Low, medium and high carbon steels and alloy steels have different uses.
Low-carbon (<0.25% C: ductile, weldable), medium-carbon (0.25–0.6%: strong, heat-treatable), high-carbon (>0.6%: hard, wear resistant), alloy steels (Cr, Ni, Mo, V improve hardenability and toughness), tool steels and HSLA. Designations AISI/SAE, EN.
AISI 1045 is common for shafts; 1018 for structural parts.
Steel types differ in carbon and alloy content, which sets their strength, weldability and corrosion resistance for each use.
Low, medium and high carbon steels and alloy steels have different uses.
Steel types differ in carbon and alloy content, which sets their strength, weldability and corrosion resistance for each use.
Higher carbon increases hardness and strength but reduces ductility and weldability.
Elements such as chromium, nickel and molybdenum improve hardenability, toughness, corrosion resistance or high-temperature strength.
Typical applications include choosing a low-carbon steel for a weldable structural section, specifying a high-carbon steel for a spring or cutting tool and selecting an alloy steel with chromium and molybdenum for a high-temperature pipe.
Study "Iron-carbon diagram" first (topic 17 of 100 in Materials & Chemical). It covers the groundwork this topic builds on.
Plain carbon vs alloy. Micro-alloying. Weldability by carbon equivalent.
AISI 1045 is common for shafts; 1018 for structural parts.
The next topic is "Heat treatment of steel", which builds directly on this one.
It is classed as Beginner in Materials & Chemical (topic 18 of 100). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
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