A method of hardfacing a valve face of an internal combustion engine and an internal combustion engine valve

Abstract

The present application relates to a kind of internal combustion engine valve sealing surface surfacing method and internal combustion engine valve.The internal combustion engine valve sealing surface surfacing method includes the following steps: pretreatment: valve blank is preheated to 100~200 ℃, then fixed;Arc is started at any point of welding torch at the outer circle of welding groove support plate, after welding 360 °, start to extinguish arc, form first layer alloy layer;Second surfacing: after moving welding torch 2~3mm to the direction of valve neck at the first layer surfacing position, arc is started, after welding 365 °, start to extinguish arc, form second layer alloy layer.The present application also provides a kind of internal combustion engine valve, and the internal combustion engine valve sealing surface surfacing is obtained by the surfacing method described in the present application.The present application effectively improves the uniformity of surfacing alloy layer thickness, reduces the risk of cracking, failure and other risks due to uneven stress distribution during use.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine manufacturing technology, specifically to a method for overlaying welding the valve sealing surface of an internal combustion engine and an internal combustion engine valve. Background Technology

[0002] The intake and exhaust valve seats used in high-power marine medium- and high-speed diesel engines must possess excellent impact resistance, corrosion resistance, and wear resistance to withstand high-temperature corrosion, combustion gas erosion, and the impact of valve seating. To improve their wear and corrosion resistance, a wear-resistant and corrosion-resistant alloy layer is welded onto the sealing cone surface. However, because the alloy layer material differs from the base material, the linear expansion coefficient of the alloy is generally lower than that of the base material. At high temperatures, the expansion of the base material is greater than that of the welded alloy layer, resulting in a thermal stress in the welded alloy layer—that is, an increase in tangential tensile stress on the sealing cone surface. If the thickness of the entire alloy layer is inconsistent and the uniformity is poor, the stress field distribution will be inconsistent, leading to stress release during use and thus the risk of cracking and failure. Summary of the Invention

[0003] The purpose of this invention is to provide a method for overlaying the sealing surface of an internal combustion engine valve and an internal combustion engine valve, so as to improve the uniformity of the thickness of the overlay alloy layer and reduce the risk of cracking and failure during use due to uneven stress distribution.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for overlaying welding on the valve sealing surface of an internal combustion engine includes the following steps:

[0006] S1. Pretreatment: Preheat the valve blank to 100℃~200℃, and then fix it;

[0007] S2. First welding: The welding torch starts an arc at any point on the outer circle of the weld pool near the plate. The welding current and welding speed are adjusted appropriately according to the condition of the molten pool and the weld formation to ensure that the alloy steel is well covered in the weld pool. After welding one circle, i.e. 360°, the arc is extinguished to form the first alloy layer.

[0008] S3. Second welding: After moving the welding torch 2-3mm towards the valve neck from the position of the first welding layer, start the arc, appropriately reduce the welding speed, increase the amount of alloy powder fed, and start extinguishing the arc after welding 365° to ensure that the second alloy layer can cover the first alloy layer, so that the overlap rate between the second alloy layer and the first alloy layer is ≥50%, so as to ensure that the alloy thickness meets the requirements and form the second alloy layer.

[0009] Based on the aforementioned technical means, a welding alloy is formed in the weld groove of the valve blank by using plasma welding process and performing at least two welding operations. By reasonably controlling the preheating temperature, welding current, and welding speed, the uniformity of the welding alloy layer thickness is effectively guaranteed, and the consistency of the welding alloy layer thickness is improved. At the same time, the welding arc initiation position is reasonably adjusted in the two welding operations, and the alloy flow direction is controlled to ensure the roundness of the alloy welding, avoid excessive melting of the base material, and ensure that the alloy is well covered to fill the edge of the weld groove. This avoids the problem of local edge collapse caused by the alloy deviating from the weld groove, and makes the fusion line between the alloy layer and the base material straight, avoiding the formation of saw-shaped welds. This further effectively ensures the uniformity of the welding alloy layer, thereby effectively reducing the risk of cracking and failure during use due to uneven stress distribution. Moreover, this welding method has the advantages of being simple and easy to implement, having strong equipment adaptability, and having a high product qualification rate.

