Description
Stainless Steel 304 Machined Parts | AISI 304 Stainless Steel CNC Screw Machine Parts
Stainless Steel 304 Machined Parts are precision-engineered components manufactured from AISI 304 austenitic stainless steel using CNC turning, CNC milling, Swiss machining, multi-spindle screw machining, and precision grinding processes. Stainless Steel Fittings India supplies SS 304 CNC screw machine parts, turned components, milled parts, and custom machined assemblies to electrical OEMs, EPC contractors, power utilities, and industrial distributors worldwide. Our AISI 304 machined components comply with ASTM A276, ASTM A479, EN 10088, and ISO 9001:2015 standards. Price: US$ 9.80/kg
Product Overview – SS 304 CNC Machined Components
CNC Turned Parts in SS 304
CNC turned components in AISI 304 stainless steel include shafts, spindles, bushings, studs, standoffs, spacers, ferrules, nipples, and precision pins manufactured on Swiss-type CNC lathes and multi-axis turning centers. These parts are dimensionally accurate to tolerances of ±0.005 mm and are widely used in instrumentation, fluid control, and electrical enclosure assemblies.
CNC Milled Parts in AISI 304
CNC milled components encompass brackets, flanges, plates, manifolds, valve bodies, housings, and structural blocks machined on 3-axis and 5-axis vertical machining centers. Surface finish options include Ra 0.8 to Ra 3.2 µm, with precision milling, pocket milling, contour milling, and face milling operations available on SS 304 bar stock and plate material.
Screw Machine Parts – SS 304
Multi-spindle and single-spindle automatic screw machine parts in AISI 304 include threaded inserts, hexagonal connectors, coupling nuts, grub screws, shoulder bolts, knurled thumb screws, precision nozzles, and fluid fittings. High-volume screw machining delivers tight tolerances at competitive per-piece costs for OEM and industrial assembly lines.
Swiss Machined Components – 304 Stainless Steel
Swiss-type CNC machining of SS 304 produces micro-turned parts, long slender shafts, miniature connectors, sensor housings, catheter fittings, pin contacts, and medical-grade components. Swiss machining supports L/D ratios up to 30:1 with diameter ranges from 0.5 mm to 32 mm, maintaining roundness, cylindricity, and surface integrity in austenitic 304 stainless.
Precision Ground Components – AISI 304
Centerless ground, cylindrical ground, and surface ground components in AISI 304 include precision shafts, gauge pins, dowel pins, ground bushings, and linear guide rails. Grinding ensures dimensional accuracy within IT5 to IT6 tolerance grades and surface roughness values as fine as Ra 0.2 µm for critical fit and function applications.
Custom Machined Assemblies – 304 SS
Sub-assemblies and machined component kits in AISI 304 stainless are produced per customer drawings, DXF/STEP/IGES files, or reverse engineering. Assembly options include press fitting, thread locking, O-ring grooves, cross-drilled holes, knurling, hex broaching, Torx pockets, and electropolishing post-processing for corrosion-critical applications.
Hydraulic and Pneumatic Machined Fittings – SS 304
Machined hydraulic fittings in SS 304 include compression fittings, tube connectors, bulkhead unions, plug fittings, elbow connectors, tee fittings, and adapters per DIN 2353, Parker, and Swagelok dimensional standards. These components handle working pressures up to 6000 PSI and temperatures from -196°C to +650°C in process piping and instrumentation loops.
Key Features of AISI 304 CNC Machined Parts
- Material: AISI / ASTM 304 austenitic stainless steel, 18% Cr – 8% Ni composition
- Dimensional tolerance: ±0.005 mm (CNC turning), ±0.01 mm (CNC milling)
- Surface finish: Ra 0.4 µm to Ra 6.3 µm as machined; Ra 0.2 µm after grinding
- Thread forms: Metric (M), UNC, UNF, BSPP, BSPT, NPT, NPTF, Whitworth
- Custom machining from customer drawings, CAD files, or samples
- Lot sizes: prototype (1 pc) to mass production (100,000+ pcs/month)
- Post-processing: passivation (ASTM A967), electropolishing, tumbling, shot blasting
- Certifications: EN 10204 3.1 Mill Test Certificate, ISO 9001:2015, RoHS compliant
Corrosion Resistance
AISI 304 stainless steel offers excellent resistance to atmospheric corrosion, mild chemical environments, food acids, and oxidizing agents up to 870°C. Its passive chromium-oxide film provides protection against rust, pitting, crevice corrosion, and stress corrosion cracking in most industrial and marine environments, making it the industry standard for machined fittings, connectors, and fasteners in chemical processing and power plant applications.
