STAINLESS STEEL 304 FASTENERS — DATASHEET, DIMENSIONS & MECHANICAL PROPERTIES

Ananka Fasteners is a global manufacturer and supplier of Stainless Steel 304 Fasteners (UNS S30400), universally recognized as 18/8 stainless steel. As the most widely specified austenitic alloy globally, SS 304 provides an exceptional baseline for corrosion-resistant structural integrity across architectural, food processing, and standard industrial applications.

Characterized by its Face-Centered Cubic (FCC) crystal lattice, SS 304 offers immense ductility, deep drawing capability, and high impact absorption even at cryogenic temperatures. All our SS 304 bolts, nuts, studs, and washers are manufactured to exact dimensional tolerances and are supported by EN 10204 Type 3.1 Material Test Certificates (MTC) ensuring 100% traceability.

For principal engineers, metallurgists, and procurement officers requiring the granular, proprietary technical specifications, manufacturing tolerances, and full load-bearing yield curves of SS 304 industrial fasteners, the complete technical datasheet must be accessed.

Standard dimensional specifications for fully threaded (DIN 933) and partially threaded (DIN 931) metric hex bolts. Note: Width Across Flats (s) may vary slightly between DIN and ISO standards for M10, M12, M14, and M22 sizes.

*Values for Strain-Hardened Class 2 vary slightly depending on fastener diameter. SS 304 cannot be hardened by thermal heat treatment; immense strength increases are achieved strictly through mechanical cold-working.

Despite its immense capabilities, SS 304 possesses a distinct, critical limitation: it is highly vulnerable to heavy concentrations of chloride ions. When deployed in marine environments or applications heavily exposed to de-icing road salts, the chloride ions chemically attack and pierce the passive chromium oxide film.

This localized breach initiates pitting and crevice corrosion inside the threads, leading to rapid, catastrophic structural failure. Therefore, for sub-sea, coastal marine, and aggressive chemical deployments, engineers must upgrade to Stainless Steel 316 (which contains 2-3% Molybdenum to resist chloride attack). For all indoor, freshwater, and standard atmospheric applications, however, 304 remains the optimal, highly cost-effective engineering choice.

The malleability and machinability of SS 304 allow it to be transformed into an enormous array of specialized fastener configurations, tailored to address specific mechanical load requirements, spatial constraints, and security needs.

In safety-critical sectors such as offshore petrochemical extraction, nuclear power generation, and aerospace engineering, a fastener is completely worthless if its metallurgical integrity cannot be legally and empirically proven. The document that guarantees this integrity is the Mill Test Certificate (MTC). The global gold standard for MTCs is defined by the European standard EN 10204 3.1. A fully integrated MTC for an SS 304 fastener acts as the component's metallurgical DNA, including:

• Complete Traceability: Records the heat number—a unique identifier linking the finished bolt back to the exact ladle of molten steel at the primary casting mill.
• Chemical Spectrography: Provides the precise, empirically measured chemical composition of the batch, proving that the Chromium, Nickel, and Carbon levels fall strictly within mandated tolerances.
• Mechanical Verification: Lists the actual results of destructive laboratory testing performed on samples from the batch (ultimate tensile strength, yield strength, elongation percentage, and hardness).
• Manufacturing Processes: Details the specific heat treatments (e.g., solution annealing) and forming processes utilized to bring the component to its final state.

The global industrial fastener market requires manufacturing entities capable of blending hyper-scale production volume with microscopic precision. Ananka Fasteners exemplifies the apex of modern industrial hardware manufacturing, servicing a roster of over 240 high-value corporate clients spanning more than 40 countries.

• Stringent Global Certification: Ananka operates under an integrated management system certified to ISO 9001:2015, ISO 14001:2015, and ISO 45001:2018. We also hold the prestigious PED 2014/68/EU (Pressure Equipment Directive) certification issued by TÜV Rheinland for explosive, high-pressure environments.
• Exotic Alloy Mastery: While we lead in SS 304 and SS 316, our true engineering prowess lies in our capacity to forge and machine exotic superalloys including Inconel 718, Nimonic, Hastelloy C276, Monel, and Titanium Grade 5.
• Customization and Capacity: Utilizing a strict 6-step in-house quality check protocol, we possess the agile manufacturing capacity to take complex, custom-engineered blueprint drawings and rapidly prototype, forge, test, and ship specialized fasteners globally.

• 1. Is SS 304 completely non-magnetic?
  In its fully annealed state, it is non-magnetic. However, processes like cold heading and thread rolling induce stress that converts some austenite to martensite, causing the finished fastener to be weakly magnetic. Post-fabrication annealing restores its non-magnetic state.
• 2. Why use SS 316 instead of SS 304?
  While 304 is excellent for standard environments, it is vulnerable to chloride ions (saltwater, de-icing salts). SS 316 contains 2-3% Molybdenum, which drastically increases its resistance to localized pitting and crevice corrosion in marine and offshore applications.
• 3. How can I prevent thread galling?
  SS 304 is highly susceptible to cold-welding (galling) under pressure. Engineers must utilize anti-seize lubricants, PTFE coatings, slow down installation RPM, or pair the 304 bolt with a dissimilar/harder nut material to reduce adhesive friction.