Production process of a low-alloy high-strength cast iron piston

Abstract

The invention provides a production technology of a low-alloy high-strength cast iron piston. An adopted production tool sequentially comprises a bottom box, a middle box and a cover box from bottom to top, and an internal cavity is defined by the bottom box, the middle box and the cover box; a piston casting is placed in the internal cavity, one end of a combustion chamber of the piston casting is upward, a top riser is formed in the cover box, and the position of the top riser corresponds to an outer ring groove of the piston casting; blind risers are formed in a skirt inner ring groove of the piston casting; blind chilling blocks are arranged at an inner platform of the piston casting; and a plurality of air outlets are formed inside an oil cavity even core of the piston casting. According to the production technology of the low-alloy high-strength cast iron piston, gas in the forging process of the oil cavity even core is led out, air holes are prevented from appearing in the outer circle of the piston, the riser and the blind risers are added, the shrinkage defect of the ring groove portion is avoided, accelerated cooling is adopted in the local part, and a metallographic phase and the hardness of a wall thickness portion can meet the standard.

Description

technical field [0001] The invention relates to a production process of a piston, in particular to a production process of a low-alloy high-strength cast iron piston. Background technique [0002] Cast iron pistons produced by traditional production techniques have the following defects: [0003] The core of the oil chamber is made of coated sand, which has a large amount of gas generation and poor exhaust, resulting in different degrees of air holes on the outer circle of the piston; the wall thickness of the ring groove is thicker than that of the thin wall of the piston. Although it is cooled by graphite sand, the metal liquid cannot be fed during the solidification and shrinkage stage, so shrinkage defects are prone to occur; the wall thickness of the inner platform and the combustion chamber is thicker, the solidification is slower, and the structure is coarse, so the metallographic and hardness are uniform. not to standard. Contents of the invention [0004] The te...

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Problems solved by technology

[0003] The core of the oil chamber is made of coated sand, which has a large amount of gas generation and poor exhaust, resulting in different degrees of pores on the outer circle of the piston; the ring groove is thicker than the thin wall of the piston, and Although it is cooled by graphite sand, the metal liquid cannot be fed during the solidification and shrinkage stage, so shrinkage defects are prone to occur; the wall thickness of the inner platform and the combustion chamber is thicker, the solidification is slower, and the structure is coarse, so the metallographic and hardness are uniform. not to standard

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