17-4 Ph Stainless Steel Acorn Nuts 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 705,DIN 917,DIN 935,ISO 7035,DIN 1587,DIN 1123 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 Acorn Nuts are available in hot forged,cold forged and bar stock machined conditions depending upon the order quantity.
17 4 PH Stainless Steel Acorn nuts are internally threaded fasteners that mate with bolts and studs to form clamped joints. TorqBolt manufactures 17 4 PH Stainless Steel Acorn nuts per ASME B18.2.2, ISO 4032/4033/4034, DIN 934/EN 24032, and DIN 6915 (heavy hex), in sizes M6–M100 and 1/4"–4".
Nut Height Categories
Standard / regular hex nut — ~0.875×D height, ASME B18.2.2 Type 1
Heavy hex nut — ~D height, full strength matched to bolt grade (A194 2H pattern)
Jam / thin nut — 0.5×D height, used as locknut against a primary nut
Coupling nut — long-form for joining two threaded rods
Cap / acorn nut — closed-end, decorative + thread protection
Locking Variants
For vibration-loaded joints, 17 4 PH Stainless Steel Acorn nuts are available as nyloc (polymer insert), all-metal prevailing-torque (DIN 980, distorted-thread style), flange-serrated (DIN 6923, integral washer face with anti-back-off teeth), and castle / slotted (DIN 935, cotter-pin retention). Each locking style trades reusability against prevailing-torque retention.
Thread & Mechanical
17 4 PH Stainless Steel Acorn nut threads are gauged per ASME B1.1 / ISO 965 to Class 2B / 6H by default; high-strength variants use 3B / 4H6H. Proof-load testing per ASTM F606 verifies the nut can develop the bolt's full strength without thread strip; hardness range is controlled to prevent stress-corrosion susceptibility (HV 250–353 typical for high-grade nuts). Each lot is EN 10204 3.1 / 3.2 certified.
Special Patterns
TorqBolt also produces 17 4 PH Stainless Steel Acorn nuts in weld-nut, T-nut, square-nut, knurled thumb-nut, and rivet-nut patterns. NACE MR0175 / ISO 15156 sour-service certification available; NORSOK M-650 qualified mills supplying high-temperature service grades.
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.
