Process performance of aluminum flame detector housing casting

Release time:

2021-06-04

The process performance of Aluminum flame detector housing is usually understood as a combination of the most outstanding performance in the process of filling the mold, crystallization and cooling.

The process performance of Aluminum flame detector housing is usually understood as a combination of the most outstanding performance in the process of filling the mold, crystallization and cooling. Fluidity, shrinkage, air tightness, casting stress, air absorption. These characteristics of Aluminum flame detector housing depend on the composition of aluminum, but are also related to casting factors, alloy heating temperature, mold complexity, pouring riser system, gate shape, etc.

Aluminum flame detector housing

1 Liquidity

Fluidity refers to the ability of the alloy liquid to fill the mold. The fluidity determines whether the alloy can cast complex castings. Eutectic alloys have the best fluidity in the Aluminum flame detector housing. There are many factors that affect fluidity, mainly the composition, temperature, and solid particles of metal oxides, metal compounds and other pollutants in the alloy liquid, but the fundamental external factors are the pouring temperature and pouring pressure (commonly known as pouring head) The heights.

In actual production, when the alloy has been determined, in addition to strengthening the smelting process (refining and slag removal), it is also necessary to improve the mold processability (sand mold air permeability, metal mold exhaust and temperature), and do not affect Under the premise of casting quality, increase the pouring temperature to ensure the fluidity of the alloy.

2 Contractility

Shrinkage is one of the main features of casting Aluminum flame detector housing. Generally speaking, the alloy is divided into three stages from liquid pouring to solidification and cooling to room temperature, namely liquid shrinkage, solidification shrinkage and solid state shrinkage. The shrinkage of the alloy has a decisive influence on the quality of the Aluminum flame detector housing. It affects the shrinkage cavity size, stress generation, crack formation and size changes of the casting. Generally, the aluminum flame detector housing shrinkage is divided into body shrinkage and linear shrinkage. In actual production, linear shrinkage is generally used to measure the shrinkage of the alloy.

3 Hot cracking

Aluminum flame detector housing thermal cracks are mainly caused by the shrinkage stress of the casting exceeding the bonding force between the metal grains. Most of them occur along the grain boundaries. From the crack fracture, the metal at the crack is often oxidized and loses its metallic luster. The cracks extend along the grain boundary, with a zigzag shape, a wide surface and a narrow inside, and some penetrate the entire end surface of the casting. Different Aluminum flame detector housings have different tendency to crack. This is because the greater the difference between the temperature at which a complete crystallization frame begins to form during the solidification of the Aluminum flame detector housing and the solidification temperature, the greater the shrinkage of the alloy, and the tendency to produce hot cracks. The larger the alloy, the hot cracking tendency is different due to the resistance of the mold, the structure of the casting, the pouring process and other factors. In production, regressive molds are often used, or measures such as improving the casting system of the aluminum flame detector housing are used to avoid cracks in the aluminum flame detector housing. The thermal cracking ring method is usually used to detect the thermal cracks of the Aluminum flame detector housing.

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