Stainless Steel 303 Fasteners Manufacturer Since 2012 Bright-Turned M3-M64 Stock, EN 10204 3.1 Certified ISO 9001:2015 & ADNOC-Approved Mumbai Works

Stainless Steel 303 Fasteners

Stainless Steel 303 Fasteners Spotlight

Sizes In StockM3 to M64 • No. 6 to 1-1/2 in UNC/UNF
Delivery TimeEx-Stock: 2-5 Days • Mill-Order: 3-4 Wks
Grade / UNSUNS S30300 / WNR 1.4305
Governing StandardASTM A582, F593, F594, ISO 3506
ConditionAnnealed (A) & Cold Worked (CW)
Alloying Elements17-19% Cr, 8-10% Ni, 0.15% min S
FormsBolt, Nut, Washer, Stud, Screw, Threaded Rod
MTC CertificateEN 10204 3.1 and 3.2
Thread SeriesISO 261 Metric, UNC & UNF per ASME B1.1
HS Code7318
Free-Machining
Sulphur-Bearing S30300
Chip-breaking bar that holds a cleaner thread profile
M3 to M64
Metric Plus UNC/UNF
Bolts, nuts, studs and washers on the shelf today
Own CNC Cells
Since 2012
Turned and threaded here, not bought from a market
ADNOC Certified
Approved Manufacturer
Audited quality system your inspector can verify
Direct Exporter
19+ Countries Served
One invoice, one point of contact, no middle desk
Made To Drawing
Any Pitch Or Length
Odd shank lengths and special heads cut on request
stainless steel 303 fasteners

 

0 · at glance

Mortec At A Glance

Established

Since 2012 • 15+ yrs experience

Manufacturing Units

2 in-house units • Taloja & Mazgaon

Stockyard Area

8,850+ sq.ft • Ready-stock inventory

Certifications

ISO 9001:2015, ADNOC • GST, IEC & MSME

Clientele

100+ clients • India & export markets

Export Reach

19+ countries • GCC, Africa & APAC

Testing Offered

Mechanical, chemical & PMI • MTC EN 10204 3.1 & 3.2

Shipment Documents

Invoice, Packing List • COO, COI, MTC, BL & Lab Report

High-Precision SS 303 Hex Bolts and Nut Manufacturer in India With 100% Dimensional Accuracy

Grade 303 exists for one reason: it cuts. Stainless Steel 303 Fasteners rely on a sulphur addition that breaks the chip cleanly. That lets us hold thread flanks tighter than a tougher austenitic allows. SS 303 Bolts also keep across-flats dimensions inside gauge on every lot. Buyers who reject parts on gauge, not paperwork, return to our Mumbai floor. Each UNS S30300 Nut is turned in-house, never bought in finished. WNR: 1.4305 Screws come off the same free-machining bar stock.

AISI 303 Studs are stocked from M3 to M64. SUS 303 Threaded Rod covers the UNC and UNF series too. So an order raised in Jebel Ali, Durban, Mombasa or Calgary ships fast. We pick from bar we already own, not from the market. Every INOX 303 Washer carries its heat number and EN 10204 3.1 certificate. Packing is built to survive a monsoon-season sea leg.

01 · Specification

Stainless Steel 303 Fasteners Specification

As a Stainless Steel 303 Fasteners manufacturer in India, we deliver quality components globally.

stainless steel 303 fasteners specification  

SS 303 Bolts Head Marking & Identification

  • ISO 3506 property class mark on the head
  • Mortec manufacturer ID stamped alongside

UNS S30300 Nut Delivery Condition

  • Passivated to ASTM A967 before packing
  • Bright turned or matte bead-blast finish

WNR 1.4305 Screws Export Compliance

  • Chamber-attested COO for GCC and Africa
  • SABER and ECAS paperwork support on request

AISI 303 Studs Third-Party Inspection

  • SGS, TUV, BV and Lloyd’s witness accepted
  • Stage inspection during turning if nominated

SUS 303 Threaded Rod Packing & Preservation

  • ISPM-15 treated wooden cases for sea freight
  • VCI liners with heat-number bin tags inside

INOX 303 Washer Special Property Checks

  • Magnetic permeability check where specified
  • Intergranular corrosion test to ASTM A262

Stainless Steel 303 Fasteners Manufacturer In Mumbai - Turning And Threading In-House Since 2012

Give us the drive, thread and quantity and our bar stock prices your job the same working day.

Request Quote Now

Offer UNS S30300 Studs and Threaded Rod Express Dispatch for Downtime Emergency At Direct Manufacturer Pricing

02 · Product Range

SS 303 Bolts And Nut Types

A working SS 303 fastener supplier in India keeps every common head and drive turned and ready, not on back-order.

