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CN-122007833-A - Welded all-steel piston and manufacturing method thereof

CN122007833ACN 122007833 ACN122007833 ACN 122007833ACN-122007833-A

Abstract

The invention discloses a welded all-steel piston and a manufacturing method thereof, wherein the manufacturing method of the welded all-steel piston comprises the following operation steps of S1, preprocessing a piston head and a piston skirt, S2, friction welding, S3, vacuum tempering, S4, filling a removable sealing medium into the internal cooling oil cavity, filling the removable solid sealing medium into the internal cooling oil cavity to enable the solid sealing medium to fill and seal the whole internal cooling oil cavity and an oil hole, S5, finishing a piston body filled with the solid sealing medium, S6, removing the sealing medium, heating the finished piston body to enable the solid sealing medium to be melted or softened, and discharging the solid sealing medium from the internal cooling oil cavity. The welded all-steel piston and the manufacturing method thereof provided by the invention can effectively improve the cleanliness of the inner cooling oil cavity and simplify the process flow.

Inventors

  • LIU MINGHUI
  • YANG KUN
  • ZHANG JINRUI
  • LIU ZHENWEI
  • ZHANG YONGGANG

Assignees

  • 湖南江滨机器（集团）有限责任公司

Dates

Publication Date
20260512
Application Date
20260324

Claims (10)

  1. 1. A method of manufacturing a welded all-steel piston, comprising the steps of: S1, preprocessing a piston head and a piston skirt, namely respectively processing the piston head and the piston skirt to preset shapes, forming an inner cooling oil cavity and an oil hole communicated with the inner cooling oil cavity, and reserving finish machining allowance at other parts; S2, friction welding, namely connecting the prefabricated piston head and the piston skirt into a whole in a friction welding mode to form a piston body, wherein the interior of the piston body forms a closed inner cooling oil cavity; s3, vacuum tempering, namely performing vacuum tempering treatment on the welded piston body; S4, filling a removable sealing medium into the inner cooling oil cavity, namely filling the removable solid sealing medium into the inner cooling oil cavity, so that the whole inner cooling oil cavity and the oil hole are filled and sealed by the solid sealing medium; S5, finishing, namely finishing the piston body filled with the solid sealing medium, including turning, boring, drilling and/or milling; And S6, removing the sealing medium, namely heating the piston body which is finished, melting or softening the solid sealing medium, and discharging the solid sealing medium from the inner cooling oil cavity.
  2. 2. The method for manufacturing a welded all-steel piston according to claim 1, wherein the removable sealing medium in the step S4 is rust-preventive paraffin, The melting point range of the antirust paraffin is 55-60 ℃.
  3. 3. The method for manufacturing a welded all-steel piston according to claim 2, wherein the step S4 specifically includes the steps of cooling the piston body after vacuum tempering to 70-80 ℃, then pouring solid anti-rust paraffin particles into the oil hole, melting and flowing the anti-rust paraffin particles by using the residual temperature of the piston body until the whole inner cooling oil cavity and the oil hole are filled, and then cooling to solidify the anti-rust paraffin into a solid state.
  4. 4. The method for manufacturing a welded all-steel piston according to claim 3, wherein the solid rust-preventive paraffin particles in step S4 have a particle diameter of 0.5 to 2.0mm.
  5. 5. The method for manufacturing the welded all-steel piston according to claim 2, wherein the rust-preventive paraffin wax in the step S4 is composed of the following components in percentage by mass: 70-85% of fully refined paraffin, 8-15% Of stearic acid, 3-8% Of barium petroleum sulfonate antirust agent.
  6. 6. The method of manufacturing a welded all steel piston according to any one of claims 1 to 5, wherein a welded horn is formed at the joint of the piston head and the piston skirt in the friction welding in the step S2; The root width d of the welded claw is not less than 0.5mm; the gap t of the welded claw is 0-0.4 mm.
  7. 7. The method of manufacturing a welded all steel piston according to any one of claims 1-5, wherein the specific process parameters of the vacuum tempering in step S3 are: The tempering temperature is 580-630 ℃, The heat preservation time is 2-4 hours, And cooling to 200-90 ℃ along with the furnace, and discharging.
  8. 8. The method of manufacturing a welded all steel piston according to any one of claims 1-5, characterized in that during the finishing process of step S5, the cutting fluid is used for cooling and the temperature of the working area is controlled to be lower than 45 ℃.
  9. 9. The method of manufacturing a welded all steel piston according to any one of claims 1-5, wherein in step S6 the piston body is inverted in flowing hot water, The temperature of the hot water is 70-100 ℃, The rust-preventive paraffin is melted by heat and discharged from the oil hole, And then carrying out physical layering recycling by utilizing the density difference of the paraffin and the water.
  10. 10. A welded all steel piston, characterized in that it is manufactured by the manufacturing method according to any one of the preceding claims 1-9.

