AISI D2 Air Hardening Tool Steel

• (Machine finish) T & B with saw-cut edges
• (Machine finish) FOUR SIDES
• HOLLOW BAR

DESCRIPTION

Ideal grade for maximum production runs. Has a machinability superior to any of the similar types of tool steel. Has excellent wear resistance, deep-hardening properties and high compressive strength.

ADVANTAGES

• Air-hardening—minimum change in size and shape during heat treatment. Most stable of all tool steels
• Deep hardening
• Very high wear-resistance

TYPICAL ANALYSIS

CARBON ……………….1.55 MOLYBDENUM ………….0.80

CHROMIUM ………….11.50 VANADIUM ………………0.90

HEAT TREATMENT

FORGING ………………………………..1900°F to 2050°F, stop at 1700°F and cool slowly

NORMALIZING ………………………...Do not normalize

ANNEALING ……………………………1650°F, furnace cool. Brinell 217 max

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

HARDENING …………………………….1850 °F, air quench to 150°F

TEMPERING ……………………………...900° F minimum. (See Dimensional Stability and Tempering)

MACHINABLITY

Has a machinability rating of 65, as compared with a rating of 100 for a 1 percent carbon tool steel.

DIMENSIONAL STABILITY

Tests normally show a slight amount of contraction after hardening with the part in the as-quenched condition or tempered below 900°F. tempering at approximately 9256 usually eliminates this contraction and brings the part virtually back to its original size. Has minimum distortion in heat treatment as compared with other tool steels.

TEMPERING RESULTS

For the tempering test, a set of specimens 1 in. square x 2-1/2 in. long was air-quenched from 1850° F. A similar set was quenched in oil. Specimens from both sets were then tempered at 100-degree intervals from 400° and 1200°F for two hours, and tested for Rockwell hardness. Results are as follows:

Results on 1-in. diameter specimens may be used as a guide in tempering tools to desired hardness. However, tools of heavy section or mass may be several points lower in Rockwell hardness for a given treatment.