Mechanical Engineering - Engineering Materials - Discussion

Discussion Forum : Engineering Materials - Section 2 (Q.No. 1)
1.
Which of the following when used in ordinary low carbon steels, makes the metal ductile and of good bending qualities?
Sulphur
Phosphorus
Manganese
Silicon
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
4 comments Page 1 of 1.

Kuru said:   5 years ago
What is the source to say manganese increases ductility and bending?

If you have any source @Pradeep please provide.

Jaijeet said:   8 years ago
Sulphur: Improve machinability.

Silicon: Make steel porous and increase magnetic permeability.

Phosphorous: Improve machinability in free cutting steel.

Cobalt: Increase red hardness.

Chromium: Corrosion resistence.

Nickel: Inprove hardenability.

Tungesten: Heat resistance.

Manganese: In low carbon steel- improve ductility and in high carbon steel-increase hardenability.

Vanadium: Increase strength and hardenability.
(7)

Sathia said:   8 years ago
Good, Thanks @Pradeep.

Pradeep said:   1 decade ago
1. Silicon: The amount of silicon in the finished steel usually ranges from 0.05 to 0.30%. Silicon is added in low carbon steels to prevent them from becoming porous. It removes the gases and oxides, prevent blow holes and thereby makes the steel tougher and harder.

2. Sulphur: It occurs in steel either as iron sulphide or manganese sulphide. Iron sulphide because of its low melting point produces red shortness, whereas manganese sulphide does not effect so much. Therefore, manganese sulphide is less objectionable in steel than iron sulphide.

3. Manganese: It serves as a valuable deoxidising and purifying agent in steel. Manganese also combines with sulphur and thereby decreases the harmful effect of this element remaining in the steel. When used in ordinary low carbon steels, manganese makes the metal ductile and of good
bending qualities. In high speed steels, it is used to toughen the metal and to increase its critical temperature.

4. Phosphorus: It makes the steel brittle. It also produces cold shortness in steel. In low carbon steels, it raises the yield point and improves the resistance to atmospheric corrosion. The sum of carbon and phosphorus usually does not exceed 0.25%.
(1)

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