Standard and heavy-hex patterns
Product formFasteners
/ 01 — TECHNICAL OVERVIEW
Nuts
Industrial fasteners secure flanged joints, valves, equipment, structures and fabricated assemblies. A complete fastener specification must combine the product type, material or strength grade, dimensional standard, thread form, diameter, pitch, length, heat-treatment condition, finish and compatible nut or washer requirement.
NESCO Pipe & Tubes supplies bolts, nuts and stud bolts for pressure piping, petrochemical, power, marine, heat-exchanger, structural and maintenance applications. Requirements can be supplied as individual items or coordinated bolting sets, subject to grade, size, quantity and specification.
The NESCO range includes stainless steel, pressure-service alloy and stainless bolting, low-temperature bolting and selected nickel-alloy grades. Material selection must account for design temperature, corrosion environment, mechanical loading and compatibility between every component in the joint.
Heat or lot traceability, Mill Test Certificates, mechanical and hardness testing, PMI, thread gauging, coating verification, matched-set packing and export documentation can be coordinated where specified in the purchase order.
How it is made
01
Compatible bar, wire or forged blanks are selected to match the bolt grade and service.
02
Cold forming, hot forging or machining produces the nut profile and bearing faces.
03
Internal threads are tapped and the grade-specific heat treatment or finishing is completed.
04
Thread fit, proof load or hardness, dimensions and grade marking are verified by lot.
Request reviewed quotation Material documents on request
/ 02 — PRODUCT DETAIL
Built around the specification.
Industrial fasteners secure flanged joints, valves, equipment, structures and fabricated assemblies. A complete fastener specification must combine the product type, material or strength grade, dimensional standard, thread form, diameter, pitch, length, heat-treatment condition, finish and compatible nut or washer requirement.
Key features01 02 03 04
Matched thread fit and strength
Plain, coated or lubricated condition
Grade marking and heat traceability
Common specification references
STD
ASTM F594 for selected stainless nuts
STD
ASTM A194 for pressure-service nuts where applicable
STD
ASME/ISO/DIN dimensional standards
Explore the fasteners range
/ 03 — AVAILABLE GRADES
Available Material Grades
NESCO supplies the material and bolting families shown below, subject to fastener type, grade, dimensions, thread, condition, finish and availability.
Material familyCommon gradesTypical selection context
General stainless fastenersASTM F593 bolts, hex cap screws and studs with ASTM F594 compatible nuts; commonly requested 304 and 316 families
Corrosion-resistant general and equipment assemblies
Pressure-service alloy and stainless boltingASTM A193 Grades B8, B8M and B16, with ASTM A194 nuts selected for the specified bolting combination
Flanges, valves and pressure equipment
Low-temperature boltingASTM A320 material grades with ASTM A194 or other specification-matched nuts
Specified low-temperature pressure joints
Nickel-alloy boltingUNS N06625, UNS N07718, UNS N08825, UNS N10276 and project-specific grades
Corrosive, high-strength and elevated-temperature service
Project-specific boltingMaterial, strength class, coating and dimensions to the approved bolting specification or drawing
OEM, structural and specialised assemblies
/ 04 — SUPPLY & CUSTOMISATION
Define the supply condition.
Final availability depends on the complete combination of material, dimensions, standard, condition, testing and quantity.
ParameterTypical information to specify
01Thread system
Metric, UNC, UNF, 8UN or specified form
02Dimensions
Diameter, pitch, length and thread engagement
03Condition
Solution annealed, heat treated or cold worked as specified
04Finish
Plain, passivated, coated, plated or lubricated subject to compatibility
05Sets
Bolt/nut/washer or stud with two nuts
06Testing
Chemical, mechanical, hardness, PMI and coating tests as required
07Marking
Grade, manufacturer and heat/lot identification
/ 05 — DIMENSIONS & SIZE RANGE
Dimensions aligned to the manufacturing route.
A complete fastener description combines material grade with a separate dimensional standard and thread designation.
Ordering itemExamplesRequired detailAcceptance control
ThreadMetric, UNC, UNF, 8UN or specialDiameter, pitch/series and classGO/NO-GO gauging
LengthUnder-head or overall by product typeMeasurement convention and toleranceAssembly grip / engagement
Head / nutHex, heavy hex, socket or drawing-specificDimensional standardAcross-flats and bearing face
FinishPlain, passivated, coated or lubricatedCoating system and thicknessFriction and corrosion compatibility
/ 06 — MANUFACTURING STANDARDS
Standards aligned for every order.
The material standard, dimensional standard and project requirements should be stated separately.
