Effects of alloying Elements on the Properties of steel. ||Engineer's Academy||

Summary

This educational video delves into the impact of alloying elements on steel properties. It explains that steel, an alloy of iron and carbon, gains enhanced characteristics through the addition of elements like chromium for corrosion resistance, nickel for strength and toughness, and molybdenum for hardness. The video also covers the role of carbon in determining steel's hardness levels and the effects of manganese, titanium, and other elements on steel's machinability and corrosion resistance. It's a comprehensive guide to understanding steel composition and its diverse applications.

Takeaways

• 🔨 Steel is an alloy primarily composed of iron and carbon, with carbon content determining its classification into low, medium, or high carbon steel.
• ⚙️ Chromium (Cr) is added to steel to enhance its luster, durability, and resistance to corrosion, including oxidation.
• 💎 Nickel (Ni) contributes to increased hardness, strength, and toughness of steel, as well as providing resistance to corrosion and oxidation.
• 🛡️ Molybdenum (Mo) boosts resistance to pitting corrosion and enhances the steel's hardness and hardenability.
• ⚖️ Carbon content in steel is directly proportional to the steel's hardness, with varying percentages defining different types of steel.
• 🌳 Manganese (Mn) is used to improve the working properties, tensile strength, and machinability of steel, and can act as a substitute for nickel.
• ⚔️ Titanium (Ti) is an alloying element that aids in carbon stabilization, forming carbides to prevent intergranular corrosion in steel.
• 🔩 Phosphorus (P), when combined with sulfur, improves machinability in low alloy steel but can increase the risk of cracking during welding.
• 🔩 Sulfur (S) also enhances machinability but is limited to 0.05 percent in steel to prevent a decrease in steel quality.
• 🌐 Selenium (Se) improves machinability and the nobility of steel, contributing to better material properties.
• 🌀 Niobium (Nb), similar to titanium, is used to stabilize carbon content in steel, enhancing its overall performance.

Q & A

What is the primary difference between iron ore and steel?

Iron ore is raw and not usable in applications due to lacking desired properties, whereas steel is an alloy of iron and carbon, possessing the necessary properties for various applications.

Why is chromium added to steel?

Chromium is added to steel to increase its luster, durability, and resistance to corrosion, such as oxidation.

What is the role of nickel in steel?

Nickel is used to increase the hardness and strength of steel, and it also provides greater toughness and resistance to bending, as well as resistance to corrosion and oxidation.

How does molybdenum affect the properties of steel?

Molybdenum increases the resistance to pitting corrosion caused by chloride and sulfur chemicals, and it also greatly enhances the hardness and hardenability of steel.

What is the relationship between carbon content and the hardness of steel?

As the percentage of carbon in steel increases, so does the hardness of the steel. Different types of steel are categorized based on carbon content, such as low carbon, medium carbon, and high carbon steel.

What properties does manganese add to steel?

Manganese is added to steel to increase its working properties, tensile strength, toughness, and hardenability. It can also serve as a substitute for nickel.

What is the purpose of titanium in steel?

Titanium is used in steel for carbon stabilization, forming carbides that minimize the occurrence of intergranular corrosion, especially in the production of cutting tools.

How does phosphorus influence the machinability of steel?

Phosphorus, when combined with sulfur, improves the machinability of steel. However, in low alloy steel, it can increase strength but also the tendency to crack during welding.

What is the typical limit of sulfur content in steel, and why?

The typical limit of sulfur content in steel is 0.05 percent because beyond this, the steel's machinability decreases with an increase in sulfur content.

How does selenium improve steel?

Selenium improves the machinability and nobility of steel, enhancing its overall performance in manufacturing processes.

What is the function of niobium in steel?

Niobium, also known as columbium, is added to steel to stabilize carbon content, similar to the function of titanium.

What property does nitrogen enhance in steel?

Nitrogen increases the strength of steel, particularly in austenitic stainless steel, contributing to its overall performance.

How does silicon contribute to the properties of steel?

Silicon is used as a deoxidizing agent in the melting process of steel, and it contributes to hardening and electrical applications in devices and circuits.

What are the effects of cobalt on steel properties?

Cobalt, being ferromagnetic, is used in alnico alloys and is known for its high radioactivity, contributing to the magnetic properties of certain steel types.

Why is copper added to steel, and what benefits does it provide?

Copper is added to steel to increase its hardness and, more importantly, to enhance its corrosion resistance.

What is the primary function of zinc in steel?

Zinc is used in steel to increase both its corrosion resistance and hardness, improving the steel's durability and performance.