Introduction to the SAE-AISI Designation System

By: Rosales Eldwin Fritz D. Sicsic Justyn Wayne M.Introduction to the SAE-AISI Designation SystemObjectives: To be able to know the specification numbers of both SAE/AISI materials.

To familiarize at least a couple of metal specification numbers regarding SAE-AISI materials. AISI AND SAE SPECIFICATION NUMBERS

There are numerous standard materials specifications. Many large consuming organizations and nearly all producers have some standards of their own. The armed forces have numerous ones. The principal agencies whose specifications are most widely used are: ASTM American Society for Testing Materials.

SAE Society of Automotive Engineers

AISI American Iron and Steel Institute Difference between AISI/SAE: SAE and AISI specification numbers are alike in terms of steels except: The AISI uses prefixes B,C,D, and E to indicate the method of manufacturing the carbon grades.In general way for steel, the first digit (or the first two digit) of the number represents the type of steel. The last two digits in four-digit numbers invariably give the approximate or average carbon content in points or hundredths of percent. Schematic Representation of AISI/SAE Steel Designation System:

The said figure demonstrates that the SAE-AISI system uses a four-digit number to designate a carbon and alloy steel and refers to its specific chemical composition. However, that there are also certain types of alloy steels that are designated by five digits ( 51XXX; 52XXX). The SAE/AISI system classifies all other alloy steel using the same four digit index as follows: 2 - Nickel steels;3 - Nickel-chromium steels;4 - Molybdenum steels;5 - Chromium steels;6 - Chromium-vanadium steels;7 - Tungsten-chromium steels;9 - Silicon-manganese steels.

In general way for steel, the first digit (or the first two digits) of the numbers represents a type of steel, for example:1XXX - is a plain carbon steel.

11XX - is a plain carbon steel with greater sulfur content for free cutting.

2XXX - is a nickel.

The last two digits in four-digit numbers invariably give the approximate or average carbon content in points or hundredths of percent, for example:

SAE 1030 or an AISI C1030 has about 0.30% carbon, spoken of as 30 points of carbon (nominal range is 0.28%-0.34%). Or in 8620, the average carbon content is close to 0.20% (range of 0.18%-0.23%).System of specification numbers for steel- AISI and SAE In the AISI system, prefixes have the following meanings: H Hardenability B acid bessemer steelC basic ,open-heart carbon steelD acid open heart carbon steelE electric-furnace steelL Lead M merchant quality steelLetters B or L in the middle of the number indicates that boron or lead, respectively, has been added as: 94 B 40 and 11 L 41.

An H at the end indicates that material can be bought on hardenability specification as:9840HCARBON STEELS10XX11XX12XX15XXPlain carbon, Mn 1.00% maxResulfurized free machiningResulfurized/rephosphorized free machiningPlain carbon, Mn 1.00-1.65% Manganese Steel13XXMn 1.75%Nickel Steels 23XX25XXNi 3.50%Ni 5.00%Nickel-chromium Steels31XX32XX33XX34XXNi 1.25%, Cr 0.65-0.80%Ni 1.75%, Cr 1.07%Ni 3.50%, Cr 1.50-1.57%Ni 3.00%, Cr 0.77%Molybdenum Steels40XX44XXMo 0.20-0.25%Mo 0.40-0.52%Chromium-molybdenum Steels41XXCr 0.50-0.95%, Mo 0.12-0.30%Nickel-chromium-molybdenum steels43XX47XXNi 1.82%, Cr 0.50-0.80%, Mo 0.25%Ni 1.05%, Cr 0.45%, Mo 0.20-0.35%Nickel-molybdenum steels46XX48XXNi 0.85-1.82%, Mo 0.20-0.25% Ni 3.50%, Mo 0.25%Chromium steels50XX51XX50XXX51XXX52XXXCr 0.27-0.65%Cr 0.80-1.05%Cr 0.50%, C 1.00% minCr 1.02%, C 1.00% minCr 1.45%, C 1.00% minChromium-vanadium steels61XXCr 0.60-0.95%, V 0.10-0.015%Tungsten-chromium steels72XXW 1.75%, Cr 0.75%Nickel-chromium-molybdenum steels81XX86XX87XX88XXNi 0.30%, Cr 0.40%, Mo 0.12%Ni 0.55%, Cr 0.50%, Mo 0.20%Ni 0.55%, Cr 0.50%, Mo 0.25%Ni 0.55%, Cr 0.50%, Mo 0.35%Silicon-manganese steels

Nickel-chromium-molybdenum steels92XX

93XX94XX97XX98XXSi 1.40-2.00%, Mn 0.65-0.85%, Cr 0-0.65%

Ni 3.25%, Cr 1.20%, Mo 0.12%Ni 0.45%, Cr 0.40%, Mo 0.12%Ni 0.55%, Cr 0.20%, Mo 0.20%Ni 1.00%, Cr 0.80%, Mo 0.25%A brief suggestion of typical uses of plain carbon wrought steel is as follows:Carbon 10-20 points, 10XX group used for tubing, forgings, pressed-steel parts, screws, rivets and for case-hardened parts.

Carbon 10-20 points, 11XX group due to high sulfur content, it is free-cutting and good for use in automatic screw machines and for other parts including screws and also may be carburized.Carbon 20-30 points General purpose grades. Used for forged and machined parts, screws; also for boiler plate and structural steel.

Carbon 30-55 points with 0.40-0.50% C, frequently used for miscellaneous forged and machined parts; shafts.

Carbon 60-90 points may be hardened to a cutting edge, especially in the higher ranges of carbon; therefore used for tools and also for springs. High strength, low ductility. Nearly always heat treated, say, to a Brinell hardness 375 or higher. THANK YOU VERRY MUCH FOR LISTENING!!