Process for manufacturing saloon car clutch pressure plate casting

Abstract

The invention provides an optimized process for manufacturing a saloon car clutch pressure plate casting on a vertical modeling production line. The process comprises the following steps of mulling sand, modeling, melting burden, inoculating iron, pouring, cooling, opening case and clearing casting, wherein in the modeling step, two and more raw castings are horizontally and asymmetrically arranged; a pouring iron liquid enters into a straight pouring channel through a pouring cup and an upper cross channel; and the straight pouring channel enters into a lower cross channel by passing through the middle of a casting cavity and then asymmetrically enters into the cavity from the lower side of the cavity. The pressure plate casting produced by using the process of the invention has a single-cast coupon tensile strength equal to or more than 250 MPa, a casting body tensile strength equal to or more than 200 MPa and the casting body hardness from 170 to 241HBS. The product metallographic structure mainly uses the A type graphite; the length of the graphite is 4 to 6 level; the matrix contains more than 95% of small pearlites and less ferrites; and all the parts of the casting have no casting flaw and meet the technical requirements of the saloon car clutch pressure plate casting.

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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