HEX NUT AND THIN HEX NUT [TABLE 5]

Hex nuts and thin hex nuts (Hex Jam Nuts) are the most common internal-threaded fasteners in the American standard system, with external dimensions manufactured to ASME B 18.2.2 Table 5. Hex nuts have standard thickness, while thin hex nuts are approximately 60% of that thickness, primarily used for locking or in space-constrained locations. Materials are classified into three series per ASTM standards: A563 carbon/alloy steel (Grade A, DH, etc.), F594 stainless steel (304/316), and F467 copper alloys (brass, silicon bronze, etc.). Through different combinations of material and strength, they can be adapted to a wide range of bolted connections — from ordinary structures to high-load and highly corrosive environments.

I. Product Features

Unified American Standard Shape: Manufactured to the width-across-flats, thickness, and across-corners dimensions specified in Table 5, precisely matching American standard bolts and studs of the same size.

Dual Thickness Design: Standard hex nuts provide full-height load bearing; thin hex nuts are approximately 0.6 times the standard thickness, usable as jam nuts in double-nut anti-loosening arrangements or in applications with limited axial space.

Three Material Series Coverage:

• ASTM A563: Carbon and alloy steel, from ordinary-strength Grade A to quenched-and-tempered high-strength Grade DH, matching different bolt grades.
• ASTM F594: Austenitic stainless steel (304/316), combining corrosion resistance with good mechanical properties.
• ASTM F467: Copper alloys and other non-ferrous metals, offering excellent electrical conductivity, non-magnetic properties, and seawater corrosion resistance.

Standard Thread Series: UNC (coarse), UNF (fine), and selected UNEF extra-fine threads, meeting various locking requirements.

Diverse Surface Treatments: Carbon steel nuts can be zinc plated, black oxidized, or phosphated; stainless steel and copper alloy nuts are mostly plain or passivated.

II. Product Advantages

Flexible High-Strength Matching: Alloy steel Grade DH nuts can safely match bolts of grade 12.9 and above, ensuring the reliability of structural connections.

Integrated Anti-Loosening Function: When used as lock nuts, thin nuts are jammed against the primary nut, generating additional friction torque that economically and effectively prevents rotational loosening.

Wide Corrosion Resistance Options: 304 stainless steel meets general weathering requirements, 316 stainless steel handles marine and chemical environments, and copper alloys suit seawater and special media.

Installation Space Savings: The greatly reduced thickness of thin nuts makes them especially suitable for thin-wall structures, compact tooling, and weight-reduction applications.

Strong Interchangeability and Compatibility: Dimensions strictly follow ASME standards, globally recognized, seamlessly matching American standard bolts and washers for easy maintenance and replacement.

III. Application Scope

General Machinery and Steel Structures: Bolted connections for various equipment frames, platforms, and bridge auxiliary structures.

Automotive and Power Equipment: Chassis components, engine accessories, exhaust pipe fastening (alloy steel for high temperatures, stainless steel for corrosion resistance).

Piping and Fluid Systems: Valve flanges, pipe clamps, pump body connections — stainless steel and copper nuts widely used in chemical and water supply/drainage applications.

Electrical and Electronic Equipment: Copper alloy nuts for conductive connections and grounding systems; stainless steel for outdoor distribution cabinets.

Marine and Ship Engineering: 316 stainless steel and copper-nickel alloy nuts used long-term in seawater piping systems and deck equipment.

Precision Assembly with Limited Space: Thin nuts widely used in tooling fixtures, instruments, and lightweight robotic arms in compact spaces.