Seamless steel pipes are extensively applied for the nuclear device, gas, petrochemical, ship building and boiler industries. Seamless steel pipes dominates 65% of market share in Chinese boiler industry.
Size: In the case of continuous charging, the size of the direct reduced iron is very important parameter. Small in size (1 ~ 2mm) materials may quickly oxidized when contacting the slag, it may be pumped flue. Size is too large (> 30mm) at the time of continuous charging can cause problems. When using a continuous charging method through the roof, should be limited to the proportion of < 2mm of sponge iron.
Impact strength: Deoxidation iron should have a good impact strength, which can prevent a lot of powder formed. A large amount of powder when applied in an electric furnace is undesirable phenomenon occurs.
Resistance to climate: direct reduced iron stored in the air, easily oxidized, and exothermic. The Deoxidation iron will reduce its long-term storage metallization rate, partly because of its loose structure, a large surface area. If the direct reduction of iron stored for six months in an open yard, its metallization rate will be reduced by 1%.
Density: Deoxidation iron from the roof into the furnace, must be able to pass through the slag layer, to stay in the slag / steel liquid interface, so you can ensure efficient heat transfer and chemical reactions. If Deoxidation iron density is too low, it will float on the surface of the slag; and high density of the liquid steel will wear to go. Therefore, it is best to direct reduced iron density control in the range of 4 ~ 6g / cm3.
Weight of the monomers: Deoxidation iron lump slag through time depends on how the timing. If the direct reduction of iron is small, remain too long in the slag, slag boiling phenomenon will occur. At this time, the slag fluidity plays a very important role. However, if the Deoxidation iron large, there will be strict control of slag liquidity requirements.
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