Bolts/Nuts: Preload 65-90% of yield strength

Component Specifications

Definition

Bolts and nuts are mechanical fasteners consisting of a male-threaded bolt and a female-threaded nut that work together to create a secure, removable joint. In industrial applications, they provide clamping force through axial tension, creating friction between joined surfaces to resist shear, tensile, and vibrational forces. Proper bolt/nut selection and installation are critical for structural integrity, safety, and maintenance accessibility in machinery.

Working Principle

Bolts create axial tension when tightened, generating clamping force that holds components together through friction. Nuts provide the counter-thread that allows controlled tension application via torque. The thread geometry converts rotational torque into linear force, with the bolt acting as a tension member and the nut as the compression element.

Materials

Typically carbon steel (Grade 5, 8.8), alloy steel (Grade 8, 10.9), stainless steel (A2/A4), or specialized alloys for corrosion/heat resistance. Coatings include zinc plating, hot-dip galvanizing, or phosphate treatments.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Preload	65-90% of yield strength
Nut Type	Hex, lock, flange
Head Type	Hex, socket, flange
Thread Type	Metric (ISO) or Imperial (UNC/UNF)
Strength Grade	8.8, 10.9, 12.9
Torque Requirements	Specified by diameter/grade

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 898, ISO 4014, ISO 4032, DIN 931, DIN 934

Parent Products

This component is used in the following industrial products

Manway

A sealed access opening in a pressure vessel for inspection, maintenance, and cleaning.

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Jib Foot Connection

Structural component that connects the jib (boom) to the crane's rotating platform or pedestal.

View Product Details

Engineering Analysis

Risks & Mitigation

Insufficient preload leading to joint failure
Over-torquing causing bolt fracture
Corrosion compromising integrity
Vibration-induced loosening
Galvanic corrosion in dissimilar metals

FMEA Triads

Trigger: Incorrect torque application
Failure: Joint separation or bolt fracture
Mitigation: Use calibrated torque wrenches, follow torque specifications, implement torque verification procedures

Trigger: Vibration in dynamic applications
Failure: Progressive loosening
Mitigation: Use lock nuts, thread locking compounds, or prevailing torque fasteners

Trigger: Corrosive environment
Failure: Strength degradation and seizure
Mitigation: Select corrosion-resistant materials, apply protective coatings, implement inspection schedules

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

ISO 4759-1 for dimensional tolerances, thread tolerances per ISO 965

Test Method

Tensile testing per ISO 898-1, torque-tension testing, salt spray testing for corrosion resistance

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Bolts/Nuts

2 companies list this product among what they make. Company figures are quoted from each company's own website; every card states where the relationship came from.

Dongturbo Electric Company Ltd

Chengdu, Sichuan, CN

Also makes: Battery System, Energy Storage/Transfer Element (for active systems), Power Plant and 6 more

Listed on the company's own website · profile compiled by CNFX from public sources

View profile Send enquiry

Hebei Haihao Flange Factory

Hebei, CN

Also makes: Forged Steel Flange

Listed on the company's own website · profile compiled by CNFX from public sources

View profile Send enquiry

Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

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Frequently Asked Questions

What is the difference between bolts and screws?

Bolts require nuts to create joints and are designed for through-holes, while screws typically thread directly into materials without separate nuts.

How do I determine proper bolt torque?

Torque depends on bolt diameter, grade, material, lubrication, and joint design. Always follow manufacturer specifications or engineering calculations.

What causes bolt loosening in machinery?

Vibration, thermal cycling, improper preload, material relaxation, or insufficient locking mechanisms can cause loosening.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Bolts/Nuts