2025-03-03
Characteristics and Inspection Methods: Post-anatomical inspection or ultrasonic inspection is conducted for appearance examination or flaw detection. The pores are smooth and circular in shape.
Causes of Generation:
① The direction of alloy liquid introduction is improper or the flow speed of the metal liquid is too high, resulting in ejection.
② The exhaust channel is blocked prematurely or the metal liquid impacts the wall head-on, forming a vortex that traps air. Such pores are mostly found in areas with poor exhaust or deep cavities.
③ The furnace charge is unclean or the melting temperature is too high, causing excessive gas content in the metal liquid. During solidification, the gas is released but fails to be fully expelled.
④ The gas generation capacity of the coating is too large or it is used excessively, and it is not thoroughly removed before pouring, causing the gas to be entrained in the casting. Such gas is mostly dark gray in color.
⑤ The setting of the high-speed switching point is improper.