Low-alloy special purpose steel

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Low-alloy special purpose steel is a grade of tool steel characterized by its proportion of iron to other elements, the kind of elements in its composition, and its treatment during the manufacturing process. The three ASTM established grades of low-alloy special purpose steel are L2, L3, and L6. [1] This grade originally contained L1, L4, L5 and L7 as well as three F grades (F1, F2, and F3) but because of falling demand only grades L2 and L6 remain in production. [2]

Tool steel

Tool steel refers to a variety of carbon and alloy steels that are particularly well-suited to be made into tools. Their suitability comes from their distinctive hardness, resistance to abrasion and deformation, and their ability to hold a cutting edge at elevated temperatures. As a result, tool steels are suited for use in the shaping of other materials.


Grade%C %Cr %Mn %Mo %P %S %Si %V Other Rockwell hardness (C)
L20.45-1.00.7-1.20.1-0.90.25 max0.030 max0.030 max0.1-0.50.1-0.3S=0.06-0.15 if specified for machining; Ni+Cu<=0.7545-63
L30.95-1.101.3-1.70.25-0.8--0.030 max0.030 max0.1-0.50.1-0.3S=0.06-0.15 if specified for machining; Ni+Cu<=0.75
L60.65-0.750.6-1.20.25-0.80.50 max0.030 max0.030 max0.1-0.5--Ni=1.25-2.0;S=0.06-0.15 if specified for machining; Ni+Cu<=0.7545-62


L2 grade steel comes in medium-carbon (0.45%-0.65%) and high-carbon (0.65%-1.1%) formats. [2]


L6 is the most commonly encountered and most frequently made variety of these steels. It is known for its high wear resistance and its toughness. [3]


Applications for the L-series of tool steels have included precision gauges, bearings, rollers, cold-heading dies, swaging dies, feed fingers, spindles, jigs, shears, punches, and drills. They are also used for machining arbors, cams, chucks, and collets. [2] [3]

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  1. Fran Cverna (1 January 2006). Worldwide Guide to Equivalent Irons and Steels. ASM International. p. 1192. ISBN   978-0-87170-822-9.
  2. 1 2 3 Edmund Isakov (15 May 2008). Cutting Data for Turning of Steel. Industrial. p. 90. ISBN   978-0-8311-3314-6.
  3. 1 2 A. Alavudeen; N. Venkateshwaran; J. T. Winowlin Jappes (1 January 2006). A Textbook of Engineering Materials and Metallurgy. Firewall Media. p. 115. ISBN   978-81-7008-957-5.