| Na/Cb |
Melting point 1950 ° C |
16- Niobium / Columbia |
| Ta |
Melting point is 3030 ° C |
17- Tantalum |
These elements are usually taken together and hardly separated from each other. It is a carbide maker element and thus it is an important stabilizing element in chemical resistant steels. Both are ferrite elements and narrower the y domain. Due to the increased thermal strength and creep strength of niobium, they are commonly used as alloying elements of high-temperature austenitic steels in boiler construction. Tantalum has a wide absorption surface for neutrons, and as a result, niobium steels with low tantalum are used in the construction of atomic power plants.
| Ni |
Melting point 1453 ° C |
18- Nickel |
Nickel increases the toughness of constructional steels even at a very low temperature, and thus serves as an alloying element for increasing the toughness of the steel-carburetor-and refining and cold stiffening.
The transition points (A1-A4) in the iron-carbon diagram go downwards, Nor is it a carbide maker.
The nickel expands the Y domain and thus more than 7% of it, the austenitic structure of high chromium steels, at a much lower temperature than the environment, is resistant to corrosion.
Nickel, alone and in high percentage, only strengthens the rust resistance of steel, and in chromium-nickel austenitic steels it creates resistance to the effects of regenerative chemicals, as well as creates the resistance to oxidizing materials.
Since the crystallization temperature of austenitic steels is high, temperatures above 600 ° C have a high thermal stability and are practically non-magnetizing. Heavily reduces the thermal and electrical conductivity.
The high percentage of nickel in the controlled alloy range gives certain physical properties to the steel, for example, low heat expansion (for example, invar nickel and iron alloy with 0.2% C, 36% Ni, 63.8% Fe)
| O |
Melting point at -7/218 ° C |
19- Oxygen |
One of the harmful elements of steel,
Due to its special effects, the type and composition of the steel are important as well as the shape and quality of their distribution. Some mechanical properties such as beats toughness, especially in the direction of transverse reduction, but tendencies such as fragility due to steel aging, hot brittleness, failure in the direction of the fiber and oblique defeat is exacerbated.
| P |
Melting point 44 ° C |
20- Phosphorus |
Since phosphorus, during the cooling of the molten material, causes the initial segregation and, due to the narrowing of the y domain, provides the secondary segregation in solid form, it is more often considered as one of the harmful elements of steel. Due to the relatively low intrusiveness, this element is also present in the field of mixed alpha and gamma crystals, the resulting segregation is hardly uniformed. Since the uniform distribution of phosphorus in steel is hardly achievable, it is attempted to maintain the percentage of phosphorus at a low level and, correspondingly, increase the percentage of phosphorus in steels up to a maximum of 0.03-0.05%. The amount of succession can not be determined with complete certainty.
A very small amount of phosphorus in steel increases the temper brittleness sensitivity of it. Phosphoric brittleness increases with increasing carbon percentage, hardening and crystalline grain size, and decreasing steel forging. Phosphoric brittleness appears in the form of a cold steel breakdown and its sensitivity to beat tension (desire for failure due to brittleness).
In low alloy construction steels with a value of about 0.1, phosphorus increases their strength and creates corrosion resistance to atmospheric agents. Copper metal improves corrosion resistance of steel. (Oxide protective steels).
Phosphorus additions can provide a guarantee of increasing the offset yield strength in chromium-nickel austenitic steels, and the phenomenon of segregation.
| Pb |
Melting point 4/324 ° C |
21- Lead |
Due to the incredibly fine distribution of suspensions such as this element, in automatic steel with an amount of about 0.2-0.5% during machining, fine filings are created and clean surface machining are achieved.
This amount of additive lead has no effect on the mechanical properties of the steels.
| S |
Melting point 118 ° C |
22- Sulfur |
Among all the steel-coated elements, sulfur has the highest degree of steels on the steel. Iron sulfide usually causes hot steel brittleness. Because low-melting α-ethoxy-sulfides form metal beads around a grid, in such a way that they create a weak bond between them and tend to fail in the formation of the grain boundary; the grain boundary is amplified by oxygen. Due to the high affinity of sulfur to the manganese element, it is also isolated as a manganese sulfide, and because of this impurity has a much less negative effect among other steel impurities, it is distributed dispersively and has a high melting point. The toughness of the steel in its transverse direction decreases dramatically by adding sulfur. Due to the lubricating properties of sulfur, the cutting edge of the cutting tools reduces the friction intensity and increases the life of the tool, thus deliberately 0.4% of this element is added to the automatic steel (auto). In addition, sulfur reduces the machining filing of automatic steel. Sulfur increases cracking due to welding.
