Standard and heavy-hex patterns
Product formFasteners
/ 01 — TECHNICAL OVERVIEW
Nuts
Industrial nuts are internally threaded components used with bolts and studs to secure flanged joints, valves, equipment, structures and fabricated assemblies. Correct selection requires the nut type, material or strength grade, dimensional standard, thread form, nominal diameter, pitch, thickness and compatibility with the mating bolt or stud.
NESCO Pipe & Tubes is a supplier, stockist, importer and exporter of industrial nuts for pressure piping, petrochemical, power, marine, heat-exchanger, structural and maintenance applications.
Heat or lot traceability, Mill Test Certificates, mechanical and hardness testing, PMI, dimensional and thread inspection, finish or coating verification, matched-set identification and export documentation can be coordinated where specified.
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 nuts are internally threaded components used with bolts and studs to secure flanged joints, valves, equipment, structures and fabricated assemblies. Correct selection requires the nut type, material or strength grade, dimensional standard, thread form, nominal diameter, pitch, thickness and compatibility with the mating bolt or stud.
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
Austenitic Stainless Steel304, 304L, 316, 316L, 321, 347, 310S and 904L
Corrosion-resistant piping, equipment and general industrial assemblies
Alloy SteelGrade 2, 2H, 7, 7M, B16 and other applicable grades
Pressure, high-temperature and specialised bolting applications
Pressure-Service Stainless SteelGrade 8, 8A, 8C, 8M and other applicable grades
Flanges, valves, pressure equipment and elevated-temperature service
Nickel AlloysAlloy 625, Alloy 718, Alloy 825, Hastelloy C276 and other project-specified grades
Severe corrosion, high-strength and elevated-temperature applications
Project-Specific MaterialsMaterial grade, strength class and coating as specified
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 A194/A194MCarbon steel, alloy steel and stainless steel nuts for bolts used in high-pressure or high-temperature service, or both
Pressure & high-temperature nuts
ASTM F594Stainless steel nuts for general corrosion-resistant service
General stainless steel nuts
ASTM A453/A453MHigh-temperature bolting materials, including nuts, with expansion coefficients comparable to austenitic stainless steels
Special high-temperature nuts
ASTM A320/A320MAlloy-steel and stainless-steel bolting for low-temperature service; includes requirements for nuts used with the bolting
Low-temperature bolting assemblies
ASME B18.2.2Dimensions for inch-series hex, square, hex-flange and coupling nuts and other covered nut types
Nut dimensions
Applicable ISO / DIN standardsNut dimensions, thread and product requirements where specified
Metric / project requirements
ASTM A962/A962MCommon requirements for bolting intended for service from cryogenic to creep-range temperatures
General bolting requirements
Project / OEM specificationCoating, lubrication, supplementary testing, marking and other joint-specific requirements
Project-specific requirements
/ 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 pumps
04
Chemical and marine equipment05
Structural assemblies06
Heat exchangers
07
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.