Element 1: H (hydrogen)
H is the most harmful elements of the general steel, steel dissolved in hydrogen will cause steel hydrogen embrittlement, white and other defects. Hydrogen, like oxygen and nitrogen, has a very low solubility in solid steel and dissolves into molten steel at high temperatures. It is too late to escape and accumulate in the organization to form high-pressure fine pores, which reduces the plasticity, toughness and fatigue strength of steel. , Serious will cause cracks, brittle broken. "Hydrogen crisp" mainly in the martensitic steel, in the ferrite steel is not very prominent, generally with the hardness and carbon content increased together.On the other hand, H can improve the permeability of steel, but also increase the coercivity and iron loss (increase the coercivity after adding 0.5 to 2 times).
Element 2: C (carbon)
C is the main element after iron, it directly affects the strength of steel, plasticity, toughness and welding performance. When the carbon content in the steel below 0.8%, with the increase in carbon content, steel strength and hardness increased, while the plasticity and toughness decreased; but when the carbon content of 1.0% or more, with the carbon content Increase, the strength of steel but decreased. With the increase of carbon content, the welding performance of steel is worse (the carbon content is more than 0.3%, the weldability is significantly decreased), the cold brittleness and aging sensitivity are increased and the atmospheric corrosion resistance is decreased.
Element 3: O (O)
O is a harmful element in steel. It is natural in the steelmaking process into the steel, although in the end of the steel to add manganese, silicon, iron and aluminum for deoxidation, but can not be removed. During the solidification of molten steel, oxygen and carbon in the solution react to produce carbon monoxide, which can cause bubbles. Oxygen in the steel mainly FeO, MnO, SiO2, Al2O3 and other forms of inclusion, so that the steel strength, plasticity reduced. Especially for fatigue strength, impact toughness and so have a serious impact. Oxygen will increase the iron loss in silicon steel, permeability and magnetic field strength weakened, magnetic aging effect intensified.
