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Questions and Answers

What is steel?

A metal consisting of iron and carbon (correct)

A nonferrous metal

A metal containing only gold

A type of plastic

What TWO factors determine the behavior and properties of a particular metal?

Chemical composition, heat treatment

What does chemical composition refer to?

The combination of materials at the atomic level

What is heat treatment?

The heating and cooling process used to change the structure of a metal Signup and view all the answers

All steels contain , __.

iron, carbon Signup and view all the answers

What is Alloy Steel?

A steel containing another material added intentionally Signup and view all the answers

What is an Electric Arc Furnace?

A type of furnace used during the steel-making process Signup and view all the answers

What are the two key organizations that combined to create the classifications of steel?

The American Iron and Steel Institute (AISI), Society of Automotive Engineers (SAE) Signup and view all the answers

What does AISI-SAE Designations refer to?

A classification system using a three- or four-number code Signup and view all the answers

What is another common classification system for metals?

Unified Numbering System (UNS) Signup and view all the answers

What are plain carbon steels?

The basic type of steel containing less than 3% elements other than iron and carbon Signup and view all the answers

Carbon steels account for over 75% of manufactured steel .

carbon steels Signup and view all the answers

What are impurities in metals?

Unwanted substances that reduce the quality of a material Signup and view all the answers

Match the following groups with their carbon content:

Low-carbon steels = Less than 0.3% carbon Medium-carbon steels = Between 0.3% and 0.5% carbon High-carbon steels = More than 0.5% carbon Signup and view all the answers

What does hardenability refer to?

A metal's ability to be hardened by normal heat treatment processes Signup and view all the answers

What characteristic do stainless steels have?

Exhibits excellent corrosion resistance Signup and view all the answers

What defines Tool steels?

Designed with high wear resistance, toughness, and strength Signup and view all the answers

What element is used to add hardness and wear resistance to steel?

Chromium Signup and view all the answers

What are nonferrous metals?

Metals that do not intentionally contain iron Signup and view all the answers

How can nonferrous metals be classified?

Using the Unified Numbering System (UNS) Signup and view all the answers

Study Notes

Steel and Definition

Steel is a metal alloy primarily composed of iron and carbon, often containing small amounts of manganese, phosphorus, sulfur, and silicon.

Metal Grades and Classification

Grades refer to numerical designations that describe the content of metal alloys.
Classification of metals helps to understand their specific properties and behaviors.

Factors Influencing Metal Properties

The behavior and properties of metals are determined by:
- Chemical composition: The atomic-level makeup of the material.
- Heat treatment: A process of heating and cooling to change the metal's structure and properties.

Steel Composition

All steel contains primarily iron and carbon.
Alloy steel contains additional materials intentionally added to enhance specific properties.

Steel Production Process

Electric arc furnaces utilize electric arcs between electrodes to transform pig iron and other materials into steel.

Organizations and Classification Systems

The American Iron and Steel Institute (AISI) and the Society of Automotive Engineers (SAE) created the classifications for steel.
AISI-SAE designations use a three- or four-number code to indicate the percentages of a steel's components.
The Unified Numbering System (UNS) employs five numbers for classification and is not limited to steel.

Types of Carbon Steel

Plain carbon steels contain less than 3% of elements other than iron and carbon, making them the most "pure" form.
Carbon steels account for more than 75% of manufactured steel, with three main groups:
- Low-carbon steels: Contain less than 0.3% carbon.
- Medium-carbon steels: Contain between 0.3% and 0.5% carbon.
- High-carbon steels: Contain more than 0.5% carbon.

Carbon Steel Series

Four series define different carbon steels:
- 10XX: No added elements.
- 11XX: Extra sulfur.
- 12XX: Extra sulfur and phosphorus.
- 15XX: Contains manganese in the range of 1.00-1.65%.

Steel Designations

"E": Stands for steels produced in an electric arc furnace.
"H": Indicates special hardenability properties of the metal.
"B": Indicates the presence of boron.
"L": Indicates the presence of lead.

Specialized Steel Types

Stainless steels are characterized by more than 15% chromium and excellent corrosion resistance.
Tool steels are designed for high wear resistance, toughness, and strength.

Additional Metal Types

Chromium is used in ferrous alloys to enhance hardness and wear resistance; stainless steels contain significant amounts of chromium.
Nonferrous metals are classified using the UNS and do not intentionally contain iron.