DJM Technical Introduction

    The role of various components in molten steel

    The role of various components in molten steel
    1, carbon (c): steel containing carbon content increased, yield point and tensile strength increase, but plastic impact and reduce, when more than 0.23% carbon, steel welding performance deteriorated, so used for welding of low alloy structural steel, carbon content is generally not more than 0.20%. High carbon content will reduce the steel atmospheric corrosion resistance ability, in the open-air yard of high carbon steel is easy to rust; in addition, the carbon can increase steel cold brittleness and aging sensitivity.
    Do. Credited, more than 2, silicon (SI): in steelmaking process and silicon as reducing agent and deoxidizer, so calm steel containing 0.15 - 0.30% silicon. If steel containing silicon content 0.50-0.60% silicon alloy elements silicon could significantly improve the steel elastic limit, yield point and tensile strength, so it is widely used for spring steel. In the quenched and tempered steel structure adding 1.0 to 1.2% of silicon, the strength can be increased 15 - 20%. Silicon and molybdenum, tungsten, chromium and other combination, can improve the corrosion resistance and antioxidant role, making a heat-resistant steel. Silicon containing 1 - 4% of the low carbon steel with high magnetic permeability, used for electrical appliances industrial silicon steel sheet. Silicon content increases, will reduce the steel welding performance.
    3, manganese (MN): in the steelmaking process, manganese is good deoxidation agent and desulfurization agent, general steel containing manganese 0.30 - 0.50%. In plain carbon steel added 0.70% above even the manganese steel, compared with the general volume of steel of steel not only enough toughness and have higher strength and hardness, improve the quenching of steel, steel to improve the performance of thermal processing, such as 16Mn steel A3 than yield point 40 higher manganese containing 11 - 14% of steel with high abrasion resistance for excavator bucket, ball mill lining board. Manganese content increased, weaken the steel corrosion resistance, reduce welding performance.
    4, phosphorus (P): in general, phosphorus is harmful elements in the steel, steel cold brittleness, the welding performance deterioration and reduce the plastic, the deterioration of the cold bending property. Therefore usually require steel phosphorus content of less than 0.045%, high-quality steel lower some.
    5, sulfur (s): sulfur are usually the harmful elements in. The steel hot brittleness, reduce the ductility and toughness of the steel, causing cracks in the forging and rolling. The sulfur is also detrimental to the welding performance and reduce the corrosion resistance. So often require that the sulfur content of less than 0.055%, high-quality steel demand is less than 0.040%. in steel by adding 0.08-0.20% sulfur, can improve the cutting process, commonly referred to as easy cutting steel.
    6, chromium (CR): in the structural steel and tool steel, chromium can significantly improve the strength, hardness and wear resistance, but also reduce the plasticity and toughness. Chromium and improve the oxidation resistance of steel and corrosion resistance, which is made of stainless steel, heat-resistant steel important alloying elements.
    7, nickel (Ni): nickel can improve the steel strength, and to maintain good plasticity and toughness. Nickel has higher to acid and alkali corrosion resistance, at high temperatures is anticorrosive and heat-resistant ability. But because the nickel is a scarce resource, so it should be as far as possible the use of other alloy elements substitute nickel chromium steel.
    8, molybdenum (MO): molybdenum can refine the grain of steel, improve hardenability and heat resistant properties, at a high temperature to maintain sufficient strength and creep resistance (for a long time in high temperature are subjected to stress, deformation and creep). Molybdenum is added to the steel structure, improve the mechanical properties. Can also inhibit the alloy steel due to a fire caused by brittle. In tool steel can improve the red.
    9, titanium (TI): titanium steel strong deoxidizing agent. It can make the steel's microstructure, grain refinement force; reduce aging sensitivity and cold brittleness. Improve the welding performance. Adding proper titanium in 9 18 chromium nickel austenitic stainless steel, can avoid the intergranular corrosion.
    10, vanadium (V): vanadium is a good agent of steel. The addition of 0.5% of vanadium in steel can refine the microstructure of grain, improve strength and toughness of vanadium and carbon formed carbide, high temperature and high pressure can improve the ability to resist hydrogen.
    11, tungsten (W): tungsten high melting point, than the major is expensive alloying elements. Tungsten and carbon formation of tungsten carbide has high hardness and wear resistance. In tool steel and tungsten, significantly improve the red hardness and heat resistance, used for cutting tools and forging die.
    12, niobium (NB): NB to grain refinement and reduce steel overheating sensitivity and temper brittleness and increase the strength, but the plastic and toughness decreased. In ordinary low-alloy steel with Nb, can improve the atmospheric corrosion resistance and high temperature resistance to hydrogen, nitrogen, ammonia corrosion. Niobium improve welding performance. Adding niobium in austenite stainless steel can prevent intergranular corrosion.
    13, cobalt (Co): cobalt is a rare precious metal, used in special steel and alloys, such as hot steel and magnetic materials.
    14, copper (Cu): WISCO Daye ore from the refining of steel, often containing copper. Copper improve the strength and toughness, in particular, atmospheric corrosion. The disadvantage is that when the thermal processing prone to hot shortness, copper content exceeding 0.5% of plastic significantly reduced. When the copper content of less than 0.50% of welding of shadowless ring.
    15 and aluminum (AL): aluminum is common deoxidizing agent in steel. Adding a small amount of aluminum in steel, grain refinement, improve the impact toughness, such as deep drawing sheet 08Al steel. Aluminum also has the oxidation resistance and corrosion resistance, aluminum and chromium, silicon combination, can significantly improve the steel at high temperature can not afford to hide and resistance to high temperature corrosion. The disadvantage of aluminum is the hot processing performance of the effect of steel, welding performance and machining performance.
    16, boron (B): the addition of trace amounts of boron in steel can improve the density and hot rolling performance of the steel, and increase the strength.
    17, nitrogen (N): nitrogen can improve the strength of steel, low temperature toughness and welding, increase the aging sensitivity.
    18, rare earth (XT): rare earth elements is refers to the periodic table of elements of atomic number special flexible joint structure, a new and high efficiency of fifteen lanthanide elements. These elements are metal, but their oxides is like "soil", so the habit said rare earth. Rare earth is added to the steel can change the composition of inclusions in steel, morphology, distribution and quality, so as to improve the properties of steel, such as toughness, weldability, cold working properties. In the plowshare steel by adding rare earth, improve the wear resistance.


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