How to do the hottest glass sintering

2022-07-30
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How to make glass sintering

1. batching: according to the designed material list, weigh various raw materials and mix them evenly in a mixer. The main raw materials of glass are: quartz sand, limestone, feldspar, soda ash, boric acid, etc

2. melting: the prepared raw materials are heated at high temperature to form a uniform bubble free liquid glass. This is a very complex physical and chemical reaction process. Glass is melted in a furnace. There are mainly two types of melting furnaces: one is a crucible kiln, where the glass frit is put in the crucible and heated outside the crucible. Only one crucible can be placed in a small crucible kiln, and up to 20 crucibles can be placed in a large crucible kiln. Crucible kiln is gap type production, and now only optical glass and color glass are produced in crucible kiln. The other is a tank furnace, in which the glass frit is melted in the furnace tank, and the open fire is heated at the upper part of the glass liquid level. The melting temperature of glass is mostly 1300~1600 ゜ C. Most of them are heated by flame, and some are heated by electric current, which is called electric furnace. At present, tank kilns are continuously produced. Small tank kilns can be several meters, and large ones can be as large as more than 400 meters

3. forming refers to the transformation of molten glass into solid products with fixed shapes. Forming can only be carried out within a certain temperature range. This is a cooling process. The glass first changes from a viscous liquid to a plastic state, and then into a brittle solid state. Forming methods can be divided into manual forming and mechanical forming

a. artificial forming. There are also

(1) blowing, using a nickel chromium alloy blowing pipe, picking up a ball of glass and blowing while turning in the mold. It is mainly used to form glass bubbles, bottles, balls (for eye cutting lenses), etc

(2) drawing. After blowing into small bubbles, more than 3million mini cars have been offline. Another worker sticks them with a top plate. The two people blow and pull while they are mainly used to make glass tubes or rods

(3) pressing: pick up a ball of glass, cut it with scissors to make it fall into the concave die, and then press it with the convex die. It is mainly used to form cups, plates, etc

(4) free forming. After picking materials, use pliers, scissors, tweezers and other tools to directly make handicrafts

b. mechanical forming. Because of the high labor intensity, high temperature and poor conditions of artificial forming, most of them have been replaced by mechanical forming except free forming. In addition to pressing, blowing and drawing, mechanical forming also has

(1) pressure friction coefficient( μ) The coefficient of friction method is used to produce thick flat glass, engraved glass, metal wire glass, etc

(2) casting method to produce optical glass

(3) centrifugal casting method is used to manufacture large diameter glass tubes, utensils and large capacity reaction pots. This is to inject the glass melt into the high-speed rotating mold. Due to the centrifugal force, the glass clings to the mold wall, and the rotation continues until the glass hardens

(4) sintering method, used to produce foam glass. It adds foaming agent to the glass powder and heats it in a covered metal mold. During the heating process, many closed bubbles are formed in the glass. This is a good heat insulation and sound insulation material. In addition, the forming of flat glass includes vertical drawing method, horizontal drawing method and float method. Float method is a method to make liquid glass flow float on the surface of molten metal (TIN) to form flat glass. Its main advantages are high glass quality (flat and bright), fast drawing speed and large output

4. after annealing, the glass undergoes intense temperature change and shape change during forming, which leaves thermal stress in the glass. This thermal stress will reduce the strength and thermal stability of glass products. If it is cooled directly, it is likely to break itself during cooling or later storage, transportation and use (commonly known as cold explosion of glass). In order to eliminate cold explosion, glass products must be annealed after forming. Annealing is to keep the temperature within a certain temperature range or slow down for a period of time to eliminate or reduce the thermal stress in the glass to the allowable value

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