SAE/AISI Steel Nomenclature System

Due to modern research and development in the field of metallurgy, there are a huge number of different steels out there. Not all are "blacksmith friendly". (Maybe one should say MOST are not "blacksmith friendly.) By "blacksmith friendly", I mean a steel which is readily available, not terribly expensive and can be both forged and heat treated in the average blacksmith shop. The purpose of this topic is to help identify some of the types of steel that exist. Many of the steels listed below are not "blacksmith friendly", but at least you will know what types of steel they are and what alloys they contain.

The numbering system show below was developed by the Society of Automotive Engineers (SAE) and The American Iron and Steel Institute (AISI). Be aware that steels with the same chemical anaylsis may have different designations in different countries. For example: AISI/SAE 4140 steel in the US is 38CrMo4KB in Italy; SCN440 in Japan; 42CD4 in France; and F.8332 in Spain.

(( The xx in the numbers below indicates how many 1/100% of carbon are in the steel along with the other alloys.))

• 10xx -- Plain carbon steel (Mn 1.00% max)
• 11xx -- Resulfurized, free cutting
• 12xx -- Resulfurized and rephosphorized, free cutting
• 15xx -- Plain carbon steel ( Mn 1.00% to 1.65%)

• 13xx -- MN 1.75%

• 23xx -- Ni 3.50%
• 25xx -- Ni 5.00%

• 31xx -- Ni 1.25%, Cr 0.65% or 0.80%
• 32xx -- Ni 1.25%, Cr 1.07%
• 33xx -- Ni 3.50%, Cr 1.50% or 1.57%
• 34xx -- Ni 3.00%, Cr 0.77%

• 40xx -- Mo 0.20% or 0.25% or 0.25% Mo & 0.042% S
• 44xx -- Mo 0.40% or 0.52%

• 41xx -- Cr 0.50% or 0.80% or 0.95%, Mo 0.12% or 0.20% or 0.25% or 0.30%

• 43xx -- NI 1.82%, Cr 0.50%to 0.80%, Mo 0.25%
• 43BVxx -- NI 1.82%, Cr 0.50%, Mo 0.12% or 0.35%, V 0.03% min
• 47xx -- Ni 1.05%, Cr 0.45%, Mo 0.20% or 0.35%
• 81xx -- Ni 0.30%, Cr 0.40%, Mo 0.12%
• 86xx -- Ni 0.55%, Cr 0.50%, Mo 0.20%
• 87xx -- Ni 0.55%, Cr 0.50%, Mo 0.25%
• 88xx -- Ni 0.55%, Cr 0.50%, Mo 0.35%
• 93xx -- 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%

• 46xx -- Ni 0.85% or 1.82%, Mo 0.20% or 0.25%
• 48xx -- Ni 3.50%, Mo 0.25%

• 50xx -- CR 0.27% or 0.40% or 0.50% or 0.65%
• 50xxx -- Cr 0.50%, C 1.00% min
• 51xx -- Cr 0.80% or 0.87% or 0.92% or 1.00% or 1.05%
• 51xxx -- Cr 1.02%, C 1.00% min
• 52xxx -- Cr 1.45%, C 1.00% min

• 61xx -- Cr 0.60% or 0.80% or 0.95%, V 0.10% or 0.15% min

• 72xx -- W 1.75%, Cr 0.75%

• 92xx -- SI 1.40% or 2.00%, Mn 0.65% or 0.82% or 0.85%, Cr 0.65%

-- AlbinDrzewianowski - 16 Apr 2009