Product Definition

Threaded / fastening components are standard and non-standard parts that use thread structures to achieve connection, fixation, locking, adjustment, and sealing between components. They are the most fundamental, most widely used, and most common connecting elements in all types of mechanical equipment, including bolts, studs, screws, nuts, washers, threaded fittings, pipe fittings, and plugs.

Production Process

Forged blanks (or bar stock cuttolength) + precision machining (CNC turning, thread rolling, tapping, milling, etc.)

Key Advantages

Dense internal structure and continuous grain flow from forging, high thread strength, excellent fatigue resistance; precision thread machining ensures thread accuracy and fit quality; supports international standards (metric, inch, US) and non-standard customization

Applicable Standards

GB/T, ISO, DIN, ANSI/ASME, BS, JIS, and other international standards; 100% customizable per customer drawings

Bolts / Studs

Head (hex / socket / square / Thead etc.) + shank with external thread

Hex head bolts, socket head cap screws, doubleend studs, anchor bolts, eye bolts, Thead bolts

Screws

Head with driving features (slot / cross / hex socket etc.), fully or partially threaded shank

Socket set screws, crossrecessed screws, selftapping screws, locating screws

Nuts

Internal thread structure, various shapes

Hex nuts, flange nuts, lock nuts, round nuts, cap nuts, weld nuts

Washers / Retaining Rings

Ringshaped flat pieces, without threads or with internal/external teeth

Plain washers, spring washers, lock washers, tab washers, retaining rings for shafts / bores

Threaded Fittings / Pipe Fittings

With internal/external threads for pipe connections

Straight connectors, elbows, tees, fitting nuts, ferrule fittings, hose fittings

Plugs / Blanking Plugs

Short externally threaded pieces with driving features on the end

Hex plugs, socket plugs, square plugs, tapered thread plugs

NonStandard Fasteners

Various special shaped threaded parts custommade per customer drawings

Nonstandard flange bolts, special fittings, special studs, combined fasteners

Carbon Structural Steel

45#, AISI 1045, SWRCH35K

Good overall performance, costeffective; suitable for fasteners with ordinary strength requirements

Alloy Steel

40Cr, 35CrMo, 42CrMo, AISI 4140, SCM435

High strength and toughness, excellent overall mechanical properties after quenching and tempering; suitable for highstrength bolts/studs

Stainless Steel

304, 316, 316L, 174PH, A270, A480

Corrosionresistant and heatresistant; suitable for chemical, marine, food, and other corrosive environments

HeatResistant Alloy Steel

25Cr2MoV, 20Cr1Mo1VNbTiB

Excellent hightemperature strength; suitable for fasteners under hightemperature conditions (e.g., steam turbines, boilers)

Copper Alloys

H62, H65, Tin Bronze

Good electrical and thermal conductivity, corrosionresistant; suitable for electrical connections and special applications

Aluminum Alloys

2A12, 6061, 7075

Lightweight requirements; suitable for aerospace and automotive lightweight fasteners

Special Alloys

Inconel, Monel, Titanium alloys (per customer request)

Extreme conditions (high temperature, strong corrosion, high strength); suitable for aerospace, chemical, marine engineering, and other highend fields

Metric Thread (M)

GB/T 193, DIN 13, ISO 68-1

China, Europe, and most regions worldwide – most commonly used

British Standard Whitworth Thread (BSW/BSF)

BS 84

United Kingdom and Commonwealth countries

US Unified Thread (UNC/UNF)

ANSI B1.1

United States, North America, and parts of the Americas

Pipe Threads (G/R/Rc/Rp)

ISO 7-1, ISO 228, BSPT, NPT

Worldwide pipe connections (G = cylindrical pipe thread; R/Rc/Rp = tapered pipe threads; NPT = US standard tapered pipe thread)

Trapezoidal Thread (Tr)

DIN 103, GB/T 5796

Power transmission screws, jacks, presses, and other forcetransmitting mechanisms

SelfTapping Thread (ST)

GB/T 5280, DIN 7500

Sheet metal connections, plastic part connections

Blank Processes

Die forging (highstrength bolts/studs) / Bar stock cuttolength (ordinary fasteners) / Cold heading (batch standard parts)

Thread Machining Methods

Thread rolling (high efficiency, high strength), thread turning (high precision, nonstandard large sizes), thread grinding (precision transmission threads)

Key Machining Equipment

CNC lathes, thread rolling machines, thread cutting machines, tapping machines, machining centers, thread grinders

Thread Machining Range

M3 – M100 (metric); 1/8″ – 4″ (inch/US)

Thread Tolerance Grades

External threads 4h – 6g; Internal threads 4H – 6H

Bolt Length Range

Up to 2,000 mm

Strength Grades

Carbon/alloy steel: up to Grade 8.8, 10.9, 12.9 (per ISO 898-1); Stainless steel: up to A2-70, A2-80, A4-70, A4-80

Heat Treatment Capabilities

Quenching and tempering, carburizing and quenching, nitriding, solution treatment (stainless steel)

Surface Finishes

Blackening, zinc plating (bluewhite / yellow / colored), hotdip galvanizing, Dacromet, phosphating, antiloosening adhesive coating, etc.

