CNC Machining Stainless Steel Services
High-quality CNC stainless steel machining with 11+ material grades available. Partwork delivers corrosion-resistant stainless steel parts across India with excellent surface finish, superior hygiene properties, and 7-12 day delivery. Upload your CAD file for instant pricing.
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Overview
Detailed Material Analysis
Stainless steel is a family of iron-based alloys containing a minimum of 10.5% chromium, which forms a passive chromium oxide layer on the surface providing exceptional corrosion resistance. These alloys are categorized into austenitic (300 series - most common), ferritic (400 series), martensitic (400 series hardenable), precipitation hardening (17-4 PH), and duplex (mixed austenite-ferrite) grades. Each category offers distinct properties including corrosion resistance, strength, formability, and machinability. Partwork specializes in precision CNC machining of all major stainless steel grades, providing comprehensive manufacturing solutions for food & beverage equipment, pharmaceutical machinery, medical devices, architectural applications, marine components, and chemical processing equipment across India.
| Property | Specification |
|---|---|
| Machinability | Fair to Good – work hardens (300 series), requires sharp tools and proper speeds/feeds |
| Corrosion Resistance | Excellent – chromium oxide passive layer resists oxidation, acids, and atmospheric corrosion |
| Tensile Strength | Good to High (515-860 MPa) – varies by grade (304: 515 MPa, 17-4 PH: 1,310 MPa aged) |
| Work Hardening | Moderate to Severe (300 series) – hardens during cutting, requires constant feed and sharp tools |
| Weldability | Excellent (300 series) to Good (400 series) – low-carbon grades (304L, 316L) best for welding |
| Hygiene & Cleanability | Excellent – smooth non-porous surface, easy to clean, FDA approved for food contact |
| Min Wall Thickness | 1.0mm (typical) – can be thinner for sheet metal work and food processing equipment |
| Max Part Size | 200 × 100 × 100 cm (varies by machine capacity and material availability) |
| Lead Time | 7-12 working days (standard) | Rush: 5-7 days available |
| Typical Price (India) | ₹200-390/kg (raw material) – SS304: ₹200-320/kg, SS316: ₹250-390/kg |
Available Grades & Standards
We offer a wide selection of grades to meet specific engineering requirements, from general purpose to high-performance flight-grade alloys.
| Grade | Category | Key Features | Typical Applications |
|---|---|---|---|
| SS304 | Austenitic | 18-8 (18% Cr, 8% Ni). Most popular. Good corrosion, formability | Food equipment, sinks, architectural, general fabrication |
| SS304L | Austenitic | Low carbon 304. Better weldability, no sensitization | Welded structures, tanks, pressure vessels, chemical equipment |
| SS316 | Austenitic | 16-10-2 (Mo added). Superior corrosion, chloride resistance | Marine, pharmaceutical, medical implants, coastal areas |
| SS316L | Austenitic | Low carbon 316. Best weldability, no sensitization | Pharmaceutical, surgical instruments, marine welded fabrication |
| SS303 | Austenitic | Free-machining 304. Sulfur added for excellent machinability | High-volume turned parts, shafts, fasteners, fittings |
| SS310 | Austenitic | 25-20 (25% Cr, 20% Ni). High temperature oxidation resistance | Furnace parts, heat exchangers, high-temp applications (800°C) |
| SS416 | Martensitic | Free-machining martensitic. Best machinability in SS | Valve stems, shafts, pump parts, screw machine products |
| SS420 | Martensitic | Hardenable to 50-55 HRC. Good corrosion + hardness | Cutlery, surgical instruments, molds, valve seats |
| SS430 | Ferritic | 17% Cr, magnetic. Good formability, lower cost than 304 | Automotive trim, appliances, decorative, indoor applications |
| 17-4 PH | PH (Precip. Hard.) | Age-hardenable to 1,310 MPa. High strength + corrosion | Aerospace, oil & gas, high-strength shafts, pump components |
| Super Duplex 2507 | Duplex | 50% austenite + 50% ferrite. Highest strength & corrosion | Offshore oil & gas, chemical tankers, seawater systems |
Common Applications
Food & Beverage Processing
- Food processing equipment and machinery (SS304, SS316)
- Dairy tanks, milk processing equipment (SS304, SS316L)
- Brewery and beverage processing (SS304, SS316)
