What’s In A Name?

AISI/SAE Steel Designations

Have you ever wondered how plain carbon and alloy grades are named? You can actually know how much carbon and what alloys are in the material by just knowing the designation.

Materials are designated by a four digit number, where

  1. the first digit indicates the main alloying element(s)
  2. the second digit indicates the secondary alloying element(s)
  3. the last two digits of these indicates the carbon content (hundredths of a percent)
    (example, in Grade 1045 the 45 indicates a nominal carbon content of 0.45 wt% C)

Here is the naming system used to determine the steel designations: Enjoy.

 

GRADE      TYPE OF STEEL & NOMINAL ALLOY CONTENT, %          

Carbon Steels

10XX               Plain carbon (Mn 1.00 max.)
11XX               Resulfurized
12XX               Resulfurized and rephosphorized
15XX               Plain carbon (max Mn range; 1.00-1.65)

 

Manganese Steels

13XX               Mn 1.75

 

Nickel Steels

23XX               Ni 3.50
25XX               Ni 5.00

 

Nickel-Chromium Steels

31XX               Ni 1.25; Cr 0.65 and 0.80
32XX               Ni 1.75; Cr 1.07
33XX               Ni 3.50; Cr 1.50 and 1.57
34XX               Ni 3.00; Cr 0.77

 

Molybdenum Steels

40XX               Mo 0.20 and 0.25
44XX               Mo 0.40 and 0.25

 

Chromium-Molybdenum Steels

41XX               Cr 0.50, 0.80, and 0.95;
Mo 0.12, 0.20, 0.25, and 0.30

 

Nickel-Chromium-Molybdenum Steels

43XX               Ni 1.82; Cr 0.50 and 0.80; Mo 0.25
43BVXX           Ni 1.82; Cr 0.50; Mo 0.12 and 0.25; V 0.03 min
47XX               Ni 1.05; Cr 0.45; Mo 0.20 and 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

 

Nickel-Molybdenum Steels

46XX               Ni 0.85 and 1.82; Mo 0.20 and 0.25
48XX               Ni 3.50; Mo 0.25

 

Chromium Steels

50XX               Cr 0.27, 0.40, 0.50, and 0.65
51XX               Cr 0.80, 0.87, 0.92, 0.95,1.00, and 1.05

 

Chromium (Bearing) Steels

50XXX             Cr 0.50
51XXX             Cr 1.02 C 1.00 min.
52XXX             Cr 1.45

 

Chromium-Vanadium Steels

61XX               Cr 0.60, 0.80, and 0.95; V 0.10 and 0.15 min

 

Tungsten-Chromium Steels

72XX               W 1.75; Cr 0.75

 

Silicon-Manganese Steels

92XX               Si 1.40 and 2.00; Mn 0.65, 0.82, and 0.85; Cr 0 and 0.65

 

High-Strength Low-Alloy Steels

9XX                  Various SAE grades

 

Boron Steels

XXBXX              B denotes boron steel

 

Leaded Steels

XXLXX              L denotes leaded steel

 


 

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