064] Insert the thoroughly dried copper rod axially into the bottom of the punch body until the copper ball head is completely exposed from the inner hole of the punch head, with an exposed length of 5mm. This length is consistent with the height of the protrusion at the head of the finished punch. During assembly, ensure that the coaxiality between the copper rod and the punch body is ≤0.03mm to avoid uneven welding thickness in the subsequent process.

[0065] Step S500: Using cobalt-based alloy welding wire of the same material as the punch body, adjust the tungsten inert gas (TIG) welding process parameters: welding current 100-140A, arc voltage 10-15V, welding speed 80-200mm / min, shielding gas ≥99.99% argon gas, gas flow rate 15-20L / min; perform surfacing welding along the inner hole of the punch head and the outer side of the ball head. Specifically:

[0066] A cobalt-based alloy welding wire with the same composition as the punch body was selected, with a diameter of 1.2mm, to ensure the metallurgical bonding performance between the weld overlay and the body, eliminating the problem of mismatched thermal expansion coefficients caused by material differences. A digital tungsten inert gas (TIG) welding machine was used, with welding current set to 200A, arc voltage to 22V, and welding speed to 100mm / min. The shielding gas was argon with a purity ≥99.99% and a flow rate of 18L / min to ensure no oxidation in the weld overlay area. A cerium tungsten electrode with a diameter of 2.0mm and a tip angle of 30° was selected. A segmented symmetrical weld overlay method was adopted, dividing the circumference of the punch head into four equal segments, each with a weld overlay length of 25mm. The odd-numbered segments were welded first, followed by the even-numbered segments, to avoid deformation of the body caused by continuous weld overlay on one side. During the weld overlay process, the angle between the welding torch and the workpiece surface was maintained at 70°-80°, the wire feed speed was uniform, and the weld overlay thickness exceeded the finished product design size by 0.8mm, leaving a machining allowance. During the welding process, the body temperature is monitored in real time and controlled to not exceed 350℃ to prevent coarse grains in the body.

[0067] Step S600: After the welding is completed, remove the copper rod and immediately place the punch workpiece into a holding furnace to cool to room temperature at a cooling rate of 2-3℃ / min. Specifically:

[0068] After the welding is completed, immediately remove the copper rod and place the punch workpiece into the holding furnace. Set the cooling rate to 2.5℃ / min and cool from 350℃ to room temperature. This slow cooling process can effectively eliminate the internal stress of the weld and prevent microcracks from appearing in the weld layer.

[0069] Step S700 involves CNC turning and grinding of the slowly cooled punch workpiece to ensure that the punch's dimensional accuracy and surface roughness meet the finished product requirements. Specifically:

[0070] A high-precision CNC lathe is used to machine the punch head after welding, ensuring the head diameter reaches the required 24mm and the dimensional accuracy is controlled within ±0.02mm. Diamond polishing paste is then used to grind the curved surface of the head, resulting in a surface roughness Ra=0.6μm, reducing the adhesion between the molten glass and the punch. Simultaneously, the punch sealing surface and thread structure are also ground to ensure the accuracy of the bottle neck forming.

[0071] The key dimensions of the punch, including head diameter, coaxiality, and thread accuracy, were inspected using a coordinate measuring machine, and all met the requirements. Hardness testing showed that the surface hardness of the punch reached HRC58, with a hardness uniformity deviation of ≤2HRC. Tensile testing of the bonding strength showed that the bond strength between the weld overlay and the body reached 480MPa. After 1000 cycles of thermal cycling at 1250℃, no cracks or peeling were observed on the punch surface.

[0072] In a preferred embodiment of this application, the inorganic high-temperature resistant coating uses zircon powder and boron nitride coating, and can be water-based or alcohol-based. However, the inorganic high-temperature resistant coating of this application is not limited to the above examples.

[0073] Example 2

[0074] The difference from Example 1 above is that the operating temperature is 800℃.

[0075] Punch body:

[0076] Cobalt-based alloy composition selection: An economical cobalt-based alloy was selected, with the following chemical composition by mass percentage: C 0.9%, Cr 27%, W 4%, Ni 2%, Fe 0.8%, with the balance being Co. This composition meets the requirements of normal operating conditions and reduces production costs.

