An extremely strong precipitation hardened stainless steel

• Well suited for high strength applciaitons
• Up to 4x stronger than 316 stainless steel
• Maintains its mechanical strength up to 600°F
• 17-4PH Chemistry & Specifications
• ASTM F593 Gr 630
• ASTM A564 Gr 630
• 17-4PH Torx screw features and benefits
• 17-4PH Datasheet

17-4 PH Torx screws are made from a precipitation hardened stainless steel most known for its exceptional strength and its ability to maintain its mechanical properties to 600°F. Compared to 316 stainless steel, 17-4 PH Torx screws yield strength is up over 4 times greater. When compared to Duplex 2205 screws, the yield strength of 17-4 PH can be up to 2-½ times greater.

17-4 Torx screws are available in 8 different aged (precipitation hardened) conditions offering a variety of mechanical properties (see below). 

Resources: 17-4PH Torque Specs

17-4 PH Screw Types: 12 Point Screws, Button Head Cap Screws, Flat Head Screws, Hex Cap Screws, Pan Head Screws, Set Screws, Socket Head Cap Screws, Tamper Resistant Security Screws, Torx Screws, Vented Screws

17-4 PH Torx Screw Features and Benefits

17-4 PH Torx screws are characterized by a 6-point star-shaped pattern, also called a star drive, spined socket or hexalobular (ISO 10664). Where Phillips heads were designed to cause the driver to cam-out (prevent overtightening), Torx screws were designed resist cam-out. This feature allows 17-4 PH Torx screws to provide increased torque as well as better torque transfer between driver and fasteners. This feature also helps to reduce wear on driver bits.

17-4 PH Torx Screw Advantages

• Resistant to cam out (process by which a screwdriver slips out of the head)
• 17-4 PH Torx screws are more difficult to strip
• Increased tamper resistance as a star driver isn’t as common
• Driver insert is less susceptible to damage when over torqued than Allen head

17-4PH Chemistry & Specifications

17-4PH Specifications: UNS S17400, AISI 630, ASTM A564-630, Werkstoff 1.4542, AMS 5604 Sheet, Strip and Plate, ASTM A 693 Plate

ASTM F593, Grade 630
This specification covers seven groups of stainless steel alloys, with ASTM F593, Grade 630 applying 17-4PH. ASTM F593 Grade 630 covers the requirements for 17-4PH stainless steel bolts, hex cap screws, and studs sized 0.25 to 1.50 inches, inclusive, in nominal diameter. It is intended for common use and for service applications requiring general corrosion resistance.

Common 17-4 Fastener Conditions:  Aged Conditions vs Tensile Strength

ASTM A564 GR 630
This specification covers bars and shapes (such as fasteners) of age hardened stainless steels such as 17-4PH. It includes hot-finished or cold-finished fasteners that are produced by hot rolling, extruding, or forging. Grade 630 shall be furnished in the solution-annealed or or age-hardened condition.