• Follow us
Home > News > Content
Technical Requirements For Furnace Furnace In Graphite Die Production
Oct 11, 2017

Graphite Die in the forging plant production, the rational size of the steel ingot before the furnace should be its refining furnace number, steel, billet weight, size, and check the surface quality, remove the surface defects. Record the location of the furnace, do the actual operation of Graphite Die production records.
The position of the steel ingot used in the Graphite Die shall be determined according to the furnace type, the bottom size, the furnace type and the size and weight of the heated ingot to determine the distance from the furnace wall, front and rear walls and burner. It is forbidden to direct the surface of the metal of the Graphite Die. Graphite Dies should be used when heating for forging. The height of the horn should not be lower than the height of the furnace under the burner. Diameter or side length of less than 150mm Graphite Die billet heating can not use horn.
Graphite Die used in the furnace into the furnace before the surface temperature is lower than 400 ℃ called cold steel ingots, 400-550 ℃ called semi-hot steel ingots, higher than 500 ℃ called hot steel ingots. Hot and cold steel ingot (billet) with a furnace, the spacing between the material must be greater than a blank diameter or side length. Should try to avoid hot and cold steel ingots mixed with a furnace.
It is strictly forbidden to put cold steel ingots (billet) beside heated graphite blanks. It is forbidden to heat the ingot (billet) directly with the actual temperature of the spindle below 0 ℃. Inspection of qualified hot steel ingot transported to the Graphite Die production workshop, should avoid cold air straight blow, should be timely furnace, shall not delay the furnace time.
The initial forging temperature of the Graphite Die is the maximum permissible heating temperature of the raw material blank in the heating furnace. Graphite Die factory from the furnace to remove the Graphite Die blank for forging before processing, according to the size of the blank, the method of transport rough and the distance between the furnace and the forging equipment, the roughness of several degrees to several degrees of temperature drop. Therefore, the real start forging the temperature is slightly lower, before the forging, Graphite Die factory should try to reduce the rough temperature drop.
The initial forging temperature of alloy structural steel and alloy tool steels is mainly limited by heat and overcooling temperatures. The over-heating temperature of the steel is about 100 to 150 ° C lower than the melting point, and the superheating temperature is about 50 ° C lower than the over-burning temperature. Therefore, the initial forging temperature of the steel should generally be lower than the melting point (or below the solidus temperature) 200 ° C.
The carbon content has the most important effect on the upper temperature of steel forging. For carbon steel Graphite Die, the initial forging temperature decreases with the increase of carbon content. For alloy structural steel and alloy die steel, usually the initial forging temperature decreases with the increase in carbon content more.
The original grain structure of the as-cast is relatively stable and the overheating tendency is small. Therefore, the forging temperature of the ingot is 20 ~ 30 ℃ higher than that of the steel billet and steel.
The so-called overheating, refers to the steel heating more than a certain temperature, it will produce austenite grain rapid growth phenomenon. The sensitivity of different steel to overheating is different, soft steel is less sensitive to overheating, and alloy steel is easy to overheat, in the heat-sensitive steel, nickel-chromium molybdenum steel is the most prominent.
Graphite Die overheating and chemical composition, smelting methods, forging temperature, thermal deformation, forging cooling rate and furnace temperature uniformity and other factors. Due to the overheating temperature or too long heating time caused by overheating, although the forging deformation can be broken overheating coarse grains, but often by the forging deformation and deformation uniformity of the restrictions, Graphite Die for more serious overheating, forging deformation is not easy to completely eliminate. Therefore, a safe initial forging temperature should be determined to prevent overheating. As for the burning, because the forging heating temperature is higher, the steel grain is extremely large, and oxygen atoms along the grain boundary intrusion, the formation of network-like oxide and fusible oxide eutectic, so that the binding force between the grains greatly weakened Followed by thermal deformation is easy to produce cracking.