Technology for manufacturing hotly-spun pressed forged steel single-piece piston with inner cooling oil cavity

Abstract

The invention discloses a technology for manufacturing a hotly-spun pressed forged steel single-piece piston with an inner cooling oil cavity, which comprises the following steps of: forging piston blanks; mechanically processing the piston blanks to obtain the piston as a semi-finished product with an inside part of the inner cooling oil cavity and a covering part for blocking the inner cooling oil cavity, heating the covering part and downwardly spinning the covering part of the inner cooling oil cavity in the piston by the hot spinning technology to contact the inside part of the inner cooling oil cavity to form a complete inner cooling oil cavity; and not processing gaps of the inside part and the covering part of the inner cooling oil cavity, remaining the gaps or simply sealing by the general welding technology, such as argon arc welding and the like, and precisely processing into the piston as a finished product. The hotly-spun pressed forged steel single-piece piston with the inner cooling oil cavity manufactured by the technology disclosed by the invention is simple in structure, relatively easy and convenient to manufacture, high in production efficiency and low in manufacturing cost, and can meet the requirements of an engine on high power, high strength, and low emission, and the like.

Description

technical field [0001] The invention relates to a manufacturing process of a piston, in particular to a manufacturing process of a hot spinning forged steel integral piston with an inner cooling oil cavity. Background technique [0002] At present, high-performance diesel engines used in trucks, construction machinery, railway locomotives, and ships require high power, low fuel consumption, low noise, and low emissions, and their strengthening degree is increasing day by day. At present, the explosion pressure of domestically developed automotive diesel engines has exceeded 20MPa, and the traditional cast aluminum pistons have been difficult to meet the reliability requirements of high-performance diesel engines. For high-power, high-load diesel engine pistons, articulated structure pistons and forged steel pistons have emerged as the times require. [0003] Piston with hinged pendulum structure, that is, the piston head and piston skirt are manufactured separately and conn...

AI Technical Summary

Problems solved by technology

But its manufacturing process is complex, the manufacturing cost is high, and the structural strength of the piston needs to be improved

[0006] Chinese patent CN2851607Y discloses another method for manufacturing forged steel pistons. In this method, the head and the skirt are forged separately, and the inner cooling oil cavity is formed by friction welding after the head and the skirt are separately processed. The friction welding is affected by the process. Due to the limited performance and accuracy of the method and equipment structure, the friction welding pistons produced in the same batch have poor consistency in length and size, resulting in a large difference between the weight of the piston and the size of the internal cooling oil chamber produced after welding, resulting in a high welding reject rate. High, directly affects the performance of the engine, and the welding flash is large (generally 4-8mm), it needs to be specially processed for the welding flash exposed outside, but the welding flash inside the internal cooling oil cavity cannot be removed, which will affect to the piston cooling effect

Laser welding equipment is complex, high cost, high technical requirements for use and maintenance, the thickness and size of the weldment is limited by the power of the laser, and strict requirements are placed on the cleanliness of the weldment and assembly quality, so its application has great limitations

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