| Sb |
Melting point 630 ° C |
23- Antimony |
Due to the reduced properties of steel toughness, this metal is one of the harmful elements in steel, this element also narrows the crystal domain of Y.
| Se |
Melting point 217 ° C |
24- Selenium |
Since the ability to improve the machining processes of the automatic steel (auto) by this element is higher than sulfur, its application is similar to that of sulfur in these steels. It decreases the corrosion resistance of steels, but is less than that of sulfur.
| Si |
Melting point is 1414 ° C |
25- Silicon |
Because with iron ore and in proportion to its chemical composition, there is also some silicon, always a part of the element is alloyed with a manganese element in steel. Also, while producing steel, some of the silicon of the furnace wall is absorbed by the molten steel. But this kind of steel is known as silicon steel, which has more than 0.4% silicon. Silicon is not one of the metals, but it is a semi-metal element such as phosphorus and sulfur.
Silicon has been de-oxidized, has played an important role in the separation of graphite, greatly narrowed the crystalline area, increased the abrasion resistance of silicon-manganese refining steel, increased the elasticity modulus, and, for other reasons, it is one of the alloying elements in the spring steel.
The resistance to steel crusting has been increased in such a way that it is an alloying element in refractory steels because it reduces the ability to form cold and hot materials, so its alloying value is limited in steel.
By increasing the percentage of silicon to 12%, the resistance to acidic steel is guaranteed, and these steels can be produced as hard and brittle casting steels, so that they can be machined only by stroke.
| Sn |
Melting point: 233.8 ° C |
26- Tin |
Because the tin, like copper under the crustal layer of steel, penetrates along the boundary of the grains, and the cracks and fractures resulting from the solder make the crystalline area Y narrower.
| Ti |
Melting point is 1727 ° C |
27- Titanium |
Due to its high affinity for oxygen, sulfur, nitrogen and carbon, this element is one of the strongest deoxidizing agents, denitridizing, sulfur adsorbents and strong carbidizers. Also, in corrosion-resistant steels, as a carbide element, it is used to stabilize the crystalline deposition, and also plays an important role in the fine crystallization of the crystalline structure. This element tightens the crystalline area Y.
In the case of an increase in its amount in steel, it causes a segregation phenomenon and because of the high force of the residual material to the permanent magnet is used in alloying alloy. Due to the formation of special nitrides, the strength of steel creep increases. However, this metal is a great deal for segregation and layering.
| V |
Melting point is 1726 ° C |
28- Vanadium |
This element causes the seeds and the casting steel structure to be crushed. It is one of the strongest carbide elements that will increase the abrasion resistance, the shear edge of the tool, and the thermal resistance of the steel, it is naturally an alloying element in high speed, hot work and heat resistant steel.
Enhances the steel return resistance to a sufficient level, and reduce the suppressive sensitivity.
Because this element causes fine crystallization of the structure and prevents the hardening of the steel in the air by preventing the formation of the corresponding carbide, it improves the welding ability of the refining steel.
Due to the formation of carbide, it increases the strength of the steel against hydrogen under pressure. Vanadium reduces the crystalline region Y and brings the curie point to a higher temperature.
| W |
Melting point 3380 ° C |
29- Wolfram |
It is one of the strongest carbide metals (its carbide is extremely hard), which tightens the crystalline area, improves toughness and prevents grain growth. This element increases the thermal resistance, resistance, and also the abrasion resistance of steel at high temperature (red state), which also increases the ability to cut steel. For the foregoing reasons, this metal is one of the most important alloying elements in the high speed steels, hot work, heat-resistant, steels of very high degree of toughness.
Tungsten raises the resignation Force and is therefore used as an important element in permanent magnet alloys.
Tungsten reduces the steel’s crust resistance. The high specific gravity of this alloying element has made the tungsten and hot steels more tangible.
| Zr |
Melting point is 1860 ° C |
31- Zirconium |
This metal is a carbide element, as a metallurgy material in deoxidizing steel, nitride and sulfur absorbent, since the oxidized product remains very small. The addition of zirconium to automatic steels has a significant effect on the formation of the corresponding sulfide, thus preventing the hot-brittleness of steel.
It increases the life of the electric elements and makes the crystalline area Y tighter.