[0010] Preferably, the alloys of the first and second alloy layers are Stellite 6# and Stellite 12# series alloys; the alloy composition of the first and second alloy layers, by mass percentage, includes: carbon (C): 1.10-1.70%, chromium (Cr): 26.0-33.0%, molybdenum (Mo): 1.0%, silicon (Si): 0.40-2.00%, nickel (Ni): 3.0%, tungsten (W): 7.0-9.50%, iron (Fe): 3.0%, sulfur (S): 0.03%, phosphorus (P): 0.03%. ): 0.03%, Oxygen (O): 0.03%, Manganese (Mn): 0.1%, balance Cobalt (Co); or including: Carbon (C): 1.10-1.70%, Chromium (Cr): 28.0-30.0%, Molybdenum (Mo): 1.0%, Silicon (Si): ≤1.50%, Nickel (Ni): 3.0%, Tungsten (W): 3.5-5.5%, Iron (Fe): 3.0%, Sulfur (S): 0.03%, Phosphorus (P): 0.03%, Oxygen (O): 0.03%, Manganese (Mn): 0.5%, balance Cobalt (Co).

[0011] Preferably, in step S2, the welding speed of the first welding is 0.7 rpm to 0.8 rpm, the welding current is 115 to 120 A, and the ion gas flow rate is 0.9 L / min.

[0012] Preferably, in step S3, the welding speed of the second welding is 0.2-0.3 rpm slower than that of the first welding, the welding speed of the second welding is 0.5-0.7 rpm, the welding current is 105-115 A, and the ion gas flow rate is 0.9 L / min.

[0013] In this process, the welding current and welding speed are adjusted appropriately according to the molten pool and the weld formation to ensure that the alloy is evenly spread throughout the weld groove of the valve blank and can be piled up with sufficient thickness, thereby further ensuring the uniformity of the thickness of the weld overlay alloy layer.

[0014] Preferably, in step S2, the amount of powder fed during the first welding process is 35% to 40%.

[0015] By controlling the amount of powder fed during the first welding pass, the uniformity of the weld alloy layer thickness was further ensured.

[0016] Preferably, in step S3, the amount of powder fed for the second welding is 40% to 45%.

[0017] By controlling the amount of powder fed during the second welding process, the uniformity of the weld overlay alloy layer thickness was further effectively ensured.

[0018] Preferably, the overlap rate between the first alloy layer and the second alloy layer is ≥50%.

[0019] By controlling the overlap rate between the first and second alloy layers to be above 50%, the alloy thickness is ensured to meet the set requirements.

[0020] Preferably, in S1, the roughness of the valve blank weld groove is ≤ Ra1.6, the coaxiality of the center hole of the disc end face and the chamfer of the rod end face is ≤ 0.05, the runout of the disc end face to the valve rod is ≤ 0.1, and the roundness of the weld groove is ≤ 0.05.

[0021] Research has shown that the physical properties of the valve blank itself can also affect the uniformity of the weld overlay thickness. Therefore, controlling the physical properties of the valve blank can further improve the uniformity of the weld overlay thickness.

[0022] Preferably, the uniformity of both the first alloy layer and the second alloy layer is ≤0.5mm.

[0023] The uniformity of the weld overlay alloy layer obtained by the above welding method is ≤0.5mm, which meets the set requirement for uniformity of weld overlay alloy layer thickness and effectively avoids the risk of cracking and failure during use due to uneven stress distribution.

[0024] The present invention also provides an internal combustion engine valve, wherein the sealing surface of the internal combustion engine valve is obtained by welding using the welding method described in the present invention.

