Aisi 304 Stainless Steel Rings manufactured at TorqBolt are corrosion resistant,low maintainence,silver finish.
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 Austenitic Stainless Steel. Being a PED certified Fasteners Manufacturer by TUV Rheinland,our fasteners are accompanied with EN 10204 3.1/3.2 certification. Aisi 304 Stainless Steel Rings are available in hot forged,cold forged and bar stock machined conditions depending upon the order quantity.
AISI 304 is most versatile and most common type of steel, it is also termed as 18/8 which is given on the basis of its composition where 18% of nickel and 8% of chromium is used. It is mostly used in day to day applications such as sinks and pans, cutlery and flatware, dairy production equipments, medical implants. It has good corrossion resistance, however pitting and corrosion resistance can occure due to chloride environments. This material however maintains acquious corrossion resiatance. It also shows good resiatnce to oxidation upto temperatures as high as 870 degrees celcious.
AISI 304 Stainless Steel Rings — Forged Ring Specifications
AISI 304 Stainless Steel 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 AISI 304 Stainless Steel 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
AISI 304 Stainless Steel 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 AISI 304 Stainless Steel ring stock destined for hydrogen / sour service, additional HIC testing (NACE TM0284) and SSC testing (NACE TM0177) per the customer's spec.
Surface & Inspection
AISI 304 Stainless Steel 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.
Austenitic Stainless Steel (300-series)
Austenitic stainless steels form the workhorse 300-series — face-centered cubic Fe-Cr-Ni alloys delivering excellent corrosion resistance, formability, weldability, and toughness from cryogenic to ~600°C. They are non-magnetic in the annealed condition and the default choice for food, dairy, pharmaceutical, marine, and general process-industry fasteners.
AISI 304 (18Cr-8Ni, UNS S30400) is the baseline; 304L (low-C) prevents weld sensitization for thicker sections. AISI 316 adds 2-3% Mo for chloride pitting resistance, and 316L is the welding-grade marine standard. 309 / 310 are the high-Cr grades for elevated temperatures (to ~1100°C). 321 / 347 are Ti / Nb-stabilized for stress-relieved welded service. 304LN / 316LN add nitrogen for higher yield without sacrificing corrosion.
Austenitic fasteners are supplied per ASTM A193 grade B8 (304), B8M (316), B8T (321), B8C (347) and ASTM A276 / A479 for general bar. EN 10204 3.1 / 3.2 certs cover mechanicals, hardness (HB ~150-217), intergranular-corrosion testing (ASTM A262 Practice E), and surface condition. NACE MR0175 sour-service compliance maintained below the hardness threshold for SSC.