Machinability and Dimensional Stability
While AISI 304 work-hardens faster than carbon steel, controlled cutting parameters, carbide tooling, high-pressure coolant, and optimized chip breaking ensure consistent dimensional stability across long production runs. CNC machines maintain sub-micron repeatability over thousands of parts, critical for OEM assembly lines requiring zero-defect component matching.
High-Temperature Performance
SS 304 machined parts retain structural integrity from cryogenic temperatures (-196°C for LNG applications) to continuous service at 870°C and intermittent use up to 925°C. This thermal range supports applications in heat exchangers, boiler fittings, exhaust system components, and high-temperature electrical enclosures in power generation plants.
Non-Magnetic and Hygienic Properties
Annealed AISI 304 is essentially non-magnetic (relative permeability µr ≈ 1.008), making it essential for machined components near sensitive electrical instruments, MRI equipment, and electrical switchgear where magnetic interference must be avoided. Its smooth, non-porous machined surface is also hygienic and easy to clean, qualifying it for food processing, pharmaceutical, and semiconductor applications.
Weldability and Post-Machining Processing
AISI 304 machined parts can be welded using TIG, MIG, laser, and resistance welding processes without requiring pre-heat or post-weld heat treatment in most applications. Post-machining passivation per ASTM A967 or AMS 2700 removes free iron and enhances the natural passive film, while electropolishing improves surface roughness, reduces bacterial adhesion, and increases corrosion resistance in pharmaceutical and food-grade machined fittings.
Customization and Drawing-Based Manufacturing
All SS 304 machined parts are produced per customer-supplied drawings (PDF, DWG, DXF, STEP, IGES, SolidWorks, AutoCAD), with full first-article inspection (FAI), PPAP documentation, CMM measurement reports, and material traceability from mill certificate to finished part. Custom part numbers, laser marking, packaging in antirust paper, and kitting services are available for OEM and EPC supply chains.
Technical Specifications
| Parameter | Specification |
|---|---|
| Material Grade | AISI 304 / UNS S30400 |
| Composition (Cr) | 18.0 – 20.0% |
| Composition (Ni) | 8.0 – 10.5% |
| Composition (C max) | 0.08% |
| Composition (Mn max) | 2.00% |
| Composition (Si max) | 0.75% |
| Tensile Strength (min) | 515 MPa (75 ksi) |
| Yield Strength (0.2% min) | 205 MPa (30 ksi) |
| Elongation (min) | 40% |
| Hardness (max) | 201 HB / 92 HRB / 210 HV |
| Density | 7.93 g/cm³ |
| Melting Point | 1400 – 1455°C |
| Max Service Temperature | 870°C (continuous), 925°C (intermittent) |
| Thermal Conductivity | 16.2 W/m·K at 100°C |
| Machining Diameter Range | 0.5 mm – 500 mm |
| Length Range | Up to 3000 mm |
| Dimensional Tolerance | ±0.005 mm (turned), ±0.01 mm (milled) |
| Surface Finish | Ra 0.2 – 6.3 µm |
| Applicable Standards | ASTM A276, A479, A484; EN 10088-3; JIS G4303 |
| Price | US$ 9.80/kg (SS 304) |
International Grade Equivalents – AISI 304 Stainless Steel
| Standard | Grade Designation | Country/Region |
|---|---|---|
| AISI / ASTM | 304 / S30400 | USA |
| EN / DIN | 1.4301 / X5CrNi18-10 | Europe / Germany |
| JIS | SUS 304 | Japan |
| BS | 304 S15 | United Kingdom |
| GOST | 08Kh18N10 | Russia |
| GB / Chinese | 0Cr18Ni9 | China |
| IS | 04Cr18Ni10 | India |
| SAF / Swedish | 2333 | Sweden |
Product Types and Variants
| Product Type | Description | Typical Size Range |
