Description

Stainless Steel Milling – SS 316 & SS 304 Milled Parts Manufacturer

Price: US$ 11.50 / kg | Ex-Works India | MOQ: 50 kg | Delivery: 15–25 working days

Stainless Steel Fittings India manufactures precision CNC-milled components in SS 316, SS 316L, SS 304, and SS 304L grades, supplying electrical OEMs, EPC contractors, power utilities, and industrial distributors worldwide. Stainless steel milling produces flat, profiled, contoured, and slotted surfaces on bar stock, billets, and pre-formed blanks using multi-axis CNC machining centres. Milled stainless steel parts offer superior dimensional accuracy, corrosion resistance, and surface finish compared to cast or forged equivalents, making them suitable for instrumentation housings, valve bodies, coupling flanges, terminal blocks, and custom structural inserts.

Detailed Product Overview

CNC Face Milling and Surface Milling of SS 316 / SS 304

Face milling operations on stainless steel involve multi-tooth face cutters, carbide insert end mills, and high-speed milling spindles. Typical applications include stainless steel flat milled plates, milled flange faces, manifold surfaces, and precision ground-ready blanks. Achievable flatness tolerances reach ±0.01 mm on SS 316L and SS 304L material. Surface finishes ranging from Ra 0.4 μm to Ra 3.2 μm are standard; mirror-polished milled faces are available on request. Related terms: CNC surface grinding of SS, stainless steel facing operation, flat bar milling, SS plate facing, precision machined flat.

Slot Milling, Groove Milling and Keyway Milling in Stainless Steel

Slot milling in austenitic stainless steel grades requires climb milling strategies, sharp carbide tooling, and controlled chip evacuation to prevent work hardening. We produce T-slots, dovetail slots, straight keyways, woodruff keyways, and stepped grooves in SS 316 and SS 304 components. Groove depths and widths are held to ISO 286 tolerance class H7/h7. Typical applications include shaft keyways, coupling hubs, motor adapters, instrumentation brackets, and pump impeller shafts. Related terms: stainless steel keyway cutting, CNC slotting of SS, dovetail slot milling SS316, groove milling stainless, stepped slot machining.

Contour Milling, Profile Milling and 3D Milling

Our 3-axis and 4-axis CNC machining centres execute complex contour milling, profiling, and 3D surface machining on SS 316 and SS 304 billets. Stainless steel profile milled parts include valve body profiles, pump casing contours, pipe end preparations, custom bracket profiles, and cam profiles. Toolpath strategies include trochoidal milling, rest machining, and adaptive clearing for heat-sensitive austenitic grades. Related terms: 3D milled SS component, contour machined stainless, profile milled flange, CNC milling SS 316L, adaptive milling stainless steel.

Thread Milling and Hole Pattern Milling on Stainless Steel

Thread milling with solid carbide thread mills produces accurate internal and external threads in SS 316 and SS 304, avoiding the torn threads common with tapping hard stainless grades. We produce metric threads (M6–M64), UNC/UNF threads, BSP threads, NPT threads, and BSPT threads in milled stainless components. Hole patterns are drilled and bored to positional tolerances of ±0.025 mm using jig boring strategies. Related terms: CNC thread milling SS 316, stainless thread milled block, hole pattern CNC milling, NPT thread milled SS, tapped hole block stainless.

Milled Stainless Steel Blocks, Adapters and Custom Blanks

Custom milled blanks in SS 316 and SS 304 are supplied as near-net-shape blocks, stepped adapters, flange blanks, riser pads, and equipment bases. Block sizes from 10 mm × 10 mm to 500 mm × 300 mm are regularly processed. These milled stainless blocks are used as sub-base manifolds, sensor mounting pads, instrument enclosures, valve adapters, and structural inserts in electrical and process plant assemblies. Related terms: SS milled block, custom stainless adapter machined, milled manifold blank SS316, precision machined blank SS304, stainless steel milled cube.

Angular Milling and Chamfer Milling on SS Parts

Angular milling and chamfer milling on stainless steel components are performed using single-angle cutters and dove-tail cutters. Chamfer angles from 15° to 75° are machined to ±0.5° tolerance. Angular milled features include bevelled sealing faces, countersink entries, tapered seat preparations, and relief chamfers on pressure-retaining fittings. These operations are standard on stainless steel tube fitting bodies, valve disc edges, and instrument port entries. Related terms: stainless steel chamfer milling, bevel milling SS316, angular cutter SS304, tapered face milling, countersink milling stainless.

