Loading page
Should I use 17-4 PH or 304 stainless steel?
Use 304 for general corrosion-resistant parts, sheet metal, and anything welded or formed; it costs about half as much. Use 17-4 PH when a stainless part needs real strength: aged to H900 it reaches about 200 ksi (1,380 MPa) tensile and 44 HRC, nearly three times annealed 304, with comparable corrosion resistance. 17-4 PH is magnetic; annealed 304 is not.
Stainless steel 17-4 PH (H900)
Stainless steel 304
By the numbers
Priced on the same representative part: plate, cnc machining, 50 pcs.
Tensile strengthMPa
17-4 PH
1379
304 SS
505
Yield strengthMPa
17-4 PH
1275
304 SS
215
Densityg/cm³
17-4 PH
7.78
304 SS
8
Max service temp°C
17-4 PH
315
304 SS
925
Elongation%
17-4 PH
14
304 SS
70
Raw material cost$/kg
17-4 PH
12
304 SS
6
Which should you pick?
Pick 17-4 PH when
- Shafts, valve stems, pins or fasteners need high strength in stainless
- Hardness above 30 HRC is needed for wear
- The part can be machined near final size, then aged with little distortion
- The part is metal injection molded or 3D printed in stainless
Pick 304 SS when
- The part is sheet, drawn, bent or welded
- It must be non-magnetic
- Annealed strength, about 31 ksi (215 MPa) yield, is enough
- Cost matters more than strength
Key differences
| 17-4 PH | 304 SS | |
|---|---|---|
| How it gains strength | One aging treatment at 900–1,150 °F (482–621 °C) | Cold work only |
| Magnetism | Magnetic in all conditions | Non-magnetic when annealed |
| Machining | Condition A is about 35 HRC; slow and hard on tools | Soft but gummy; work-hardens |
| Heat treat distortion | Shrinks about 0.0004–0.0006 in/in when aged to H900 | Not heat treated |
| Condition choices | H900 for peak strength; H1025–H1150 for toughness and stress corrosion resistance | Annealed or cold-worked tempers |
| Product forms | Bar, plate, forgings, MIM feedstock and AM powder | Sheet, plate, bar, tube, wire and pipe |
Questions
Is 17-4 PH as corrosion resistant as 304?
Comparable in most atmospheres and fresh water. Neither is a chloride grade; for salt exposure, 316 is the better call. The H1025–H1150 conditions resist stress corrosion better than H900.
Which 17-4 PH condition should I specify?
H900 gives peak strength, about 200 ksi (1,380 MPa) and 44 HRC, with low impact toughness. H1150 gives about 145 ksi (1,000 MPa) and 33 HRC with much better toughness. H1025 is a common middle ground for shafts and valve parts.
Can 304 be hardened like 17-4 PH?
No. 304 cannot be hardened by heat treatment, only by cold work, as in quarter-hard to full-hard strip. For a hardenable stainless, use 17-4 PH or a martensitic grade such as 410 or 440C.
Try both on your part.
The builder prices the same geometry in every suitable process and material, with DFM for each.