1. Carbon (C) influences the melting point of steel, that is, it lowers the melting point, making it easier to melt. It also makes the steel harder to harden. The toughness and expansion rate are reduced. Reduced forging and brazing properties
2. Silicon (Si) Silicon in iron will combine with carbon. Formed silicon carbide (Sic), which is very hard. Therefore, steel with too much silicon is brittle and fragile. The bonding properties and the misalignment are reduced. But it has good corrosion resistance.
3. Manganese (Mn) Manganese mixed in raw steel makes the steel hard and wear-resistant. and the melting point also increased.
4. Phosphorus (P) Phosphorus, if there is a lot of iron ore, will make it more difficult to smelt. And if there is a lot of steel, it will become brittle at cold temperatures. But if there is less, it allows to be able to cast a thin, easy to melt, easy to pour into the form.
5. Sulfur (S) Sulfur, if there is a lot of steel, will make the steel brittle and easily broken at high temperatures, making it difficult to melt and inconvenient to pour into the form.
Therefore, high-temperature applications are not good.
2) Influence of elements on cast iron
1. Carbon Cast iron that contains a lot of carbon is very hard. but will have a low melting point The temperature and mix ratio can be viewed from Iron Carbon.
2. Silicon is a graphite stabilizer in cast iron. If cast iron contains a lot of silicon, it is gray cast iron.
3. Sulfur affects castiron, i.e. it prevents carbon from gathering in the grafted form, causing less graphite Cast iron with a high content of sulfur is white cast iron.
4. Manganese When combined with sulfur, manganese sulfide is obtained. This manganese sulfide is the one that helps the carbon dissociation together in the form of
graphite, but manganese itself helps carbon combine iron to form Cementite and maintain the Cementite structure. However, cast iron with a cementite structure will require more manganese content than manganese sulfite. (chemical composition S l parts Mn. 1.72 parts)
5. Phosphorus has no effect on the aggregation of carbon in cast iron. Phosphorus will help iron water flow easily. It combines with iron to form Phosphide, which has a low melting point (Fe – Fe3C – Fe3P has a melting point of about 9,600˚C).
3) Influence of Elements on Alloy Cast Iron
1. Chromium (Cr) combines with carbon in cast iron to form chromium carbide. Cast iron has high abrasion resistance properties. Have a long service life
2. Manganese (Mn) combines with carbon to form a carbide. make steel harder But if there is a lot, cast iron becomes brittle.
3. Copper (Cu) helps to create a strong structure in cast iron, but if there is more (more than 2%), it will reduce the ability to withstand tensile strength.
4. Phosphorus (P) will increase corrosion resistance from sulfuric acid salts. and acetic acid But if there is a lot, cast iron becomes brittle. have low tensile stress.
5. Nickel (Ni) keeps cast iron from rusting and also helps form graphite
6. Molybdenum (Mo) makes cast iron more resistant to swelling at high temperatures and thus better hardenability.
4) Objectives of bringing various elements to mix in iron
1. To be able to withstand high impact loads.
2. To maintain the surface hardness to resist wear or cutting.
3. To increase resistance to chemical changes
4. To enhance mechanical properties in high or low temperature applications.
5. To increase the strength to carry the load (Load)
6. To maintain good machinability on machines
7. To enhance mechanical properties as well as the control of the composition, which affects the ability to harden. and increase the toughness
5) Properties of elements when mixed in steel
– Chromium (Chromium: Cr) increases strength. rust resistance and resistant to corrosion
– Manganese (Manganese: Mn) increases the durability of impact. Increase toughness and wear resistance
– Nickel (Nickel: Ni) increases corrosion resistance. increase the toughness and strength
– Molybdenum (Molybdenum: Mo) increases the hardness. high heat resistance Retains hardness at high temperatures and wear resistance
– Vanadium (Vanadium: V) increases toughness, hardness and maintains hardness at high temperatures.
– Silicon (Silicon: Si) increases corrosion resistance.
– Tungsten (Tungsten: W) maintains hardness at high temperatures. increase strength and resistant to corrosion.