303 Stainless Steel Hex Bolts

303 Stainless Steel Hex Bolts

DIN 931 / DIN 933 • M3-M64
  • Full or part thread under the head
  • Across-flats held to gauge every lot
UNS S30300 Nut

ASTM F593 Type 303 Hex Nuts

DIN 934 / ISO 4032 • M3-M64
  • Proof load class matched to the bolt
  • Heavy hex and thin nut also stocked
INOX 303 Washer

INOX 303 Washer

DIN 125 / DIN 127 • Custom OD
  • Flat, spring and heavy-duty patterns
  • Bore and thickness cut to drawing
AISI 303 Studs

AISI 303 Studs

ASTM F593 • Double-End
  • Equal or unequal thread projections
  • Supplied with matched 303 nut pairs
SUS 303 Threaded Rod

SUS 303 Threaded Rod

DIN 976-1 • 1 m & 3 m Lengths
  • Continuous thread, cut down on site
  • Deburred ends for easy nut start
Stainless Steel Grade 303 Socket Head Cap Screw

Stainless Steel Grade 303 Socket Head Cap Screw

DIN 912 / ISO 4762 • M3-M36
  • Clean hex socket, no cam-out on assembly
  • Counterbore-friendly head diameter
WNR 1.4305 Screws

WNR 1.4305 Screws

DIN 84 / ISO 1207 • M2-M12
  • Slotted cheese, pan and csk heads
  • Small-diameter runs on Swiss lathes
SS 303 Grub Screw

SS 303 Grub / Set Screw

DIN 916 / ISO 4029 • M3-M20
  • Cup, cone, flat and dog point ends
  • Locks collars, pulleys and couplings
03 · Cross-Reference

AISI 303 Studs Material Equivalent Grades

Free-machining 18/8 chemistry carries different international designations, here are six common standards for Grade 303.

USAASTM / AISI (USA)

  • UNS S30300
  • AISI / SAE 303
  • ASTM A582 (Bar)
  • ASTM F593 Group 1 (Bolts)
  • ASTM F594 Group 1 (Nuts)

GermanyDIN / EN (Germany)

  • Werkstoff 1.4305
  • EN X8CrNiS18-9
  • EN 10088-3

JapanJIS (Japan)

  • SUS 303
  • JIS G4303 (Bar)

UKBS (United Kingdom)

  • BS 970 Part 1, 303S31
  • Now follows EN 10088-3 (1.4305)

FranceAFNOR (France)

  • Z8CNF18-09
  • X8CrNiS18-9 equivalent

ChinaGB (China)

  • Y1Cr18Ni9
  • GB/T 1220 (Bar)
04 · Composition

UNS S30300 Nut Chemical Composition

Composition limits per ASTM A582/A582M for free-machining Type 303 bar, the feedstock every 303 fastener is turned from.

Chemical Composition - UNS S30300 per ASTM A582 (% by weight)
Cr17.00-19.00Chromium
Ni8.00-10.00Nickel
S0.15 minSulphur
C0.15 maxCarbon
Mn2.00 maxManganese
Si1.00 maxSilicon
P0.20 maxPhosphorus
Mo0.60 maxMolybdenum
FeBalanceIron
05 · Strength Data

WNR 1.4305 Screws Mechanical Properties

ISO 3506 property classes define fastener strength, with class A1 covering free-machining 303.

Tensile Strength (Class A1-70)700 MPa min
0.2% Proof Stress (Class A1-70)450 MPa min
Tensile Strength (Class A1-50)500 MPa min
0.2% Proof Stress (Class A1-50)210 MPa min
Nut Proof Load Stress (A1-70, ISO 3506-2)700 MPa
Elongation After Fracture (Class A1-70)0.4d min
06 · Physical Data

Physical Properties of Stainless Steel 303 Fasteners

Reference physical values for UNS S30300 / WNR 1.4305 bar stock, useful for design load, thermal and electrical calculations.

Physical Properties - UNS S30300 (Annealed Condition)
ρ8.03 g/cm³Density
E193 GPaElastic Modulus
α17.3 µm/m·°CMean Coeff. of Thermal Expansion (0-100°C)
k16.3 W/m·KThermal Conductivity
Cp500 J/kg·KSpecific Heat (0-100°C)
Ω0.72 µΩ·mElectrical Resistivity
μ1.008Magnetic Permeability (Annealed)
MP1400-1420°CMelting Range
07 · Hardness Data

Stainless Steel 303 Fasteners Hardness

Typical hardness values for UNS S30300 in the annealed condition, before any cold-work strengthening from thread rolling.

