AISI 4142 Multipurpose Alloy Steel This steel, also known as "Chrome – Moly" maintains exceptional fatigue, abrasion and impact resistant qualities as a result of its main alloying elements of chromium and molybdenum. Our 4142 product can be heat treated to increase its toughness and wear resistance. On its annealed state it can be readily formed and machined. It is useful in applications that require a lower hardness and less wear resistance than a fully heat treated tool steel, but it can be flame-hardened where a hardness is desired. Typical applications include: -  Crankshafts     -  Gears    -  Axies -  Shafts The chemical composition of our grade 4142 ground flat stock falls within ranges that are rigidly monitored. These chemical ranges are shown below * Precision Ground Tolerances  Thickness: +/-.001"  Width - Up to 8": -.000/+.005" Width - 9" and Over: -.000/+.015" Square:  +/-.001" Length - 18": Length - 24": Length - 36": Squareness (All Edges): +1/4" +1/2" +5/8" .003" per Inch Close Window *Source: Steel Products Manual – "TOOL STEELS" a publication of the Iron and Steel      Society  - June 2000