XM-12 / 1.4545 / 15-5 PH
15-5PH is a variant of the older 17-4PH chromium-nickel-copper precipitation hardening stainless steel. Both alloys exhibit high strength and moderate corrosion resistance. High strength is maintained to approximately 600 degrees F. The 15-5 alloy was designed to have greater toughness than 17-4. This improved toughness is achieved by reduced delta ferrite content and control of inclusion size and shape. The fabrication characteristics of 15 – 5 PH are similar to those of other precipitation hardening grades; they can be age hardened by a single step, low temperature treatment.
Material Data Sheet
UNS S15500
AMS5658
AMS5659
ASTM 564
DFARS Compliant
AMS5862
AMS5562
Main fields of application of 1.4545
valve parts,
fittings and fasteners,
shafts,
gears,
chemical process equipment,
paper mill equipment,
aircraft components,
nuclear reactor components.
Chemical composition of 1.4545
| Cr | 14,0 - 15,5 | Si | 1,0 |
|---|---|---|---|
| Ni | 3,5-5,5 | Mn | 1,0 |
| Cu | 2,5-4,5 | P | 0,04 |
| C | max 0,07 | S | 0,03 |
| Nb + Ta | 0,15 - 0,45 |
Heat treatment
The key to the properties of precipitation hardening stainless steels lies in heat treatment.
Heat treatments are used to strengthen 15-5 alloys. There are eight standard conditions for 15-5 stainless steel after treatment – H 900, H 925, H 1025, H 1075, H 1100, H 1150, H 1150+1150 and H 1150-M. Heat treating 15-5 PH follows the following steps:
Conditioning using austenite.
Air cooling, which turns the austenite into martensite.
Precipitation hardening until the desired condition is reached.
15-5 PH can be further heat-treated when in precipitation-hardened condition to provide improved resistance to stress corrosion cracking for high temperature applications. Fabrication is recommended after the metal has been heat treated to minimize distortion and stress
Mechanical Properties
| Condition | UTS | Yield Strenght | Elongation | Reduction of area | Hardness Brinell | Hardness Rockwell |
|---|---|---|---|---|---|---|
| H900 | 190.000 | 170.000 | 6 | 15 | 388 | C40 |
| H1025 | 155.000 | 125.000 | 8 | 27 | 331 | C35 |
| H1075 | 145.000 | 125.000 | 9 | 28 | 311 | C32 |
| H1150 | 135.000 | 105.000 | 11 | 30 | 277 | C28 |
| H1150m | 115.000 | 75.000 | 14 | 35 | 255 |