[0077] Precision casting process: lost-wax casting, wax pattern accuracy ±0.05mm, alloy melting temperature 1550-1620℃, mold shell preheating temperature 750℃, and cooling to room temperature with the mold shell after casting.

[0078] Body structure: The head has a reserved inner hole with a diameter of 18mm and a depth of 12mm, and the inner hole wall roughness Ra≤3.2μm.

[0079] Preparation of copper forming core mold:

[0080] The copper rod is made of T2 copper, with a diameter of 17.7mm.

[0081] Ball end machining: CNC turning of ball end radius 9mm, surface roughness Ra≤1.6μm, ball end diameter is 0.3mm smaller than inner hole.

[0082] The coating is applied using zircon powder and boron nitride paint, with a thickness of 0.05 mm, and allowed to air dry for 3 hours.

[0083] Preheating the punch body:

[0084] A box-type resistance furnace is used, with a heating rate of 5℃ / min. After heating to 200℃, the temperature is held for 30 minutes, and the furnace exit temperature is ≥170℃.

[0085] Core mold assembly: After the copper rod is inserted into the body, the length of the ball head protruding from the inner hole is 4mm, and the coaxiality is ≤0.03mm.

[0086] Tungsten inert gas (TIG) welding overlay:

[0087] Welding material selection: Cobalt-based alloy welding wire with the same composition as the body material, 1.2mm in diameter.

[0088] Welding parameters: welding current 180A, arc voltage 20V, welding speed 80mm / min, argon flow rate 15L / min.

[0089] Welding process: The circumference is divided into 4 segments, each 20mm long, and symmetrical welding is performed on each segment. The thickness of the weld layer exceeds the design size by 0.5mm, and the body temperature is controlled not to exceed 320℃.

[0090] Insulation and slow cooling:

[0091] After removing the copper rod, place it in a heat-preserving furnace and cool it to room temperature at a rate of 2℃ / min.

[0092] Precision machining:

[0093] After CNC turning, the head diameter is 20mm with a dimensional accuracy of ±0.02mm; after grinding, the surface roughness Ra=0.7μm.

[0094] Quality Inspection:

[0095] Dimensional inspection meets standards; surface hardness HRC55, bonding strength 450MPa; 1000 cycles of thermal cycling at 1150℃ show no damage.

[0096] The punch obtained in Example 1 is suitable for ultra-high temperature conditions up to 1250℃, solving the problem of easy oxidation and peeling of traditional welded punches under such conditions, and its service life is increased by 2.5 times compared with the traditional solution. The punch obtained in Example 2 meets the needs of conventional glass bottle production, with a production cost reduction of 15% compared with Example 1 and a service life increase of 2 times compared with the traditional solution. When the punches of both examples are mass-produced, the dimensional consistency deviation is ≤0.03mm, which fully meets the requirements of industrial mass production.

[0097] In some embodiments, it may also include:

[0098] After the preheating treatment described in step S300 is completed, the punch body is protected with an inert gas, namely nitrogen, at a flow rate of 10-15 L / min when it exits the furnace to prevent oxidation and discoloration at room temperature. During the heat preservation and slow cooling process described in step S600, alumina insulation cotton with a thickness of 50-80 mm is filled into the heat preservation furnace to cover the punch workpiece. Simultaneously, when the temperature slowly cools to 100°C, dry nitrogen is introduced into the heat preservation furnace to remove moisture and prevent oxidation and corrosion of the punch surface. The cobalt-based alloy welding wire described in step S500 has a diameter of 1.0-1.2 mm. Before welding, the welding wire undergoes pretreatment. The pretreatment steps involve placing the welding wire in an ultrasonic cleaner and cleaning it with anhydrous ethanol for 10-15 minutes to remove surface oil and oxide scale, followed by drying it in a 120°C oven for 30 minutes.