Hardness - UNS S30300 (Annealed Condition)
HB160 maxBrinell Hardness
HRB83 maxRockwell B Hardness
HV167 maxVickers Hardness
HK180 maxKnoop Hardness

SS 303 Bolts Exporter In India Shipping To Jebel Ali, UAE

Dubai and Abu Dhabi consignments load at Nhava Sheva with the COO and MTC already inside the file.

Request Export Quote
08 · Grade Selection

SS 303 vs SS 304 vs SS 316 Fasteners

The single most-asked question before a 303 order is released - settled here in one screen.

SS 304 (S30400)

  • Sulphur: 0.030 max, not free-machining
  • Machining Speed: Slow, gummy chip
  • Weldable: Yes, readily
  • Best For: Welded and cold-formed joints
  • Relative Cost: Baseline

SS 303 (S30300)

  • Sulphur: 0.15 min, free-machining by design
  • Machining Speed: Fastest of the three
  • Weldable: Not recommended
  • Best For: Turned bolts, studs, shaft hardware
  • Relative Cost: Comparable, lower machining cost

SS 316 (S31600)

  • Sulphur: 0.030 max, plus 2-3% Mo
  • Machining Speed: Slowest, work hardens
  • Weldable: Yes, readily
  • Best For: Coastal, chloride and chemical duty
  • Relative Cost: Highest
09 · How It Is Made

SUS 303 Threaded Rod Machining & Thread Production Route

Grade 303 fasteners are turned from bar because sulphide inclusions reduce ductility, yielding tighter dimensions.

1

Bar Selection

Certified S30300 bar released against heat number and ladle analysis.

2

CNC Turning

Head, shank and undercut cut in one setup to protect concentricity.

3

Threading

Rolled where strength matters, single-point cut for odd pitches.

4

Deburr & Passivate

Free iron removed, then ASTM A967 passivation restores the film.

5

Gauge & Pack

Ring and plug gauged, batch tagged, then crated for dispatch.

10 · Know The Limits

INOX 303 Washer Welding, Magnetism & Corrosion Limits

Honest limits stated up front, because a returned container costs more than a corrected specification. Buyers in Durban, Dubai, Mombasa and Calgary check these six points before release.

Annealed: Non-Magnetic
After Cold Work: Weakly Magnetic
Welding: Not Recommended
Chloride Service: Specify 316
Hardening: Cold Work Only
Pitting Resistance: Below 304
11 · Assembly Guidance

303 Stainless Steel Hex Bolts Galling, Torque & Anti-Seize

Thread seizure ruins more stainless joints on site than corrosion ever does. Grade 303 handles it better than most austenitics, and these four habits close the gap entirely.

Why 303 Galls Less Than 304

  • Sulphide inclusions act as a solid lubricant
  • Cleaner thread flank means less cold welding

Anti-Seize On Every Thread

  • Nickel or moly paste applied thinly before start
  • Recalculate torque once a lubricant is added

Run Down Slowly, By Hand

  • Impact wrenches generate seizing friction heat
  • Stop and back off at the first sign of drag

Match The Nut To The Bolt Class

  • Pair an A1-70 nut with an A1-70 bolt
  • Never torque above the weaker component
12 · Industries

Stainless Steel Type 303 Bolts And Nut Applications

Sectors that order repeat lots from us as their Stainless Steel 303 fasteners stockist in India.

Machine Building & Jigs
Pump & Motor Shaft Hardware
Electrical Switchgear Parts
Aircraft Fittings & Bushings
Automotive Components
Instrumentation Assemblies
HVAC & Appliance Hardware
General Engineering Fabrication
13 · Size Range

SS 303 Hex Bolts Dimensions & Thread Chart

Fastest Moving M5 M6 M8 M10 1/4 in 3/8 in 1/2 in
Unified Thread Pitch - Threads Per Inch, ASME B1.1
Nominal SizeUNC (TPI)UNF (TPI)Nominal SizeUNC (TPI)UNF (TPI)
No. 632401/2 in1320
No. 832365/8 in1118
No. 1024323/4 in1016
1/4 in20287/8 in914
5/16 in18241 in812
3/8 in16241-1/4 in712
7/16 in14201-1/2 in612

Metric Coarse Pitch We Hold

M3 - M60.50, 0.70, 0.80 and 1.00 mm pitch
M8 - M161.25, 1.50, 1.75 and 2.00 mm pitch
M20 - M362.50, 3.00, 3.50 and 4.00 mm pitch
M42 - M644.50, 5.00, 5.50 and 6.00 mm pitch

Free Quote On Your Exact Size

List the size, pitch, head style, length and quantity in one line and skip the back-and-forth - our desk replies with a same-day ex-Mumbai figure and the stock position against each item.

