Steel is an alloy of iron and carbon, often modified with other elements to achieve specific industrial performance. Its metallurgy is defined by the relationship between chemical composition, microstructure, and the resulting mechanical and physical properties uml.edu.ni 1. Fundamental Metallurgical Properties
Classifies steel by application and mechanical properties (e.g., S235JR where 'S' stands for structural steel and '235' is the yield strength in MPa). Summary of Common Steel Grades Steel Type Common Grade Key Characteristics Typical Use Case Low Carbon AISI 1018 / ASTM A36 High ductility, excellent weldability, low cost Structural beams, automotive panels Medium Carbon Balanced strength and ductility, heat-treatable Gears, shafts, crankshafts High Carbon Exceptional hardness, high wear resistance, low ductility Cutting tools, high-strength wires Alloy Steel AISI 4140 (Chromoly) High fatigue strength, toughness, deep hardenability Aircraft components, oil & gas drill collars Stainless Steel Grade 304 / 316 Superior corrosion resistance, excellent hygiene Medical devices, chemical processing Tool Steel Retains hardness at high temperatures, wear-resistant Stamping dies, injection molds 4. Industrial Applications of Steel Steel is an alloy of iron and carbon,
| Series | Structure | Corrosion Resistance | Example | Application | |--------|-----------|----------------------|---------|-------------| | 300 (Austenitic) | FCC, non-magnetic | Excellent | 304, 316 | Food equipment, chemical plants | | 400 (Ferritic/Martensitic) | BCC, magnetic | Good | 410, 430 | Cutlery, automotive trim | | 200 series | Austenitic, Mn-substituted | Moderate | 201 | Utensils, architectural | Summary of Common Steel Grades Steel Type Common
: The ability of the steel to deform under stress without fracturing. Hardenability low cost Structural beams
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