Steel and Stainless Steel Fundamentals

In Steel and Stainless Steel Fundamentals, Types, and Applications, you'll learn ...

• The different types of metal crystal structures for steels and stainless steels
• The distinction between impurities, interstitial alloying elements, and substitutional alloying elements
• Fundamental concepts of alloying relevant to steels and stainless steels
• Common alloying elements in steels and stainless steels and their effects on microstructure, properties, and heat treatment
• The iron-carbon and iron-chromium phase diagrams and critical equilibrium phases and microstructures

Overview

Credit: 4 PDH

Length: 65 pages

Steels and stainless steels are the most commonly used types of engineering alloys. In general, steels and stainless steels can be alloyed and heat-treated to achieve a wide range of strength, ductility, and toughness. Steels’ versatility combined with its comparatively low cost to make, process and form into components makes it the most important engineering alloy. Stainless steels are ferrous alloys with the addition of ~11 wt.% - 12 wt.% chromium and other elements such as nickel and molybdenum to increase corrosion resistance. This property leads to stainless steels’ use in demanding environments where corrosion and oxidation may cause mechanical property degradation.

The raw materials and recycled scrap to make steels and stainless steels are generally abundant and inexpensive. Over 1.6 billion metric tons of carbon steel, tool steel, and stainless steel are produced annually, which is a significantly higher quantity than any other engineering alloy. Steels (both carbon and tool steels) and stainless steels are used in many industries including automotive, defense, power generation, petrochemical, heavy equipment and machinery, refineries, ships, railways, weapons, buildings, construction, power tools, household appliances, commercial kitchens, food processing, and surgical instruments.

Many engineers require knowledge of steel and stainless steel fundamentals, properties, microstructure, and applications to ensure that a component or structure does not fail. For example, civil and structural engineers must select plain carbon steels with sufficiently high strength for buildings so that deformation does not occur. A mechanical engineer may decide between stainless steels with different strengths and corrosion resistance for use in a petrochemical process. A biomedical engineer may decide on different types of austenitic stainless steels for a surgical instrument. Materials engineers and manufacturing engineers must understand how to make steels and stainless steels and then heat-treat components and fabricate structures.

This course first reviews essential fundamental aspects of steels and stainless steels including crystallographic structures, alloying, impurities, and common alloying elements. The second part of the course covers iron-carbon and iron-chromium phase diagrams including details on the most common phases that form in steels and stainless steels. This section of the course covers both equilibrium and non-equilibrium phases and microstructures. We also discuss the topics of sensitization and stabilization related to the undesirable presence of chromium carbides in stainless steels. In the third part of the course, we discuss different types of heat treatment processes relevant for many steels and stainless steels. We cover annealing, quenching and tempering, and precipitation hardening. In this section, we also discuss the hardenability of steels. In the fourth part of the course, we discuss categories of carbon steels, tool steels and stainless steels and their mechanical properties and applications. We also discuss carbon steel, tool steel, and stainless steel numbering systems in this section. Examples are provided throughout the discussion.