[0025] The beneficial effects of this invention are:

[0026] The welding method for the valve sealing surface of an internal combustion engine of the present invention forms a welding alloy in the weld groove of the valve blank by employing at least two welding operations. By reasonably controlling the preheating temperature, welding speed, and welding current, the uniformity of the welding alloy layer thickness is effectively guaranteed, and the consistency of the welding alloy layer thickness is improved. At the same time, the welding arc initiation position is reasonably adjusted in the two welding operations to ensure the roundness of the alloy welding and avoid excessive melting of the base material. This avoids the problem of local edge collapse caused by the alloy deviating from the weld groove, and ensures that the fusion line between the alloy layer and the base material is straight, avoiding the formation of a saw-like shape. This further effectively guarantees the uniformity of the welding alloy layer, thereby effectively reducing the risk of cracking and failure during use due to uneven stress distribution. Moreover, this welding method has the advantages of being simple and easy to implement, having strong adaptability to equipment, and high product qualification rate. It has promotion and application value in the field of internal combustion engine manufacturing technology. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the valve blank fixed on the valve tooling according to the present invention (the welding operation has been completed).

[0028] Wherein, 1-valve blank, 11-valve seat, 111-valve disc end face, 112-valve outer circle, 12-first alloy layer, 13-second alloy layer; 2-valve tooling. Detailed Implementation

[0029] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0030] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0031] Example 1

[0032] like Figure 1 As shown, a method for overlaying welding on the valve sealing surface of an internal combustion engine includes the following steps:

[0033] S1. Pretreatment: Preheat valve blank 1 to 150℃, then use valve fixture 2 to fit the valve plate end face 111 of valve seat 11 and valve outer circle 112 of valve blank 1 to fix valve blank 1. Then, clamp valve fixture 2 onto valve welding equipment positioner to adjust valve blank 1 so that the angle between valve plate end face 111 and horizontal plane is 50° to ensure that the weld groove is in the state of boat-shaped weld. Among them, valve fixture 2 is suitable for fixing valve blank 1 with valve stem diameter between Φ10mm and Φ20mm, total length of valve blank 1 between 150 and 750mm, and valve plate diameter between Φ40mm and Φ150mm.

[0034] S2, First welding: The welding torch is positioned at the outer circumference of the valve seat 11 of the valve blank 1 in the weld groove (i.e., Figure 1 The arc is started at any point (point A) in the middle. The welding speed is 0.75 rpm, the welding current is 120 A, the powder feed is 40%, the ion gas flow rate is 0.9 L / min, and the arc is extinguished after welding one 360° circle to form the first alloy layer 12.

[0035] S3. Second welding: After moving the welding torch 2-3mm towards the valve neck from the position of the first welding layer, start the arc, adjust the welding speed to 0.5rpm, the welding current to 110A, the powder feed rate to 45%, and the ion gas flow rate to 0.9L / Min, and weld the second alloy layer 13, ensuring that the overlap rate between the second alloy layer 13 and the first alloy layer 12 is about 60%, and ensuring that the alloy thickness meets the requirements; after welding the second alloy layer 365°, start extinguishing the arc to form the second alloy layer 13.

[0036] The welding method for the valve sealing surface of the internal combustion engine in this embodiment is applicable to valve blanks with weld roughness Ra≤1.6, disc end face valve stem runout≤0.1, and weld roundness≤0.05;

[0037] In this embodiment, the alloys of the first and second alloy layers are Stellite 6# series alloys. The composition of this series of alloys, by mass percentage, includes: carbon: 1.10-1.70%, chromium: 26.0-33.0%, molybdenum: 1.0%, silicon: 0.40-2.00%, nickel: 3.0%, tungsten: 7.0-9.50%, iron: 3.0%, sulfur: 0.03%, phosphorus: 0.03%, oxygen: 0.03%, manganese: 0.1%, with the balance being cobalt.

[0038] Alternatively, the alloys of the first and second alloy layers may be Stellite 12# series alloys, which, by mass percentage, include: carbon: 1.10–1.70%, chromium: 28.0–30.0%, molybdenum: 1.0%, silicon: ≤1.50%, nickel: 3.0%, tungsten: 3.5–5.5%, iron: 3.0%, sulfur: 0.03%, phosphorus: 0.03%, oxygen: 0.03%, manganese: 0.5%, with the balance being cobalt.

