AISI A2 Air Hardening Tool Steel

(Machine finish) T & B WITH SAW-CUT EDGES
(Machine finish) FOUR SIDES
PRECISION GROUND
HOLLOW BAR
DRILL ROD

DESCRIPTION

An air-hardening tool steel containing five percent chromium. Replaces the oil hardening ( 0 1 type) when safer hardening, less distortion and increased wear-resistance are required. Provides an intermediate grade between the oil hardening and the high carbon, high chromium (d 2) types.

ADVANTAGES

Low distortion in heat-treatment
Good machinability
High abrasion-resistance and hardness
Good toughness for severe service
Deep hardening properties in large sections

TYPICAL ANALYSIS

CARBON…..1.00 MOLYBDENUM…..1.10 MANGANESE…..0.60

VANADIUM…..0.25 CHROMIUM…..5.25

HEAT TREAT

FORGING……………… 2000° to 2050° F, stop at 1700°F, cool slowly

NORMALIZING……… Do not normalize

ANNEALING…………. 1650° F, furnace cool, average Brinell 212

PREHEATING………… 1200° F, prior to hardening

HARDENING…………. 1775° F, air quench to 150°F

TEMPERING………….. 350° to 400° F, resulting hardness, Rockwell C 60-61

MACHINABILITY

Machines easily when properly annealed to 212 Brinell. Has a factor of 65 as compared with a one percent carbon tool steel which has a rating of 100.

TEMPERING RESULTS

The Rockwell C hardness obtained on specimens 1 in square when quenched in air from 1800° F, and quenched in oil from 1750° F and tempered at various temperatures are as follows:

	Hardness Rockwell C
Tempering Temperatures F	1800 F Air-Quench	1750 F Oil-Quench
None	64	65
300	62	62.50
400	60	61
500	56	57.50
600	56	56
700	56	56
800	56	56
900	56	56
1000	56	55
1100	50	50
1200	43	45
1300	34	34

These results may be used as a guide in tempering tools to desired hardness. However, since 1 in. specimens were used in this test, tools of heavy section or mass may be several points lower in Rockwell hardness for a given treatment.