17-4 PH Stainless Steel (AISI 630)
17-4 PH is a precipitation hardening, martensitic stainless steel (17Cr-4Ni). It is noted for its high strength and hardness, excellent corrosion resistance and easy heat treatment. 17-4PH is usually machined to finished dimension in the solution heat treated and then strengthened by age hardening via the low temperature treatment process described below. 17-4 PH is magnetic in both the solution treated and age hardened conditions.
TYPICAL CHEMISTRY: C 0.07 max. Mn 1.00 max. P 0.040 max. S 0.030 Si 1.00 max. Cr 15.00/17.50 Ni 3.00/5.00 Cu 3.00/5.00 Cb + Ta 0.15/0.45
MACHINABILITY: 17-4PH is readily machinable in the solution treated and various age hardened conditions. More specifically, in the solution treated condition, this grade machines comparably to 302 and 304 stainless steels. In the hardened condition, when aged at 900° F (Condition H900) which produces a hardness of about HRC 44 the machinability is approximately 60% poorer than in the solution treated condition. When aged at 1100° F (H1100) which produces a hardness of about HRC 34, the machinability of this grade improves dramatically.
THERMAL CYCLING: No protective atmosphere is required for thermal cycling 17-4PH during aging or solution annealing because this grade is very low in carbon content.
Age Hardening° F Time at Heat Tensile Yield Rockwell “C”
(Hours)
H900 (482° C) 1 200,000 185,000 44
H925 (495° C) 4 190,000 175,000 42
H1025 (522° C) 4 170,000 165,000 38
H1075 (579° C) 4 165,000 150,000 36
H1100 (593° C) 4 150,000 135,000 35
H1150 (621° C) 4 145,000 125,000 33
WELDING: 17-4PH is readily weldable. A 17-4PH electrode is available and should be used where mechanical properties must be equivalent to the base metal. Preheating and post heating are not necessary. A maximum inter-pass temperature of 250° F should be maintained. To obtain the best possible weld microstructure, the material should be solution annealed after welding and then aged hardened as required. Where a weld deposit is not required to have the mechanical properties of the parent metal, a 304 or 308 type stainless steel rod may be used.
The values shown in this data sheet are to be used as a guide for estimating purposes only.
| Principal Design Features | One of the most widely used precipitation hardening grades in the business. While soft and ductile in the solution annealed condition, it is capable of high properties with a single precipitation or aging treatment. Characterized by good corrosion resistance, high harness, toughness and strength. |
| Applications | Commonly used in both aircraft and gas turbines, nuclear reactor, paper mill, oil field, powder metal injection molding industry, and chemical process components. |
| Machinability | Long, gummy chips characterize this alloys machinability. It can be machined in the annealed condition, however condition H1150M will yield best results. Post machining solution treatment of parts will be required prior to final hardening if machining in this condition. |
| Forming | This alloy is capable of being only mildly formed. If forming is required, do so in the overaged condition for best results. |
| Welding | Successfully welded by common fusion and resistance methods, this alloy should not be joined by oxyacetylene welding. AWS E/ER630 filler metal is recommended if required. |
| Heat Treatment | CONDITION A–Soak at 1900 F (1038 C) for 30 minutes and cool below 60 F (16 C) for complete martensite transformation. CONDITION H 950- Treat Condition A material at 900 F(482 C) for 1 hour, air cool.. CONDITION H925, H1025, H1075, H1100, H1150- Soak solution treated material for 4 hours at specified temperature, air cool, CONDITION H1150M- Soak solution treated material at 1400 F (760 C) for 2 hours, air cool, then re-heat to 1150 F (620 C) for 4 hours and air cool. |
| Forging | Soak for 1 hour at 2150 F (1177 C) prior to forging. Do not work below 1850 F (1010 C). Post-work solution treatment is required prior to final hardening. |
| Hot Working | 17-4 PH can be easily hot worked using most of the common processes. It is suggested that material be solution treated at 1900 F(1038 C) then formed during cooling while the material is still austenitic. Post-work solution treatment is required prior to final hardening. |
| Cold Working | Despite its high initial yield strength, 17-4 can be cold worked successfully by most common methods |
| Annealing | 1900 F (1038 C), hold for 1/2 hour, rapid cool. |
| Hardening | This alloy has good ductility and may be readily formed by all conventional methods. Because the alloy is stronger than regular steel it requires more powerful equipment to accomplish forming. Heavy-duty lubricants should be used during cold forming. |
Physical Data :
| Density (lb / cu. in.) | 0.28 |
| Specific Gravity | 7.74 |
| Specific Heat (Btu/lb/Deg F – [32-212 Deg F]) | 0.11 |
| Electrical Resistivity (microhm-cm (at 68 Deg F)) |
588 |