Pocketing and Cavity Milling in SS 316 and SS 304

Pocket milling and cavity milling in austenitic stainless grades require rigid machine setups, anti-vibration toolholders, and coolant-through tooling to manage the low thermal conductivity of SS 316. Typical pocketed components include housing recesses, manifold cavities, o-ring grooves, spool bores, and sensor well pockets. Floor tolerances of ±0.02 mm and wall parallelism within 0.015 mm are routinely achieved. Related terms: stainless steel pocket milling, cavity machined SS, o-ring groove milling SS316, manifold cavity milling, deep pocket milling stainless.

Milled Stainless Steel Thin-Wall and Sheet Components

Thin-wall milling of stainless steel sheet and plate sections (wall thickness 0.5 mm–3 mm) is performed using high-speed spindles with reduced radial engagement to minimise deflection. Products include milled stainless steel cover plates, shim stock, precision spacers, and membrane flanges. Flatness is maintained within 0.03 mm per 100 mm span. These components are used in electrical panel assemblies, switchgear enclosures, power utility equipment, and EPC skid packages. Related terms: thin wall milling SS, stainless steel sheet milling, precision milled shim SS316, flat milled cover plate, SS304 milled spacer.

Key Features of Our SS Milled Parts

• Tolerances to IT6 / ISO 286 as standard; IT5 achievable on selected features
• Surface finish Ra 0.4–3.2 μm; electropolishing and passivation available
• Multi-axis CNC milling (3-axis, 4-axis) with live tooling
• Full material traceability — MTCs to EN 10204 3.1 / 3.2
• Price: US$ 11.50 / kg ex-works India
• Batch sizes from prototype (1 piece) to high-volume production
• Compliant with RoHS, REACH, and export documentation available

Dimensional Accuracy and Tolerance Control

Our CNC machining centres are calibrated quarterly to ISO 9283 standards. Linear positional accuracy is maintained at ±0.008 mm on axes up to 600 mm travel. All milled stainless parts undergo first-article inspection (FAI) to AS9102 equivalent, with CMM reports available. Tight-tolerance milled features such as bearing bores, precision location holes, and sealing faces are verified on Zeiss or Renishaw CMM equipment. Geometric tolerances including parallelism, perpendicularity, angularity, and flatness are reported in full inspection reports.

Corrosion Resistance of Milled SS 316 and SS 304

SS 316 milled parts resist chloride pitting, crevice corrosion, and intergranular corrosion due to the 2–3% molybdenum content. SS 304 milled parts are suitable for indoor electrical enclosures, food-grade installations, and chemical dosing environments without atmospheric chloride. Post-milling passivation (per ASTM A967 or AMS 2700) restores the native chromium oxide layer disturbed during cutting, ensuring maximum corrosion resistance. Electropolished milled SS 316L components achieve Ra below 0.4 μm and enhanced passive film thickness.

Heat Treatment and Material Condition

Stainless steel milled parts are supplied in the annealed and pickled condition (solution annealed at 1050–1100°C, water quenched) unless otherwise specified. Cold-worked bar stock in 1/4 hard or 1/2 hard condition is available for applications requiring higher tensile strength. Stress relief annealing after milling is offered for thin-wall or complex geometry components to minimise residual machining stresses. Material hardness is maintained below 200 HB (SS 304) and 217 HB (SS 316) per ASTM A276.

Surface Treatment Options for Milled Stainless Steel

Available surface treatments post-milling include: chemical passivation (citric acid or nitric acid per ASTM A967), electropolishing (mirror finish, Ra <0.2 μm), glass bead blasting (satin finish), pickling and passivation (mixed acid), PVD coating, and hard chrome plating. Each treatment is specified per customer requirement and is compatible with SS 316, SS 316L, SS 304, SS 304L, SS 321, and SS 310S milled components.

Compliance with International Design Standards

Our milled stainless steel parts are manufactured in compliance with ASME B16.5, ASME B16.11, DIN 2353, ISO 8434, BS EN 10088, ASTM A276, ASTM A479, and customer-specific drawings. DFM (Design for Manufacturability) reviews are offered at quotation stage. Engineering changes are tracked through an ECN (Engineering Change Notice) system with full document control under ISO 9001:2015.

Packaging, Labelling and Export Compliance

Milled stainless steel components are individually wrapped in VCI (Volatile Corrosion Inhibitor) film, packed in labelled poly bags with heat seal, and placed in export-grade wooden crates or cartons. Each shipment includes material test certificates (MTCs), packing lists, commercial invoices, and country-of-origin certificates. Export from India under IEC code; ECCS, ETA, and BIS documentation available on request.

Technical Specifications

Raw Material Grades and International Equivalents

Product Types / Variants

Applications by Industry

Manufacturing Process

1. Material Procurement: CRSS-certified stainless steel bar, plate, and billet sourced from prime mills with EN 10204 3.1 MTCs.

