Hexagon Bolts
- ANSI B18.2.1
- ANSI B18.2.3.1M
- DIN 931
- DIN 933
- BS 1768
- UNI 5731
- UNI 5737
- UNI 5739
- ISO 4014
- ISO 4017
- BS 1769
- BS 3692
15 5 PH Stainless Steel is a high-performance alloy used wherever standard fasteners cannot meet the corrosion, temperature, or strength envelope. TorqBolt manufactures the full 15 5 PH Stainless Steel fastener range — bolts, nuts, screws, washers, studs, and custom forgings — under one ISO 9001:2015 quality system, with PED 2014/68/EU module-H qualification for pressure-equipment service.
15 5 PH Stainless Steel is specified in oil & gas wellhead components, refinery heat exchangers, petrochemical reactors, power-generation turbines, marine offshore platforms, and pharmaceutical / food-grade processing. Its corrosion resistance, high-temperature strength, and weldability make it the default for service conditions outside the carbon and standard-stainless envelope.
15 5 PH Stainless Steel fasteners are supplied with EN 10204 3.1 (mill cert) or 3.2 (third-party witnessed) material test reports as standard. Additional certification packages: NACE MR0175 / ISO 15156 (sour service), NORSOK M-650 (subsea / topside), API 6A (wellhead), API 20E (subsea bolting), PED 2014/68/EU (pressure equipment). Third-party inspection by TUV, Lloyd's, BV, DNV, SGS, and Intertek arrangeable on order.
Stock items in standard 15 5 PH Stainless Steel fastener sizes ship in 1–2 weeks; custom-manufactured items in 4–6 weeks subject to material availability. Diameters M6–M100 and 1/4"–4", lengths 10 mm–3000 mm covered in-house; oversize / non-standard sizes quoted to specification.
Precipitation-hardening (PH) stainless steels combine the corrosion resistance of austenitic stainless with the high strength of martensitic grades. A two-step heat treatment — solution anneal followed by ageing at 480-620°C — precipitates Cu, Ti, or Al-rich phases that lock the matrix at tensile strengths up to 1300 MPa with minimal distortion.
17-4 PH (UNS S17400 / AMS 5643) is the dominant grade: Cu-precipitation hardened, with corrosion roughly equivalent to AISI 304. Five standard ageing conditions H900 (highest strength), H925, H1025, H1075, H1150 trade strength against fracture toughness. 15-5 PH (S15500) is the through-thickness-tougher variant with reduced delta-ferrite. 13-8 PH (S13800) and 17-7 PH (S17700) are higher-strength variants for aerospace + spring fasteners.
PH fasteners are supplied per ASTM A693 / AMS 5643 with EN 10204 3.1 / 3.2 certification including hardness (HRC 32-48 by condition), tensile, and Charpy impact. NACE MR0175 service for PH grades is restricted to specific heat-treat conditions (H1150 only for 17-4) due to SSC susceptibility. Welding requires post-weld solution + age cycle to recover full strength.