Introduction of boiling steel plate and killing steel plate

1. boiling steel plate is made of ordinary carbon structural steel boiling steel hot rolled steel plate. Boiling steel is a kind of incomplete deoxygenation steel, only a certain amount of weak deoxidizer to the liquid steel deoxygenation, the liquid steel oxygen content is high, when the molten steel is injected into the ingot mold, carbon oxygen reaction produces a lot of gas, resulting in liquid steel boiling, boiling steel hence named. The carbon content of the boiling steel is low, and the silicon content of the steel is also low because of the deoxidation of ferrosilicon (Si< 0.07%). The outer layer of boiling steel is crystallized under the conditions of intense agitation of liquid steel caused by boiling, so the surface is pure, dense, good surface quality, good plasticity and stamping performance, no large concentrated shrinkage hole, less cutting head, high yield, and the production process of boiling steel is simple, the consumption of ferroalloy is less, and the cost of steel is low. Boiling steel plates are widely used in the manufacture of various stamping parts, construction and engineering structures and some less important machine structural parts. But the core of the boiling steel has more impurities, more serious segregation, less dense structure and uneven mechanical properties. At the same time, due to the high gas content in the steel, the toughness is low, the cold brittleness and aging sensitivity are large, and the welding performance is poor. Therefore, the boiling steel plate is not suitable for manufacturing welding structures and other important structures that bear impact loads and work at low temperatures.

2. the killing steel plate is made of ordinary carbon structural steel hot rolled killing steel plate. The killed steel is completely deoxidized steel, the liquid steel is fully deoxidized with ferromangmanganese, ferrosilicon and aluminum before pouring, the oxygen content of the liquid steel is low (generally 0.002-0.003%), the liquid steel is calm in the ingot mold, does not produce boiling phenomenon, the killed steel is named. Under normal operating conditions, there are no bubbles in the killed steel, and the structure is uniform and dense. Due to the low oxygen content, the oxide inclusion in steel is less, the purity is higher, and the cold brittleness and aging tendency are small; At the same time, the seperation of the killed steel is smaller, the performance is more uniform, and the quality is higher. The disadvantages of the killed steel are concentrated shrinkage holes, low yield and high price. Therefore, the sedative steel is mainly used for components that withstand impact at low temperatures, welded structures and other components that require high strength.