ReferenceWhat it coversRole
ASTM A193/A193MAlloy-steel and stainless-steel bolting for high-temperature or high-pressure service and other special-purpose applications
Pressure bolting
ASTM A194/A194MCarbon, alloy and stainless steel nuts for high-pressure or high-temperature service
Compatible nuts
ASTM A320/A320MAlloy-steel and stainless-steel bolting for low-temperature service
Low-temperature bolting
ASTM F593 / F594Stainless steel bolts, hex cap screws and studs, with compatible stainless steel nuts
General stainless fasteners
ASTM A453/A453MHigh-temperature bolting with expansion coefficients comparable to austenitic stainless steel
Special high-temperature service
ASME B18 / ISO / DINProduct geometry, thread form and dimensions under the selected standard
Dimensions
Project bolting specificationCoating, lubrication, tightening, lot testing, marking and supplementary requirements
Joint-specific
/ FASTENER SELECTION GUIDE
Specify the complete bolting assembly.
Select the product form together with its material grade, thread, dimensions, compatible nuts or washers, finish and service conditions. The approved joint design governs final selection.
Fastener typeTypical use
BoltsHeaded fasteners for equipment, structures and assemblies requiring a defined grip length
NutsInternally threaded components selected to match bolt or stud material, strength, thread and service
Stud BoltsFully threaded or double-ended bolting commonly supplied with compatible nuts for flanged pressure joints
/ 07 — INSPECTION & TESTING
Evidence before dispatch.
01Heat or lot traceability and MTC review
02Diameter, pitch, length and GO/NO-GO thread-gauge inspection
03Head, nut, bearing-face and chamfer dimensions
04Hardness, tensile, yield, proof-load or impact testing as required by the specification
05PMI for stainless and alloy verification when specified
06Coating thickness and lubricant verification where ordered
07Grade marking, nut compatibility and matched-set checks
08Quantity, segregation and protective packing verification before dispatch
PACKAGING & MARKING
Protected and traceable.
01Bolting segregated by grade, heat/lot, size and finish
02Matched stud-and-nut sets bagged or boxed when ordered
03Threads protected from impact and contamination
04Moisture-resistant export cartons and timber cases
05Labels show standard, grade, thread, length, quantity and PO
/ 08 — APPLICATIONS & INDUSTRIES
Engineered for demanding service environments.
From process plants to marine systems, NESCO coordinates material, dimensions and documentation around the operating conditions of each application.
01
Flanged piping joints02
Pressure vessels03
Valves and pumps04
Chemical and marine equipment05
Structural assemblies06
Heat exchangers07
Power plants08
Maintenance and shutdownsIndustries servedOne supply partner across critical sectors.
Pressure pipingOil & gasPetrochemicalsPower generationMarineStructural fabricationHeat exchangersMaintenance shutdowns
/ 09 — WHY NESCO PIPE & TUBES
Built for buyers who cannot leave details to chance.
From specification review to export documentation, NESCO coordinates the technical and commercial details as one complete supply requirement.
01
Specification control
NESCO reviews the grade, product standard, dimensions, condition and acceptance criteria as one coordinated requirement.
02
Multi-material sourcing
Stainless steel, duplex and nickel-alloy fastener requirements can be combined within one project enquiry.
03
Traceable documentation
Heat numbers, MTCs and agreed inspection records are aligned with the purchase order before dispatch.
04
Inspection coordination
PMI, dimensional checks, NDT and third-party witnessing can be arranged against an approved inspection plan.
05
Value-added processing
Cutting, machining, thread-related requirements, coating, lubrication or protective finishing can be reviewed with the fastener specification.
06
Export-ready packing
Identification, surface protection and packing are planned around product geometry and the final transport route.
07
Responsive RFQ review
Technical and commercial inputs are consolidated early so queries are resolved before quotation and production.
08
One accountable supply desk
NESCO provides a single contact for material, processing, documentation, packing and delivery coordination.
/ 10 — FREQUENTLY ASKED QUESTIONS
Clear answers before you specify.
Quick guidance on product selection, standards, dimensions, inspection and documentation. For project-specific requirements, NESCO will review the complete enquiry with your team.
01How should nut grade be matched to a bolt?
Nut material, strength, temperature rating, thread fit and coating should be selected as a compatible bolting system under the project specification.
02What is a heavy-hex nut?
A heavy-hex pattern has larger across-flats and thickness dimensions than a regular hex nut and is common in pressure-service bolting.
03What information is essential for fastener quotation?
Provide fastener type, material/strength grade, dimensional standard, diameter, pitch, length, finish, nut/washer requirement, quantity and certificates.
04Can stainless and alloy bolting grades be interchanged?
No. Strength, temperature capability, corrosion behaviour and matching nut requirements differ; substitutions require approval from the responsible engineer.
05Why must coating and lubricant be stated?
Surface condition influences corrosion protection, friction and tightening load. It must be compatible with the service and assembly procedure.
06Can fasteners be supplied as matched sets?
Bolts, studs, nuts and washers can be packaged as coordinated sets when grades, quantities and marking requirements are specified.
/ 11 — REQUEST FOR QUOTATION Nesco direct sales desk
Ready to source?Start with the details you already have.
Our team will review the grade, dimensions, testing and delivery requirements together.