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Analysis of the reasons why the silicon carbon rods are easy to fracture


Nov 20,2023

1, the reasons for damage to the heating element of the silicon carbon rod 1. silicon carbon rod components of substandard quality: resistance value is low (1.7 ohms) and resistance value is inconsistent with the aluminum melting silicon carbon rod requirements for the selection of the resistance value of 2.2 ~ 2.6 ohms; silicon carbon rod components packaging does not comply with the provisions of the wooden box hanging type, so the long-distance transport by car in the silicon carbon rod components cracks, not easily detected by the naked eye; components in the case of dampness This is not allowed in the operation of melting aluminum in the resistance furnace.
In an oxidizing atmosphere, . High use temperature of 1800 ℃, silicon molybdenum rod heating element resistance with the temperature increases rapidly, when the temperature remains unchanged resistance value is stable. Under normal circumstances, the resistance of the element does not change with the length of time of use, therefore, the new and old silicon molybdenum rod electric heating element can be mixed use.
According to the structure of the heating equipment device, the working atmosphere and temperature, the surface load of the electric heating element for the correct choice, is the silicon molybdenum rod electric heating element of the service life of the key.
2. Silicon carbon rod use unreasonable: each phase of the carbon and silicon rod element resistance value should be matched one to one, not installed regulator transformer should be more so, which is to avoid damage to the main measures of the element, and by the manufacturers may not do this; silicon carbon rod element cold end is not wrapped in aluminum and preheating; electricians, melting workers do not know much about normal use of the element's measures.
3. Silicon carbon rods there are micro-cracks: optical microscope and electron microscope on the port of room temperature silicon carbon rods to observe, found in the Si and SiC large grains at the crack, and in the Si grains in the Friends crack branching, element fracture surface occurs in the deconvolution and intergranular hybrid rupture.
Silicon carbon rods used in high temperature oxidizing atmosphere, the surface generates a layer of bright dense quartz (SiO2) glass film, can protect the inner layer of silicon molybdenum rods no longer oxidized, so the silicon molybdenum rods components with high temperature oxidation resistance.