[0099] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for manufacturing a cobalt-based alloy glass mold punch, characterized in that, Includes the following steps: Step S100: The punch body is made of cobalt-based alloy material through precision casting process. The head of the punch body has a reserved inner hole structure, and the inner hole size is determined according to the design parameters of the finished punch head. Step S200: Select a copper rod and process one end into a ball head. The diameter of the ball head is smaller than the inner diameter of the punch body head. Coat the surface of the ball head with an inorganic high-temperature resistant coating of 0.05-0.1 mm. After coating, place it in a ventilated environment to dry naturally. Step S300: Place the precision-cast punch body into a heat treatment furnace and heat it to 200°C at a heating rate of 5-8°C / min. Hold it at that temperature for at least 30 minutes. Remove the punch from the furnace after holding it at that temperature. Step S400: Insert the dried copper rod into the bottom of the punch body until the ball of the copper rod is completely exposed from the inner hole of the punch body, and the exposed length is consistent with the height of the protrusion of the finished punch head. Step S500: Using cobalt-based alloy welding wire of the same material as the punch body, adjust the tungsten inert gas (TIG) welding process parameters: welding current 100-140A, arc voltage 10-15V, welding speed 80-200mm / min, shielding gas argon with purity ≥99.99%, and gas flow rate 15-20L / min; perform surfacing welding along the inner hole of the punch head and the outer side of the ball head. Step S600: After the welding is completed, remove the copper rod and immediately place the punch workpiece into the heat preservation furnace to cool it to room temperature at a cooling rate of 2-3℃ / min. Step S700: The punch workpiece after slow cooling is subjected to CNC turning and grinding to ensure that the dimensional accuracy and surface roughness of the punch meet the requirements of the finished product.

2. The method for manufacturing a cobalt-based alloy glass mold punch according to claim 1, characterized in that, The chemical composition of the cobalt-based alloy in step S100 is as follows (by mass percentage): C 0.9-1.8%, Cr 20-30%, W 3.5-15%, Ni ≤ 3%, Fe ≤ 3%, with the balance being Co.

3. The method for manufacturing a cobalt-based alloy glass mold punch according to claim 1, characterized in that, The inorganic high-temperature resistant coating mentioned in step S200 is an alumina-zirconia composite coating with a temperature resistance of ≥1500℃.

4. The method for manufacturing a cobalt-based alloy glass mold punch according to claim 1, characterized in that, In step S500, during the welding process, a segmented symmetrical welding method is adopted, with each segment having a welding length of 20-30mm, or A continuous welding method is adopted, and the interlayer temperature is controlled below 800℃ during continuous welding to avoid local overheating of the punch body.

5. The method for manufacturing a cobalt-based alloy glass mold punch according to claim 1, characterized in that, Step S700 is followed by a quality inspection step, which includes dimensional accuracy inspection, hardness inspection, weld bonding strength inspection and thermal fatigue performance testing. The hardness test requires the surface hardness of the punch to reach HRC40-55, and the bonding force test uses the tensile method, with a bonding strength ≥450MPa.

6. The method for manufacturing a cobalt-based alloy glass mold punch according to claim 1, characterized in that, The precision casting process described in step S100 is vacuum lost-wax casting. The shell is a silica sol shell, the shell baking temperature is 900-1050℃, and the baking time is 1-2h. The alloy melting vacuum degree is ≤5Pa, and the casting temperature is 1550-1600℃ to avoid porosity and inclusion defects during the casting process.

7. The method for manufacturing a cobalt-based alloy glass mold punch according to claim 1, characterized in that, After the preheating treatment described in step S300 is completed, the punch body is protected with an inert gas when it comes out of the furnace. The protective gas is nitrogen, and the gas flow rate is 10-15 L / min to prevent the punch body from oxidizing and discoloring at room temperature.

8. The method for manufacturing a cobalt-based alloy glass mold punch according to claim 1, characterized in that, During the heat preservation and slow cooling process described in step S600, alumina insulation cotton with a thickness of 50-80mm is filled into the heat preservation furnace to cover the punch workpiece; at the same time, when the temperature is slowly cooled to 100℃, dry nitrogen gas is introduced into the heat preservation furnace to remove moisture from the furnace and prevent oxidation and corrosion of the punch surface.

9. The method for manufacturing a cobalt-based alloy glass mold punch according to claim 1, characterized in that, The diameter of the cobalt-based alloy welding wire mentioned in step S500 is 1.0-3.2mm; the welding wire is pretreated before welding. The pretreatment steps are to put the welding wire into an ultrasonic cleaner and clean it with anhydrous ethanol for 10-15 minutes to remove surface oil and oxide scale, and then put it into a 120℃ oven to dry for 30 minutes.

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