Inspection Equipment

Thread comprehensive measuring instruments, CMM, universal tensile testing machine, hardness tester, torque tester, salt spray test chamber, metallurgical microscope, vision measuring machine

Chemical Composition

Content of C, Si, Mn, S, P, Cr, Mo, Ni, etc.

Spectrometric analysis, carbonsulfur analysis

Mechanical Properties

Tensile strength, yield strength, elongation, reduction of area (tensile test); hardness (Brinell / Rockwell / Vickers); impact toughness (AkU / AkV)

ISO 898-1, ASTM A370, GB/T 228, GB/T 229

Torque / Preload

Torque coefficient, friction coefficient, proof load test

ISO 16047, GB/T 16823

Metallographic Structure

Grain size, nonmetallic inclusions, decarburization depth, carburization depth, tempered structure

ISO 898-1, GB/T 13298, GB/T 224

Thread Inspection

Thread go/nogo gauge inspection, thread flank angle, pitch error, pitch diameter

Thread gauges, thread comprehensive measuring instruments

NonDestructive Testing (NDT)

Surface cracks, internal defects, hydrogen embrittlement inspection

Magnetic particle testing (MT), ultrasonic testing (UT)

Salt Spray / Corrosion Resistance

Neutral salt spray test (NSS), copperaccelerated salt spray test (CASS)

ISO 9227, ASTM B117

Construction & Mining Machinery

Highstrength bolts, slewing bearing connection bolts, track shoe bolts, bucket tooth bolts, hydraulic line fittings

Automotive & Commercial Vehicles

Cylinder head bolts, connecting rod bolts, wheel hub bolts, suspension bolts, body fasteners, brake line fittings

Oil & Gas

Flange bolts, wellhead equipment studs, highpressure pipe fittings, valve fasteners, corrosionresistant fittings

Wind Power

Wind tower connection bolts, blade bolts, gearbox highstrength studs, foundation anchor bolts

Marine & Offshore

Marine studs, pipe fittings, deck fasteners, corrosionresistant bolts

Aerospace

Hightemperature alloy bolts, titanium alloy screws, selflocking nuts (highend materials, special certifications)

General Industry & Hydraulics

Hydraulic manifold fittings, pipe fittings, equipment mounting bolts, power transmission screws

Power & Energy

Steam turbine bolts, boiler fasteners, transmission tower bolts, substation grounding bolts

Standard Parts Procurement

Supply standard fasteners per GB, ISO, DIN, ANSI, and other standards in batches; maintain regular stock for fast delivery

Custom NonStandard per Drawing

Custom nonstandard threaded / fastening parts per customer CAD/3D drawings

Joint Development

Codesign and optimization of connection solutions with customers

SemiFinished Delivery

Delivered preheattreatment or partially threaded

Finished Delivery

Fully machined (including heat treatment, surface finish, rustpreventive packaging), ready for assembly line use

OEM / ODM Services

Support for custom branding, marking, and kit packaging

FullRange Thread Systems

Supports metric, inch, and US thread systems, covering M3–M100 and inch 1/8″–4″, meeting global customer standard requirements

HighStrength Advantage

Up to Grade 12.9 (ISO 898-1); forging + quenching & tempering + thread rolling ensures thread fatigue strength for heavyload applications

Integrated Forging + Machining

For highstrength fasteners, blank quality is controlled from the forging source – avoids cutting through grain flow found in barstock machining, significantly improving thread fatigue performance

FullProcess Testing

Comprehensive testing covering mechanical properties, thread accuracy, and salt spray tests to meet various inspection standard requirements

Flexible Customization

Supports both standard parts bulk supply and nonstandard parts customization in parallel, flexibly meeting different customer needs

Professional Service

Dedicated foreign trade team provides full followup, transparent order status, and multimodal shipping support

Complete Grain Flow (Forging vs. BarStock Machining)

When highstrength fasteners are manufactured using forging, the metal grain flow is continuously distributed from the head through the shank, without being cut off. In stressconcentrated areas such as thread roots, the continuous grain flow significantly improves fatigue life. In contrast, direct machining from bar stock cuts through the grain flow, resulting in markedly lower fatigue strength.

Thread Rolling vs. Thread Turning

Thread rolling (rolling/knurling) creates compressive residual stress on the thread surface through plastic deformation, increasing thread strength by 20%–30%, providing superior surface roughness (Ra 0.4–0.8 μm), and offering extremely high production efficiency. Thread turning is suitable for largesize, nonstandard threads, and smallbatch highprecision applications.

Decarburization Control

During heat treatment, the carbon potential in the furnace is strictly controlled to ensure no decarburization on thread surfaces, guaranteeing thread wear resistance and fatigue strength.

Locking Solutions

Capable of providing various antiloosening solutions including adhesive coating (nylon patch / anaerobic adhesive), Spiralock threads, lock nuts, spring washers, and other locking options as a complete package.