Numbering Systems for Alloys

Ref: “Engineering Materials – Properties and Selection”, K.G. Budinski and M. K. Budinski, 7th ed., Prentice Hall, 2002 (Chap. 8 – 16)

How can you tell the others exactly which kind of material you want?

What do these codes mean?

AISI 1020 steel ASTM A 29 grade 1020 steel UNS G10200 SAE 1006

6061-T6 3003-H38

What You Should Include in the Specifications of a Material?

Description: e.g. steel, hot-finished, low-carbon, bar, ASTM A29 grade B

Dimension Chemical composition Mechanical properties Dimension tolerance: LWH, flatness, etc. Finish: hot-rolled, cold rolled, patterned Special requirements: heat treatment,

texture, etc.

Ferrous Alloys

Some Specifications applicable to Steel Products and other Metals

Specifications

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

ASTM(UNS)

American Society for Testing and Materials (www.astm.org)

ASME American Society of Mechanical Engineers

MIL U.S. Department of Defense

AMS Aerospace Materials Specification

BS British Standards Institution(http://www.bsi-global.com/index.xalter)

EN European Committee for Standardization (http://www.cenorm.be)

Classifications of Steel

The Most Widely Used System for Designating Steels SAE-AISI

Unified Numbering System (UNS) Developed by ASTM and

SAE Not a specification but

only identify an alloy covered by other standards

The 5 digits closely related to the original identification system. E.g. AISI 1020 = G10200

Adopted by the Copper Development Association as official identification system for Cu alloys

Most Frequently Used Carbon and Alloy Steels in the US

SAE 1010: formed sheet-metal parts SAE 1020: general machine applications SAE 1040: flame- or induction-hardened

parts ASTM A36: structural steel SAE 4140: high-strength machine parts SAE 4340: high-strength machine parts SAE 8620: carburized wear parts

Tool Steel Categories

Tool Steel Types High alloy content and thus high hardenability Melted by electric furnace for cleanliness and

alloy content control Melted in small heats and subjected to tight

quality control

Stainless Steel Family

Crucial Properties of Stainless Steels

A Repertoire of Stainless Steels

Type Uses

430S43000

For rust resistance on decorative an nonfunctional parts

416S41600

Hardened to 30 HRC and use for jigs, fixtures and base plates

420S42000

Harden to 50-52 HRC for tools that do not require high wear resistance (e.g. injection-molding cavities, nozzles, holding blocks, etc)

440CS44004

Harden to 58-60 HRC for cutting devices, punches and dies

A Repertoire of Stainless SteelsType Uses

303S30300

For fasteners and shafts where only rust or splash and spill resistance are needed

304/L All types of chemical immersion

316/L All types of chemical immersion where 304 is not adequate

17-4 PHS17400

High stress fasteners, shafting, agitators and machine supports; age hardened

17-7 PHS17700

Harden to condition CH900 for chemical-resistant springs

Aluminium Alloys

Wrought Aluminium Alloys – Aluminum Association designation system

Major Alloying Elements Series

Commercially pure aluminium (99% min) 1000

Copper (major alloying element) 2000

Manganese 3000

Silicon 4000

Magnesium 5000

Magnesium and silicon 6000

Zinc 7000

Other elements 8000

Unused series 9000

Second digit designates mill control on specific elements

The last two digits have no significance,

except…

Indicate the Al content above 99%, e.g. 1040

has 99.40% Al

Cast Aluminium Alloy Designations

Major Alloying Elements Series

Aluminium + silicon 1-99 (old system)

99.5 min. aluminium 1xx.x

Copper 2xx.x

Silicon + copper or magnesium 3xx.x

Silicon 4xx.x

Magnesium 5xx.x

Unused series 6xx.x

Zinc 7xx.x

Tin 8xx.x

Other Element 9xx.x

The last digit indicates product

form: 0 for a casting, 1 for ingot form

Additional Designation of the state of the Aluminium Alloy

Al alloys can be precipitation hardened and work-hardened to different extents.

xxxx-F As fabricated, no special control

xxxx-W Solution heat-treated (used only on alloys that naturally age harden)

xxxx-O Annealed (Wrought alloys only)

xxxx-H Strain hardened (cold worked to increase strength), wrought alloys only

xxxx-T Thermally treated to produce effects other than F, O, or H

Types of Strain Hardening and thermal treatment

xxxx-H1 Strain hardened only

xxxx-H2 Strain hardened and partially annealed

xxxx-H2 Strain hardened and stabilized by low-temperature thermal treatment

xxxx-H4 Strain hardened and lacquered or painted

Degree of Strain Hardening

The second digit indicate the degree of strain hardening

1 indicates smallest amount of cold-work and 8 indicates maximum of cold work

xxxx-H_2 Quarter-hard

xxxx-H_4 Half-hard

xxxx-H_6 Three-quarters hard

xxxx-H_8 Full-hard

Temper Designations

xxxx-T1 Cooled from a hot working temperature and naturally aged

xxxx-T2 Cooled from an elevated temperature, cold worked, and naturalled aged (means annealed for cast products)

xxxx-T3 Furnace solution heat treated, quenched and cold worked

xxxx-T4 Furnace solution heat treated, quenched, and naturally aged

xxxx-T5 Quenched from a hot-work temperature and furnace aged

Temper Designations

xxxx-T6 Furnace solution heat treated quenched and furnace aged

xxxx-T7 Furnace solution heat treated and stabilized

xxxx-T8 Furnace solution heat treated, quenched, cold worked, and furnace aged

xxxx-T9 Furnace solution heat treated, quenched, furnace aged and cold-worked

xxxx-T10 Quenched from an elevated temperature shaping process, cold worked, and furnace aged

Other variations can be denoted by adding more digits after these designations

Examples

3003-H38: 3003 alloy cold finished to full hard temper and stress relieved by a low temperature treatment

6061-T6: 6061 alloy, solution heat treated and furnace aged hardened.

Most commonly used Aluminium alloys

Wrought alloys 1100 (pure Al) 2024* 3003 5052 6061* 6063* 7075*

Sand Cast 355.0*

Die Cast 380.0

*: can be age hardened

Blue shaded: mainly for aerospace applications

More to come…

Steels and Al alloys are the most widely used alloys

Other important classes are Cu alloys, Mg alloys, Ni alloys and Ti alloys, etc.

ASM Metals Handbook or ASTM yearbooks are always good places to start when looking for the alloys information