Material
Stainless 17-4 PH Parts
When stainless needs to be strong, not just clean.
17-4 PH is the stainless for parts where 304 would bend or wear out: heat-treatable to roughly 190 ksi tensile in the H900 condition while keeping corrosion resistance close to 304. It’s the grade of pump shafts, valve internals, actuator parts, and tooling that has to stay accurate under load. Put the condition (H900, H1025, H1150) on the print like a tolerance and send it through the quote form. Quotes in 24-48 hours.
Updated June 2026
Stainless 17-4 PH
Heat-treatable stainless: high strength and corrosion resistance in one part. Slow to cut, priced accordingly.
Typical parts
- Shafts & gears
- Valve components
- Tooling & wear parts
- High-strength fasteners
Stainless that takes heat treatment
Most stainless trades strength for corrosion resistance; 17-4 PH (precipitation-hardening, also sold as AISI 630) largely refuses the trade. It’s supplied in the soft Condition A, cuts cleanly in that state, and then a single low-temperature aging cycle (900 to 1150 °F, depending on the condition) brings it to full strength with minimal distortion, no quench, and no scale. That’s why tight-tolerance parts can be finished close to final size before hardening.
Pick a condition like you’d pick a tolerance
H900 is peak strength (about 190 ksi tensile and 170 ksi yield) for maximum load capacity. H1025 gives up some of that for meaningfully better toughness and is a sane default for shafts and dynamic parts. H1150 is the tough, shock-tolerant end of the range, with the best resistance to stress-corrosion cracking. The condition is just a callout on your print, same as a finish, and if you’re not sure which fits, engineering support can help you pick before anything is quoted.
Where it fits, and where it doesn’t
17-4 replaces 304 when parts deform or wear: shafts, valve stems and seats, pump internals, actuator components, latches, and fixture or tooling details that have to hold dimension under stress. It also replaces plated alloy steels like 4140 when you’d rather not manage a coating just to fight rust: the corrosion resistance is in the base metal.
Honest limits: it’s magnetic (it’s martensitic: the magnet test proves nothing about whether stainless is “real”), its corrosion resistance sits a notch below 304, and chloride-heavy environments like marine or brine service are better served by 316, or by H1150 if 17-4’s strength is still required.
Questions
Before you send a job.
01 What do H900, H1025, and H1150 actually mean?
The aging temperature in degrees Fahrenheit. Condition A material is held at that temperature and cooled, and the precipitates that form set the properties: lower temperature, higher strength (H900); higher temperature, more toughness (H1150). The number on your print is the whole specification.
02 Which condition should I call out?
H900 when the math demands maximum strength. H1025 as the balanced default for shafts and dynamic loads. H1150 for shock, impact, or stress-corrosion exposure. If the print doesn’t say, expect the question: the condition changes the part’s behavior too much to guess.
03 How does 17-4 compare to 304?
Three to four times the yield strength, slightly lower corrosion resistance, and it’s magnetic. 304 wins for welded assemblies, food contact, and chloride exposure. 17-4 wins the moment strength, wear, or holding tolerance under load enters the picture.
04 Is 17-4 magnetic?
Yes, it’s martensitic, so it pulls a magnet about like carbon steel does. If a requirement says “non-magnetic stainless,” 17-4 is the wrong grade and 303, 304, or 316 is the right neighborhood. A magnet tells you the stainless family, not the quality.
05 Why pick 17-4 over 4140 or another alloy steel?
Comparable strength without the rust management. 4140 needs plating, coating, or oil to live anywhere damp, and every coating is a process, a cost, and a thing that wears off. 17-4 carries its corrosion resistance in the base metal. If the part lives dry and budget rules, 4140 still makes sense. Both quote fine.
Related
Where to go next.
Stainless 303 & 304
The general-purpose stainless picks.
View →Stainless Steel
The grade guide across 303, 304, 316, and 17-4.
View →Precision Grinding
Ground diameters and tight fits on hardened parts.
View →Shafts & Pins
Hardened shafts and pins that hold their fit.
View →Get a Quote
Print + condition callout in, quote back in 24-48 hours.
View →Get Started
Send us your files.
We’ll take it from there.
A quote in 24-48 hours, no minimums. Like the quote, and we’ll make your parts and ship them to you.
Get a Quote