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AISI/SAE Steel and Alloys - Designation System

The AISI/SAE carbon steel and alloys naming conventions.

AISI/SAE steel numbers are indicated below.

  • AISI - American Iron and Steel Institute
  • SAE - Society of Automotive Engineers

Alloy steels and carbon steels can be designated with specific grades by a four-digit AISI/SAE numerical index system. The system is based on the chemical compositions of the steels and alloys.

Example AISI/SAE No. 1020

  • the first digit indicates that this is plain carbon steel.
  • the second digit indicates there are no alloying elements
  • the last two digits indicates that the steel contains approximately 0.20 percent carbon

Example AISI/SAE No. 4340

  • the first two digits indicates a Nickel-Chromium-Molybdenum alloy steel
  • the last two digits indicates carbon content roughly 0.4 percent
AISI/SAE Steel and Alloys - Designations
Steel/AlloyChemical Composition
10XX Carbon steels Plain carbon, Mn 1.00% max
11XX Resulfurized free machining
12XX Resulfurized / rephosphorized free machining
15XX Plain carbon, Mn 1.00-1.65%
13XX Manganese steel Mn 1.75%
23XX Nickel steels Ni 3.50%
25XX Ni 5.00%
31XX Nickel-chromium steels Ni 1.25%, Cr 0.65-0.80%
32XX Ni 1.75%, Cr 1.07%
33XX Ni 3.50%, Cr 1.50-1.57%
34XX Ni 3.00%, Cr 0.77%
40XX Molybdenum steels Mo 0.20-0.25%
44XX Mo 0.40-0.52%
41XX Chromium-molybdenum steels Cr 0.50-0.95%, Mo 0.12-0.30%
43XX Nickel-chromium-molybdenum steels Ni 1.82%, Cr 0.50-0.80%, Mo 0.25%
47XX Ni 1.05%, Cr 0.45%, Mo 0.20-0.35%
46XX Nickel-molybdenum steels Ni 0.85-1.82%, Mo 0.20-0.25%
48XX Ni 3.50%, Mo 0.25%
50XX Chromium steels Cr 0.27-0.65%
51XX Cr 0.80-1.05%
50XXX Cr 0.50%, C 1.00% min
51XXX Cr 1.02%, C 1.00% min
52XXX Cr 1.45%, C 1.00% min
61XX Chromium-vanadium steels Cr 0.60-0.95%, V 0.10-0.15%
72XX Tungsten-chromium steels W 1.75%, Cr 0.75%
81XX Nickel-chromium-molybdenum steels Ni .30%, Cr 0.40%, Mo 0.12%
86XX Ni .55%, Cr 0.50%, Mo 0.20%
87XX Ni .55%, Cr 0.50%, Mo 0.25%
88XX Ni .55%, Cr 0.50%, Mo 0.35%
92XX Silicon-manganese steels Si 1.40-2.00%, Mn 0.65-0.85%, Cr 0-0.65%
93XX Nickel-chromium-molybdenum steels Ni 3.25%, Cr 1.20%, Mo 0.12%
94XX Ni 0.45%, Cr 0.40%, Mo 0.12%
97XX Ni 0.55%, Cr 0.20%, Mo 0.20%
98XX Ni 1.00%, Cr 0.80%, Mo 0.25%

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    Properties of gases, fluids and solids. Densities, specific heats, viscosities and more.

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