[0039] This embodiment also provides an internal combustion engine valve, the sealing surface of which is welded using the welding method described in this embodiment.

[0040] After testing, the uniformity of the alloy layer after welding using the welding method for the valve sealing surface of the internal combustion engine in this embodiment is ≤0.5mm.

[0041] In summary, the welding method for the valve sealing surface of an internal combustion engine of the present invention forms a welding alloy in the weld groove of the valve blank by employing at least two welding operations. By rationally controlling the preheating temperature, welding temperature, and welding angle, the uniformity of the welding alloy layer thickness is effectively ensured, and the consistency of the welding alloy layer thickness is improved. Simultaneously, the two welding operations rationally adjust the arc initiation position, ensuring the roundness of the alloy weld and avoiding excessive melting of the base material. This prevents the alloy from deviating from the weld groove, thus avoiding the problem of local edge collapse. Furthermore, the fusion line between the alloy layer and the base material is straight, avoiding saw-like formation, further effectively ensuring the uniformity of the welding alloy layer. This effectively reduces the risk of cracking and failure during use due to uneven stress distribution. Moreover, this welding method has the advantages of being simple and easy to implement, highly adaptable to equipment, and having a high product qualification rate. It has significant application value in the field of internal combustion engine manufacturing technology.

[0042] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A method for overlaying welding onto the valve sealing surface of an internal combustion engine, characterized in that, Includes the following steps: S1. Pretreatment: Preheat the valve blank to 100℃~200℃; S2. First welding: The welding torch starts an arc at any point on the outer circle of the weld pool, and welds a 360° circle to form the first alloy layer; the welding speed for the first welding is 0.7rpm~0.8rpm, and the welding current is 115~120A. S3. Second welding: After moving the welding torch 2-3mm towards the valve neck from the position of the first welding layer, start the arc and weld 365° to make the overlap rate of the second alloy layer with the first alloy layer ≥50%, thus forming the second alloy layer; the welding speed of the second welding is 0.5-0.7rpm and the welding current is 105-115A.

2. The welding method for the valve sealing surface of an internal combustion engine according to claim 1, characterized in that, The alloy composition of the first alloy layer and the second alloy layer, by mass percentage, includes: carbon: 1.10-1.70%, chromium: 26.0-33.0%, molybdenum: 1.0%, silicon: 0.40-2.00%, nickel: 3.0%, tungsten: 7.0-9.50%, iron: 3.0%, sulfur: 0.03%, phosphorus: 0.03%, oxygen: 0.03%, manganese: 0.1%, with the balance being cobalt; or includes: carbon: 1.10-1.70%, chromium: 28.0-30.0%, molybdenum: 1.0%, silicon: ≤1.50%, nickel: 3.0%, tungsten: 3.5-5.5%, iron: 3.0%, sulfur: 0.03%, phosphorus: 0.03%, oxygen: 0.03%, manganese: 0.5%, with the balance being cobalt.

3. The welding method for the valve sealing surface of an internal combustion engine according to claim 1, characterized in that, In S2, the amount of powder fed for the first welding is 35%~40%.

4. The welding method for the valve sealing surface of an internal combustion engine according to claim 1, characterized in that, In S3, the amount of powder fed for the second welding is 40%~45%.

5. The welding method for the valve sealing surface of an internal combustion engine according to claim 1, characterized in that, In S1, the roughness of the valve blank weld groove is ≤ Ra1.6, the runout of the disc end face to the valve stem is ≤ 0.1, and the roundness of the weld groove is ≤ 0.

05.

6. The welding method for the valve sealing surface of an internal combustion engine according to claim 1, characterized in that, The uniformity of the first alloy layer and the second alloy layer is ≤0.5mm.

7. A valve for an internal combustion engine, characterized in that, The valve sealing surface of the internal combustion engine is welded using the welding method described in any one of claims 1 to 6.

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