Product Overview This product is a stainless steel hex head bolt and nut assembly manufactured from SS304 (A2) and SS316L (A4) austenitic stainless steel, conforming to DIN 931 / DIN 933 / ISO 4014 / ISO 4017 dimensional standards and ASTM A193 Grade B8 / B8M material specifications. The product line includes hex head bolts, hex nuts, and stud bolts in sizes ranging from M6 to M36 (M42–M48 on request), with full-thread and partial-thread configurations available. The SS304 (A2-70) grade offers excellent general corrosion resistance for industrial and construction applications, while the SS316L (A4-70) grade contains 2–3% molybdenum for superior resistance to chloride pitting and crevice corrosion — making it the preferred choice for coastal, marine, and chemical processing environments. The hex nut is supplied as a companion component, matched in grade and property class to ensure full compatibility and reliable preload. Material & Grade Parameter SS304 / 304L (A2) SS316 / 316L (A4) Material AISI 304 / 06Cr19Ni10 AISI 316L / 022Cr17Ni12Mo2 Grade A2-70 per ISO 3506-1 A4-70 per ISO 3506-1 Chemical Composition C ≤ 0.08%, Mn ≤ 2.0%, Si ≤ 0.75%, Cr 18.0–20.0%, Ni 8.0–10.5%, S ≤ 0.03%, P ≤ 0.045% C ≤ 0.03%, Mn ≤ 2.0%, Si ≤ 0.75%, Cr 16.0–18.0%, Ni 10.0–14.0%, Mo 2.0–3.0%, S ≤ 0.03%, P ≤ 0.045% Tensile Strength (σb) ≥ 700 MPa ≥ 700 MPa Yield Strength (σ0.2) ≥ 450 MPa ≥ 450 MPa Elongation (δ5) ≥ 40% ≥ 40% Hardness ≤ 187 HRB / ≤ 200 HB ≤ 187 HRB / ≤ 200 HB Salt Spray Resistance ≥ 500 hours ≥ 1,000 hours Magnetic Permeability Non-magnetic (slightly magnetic when cold worked) Non-magnetic SS304 (A2-70) is a general-purpose austenitic stainless steel offering excellent corrosion resistance, good cold-working properties, and reliable performance across a wide temperature range. It is the most widely specified stainless steel grade for fasteners in industrial, construction, and equipment applications. SS316/316L (A4-70) contains 2–3% molybdenum, which provides significantly better resistance to chlorides and pitting corrosion. The “L” designation indicates low carbon content (≤ 0.03%), which reduces the risk of carbide precipitation during welding and improves intergranular corrosion resistance. A2-70 / A4-70 designation: The “A” indicates austenitic stainless steel, the number “2” or “4” indicates the steel group (A2 = 304-class, A4 = 316-class molybdenum-bearing), and “70” indicates a minimum tensile strength of 700 MPa per ISO 3506-1. Standards & Specifications Parameter Details Product Type Hex Head Bolt / Hex Nut / Stud Bolt (companion nut supplied) Dimensional Standards DIN 931 (partial thread) / DIN 933 (full thread) / ISO 4014 / ISO 4017 / ASME B18.2.1 Material Standards ASTM A193 B8 / B8M / ISO 3506-1 / GB/T 3098.6 Thread Size M6, M8, M10, M12, M16, M20, M24, M30, M36 (M42–M48 on request) Thread Pitch M6×1.0, M8×1.25, M10×1.5, M12×1.75, M16×2.0, M20×2.5, M24×3.0, M30×3.5 Length Range 10 mm – 300 mm (customizable) Thread Tolerance 6g (metric) Surface Finish Plain / Passivated / Polished Product Grade A (per DIN / ISO) DIN 931 specifies partially threaded hexagon head bolts with a plain shank, while DIN 933 specifies fully threaded hexagon head bolts. Both standards cover metric coarse threads from M6 to M36 in product grades A and B, and are functionally equivalent to ISO 4014 (partial thread) and ISO 4017 (full thread). ASTM A193 is the dominant material specification for stainless steel bolting in refinery, petrochemical, and oil & gas applications. Grade B8 is made from AISI 304 stainless steel with carbide solution treatment; Grade B8M is made from AISI 316 stainless steel. B8 bolts achieve a minimum tensile strength of 75 ksi (515 MPa) and minimum yield strength of 30 ksi (205 MPa) in Class 1 condition. Key Dimensions (Reference — DIN 933 / ISO 4017) Thread Size (d) Pitch (P) mm Width Across Flats (s) mm Head Height (k) mm Hex Nut Height (m) mm M6 1.0 10.0 4.0 5.0 M8 1.25 13.0 5.3 6.5 M10 1.5 16.0 6.4 8.0 M12 1.75 18.0 7.5 10.0 M16 2.0 24.0 10.0 13.0 M20 2.5 30.0 12.5 16.0 M24 3.0 36.0 15.0 19.0 M30 3.5 46.0 18.7 24.0 M36 4.0 55.0 22.5 29.0 All dimensions are in accordance with DIN 931 / DIN 933 / ISO 4014 / ISO 4017 standards. Nut dimensions per DIN 934 / ISO 4032. Mechanical Properties (Reference — A2-70 / A4-70) Property A2-70 (SS304) A4-70 (SS316) Tensile Strength ≥ 700 MPa ≥ 700 MPa Yield Strength (0.2% offset) ≥ 450 MPa ≥ 450 MPa Elongation ≥ 40% ≥ 40% Hardness ≤ 187 HRB ≤ 187 HRB Service Temperature Range −196°C to +800°C −196°C to +800°C Salt Spray Resistance ≥ 500 hours ≥ 1,000 hours Both A2-70 and A4-70 grades achieve a minimum tensile strength of 700 MPa and a 0.2% proof