AISI P20 Alloy Pre-Hardened Mold Steel

DESCRIPTION

A chrome-moly tool steel made specifically to fill the requirements for the machined cavities and forces used in zinc die casting and plastic molding. Delivered fully quenched and tempered to approximately Brinell 300. Other hardness levels may be obtained through additional heat treatment.

ADVANTAGES

TYPICAL ANALYSIS

CARBON …………….0.35 MANGANES ……………..0.80

SILICON …………….0.50 CHROMIUM …………….1.70

MOLYBDENUM …….0.45

HEAT TREATMENT

For most zinc die casting and plastic molding operations, no further heat treatment is required. However, if the material is committed to reforging, or if higher hardness is required, or stress relieving is necessary after heavy machining, the following cycles are suggested:

STRESS RELIEVING…………………..1000°F, air cool

FORGING ………………………………..2000°F, stop at 1700°F and cool slowly

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

ANNEALING ……………………………1450°F to 1500°F, furnace cool, Brinell 207 max.

HARDENING …………………………….1550 °F, oil quench to 150°F

TEMPERING ……………………………...300° to 400° F for Rockwell C-54/55

NITRIDING………………………………...1000° to 1025° F for 25 hours produces 0.025 in. case depth

CARBURIZING……………………………1700° F for 8 hr produces approx 0.05 in. case depth

MACHINABILITY

Has a machinability rating of 65 in the prehardened condition, as compared with a rating of 100 for a one percent carbon tool steel. For rehardening P20 should be annealed first.

TEMPERING RESULTS

The temperature varies with the size of the piece and the application. Following are results of tests performed on a 1in. round specimen quenched in oil from 1555F. For large sections, the mechanical properties may be somewhat lower requiring an adjustment in tempering temperature.