Insufficient Hardness: Analysis suggests that the full fiber trolley quenching furnace has been in use for a long time, and although some additional quantities have been added, its cooling capacity has significantly decreased. Furthermore, the crane used for the trolley furnace quenching is not a quenching crane, and its operating speed is slower, resulting in an extended time from the furnace exit to the oil immersion. This causes the workpiece to not maintain sufficient quenching temperature before immersion. The two workpieces are combined together, leading to an excessively large quenching cross-sectional area. Inadequate cooling speed results in insufficient martensitic transformation, with a significant amount of residual austenite and other structures remaining. The workpiece is mounted on a tray with a heavy weight, which requires the dissipation of a large amount of heat during the cooling process, also affecting the workpiece cooling speed.
Due to the above reasons, the cooling process of the workpiece was insufficient, resulting in the surface areas requiring quenching failing to form enough martensitic structures, leading to insufficient surface hardness. Deformation issue: During the cooling process, the surface areas requiring quenching on the sliding plate, which were not carbonized, mainly transformed into martensite. The method of assembling the workpiece was improved by first separating the two assembled workpieces with sleeves, then joining them together, thus maintaining a gap. This increased the quenching area and reduced the cross-sectional area of quenching, ensuring sufficient cooling speed while allowing both sides of the sliding plate to contact with the quenching oil, achieving even cooling on both sides of the workpiece and reducing thermal stress. This not only ensured the necessary cooling speed for martensite but also minimized deformation caused by thermal stress. (3) Increasing the quenching temperature can ensure the quenching temperature of the workpiece before immersion in oil.
