PRECIPITATION HARDENING STAINLESS STEELS
Precipitation hardening (PH) stainless steels are the group of stainless steels that reach very high strength through a low temperature heat treatment known as ageing. The increase in strength comes from the fine precipitate particles that form within the structure.
The most important practical advantage of this group is that the material can be machined in the soft, solution treated condition (Condition A) and then aged once machining is complete. Because the ageing temperature is relatively low, distortion and dimensional change in the part are minimised — a decisive advantage in complex, close-tolerance parts.
Final strength is determined by the ageing condition selected. Low temperature conditions such as H900 give the highest strength, while higher temperature conditions such as H1025 and H1150 give up some strength in return for greater toughness and corrosion resistance. These grades are used in the aerospace, defence, energy and marine sectors in shafts, fasteners, valves and structural parts.
Choosing a grade. For applications requiring the highest strength and hardness, 1.4542 / 17-4 PH (AISI 630) is the most common grade in the group. Where a cleaner internal structure and better transverse toughness are needed at the same strength level, 1.4545 / 15-5 PH is the choice. For aerospace parts where fracture toughness and transverse properties are critical, 1.4534 / 13-8 PH is used. For applications involving thin sections, springs and forming, the semi-austenitic 1.4568 / 17-7 PH is suitable.
OUR PRECIPITATION HARDENING GRADES
- 1.4534 / 13-8Ph
- 1.4545 / 15-5Ph
- 1.4542 / 17-4Ph / AISI 630
- 1.4568 / 17-7Ph
- Custom 455 / (S45500)
Tell us the ageing condition you are aiming for (H900, H1025, H1150 and so on) and your size requirements, and we will review stock availability together — contact us.