Description

Welded all-steel piston and manufacturing method thereof Technical Field The invention relates to the technical field of pistons of internal combustion engines, in particular to a welded all-steel piston and a manufacturing method thereof, which are particularly suitable for high-power density diesel engines, natural gas engines and the like. Background Welded steel pistons are typically of split construction, i.e., after the piston head and skirt are separately machined, they are joined together by friction welding or the like, and an internal cooling gallery is formed therein for cooling. In order to lead the cooling liquid into and out of the inner cooling oil cavity, an oil inlet hole and an oil outlet hole which are communicated with the inner cooling oil cavity are formed in the piston. In the prior art manufacturing process, after the welding of the piston blank is completed, subsequent finishing processes are required, including working procedures such as turning, drilling, milling a pin hole crescent groove and the like. In the process, the hollow internal cooling oil cavity is easy to enter cutting fluid to cause corrosion in the cavity, and meanwhile, foreign matters such as metal scraps generated by processing are also easy to enter the internal cooling oil cavity through oil holes or other gaps, are difficult to clean thoroughly, and seriously affect the cleanliness of a piston and the quality of a final product. In order to solve the problems, the prior art adopts a method that before finish machining, a special rubber or plastic plug is used for plugging the oil inlet and outlet of the internal cooling oil cavity so as to seal the oil cavity. However, the scheme has the following defects that firstly, the plug is a special part, the cost is high, the plug is easy to fall off due to corrosion, aging or vibration in the processing process, so that sealing is invalid, secondly, before the working procedures of milling a pin hole crescent groove and the like, the plug is required to be removed, steel scraps generated at the moment are easy to fall into an internal cooling oil cavity, the deburring and blowing cleaning working procedures are added subsequently, but the steel scraps revolve in the cavity and are difficult to thoroughly clean, and in addition, a welding seam gap formed by welding is easy to conceal foreign matters. In general, the existing process flow is long, and the cleanliness of an internal cooling oil cavity is difficult to ensure. Disclosure of Invention In order to solve the technical problems, the invention provides a welded all-steel piston and a manufacturing method thereof, which can effectively improve the cleanliness of an internal cooling oil cavity and simplify the process flow. The technical scheme provided by the invention is as follows: A manufacturing method of a welded all-steel piston comprises the following operation steps: S1, preprocessing a piston head and a piston skirt, namely respectively processing the piston head and the piston skirt to preset shapes, forming an inner cooling oil cavity and an oil hole communicated with the inner cooling oil cavity, and reserving finish machining allowance at other parts; S2, friction welding, namely connecting the prefabricated piston head and the piston skirt into a whole in a friction welding mode to form a piston body, wherein the interior of the piston body forms a closed inner cooling oil cavity; s3, vacuum tempering, namely performing vacuum tempering treatment on the welded piston body; S4, filling a removable sealing medium into the inner cooling oil cavity, namely filling the removable solid sealing medium into the inner cooling oil cavity, so that the whole inner cooling oil cavity and the oil hole are filled and sealed by the solid sealing medium; S5, finishing, namely finishing the piston body filled with the solid sealing medium, including turning, boring, drilling and/or milling; And S6, removing the sealing medium, namely heating the piston body which is finished, melting or softening the solid sealing medium, and discharging the solid sealing medium from the inner cooling oil cavity. Preferably, the removable sealing medium in the step S4 is a rust-proof paraffin, The melting point range of the antirust paraffin is 55-60 ℃. Preferably, the step S4 specifically comprises the following operation processes of cooling the piston body after vacuum tempering to 70-80 ℃, then pouring solid antirust paraffin particles into the oil hole, melting and flowing the antirust paraffin particles by using the residual temperature of the piston body until the whole internal cooling oil cavity and the oil hole are filled, and then cooling to solidify the antirust paraffin into a solid state. Preferably, the solid rust-proof paraffin particles in the step S4 have a particle size of 0.5 to 2.0mm. Preferably, the rust-proof paraffin wax in the step S4 comprises the following components in percentage by mass: 70-85% of fully