stress of 450 MPa per ISO 3506-1. SS304 and SS316 bolts maintain their mechanical properties across a wide temperature range from cryogenic (−196°C) to elevated (+800°C) temperatures. Applications Stainless steel hex bolts and nuts are widely used across industries: Oil & Gas Flanged Connections — Pipeline flanges, valve bonnets, wellhead equipment, pump and compressor mounting Petrochemical & Chemical Processing — Reactor vessels, heat exchangers, pressure vessels, piping supports Desalination & Marine — Seawater piping flanges, offshore platform connections, cooling water lines Power Generation — Turbine casings, generator connections, steam piping Food & Pharmaceutical — Sanitary piping systems, hygienic equipment assembly Construction & Infrastructure — Structural steel connections, facade fastening, anchor bolting Solar & Renewable Energy — Mounting systems, battery module assembly, panel frames Automotive & Transportation — Engine mounts, exhaust system connections, chassis components Regional insight: In GCC refinery and petrochemical projects, the most common stainless steel bolting requirement is A193 B8/B8M stud bolts paired with A194 Grade 8/8M nuts. For coastal and desalination applications, SS316L hex bolts are the minimum specification due to the aggressive chloride environment of the Arabian Gulf. GCC market context: Stainless steel hex bolts to DIN 931, DIN 933, and ISO 4014 in grades 304, 316, and super duplex are available from UAE manufacturers serving the mechanical engineering, oil & gas, and construction sectors. In Saudi Arabia, leading bolt manufacturers supply stainless steel bolts in grades SS 304, SS 316, and SS 321, with duplex and super duplex options for demanding conditions, following standards including ASTM A193, ASME B18.2.1, and DIN 933. Surface Finish & Corrosion Protection Finish Appearance Corrosion Resistance Recommended Environment Plain (Natural Stainless) Silver-gray, matte Excellent — natural passive layer General industrial, indoor/outdoor Passivated Silver-gray, cleaner surface Enhanced — removes surface contamination Coastal, chemical, hygienic applications Polished Bright, reflective Excellent Decorative, architectural, food equipment SS304 provides excellent corrosion resistance in most atmospheric, freshwater, and mild chemical environments. The natural passive chromium oxide layer forms spontaneously on the surface and is self-repairing if damaged. Passivation (per ASTM A967 / GSO ISO 16048) is recommended to maximize corrosion resistance by removing surface contaminants and free iron. Limitation: SS304 is not recommended for chloride-rich environments such as seawater immersion, salt spray, or coastal exposure within 10–20 km of the coast, where SS316L (A4) should be specified instead. Quality Assurance All products are manufactured under strict quality control procedures in accordance with DIN 931 / DIN 933, ISO 4014 / ISO 4017, ASTM A193, and ISO 3506-1 standards. Material test certificates (EN 10204 3.1), dimensional inspection reports, and third-party inspection reports can be provided upon request. Quality control steps performed on each production batch: Chemical composition verification of the stainless steel material Tensile and yield strength testing per ISO 3506-1 Thread gauge inspection (go/no-go gauges) for 6g tolerance Hardness testing to confirm ≤ 187 HRB Visual inspection for surface defects and corrosion Packaging & Customization Export Packing: Carton / wooden case / steel pallet Domestic Packing: Standard corrugated box / plastic bag / bundle OEM/ODM: Available — custom sizes, thread types (metric / UNC / UNF / BSW), materials (SS304, SS316, SS316L, SS201), and surface finishes can be produced according to drawings or samples Nut Supply: Companion hex nuts matched in grade and property class (A2-70 nut for A2-70 bolt; A4-70 nut for A4-70 bolt) MOQ: Negotiable Ordering Information To place an order or request a quotation, please specify: Product type — Hex head bolt (partial thread / full thread) / Hex nut / Stud bolt assembly Standard — DIN 931 / DIN 933 / ISO 4014 / ISO 4017 / ASTM A193 Material grade — SS304 (A2-70) / SS316 (A4-70) / SS316L / SS201 Thread size and pitch — e.g., M16 × 2.0 or M20 × 2.5 Length — Specify total length and thread length if applicable Surface finish — Plain / Passivated / Polished Anti-seize — Required? (Yes/No); type (moly-based / nickel-based / PTFE) Quantity — With any tolerance for over/under shipment Certification — EN 10204 3.1 MTC / ISO 3506-1 compliance / SASO (for Saudi Arabia) / EAC DoC + GOST-K (for Kazakhstan) Special requirements — Marking, packaging, companion nut grade, etc.