- Commercial kitchen equipment, sinks, countertops (SS304)
Pharmaceutical & Medical
- Pharmaceutical processing equipment (SS316L, SS304L)
- Surgical instruments and medical tools (SS316L, SS420)
- Medical implants and orthopedic devices (SS316L, 17-4 PH)
- Clean room equipment and sterile processing (SS316L)
Chemical & Petrochemical
- Chemical reactors and pressure vessels (SS316, SS316L)
- Heat exchangers and condensers (SS316, SS304)
- Pump components and valve bodies (SS316, 17-4 PH)
- Piping and flanges for corrosive fluids (SS316L)
Marine & Offshore
- Marine pumps and valves (SS316, Super Duplex)
- Seawater piping and fittings (SS316, Super Duplex)
- Offshore platform components (Super Duplex, 17-4 PH)
- Ship deck fittings and fasteners (SS316, 17-4 PH)
Architectural & Construction
- Handrails, balustrades, and railings (SS304, SS316)
- Decorative panels and cladding (SS304, SS430)
- Fasteners and structural components (SS304, SS316)
- Elevator cabins and interior fittings (SS304)
Surface Finishing Options
| Finish | Time | Cost |
|---|---|---|
As-Machined (Mill Finish) Prototypes, internal non-visible parts | — | ₹0 |
Passivation Remove free iron, enhance corrosion resistance (standard for SS) | +3-5 days | +₹500-1,500 |
Electropolishing Mirror finish Ra 0.2-0.4 μm (pharmaceutical, medical, food) | +4-6 days | +₹1,500-4,000 |
Bead Blasting (Satin) Uniform matte finish, hides minor scratches (architectural) | +2-4 days | +₹400-1,200 |
Polishing (180-600 Grit) Reflective finish (decorative, architectural, kitchen equipment) | +3-6 days | +₹800-2,500 |
Powder Coating Custom colors, additional protection (architectural, outdoor) | +3-5 days | +₹500-1,500 |
PVD Coating (Gold/Black) High-end decorative, wear resistance, luxury finishes | +5-8 days | +₹2,000-5,000 |
Heat Treatment (420, 17-4) Hardening SS420 (50-55 HRC) or aging 17-4 PH (44 HRC) | +5-8 days | +₹2,000-6,000 |
Frequently Asked Questions
Everything you need to know about machining Stainless Steel Machining.
SS304 (18-8) contains 18% chromium and 8% nickel, providing good corrosion resistance suitable for most indoor applications, food equipment, and general fabrication. SS316 (16-10-2) contains 16% chromium, 10% nickel, and 2-3% molybdenum, offering superior corrosion resistance especially against chlorides, acids, and marine environments. SS316 is more expensive (₹250-390/kg vs ₹200-320/kg for SS304) but essential for pharmaceutical, medical, marine, and coastal applications.
- Food processing equipment: SS304, SS304L (dairy: SS316L for acid cleaning)
- Pharmaceutical/medical: SS316L (implants, instruments), SS304L (equipment)
- Marine/coastal: SS316, SS316L (super aggressive: Super Duplex 2507)
- High-volume machining: SS303 (free-machining, best machinability)
- High strength required: 17-4 PH (age-hardenable to 1,310 MPa)
- Architectural/decorative: SS304 (indoor), SS316 (outdoor/coastal), SS430 (budget)
Austenitic stainless steels (300 series) have a face-centered cubic (FCC) crystal structure that transforms to body-centered tetragonal (BCT) martensite under mechanical stress, creating an extremely hard work-hardened layer. Best practices: Use sharp tools, maintain constant feed, use high-pressure coolant, and take appropriate depth of cut.
Standard CNC machining: ±0.05mm to ±0.08mm. Precision CNC machining: ±0.025mm to ±0.05mm achievable with proper tooling. Free-machining grades (SS303, SS416) allow tighter tolerances. After electropolishing, material removal is 0.005-0.02mm per surface.
- Simple turned parts: 5-7 working days
- Standard CNC machining (3-axis): 7-10 working days
- With passivation: +3-5 days
- With electropolishing: +4-6 days
- Medical/pharmaceutical: 12-18 days
Raw material cost: SS304 ₹200-320/kg, SS316 ₹250-390/kg. Machining cost is 20-40% higher than carbon steel. Surface finishing adds cost (e.g., Electropolishing ₹1,500-4,000). Material accounts for 25-35% of total cost, machining 50-60%, finishing 10-25%.
Yes, we provide EN 10204 3.1 mill test reports, FDA material certification for food contact surfaces (FDA 21 CFR 177.2600), and USP Class VI certification for pharmaceutical equipment (on request).
Yes, especially low-carbon grades (SS304L, SS316L). SS303 is not recommended due to sulfur content. 17-4 PH requires solution annealing + aging after welding.
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