Chapter 5

Among the most useful of all metalsContain iron as their base metalCarbon and alloy steelsStainless steelsTool & die steelsCast ironsCast steelsFerrous metals and alloys

A ferrous alloy, as simple as a mixture of iron and carbon, but also containing a number of alloying elements to impart various properties

TABLE 5.1 Applications for Selected Carbon and Alloy Steels

Sheet steel for automobiles, appliances, containersPlates for boilers, ships, bridgesStructural steel such as I-beams, axles, bar products, railroad ties, crankshaftsTools, dies and moldsRods and wire for fasteners such a s bolts, rivets, nuts, and staplesThe average US passenger vehicle contains about 2700 lb of steel (60% of its weight)Examples of ferrous alloy uses

AISI and SAE designate carbon and alloy steels using 4 digits. The first two digits indicate the alloying elements and their percentagesThe last two digits indicate the carbon content by weightASTM has another designation systemDesignations for steel

Letter gives the general class of alloyG- ANSI and SAE carbon steelsJ- Cast steelsK-Miscellaneous steels and ferrous alloysS-stainless steelsT-tool steels5 digit number gives chemical composition

UNS (Unified Numbering System) is the present system

Classified by their proportion (by weight) of carbon contentLow-carbon steel or mild steel (

TABLE 5.2 Typical Mechanical Properties of Selected Carbon and Alloy Steels

Corrosion resistanceHigh strengthHigh ductilityHigh chromium contentThey are called STAINLESS because, in the presence of oxygen (air), they develop a thin, hard, adherent film of chromium oxide that protects the metal from corrosion.

Stainless Steels

TABLE 5.5 Mechanical Properties and Typical Applications of Selected Annealed Stainless Steels at Room Temperature

Specially alloyed steels designed for High strengthImpact toughnessWear resistance at room & elevated temperaturesUsed in forming & machining metalsTool and Die Steels

TABLE 5.6 Basic Types of Tool and Die Steels

TABLE 5.7 Processing and Service Characteristics of Common Tool and Die Steels

TABLE 5.8 Typical Tool and Die Materials for Metalworking Processes