What is the reason for the formation of air holes in the brake disc?
TIME：2020.02.06
The brake disc, in short, is a round disc that rotates as the car travels. The brake caliper holds the brake disc to create braking force, which holds the brake disc to slow down or stop the car when the brake is applied. The brake disc has good braking effect and is easier to maintain than the drum brake. Because disk brake than drum brake of good heat dissipation, in high-speed braking state, not easy to produce heat recession, so its high-speed braking effect is good. But during use, the brake disc will form air holes. And Brake disc formation blowhole what is the cause of it? When the molten iron quickly flooded the disc core, a large number of sudden gas, or high-temperature Molten Iron and a high water-bearing sand mass (mixed sand uneven) contact, causing gas explosion, choking fire, formed choking holes. In addition, the formed high-pressure gas invades the molten iron and floats up to escape. When the casting mould can not discharge it in time, the gas spreads into a gas layer between the molten iron and the upper and lower surfaces of the mould, occupying part of the space on the upper surface of the disc, if the liquid iron at this time is solidification, or viscosity is very large, loss of mobility, gas space can not be re-filled, leaving the surface pores. Under normal circumstances, the gas produced by the core can not be released through the liquid iron in time. It remains on the surface of the disc, sometimes exposed as a single blowhole, and sometimes exposed after the oxide scale has been removed by shot peening, sometimes only after the mechanical processing can be found, this will cause the waste of processing time. When the disc core of the brake disc is thick, the time for liquid iron to rise through the disc core and submerge the disc core is longer, and the gas produced before submerge has more time to flow freely through the sand gap to the upper surface of the core, there is less resistance to flow outwards or inwards through the horizontal direction, so surface stomata defects are seldom formed, but isolated stomata may occur. The above is about the brake disc blowhole formation reason, the temperature is affects the blowhole an important factor. I hope the above can help you, thank you for your reading, if you have any questions, welcome to call the consultation.
