The production process of the casting of the pressure plate of the car clutch

Abstract

Production optimization process of car clutch pressure plate castings on vertical molding production line, the steps include sand mixing, molding, furnace charge smelting, tapping inoculation treatment, pouring, cooling, unpacking, and casting cleaning; among the molding processes, two and two More than two casting blanks are arranged horizontally and symmetrically. The pouring molten iron enters the sprue through the sprue cup and the upper runner. The sprue passes through the middle of the casting cavity and then enters the lower runner, and then passes symmetrically into the cavity. The tensile strength of the single-cast test bar of the pressure plate casting produced by the present invention is ≥250MPa, the tensile strength of the casting body is ≥200MPa, and the hardness of the casting body is 170-241HBS; the metallographic structure of the product is mainly A-type graphite, and the graphite length is 4 ~Grade 6, the matrix structure is more than 95% of fine pearlite and a small amount of ferrite; there are no casting defects in all parts of the casting, which fully meets the technical requirements of the clutch pressure plate casting of the car.

Description

technical field [0001] The invention relates to the field of casting, in particular to a production process of a pressure plate casting of a car clutch. Background technique [0002] Car clutch pressure plate castings, the material grade is HT250, the chemical composition requirements are: C3.1-3.5%, Si 1.8-2.4%, Mn 0.4-0.8%, P≤0.35%, S≤0.125%; product metallographic structure Requirements: Type A graphite mainly, graphite length 4~6 grades, matrix structure requires pearlite ≥ 95%; mechanical performance requirements: tensile strength of single cast test bar ≥ 250MPa; tensile strength of casting body ≥ 200MPa; hardness of casting body is 170~241HBS, no casting defects are allowed in each part of the casting. [0003] The process arrangement of the two platen castings on the vertical production line in the existing production process is a process arrangement with one high and one low on both sides of the sprue, so that the molten iron filling process of the two castings is ...

AI Technical Summary

Problems solved by technology

[0003] The process arrangement of the two platen castings on the vertical production line in the existing production process is a process arrangement with one high and one low on both sides of the sprue, so that the molten iron filling process of the two castings is completely different, resulting in two castings The quality status is not the same: (1) The temperature field status of the two castings is different and the hardness of the product is different; (2) Due to the different temperature status, it is necessary to set a riser for feeding, which reduces the process yield of the product (only 55 %); (3) The asymmetric process layout causes the molten iron to enter the cavity unstable, resulting in casting defects such as slag inclusion and sand washing, and the scrap rate remains high

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