17-4 Ph Stainless Steel Flange Rings manufactured at TorqBolt are high strength, good corrosion resistance, good mechanical properties at temperatures up to 600°F (316°C).
Dimensional standards as per DIN 471,DIN 472,DIN 5417,DIN 983,AS 568,BS 1806,ISO 3601,DIN 3771 are provided.
The raw material of these fasteners is classified as Martensitic Precipitation Hardening stainless steel. Being a PED certified Fasteners Manufacturer by TUV Rheinland,our fasteners are accompanied with EN 10204 3.1/3.2 certification. 17-4PH Flange Rings are available in hot forged,cold forged and bar stock machined conditions depending upon the order quantity.
17 4 PH Stainless Steel Flange rings are seamless rolled or open-die forged components used as pressure-vessel flanges, valve bodies, hub-mount blanks, and shaft-end retention rings. TorqBolt supplies 17 4 PH Stainless Steel Flange rings per ASTM A182 (forged flange standard), ASTM A266/A668 (carbon ring), and EN 10222 (pressure-purpose forging), in OD sizes from 50 mm up to 3000 mm.
Forging Process
Rings are produced via either seamless ring rolling (radial-axial mill, for OD > 200 mm) or open-die hammer forging (for short-run / oversize parts). Reduction ratio ≥ 4:1 from billet to final ring is enforced for grain-flow continuity. Heat treatment is per the alloy spec — solution-anneal + quench + age for precipitation-hardening alloys; quench & temper for low-alloy steels.
Dimensional Tolerance
17 4 PH Stainless Steel Flange rings are supplied to ASTM A788 dimensional tolerances by default: OD ±1.5 mm or ±1% (whichever is larger), ID ±1.5 mm, height ±0.8 mm. Tighter tolerances (machined finish, ±0.1 mm) available for direct-mount applications. Out-of-roundness controlled to 1.5 mm; concentricity 0.2 mm/100 mm.
Mechanical Testing
Each ring lot ships with full mechanical certification: tensile (ASTM E8), Charpy impact (ASTM E23) at the application's MDMT, hardness traverse, and grain size per ASTM E112. For 17 4 PH Stainless Steel Flange ring stock destined for hydrogen / sour service, additional HIC testing (NACE TM0284) and SSC testing (NACE TM0177) per the customer's spec.
Surface & Inspection
17 4 PH Stainless Steel Flange rings ship rough-machined or finish-machined per drawing. Standard NDT: 100 % UT (ASTM A388 reference) and surface MT/PT to ASTM E709 / E165. Radiography on request. Each ring is hard-stamped with heat number, lot, and certification reference for traceability through the dispatch chain.
Precipitation-Hardening (PH) Stainless Steels
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.
