Technical guide3 min read
How should you specify 17-4 PH material condition?
17-4 PH is bought in a heat-treatment condition, not just a grade. What Condition A and the H conditions mean and how to specify them.
Short answer: always state the condition with the grade. 17-4 PH (UNS S17400) is a precipitation-hardening stainless steel supplied solution treated, called Condition A, and then aged to reach its strength. The H number in an aged condition is the ageing temperature in degrees Fahrenheit. A higher number means a lower strength and better toughness and ductility.
| Condition | What it means |
|---|---|
| A | Solution treated. Machinable, and aged after machining if the part needs full strength |
| H900 | Aged at 900 degrees F (about 480 degrees C). Highest strength, lowest toughness |
| H1025 | Aged at 1,025 degrees F. A common balance of strength and toughness |
| H1075 | Aged at 1,075 degrees F. Lower strength, better toughness |
| H1150 | Aged at 1,150 degrees F. Lowest strength of these, best toughness and stress-corrosion resistance |
Scroll the table horizontally to see all columns.
What to state when you order
- Grade and UNS number, and the specification, for example ASTM A564 for bar.
- The condition, for example Condition A or H1025, and whether ageing is done before or after machining.
- Size, tolerance and finish.
- The certificate you need, and any hardness or mechanical test requirement.
Grades covered
Products covered
Specifying for a live project?
Send the service conditions and we will tell you what we would specify, and what we hold.