Chapter 5

  Among the most useful of all metals  Contain iron as their base metal  Carbon and alloy steels  Stainless steels  Tool & die steels  Cast irons  Cast steels Ferrous 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, containers  Plates for boilers, ships, bridges  Structural steel such as I-beams, axles, bar products, railroad ties, crankshafts  Tools, dies and molds  Rods and wire for fasteners such a s bolts, rivets, nuts, and staples  The 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 percentages  The last two digits indicate the carbon content by weight  ASTM has another designation system Designations for steel

  Letter gives the general class of alloy  G- ANSI and SAE carbon steels  J- Cast steels  K-Miscellaneous steels and ferrous alloys  S-stainless steels  T-tool steels  5 digit number gives chemical composition UNS (Unified Numbering System) is the present system

  Classified by their proportion (by weight) of carbon content  Low-carbon steel or mild steel (<.30% Carbon)  Medium-carbon steel (0.3%<Carbon<0.6%)  High-carbon steel(>0.6% Carbon)  Resulfurized carbon steels  Alloy steels – steels containing significant amounts of alloying elements Carbon Steels

 TABLE 5.2 Typical Mechanical Properties of Selected Carbon and Alloy Steels

  Corrosion resistance  High strength  High ductility  High chromium content  “They 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 strength  Impact toughness  Wear resistance at room & elevated temperatures  Used in forming & machining metals Tool 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