|---|---|---|
| CNC Turned Parts | Shafts, bushings, spacers, pins, standoffs, ferrules | Ø 0.5 – 200 mm |
| CNC Milled Parts | Brackets, housings, manifolds, valve bodies, flanges | Up to 500 × 500 × 300 mm |
| Screw Machine Parts | Threaded connectors, inserts, nozzles, adapters | Ø 2 – 50 mm |
| Swiss Machined Parts | Micro-parts, slender shafts, medical components | Ø 0.5 – 32 mm, L/D up to 30:1 |
| Ground Components | Precision shafts, pins, guide rods, gauge pins | Ø 2 – 100 mm, Ra down to 0.2 µm |
| Hydraulic Fittings | Compression, bulkhead, tube connectors per DIN 2353 | 1/8″ – 2″ / 6 – 50 mm tube OD |
| Hexagonal Nipples | BSP, NPT, Metric threaded hex nipples | 1/8″ – 2″ BSP/NPT |
| Hex Reducing Bushes | Male-female reducing adapters, hex head | 1/8″ – 2″ × 1/4″ – 1.5″ |
| Square Head Plugs | Solid plugs with square drive, BSP/NPT threaded | 1/8″ – 2″ |
| Custom Assemblies | Multi-component sub-assemblies per drawing | As per customer specification |
Applications in Industry
| Industry Sector | Application of SS 304 Machined Parts |
|---|---|
| Electrical & Power Generation | Switchgear components, busbar spacers, transformer fittings, cable gland bodies, earthing connectors, instrument enclosure hardware |
| Oil & Gas / Petrochemical | Instrumentation tube fittings, valve stems, pump shafts, heat exchanger baffles, nozzle assemblies, manifold blocks |
| Chemical Processing | Corrosion-resistant reactor fasteners, agitator shafts, dosing nozzles, pipe flange studs, pressure vessel fittings |
| Food & Beverage | Hygienic fittings, mixing shafts, valve bodies, conveyor components, clean-in-place (CIP) nozzles |
| Pharmaceutical | Electropolished process fittings, filling machine parts, reactor vessel components, cleanroom hardware |
| Water Treatment | Pump impeller components, membrane housing fittings, strainer elements, valve stems |
| Automotive & Aerospace | Exhaust brackets, sensor fittings, hydraulic line connectors, structural standoffs |
| Construction & Infrastructure | Structural fasteners, architectural connectors, railing fittings, curtain wall hardware |
| Semiconductor & Electronics | Ultra-clean vacuum fittings, wafer handling components, precision standoffs, non-magnetic hardware |
Manufacturing Process
Our SS 304 machined parts are produced through a controlled, multi-stage manufacturing process aligned with ISO 9001:2015 and customer-specific quality plans:
- Raw Material Procurement: AISI 304 bar stock, sheet, plate, and tube sourced from certified mills (Jindal, Mukand, Outokumpu, Acerinox) with EN 10204 3.1 Mill Test Certificates verifying chemical composition, mechanical properties, and heat numbers.
- Material Inspection: Incoming material is PMI-tested (Positive Material Identification via XRF), dimensional inspection of bar diameter/straightness, and hardness verification before release to production.
- CNC Machining: Parts are programmed using CAM software (Mastercam, SolidCAM) and machined on Mazak, DMG Mori, Haas, or equivalent CNC turning and machining centers with live tooling, sub-spindles, and bar feeders for unattended production.
- In-Process Quality Control: CMM (Coordinate Measuring Machine) checks, SPC (Statistical Process Control) data collection, and in-process gauging at defined inspection frequencies ensure dimensional conformance throughout the production run.
- Secondary Operations: Thread tapping, thread rolling, knurling, drilling, boring, reaming, hex broaching, slotting, and gear hobbing are performed as required on the machined blanks.
