High Tensile Hex Bolt Grade 8.8 — DIN 931 / DIN 933

Description

Product Overview
High Tensile Hex Bolt Grade 8.8 — DIN 931 / DIN 933 is a high-strength carbon steel hex-head fastener engineered for structural and mechanical assemblies where elevated tensile strength and reliable thread engagement are required. Commonly used in heavy machinery, structural steelwork, automotive subassemblies, and industrial equipment fabrication, these bolts deliver dependable clamping force and fatigue resistance under dynamic and static loads. The 8.8 grade (medium carbon, quenched and tempered) combines high tensile capacity with ductility, minimizing brittle failure risk while simplifying installation with standard DIN 931 (partially threaded) and DIN 933 (fully threaded) geometries. For strategic procurement, these bolts reduce lifecycle maintenance, lower rework rates, and standardize parts across heavy industrial applications.

Key Specifications & Technical Characteristics

• Material: Medium carbon steel, quenched and tempered (commonly specified as C45 or equivalent alloy adjusted for heat treatment).

• Mechanical grade: 8.8 (minimum tensile strength 800 MPa, minimum yield strength 640 MPa).

• Standards: DIN 931 (hex bolt, partially threaded) and DIN 933 (hex bolt, fully threaded).

• Thread form: Metric coarse thread (e.g., M8–M36 options), ISO metric profile, tolerance class 6g (standard) unless otherwise specified.

• Surface finish: Options include plain/black (minimised corrosion resistance), hot-dip galvanized (HDG) to ISO 1461, zinc plated passivated, and Class 10/100 lubricant coating; specify per order.

• Physical characteristics: Hex head geometry to DIN profile; nominal lengths per DIN ranges; diameter and length tolerances to ISO 4014/4017 equivalence.

• Packaging: Bulk loose in palletized steel drums or heavy-duty polybags within wooden crates; cartons and jumbo bags available for smaller diameters; standard palletization and dunnage for export shipping.

• Typical weight density: Steel fastener mass per piece varies by size — packing labelled by net/ gross weight per carton; bulk weight documented per shipment.

• Traceability: Heat number and batch stamping available on request; mill certificates (EN 10204 3.1 or 2.2) supplied with shipment.

• Shelf life: Indefinite under normal dry storage; recommended storage in humidity-controlled environment for galvanized/plated finishes to prevent flash corrosion.

Core Industrial Applications

• Construction & Structural Steelwork: Primary fastener for bolted connections in steel frameworks, bridge components, and pre-fabricated structures where high clamp load and shear capacity are required.

• Heavy Machinery & Equipment Manufacturing: Used in gearboxes, frames, and mounting assemblies subject to cyclic loading; 8.8 grade offers optimal balance of strength and toughness.

• Automotive & Commercial Vehicles: Subframe connections, suspension mounts, and drivetrain brackets where standardized high-tensile fasteners reduce warranty risk.

• Energy & Utilities: Applied in turbine housings, support structures, and mechanical assemblies in oil & gas, mining equipment, and power generation plants.

• Advantages vs alternatives: Compared with lower-grade (4.6/5.6) bolts, grade 8.8 provides significantly higher tensile and yield strengths, reducing required bolt diameter or count; compared with grade 10.9/12.9, 8.8 offers improved ductility and lower cost while still meeting most industrial strength needs. The availability in both partially and fully threaded forms (DIN 931/933) ensures correct joint design and ease of installation.

Competitive Advantages

• Quality consistency: Manufactured to ISO/DIN tolerances with batch testing and optional EN 10204 mill certification; dimensional and mechanical testing performed per customer sampling plans.

• Supply reliability: Established production and inventory management for continuous replenishment; capacity to support long-term contracts and approved vendor lists.

• Logistics capability: Export-ready packaging, containerized loading plans, and coordination for FOB/CIF/DDP terms; dedicated pallet and lashing procedures for steel fasteners to minimize in-transit damage.

• Price competitiveness: Economies of scale for bulk 20 MT orders, competitive unit pricing with transparent cost breakdowns for coatings and certification.

• Sustainability: Optimization of material yield and heat-treatment processes reduces scrap; recyclable steel content and optional low-VOC plating processes available upon request.

• Technical support & documentation: Engineering datasheets, torque charts, installation guidance (recommended pre-load/torque per diameter and lubrication), and on-demand batch test reports provided to support qualification and QA processes.

Commercial & Supply Information

• Minimum order quantity (MOQ): BULK 20MT.

• Loading capacity: Specify common container loadouts — up to approximately 20 MT per 20-ft container for dense bulk packaging; up to ~24 MT per 40-ft container depending on packing method and port/road limits. Final loading plan confirmed at order.