Question

The main constituents of stainless steel are:

• A. Iron, chromium, nickel and carbon
• B. Iron, carbon, chromium and tungsten
• C. Iron, nickel, carbon and vanadium
• D. Iron, nickel, carbon and tungsten

Hint:

Remember that chromium is the key element that gives stainless steel its corrosion-resistant properties, and nickel adds strength and toughness.

Answer 1

The Correct Option is A

Step 1: Understanding Stainless Steel Composition
Stainless steel is an alloy made primarily from iron, chromium, nickel, and carbon. Let's break down each component:

1. Iron (Fe): Iron is the base metal in stainless steel. It provides the bulk structure and strength to the material. It is malleable and forms the core matrix of the alloy.
2. Chromium (Cr): Chromium is a crucial element in stainless steel. It is responsible for its corrosion resistance and durability. Typically, stainless steel contains at least 10.5% chromium by weight, which forms a protective oxide layer on the surface of the steel, preventing rust and oxidation.
3. Nickel (Ni): Nickel is added to stainless steel to enhance its strength and toughness. It also improves the steel's resistance to corrosion, especially in acidic or alkaline environments. Nickel gives stainless steel its characteristic shine and smooth texture.
4. Carbon (C): Carbon is used to increase the hardness of stainless steel. However, too much carbon can make the steel brittle. The amount of carbon is typically kept to a low level (less than 2%) to balance strength and ductility.

Step 2: Common Types of Stainless Steel
There are various grades of stainless steel, with the most common being 304 and 316 grades. Both contain iron, chromium (usually around 18-20%), nickel (8-10%), and small amounts of carbon. The specific proportions of these elements vary depending on the grade and desired properties.

• 304 Stainless Steel: The most commonly used stainless steel, known for its corrosion resistance and general-purpose strength. It typically contains 18% chromium and 8% nickel, with a low carbon content.
• 316 Stainless Steel: A higher-grade stainless steel with better resistance to chloride corrosion (ideal for marine environments). It contains 16-18% chromium, 10-14% nickel, and also includes 2-3% molybdenum.

Step 3: Conclusion
The correct answer is option (1), as iron, chromium, nickel, and carbon are the main constituents of stainless steel. Tungsten, vanadium, and other elements are sometimes included in specialized grades of steel, but they are not the primary components of standard stainless steel.
Conclusion:

Iron, chromium, nickel, and carbon