- Surface Treatment: Parts undergo passivation (ASTM A967 / AMS 2700), electropolishing (ASTM B912), shot blasting, tumbling, or manual finishing to achieve specified surface roughness and corrosion resistance levels.
- Final Inspection: 100% dimensional inspection or AQL sampling (ISO 2859-1), thread gauging (Go/No-Go), surface roughness measurement, visual inspection under 10× magnification, and leak testing for hydraulic components.
- Packaging and Dispatch: Parts are individually wrapped in VCI (Volatile Corrosion Inhibitor) poly bags, packed in corrugated boxes with foam inserts, labeled with part numbers, heat numbers, and customer PO references, and dispatched with full documentation including MTC, COC, FAI reports, and packing lists.
Quality Standards and Certifications
| Standard / Certification | Scope |
|---|---|
| ISO 9001:2015 | Quality Management System – Manufacturing and Supply |
| ASTM A276 / A276M | Standard Specification for SS Bars and Shapes |
| ASTM A479 / A479M | SS Bars and Shapes for Use in Boilers and Pressure Vessels |
| ASTM A967 / AMS 2700 | Passivation specification for stainless steel parts |
| EN 10204 Type 3.1 | Material Test Certificate with third-party witness |
| EN 10088-3 | European standard for stainless steel semi-finished products |
| ISO 2859-1 | Sampling procedures for inspection by attributes (AQL) |
| RoHS / REACH | Compliance with EU hazardous substance regulations |
| PED 2014/68/EU | Pressure Equipment Directive (for hydraulic fittings) |
Why Choose Stainless Steel Fittings India for SS 304 Machined Parts?
- 25+ Years Manufacturing Experience: Specialized in precision stainless steel machined components for global industrial markets since 1999.
- Full Traceability: Heat-wise material traceability from raw bar to finished part, with EN 10204 3.1 MTCs available for all orders.
- Global Export Network: Regular supply to USA, UK, UAE, Saudi Arabia, Germany, Australia, Singapore, Canada, Brazil, and 50+ countries.
- Drawing-Based Manufacturing: In-house design support, DFM (Design for Manufacturability) review, and reverse engineering capability.
- Competitive Pricing: SS 304 Machined Parts starting from US$ 9.80/kg with volume discounts for OEM and EPC orders.
- Fast Lead Times: Standard parts shipped within 7–14 days; custom parts within 3–6 weeks depending on complexity.
- Quality Documentation: MTC, COC, CMM reports, FAI, PPAP, and RoHS/REACH declarations supplied with every shipment.
- Single-Source Supply: Machined parts, fittings, fasteners, forgings, and castings all available from one certified stainless steel manufacturer.
Frequently Asked Questions (FAQ)
1. What is the minimum order quantity for SS 304 machined parts?
Our MOQ is flexible: prototypes start at 1 piece for custom drawn parts. For standard catalogue items and high-volume screw machine parts, MOQ is typically 100–500 pieces depending on part complexity and size.
2. What is the price of Stainless Steel 304 machined parts?
SS 304 machined parts are priced from US$ 9.80/kg for standard turned and screw machine components. Complex milled parts, Swiss-machined micro-parts, and sub-assemblies are priced on a per-piece basis based on machining time and material consumption. Contact us for a formal quotation with your drawing or specification.
3. What is the difference between AISI 304 and AISI 316 for machined parts?
AISI 316 contains 2–3% molybdenum, providing superior resistance to chloride-induced pitting and crevice corrosion compared to AISI 304. For applications in marine environments, chlorinated process streams, or pharmaceutical cleanrooms, SS 316 is preferred. For most industrial, atmospheric, and fresh-water applications, SS 304 offers adequate corrosion resistance at a lower material cost.
4. What tolerances can you achieve on SS 304 CNC machined parts?
Standard CNC turning tolerances are ±0.01 mm; precision turning achieves ±0.005 mm. CNC milling holds ±0.01 mm on features and ±0.005 mm on precision bores. Ground components achieve IT5 to IT6 tolerances with surface roughness down to Ra 0.2 µm.