Get My Free Quote
14 · Codes We Follow

ASTM F593 Type 303 Hex Nuts Governing Standards

Every 303 fastener leaving our floor is checked against the specification your drawing names, not a house standard.

ASTM A582
ASTM F593 Group 1
ASTM F594 Group 1
ISO 3506-1 Class A1
ISO 3506-2 Class A1
EN 10088-3
ASME B18.2.1 / B18.2.2
JIS G4303
ASTM A967 Passivation
Client-Specific
Global Reach

Where Our Stainless Steel 303 Fasteners Ship

Ex-stock and mill-order dispatch to buyers across the Gulf, Africa, the Americas and Asia-Pacific, alongside strong domestic demand from Mumbai, Ahmedabad, Bengaluru, Chennai and Pune.

Key Export Markets
UAEUAE
Saudi ArabiaSaudi Arabia
TurkeyTurkey
CanadaCanada
UKUnited Kingdom
SingaporeSingapore
USAUnited States
MexicoMexico
ThailandThailand
ItalyItaly
NetherlandsNetherlands
GermanyGermany
PhilippinesPhilippines
MalaysiaMalaysia
UgandaUganda
IndonesiaIndonesia
South AfricaSouth Africa
VietnamVietnam
VenezuelaVenezuela

ASTM F593 Type 303 Hex Nuts Supplier In Chennai - EN 10204 3.1 On Every Lot

Chennai and Tamil Nadu plants draw from the identical certified lots we release to export accounts.

Get Supplier Quote
15 · Turnaround

Stainless Steel Grade 303 Socket Head Cap Screw Delivery Estimate

After order confirmation, your chosen freight mode determines the overall delivery timeline.

Ex-Stock Dispatch

Stocked SS 303 bolt and nut sizes are packed and gated out inside 2-5 working days

Sea Freight

Budget-friendly FCL or LCL movement, generally 1-4 weeks by discharge port

Air Freight

Wheels-up within 3-7 days when a plant stoppage cannot wait on a vessel schedule

Country-Specific ETA

Name the consignee port and we commit to a dated arrival window in writing

16 · Quality

SS 303 Bolts Testing & Certification

Whichever checks you nominate are recorded on the certificate that travels with the consignment.

PMI Testing
Tensile & Proof Load Test
Hardness Test
Thread Gauge Inspection
MTC 3.1 & 3.2
Chemical Analysis
Third-Party Inspection
Heat Number Traceability
17 · FAQs

Stainless Steel 303 Fasteners FAQs

The five questions our 303 desk answers most, straight from the buyers who ask them.

What is SS 303 Bolts material?

SS 303 Bolts use free-machining 18/8 austenitic steel (UNS S30300) with added sulphur.

What is the difference between UNS S30300 Nut and 316 stainless?

UNS S30300 Nut has no molybdenum; 316 adds molybdenum for far better chloride resistance.

Is AISI 303 Studs or 304 stainless better?

AISI 303 Studs machine faster; 304 welds better and resists corrosion better overall.

Can ASTM F593 Type 303 Hex Nuts be welded?

Not recommended - sulphide inclusions cause hot cracking; use 304 or 316 instead.

Is Stainless Steel Type 303 Bolts and Nut magnetic?

Essentially non-magnetic when annealed, though cold working can leave weak surface magnetism.

Why Mortec Manufacturing Co For Stainless Steel 303 Fasteners?
Sulphur-bearing S30300 bar machines to tighter thread profiles
Bright-turned SS 303 bolts and studs stocked M3 to M64
Heat-numbered mill certificates trace each SS 303 fastener lot
Drawing-specific pitches and sea-freight crating for overseas orders

Materials



Products

Certifications & Credentials
Certified to PED 2014/68/EU for the manufacture of forged steel products
Stock, distribute and trade Steel Flanges, Nuts and Bolts, and precision-machined parts in Nickel Alloys, High Temperature Alloys and Super Alloys
Since 2012, exporting Oil and Gas piping items built to NACE MR0175 / ISO 15156 across the Egypt, Tunisia, Netherlands, Azerbaijan, South Africa, Algeria, Saudi Arabia and Morocco
Hold the largest import and stock inventory of bolting accessories, in both ferrous and non-ferrous metals, in India

Authorized Supplier For The Following Companies - Material At Reseller Price For Traders

Associated Companies - ADNOC, SABIC, Saudi Aramco, GASCO, ORPIC, KNPC, QATARGAS

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