5. Do you provide material test certificates for SS 304 machined parts?
Yes. All SS 304 machined parts are supplied with EN 10204 3.1 Mill Test Certificates (MTC) confirming chemical composition and mechanical properties, traceable to the original steel mill heat number. Third-party inspection by SGS, Bureau Veritas, or TÜV is available on request.
6. What surface treatments are available for AISI 304 machined components?
Available surface treatments include: electropolishing (ASTM B912), passivation (ASTM A967 / AMS 2700), shot blasting (Sa 2.5), vibratory tumbling and deburring, glass bead blasting, and manual mirror polishing. For food and pharmaceutical applications, electropolishing to Ra 0.4 µm or finer is recommended.
7. Can you machine SS 304 parts from customer-supplied drawings?
Yes. We manufacture 100% to customer drawings in PDF, DWG, DXF, STEP, IGES, or SolidWorks formats. Our engineering team performs DFM review and provides feedback on drawing tolerances, material suitability, and machining feasibility before production confirmation.
8. What is the lead time for custom SS 304 CNC machined parts?
Prototypes: 7–14 working days after drawing approval. Production orders (500–10,000 pieces): 3–6 weeks. High-volume orders (50,000+ pieces): 6–10 weeks. Expedited production is available at a premium for urgent OEM and EPC project requirements.
9. Which industries do you supply SS 304 machined parts to?
We supply to electrical OEMs, EPC contractors, power utilities, oil and gas companies, chemical plants, water treatment facilities, pharmaceutical manufacturers, food and beverage processors, automotive Tier-1 suppliers, construction contractors, and semiconductor equipment manufacturers globally.
10. Is AISI 304 stainless steel magnetic after machining?
Annealed AISI 304 is essentially non-magnetic. However, cold working during machining (turning, milling) can induce slight martensite transformation, resulting in weak ferromagnetism. For applications requiring strict non-magnetic properties (relay components, electrical instruments), solution annealing at 1050–1100°C after machining restores full austenitic, non-magnetic properties.
Equivalent Terms – Multilingual Reference
| Language | Equivalent Terms |
|---|---|
| Spanish | Piezas mecanizadas de acero inoxidable 304, Partes CNC de acero inoxidable AISI 304, Componentes torneados de acero inoxidable 304, Piezas de tornillo CNC en acero inoxidable |
| Russian | Обработанные детали из нержавеющей стали 304, Детали CNC из нержавеющей стали AISI 304, Точёные компоненты из нержавеющей стали 304, Фрезерованные детали из нержавеющей стали |
| French | Pièces usinées en acier inoxydable 304, Composants CNC en inox AISI 304, Pièces tournées en acier inoxydable 304, Pièces de décolletage inox 304 |
| Portuguese | Peças usinadas em aço inoxidável 304, Componentes CNC em aço inox AISI 304, Peças torneadas de aço inoxidável 304, Peças de parafuso CNC em inox |
| Italian | Parti lavorate in acciaio inossidabile 304, Componenti CNC in acciaio inox AISI 304, Parti tornite in acciaio inossidabile 304, Pezzi di tornitura CNC inox |
Related Stainless Steel Machined Parts – Internal Links
- Stainless Steel 316 Machining, CNC Machining of 316 Stainless Steel
- Stainless Steel Machined Hydraulic Fittings
- Stainless Steel Swiss Machining
- Stainless Steel Milling, SS 316 and 304 Milled Parts
- Stainless Steel CNC Machined Parts Components
- Stainless Steel Machined Ferrules & Hose Crimping Ferrules
- Stainless Steel Hexagonal Reducing Bush Male Female
- Stainless Steel Hexagonal Nipples
- Stainless Steel Square Head Plugs
Request a Quote – SS 304 Machined Parts
Contact Stainless Steel Fittings India today for a competitive quotation on AISI 304 CNC machined parts, turned components, and screw machine parts. Send your drawings, specifications, or quantity requirements to our technical sales team. SS 304 machined parts priced from US$ 9.80/kg. We export to 50+ countries with fast lead times and full quality documentation.
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