2. Sawing / Pre-cutting: Raw material cut to near-net-shape using circular saws or bandsaw to minimise machining stock.

3. CNC Milling Setup: Component clamped in precision vices or custom fixtures on 3-axis / 4-axis machining centres (Fanuc / Siemens control).

4. Roughing: High-feed roughing passes remove bulk material at controlled cutting speeds (15–25 m/min for SS 316) with through-spindle coolant.

5. Semi-finishing and Finishing: Carbide insert end mills and solid carbide cutters execute semi-finish and finish passes to final dimension.

6. Thread Milling / Special Features: Threads, o-ring grooves, and special profiles milled in the same setup where possible to maintain positional accuracy.

7. Deburring and Cleaning: Manual and vibratory deburring; ultrasonic cleaning in deionised water.

8. Surface Treatment: Passivation, electropolishing, or blasting as specified.

9. Inspection: CMM dimensional inspection, surface roughness measurement, and hardness check.

10. Marking, Packing and Dispatch: Laser or electrochemical marking; VCI packing; export documentation.

Quality Standards and Certifications

Why Choose Stainless Steel Fittings India for SS Milled Parts?

• 22+ years of precision machining experience in stainless steel grades
• Dedicated CNC milling division with 3-axis, 4-axis machining centres
• In-house CMM inspection, surface roughness lab, and hardness testing
• Competitive price: US$ 11.50 / kg — no minimum order surcharge above 50 kg
• Fast global delivery: India to USA, UK, UAE, Germany, Singapore, Australia
• Full documentation: MTC 3.1/3.2, COO, MSDS, packing list, commercial invoice
• Engineering support: DFM review, tolerance feasibility analysis, material selection
• Proven supply track record with electrical OEMs, EPC contractors, power utilities

Frequently Asked Questions

Q1: What is the difference between SS 316 and SS 304 for milled parts?

SS 316 contains 2–3% molybdenum, which provides superior resistance to chloride-induced pitting and crevice corrosion compared to SS 304. For marine, chemical, or saline environments, SS 316 milled parts are preferred. SS 304 milled parts are cost-effective for indoor electrical and food-grade applications without aggressive chloride exposure.

Q2: What tolerances can you hold on CNC milled stainless steel parts?

Standard tolerance is ±0.01 mm (IT6 per ISO 286). IT5 tolerance (±0.005 mm) is achievable on critical features such as bearing bores and sealing faces. All tolerances are verified with calibrated CMM equipment.

Q3: What surface finishes are available on milled SS 316 and SS 304 parts?

Standard milled surface finish is Ra 1.6–3.2 μm. Electropolished finish reaches Ra <0.4 μm. Bead-blasted satin finish (Ra 0.8–1.6 μm) and mirror-polished (Ra <0.2 μm) are also available. Finish selection depends on the application’s hygiene, corrosion, or aesthetic requirements.

Q4: What is the minimum order quantity for milled stainless steel parts?

Minimum order quantity is 50 kg or 10 pieces, whichever is lower. Prototype single-piece orders are accepted at a setup charge. For production runs above 500 kg, volume pricing is available.

Q5: Do you supply material test certificates (MTCs) with milled parts?

Yes. All milled stainless steel parts are supplied with EN 10204 3.1 MTCs as standard. 3.2 witnessed inspection certificates are available upon request at additional cost, subject to third-party inspection scheduling.

Q6: Can you mill complex 3D profiles in SS 316?

Yes. Our 4-axis CNC machining centres execute complex 3D contouring, undercut profiles, and compound angular features in SS 316, SS 316L, and SS 304. CAD/CAM files in STEP, IGES, or DXF format are accepted for quoting.

Q7: What thread standards do you support in milled stainless components?

We support metric (ISO M series), UNC, UNF, BSP (British Standard Pipe), BSPT, NPT (American National Pipe Taper), NPTF, and G-thread standards. All threads are gauged with certified plug and ring gauges.

Q8: What is your typical lead time for milled SS parts?

Standard lead time is 15–25 working days from drawing approval. Express production (7–10 working days) is available for urgent orders subject to schedule availability. Shipping via air or sea freight from India.

Q9: Do you offer passivation and electropolishing after milling?

Yes. Post-milling chemical passivation per ASTM A967 (citric or nitric acid) and electropolishing are both offered in-house. These processes restore the passive chromium oxide layer and are mandatory for food, pharma, and high-purity fluid applications.

Q10: Which export markets do you supply milled SS 316 and SS 304 parts to?

We supply to USA, UK, Germany, UAE, Saudi Arabia, Singapore, Australia, South Africa, Canada, Netherlands, and other global markets. All exports comply with Indian foreign trade policy; ECCS and country-of-origin certificates are provided.

Equivalent Terms in Other Languages

Related Products (Internal Links)

• Stainless Steel Machined Parts & Turned Components
• Stainless Steel Swiss Machining
• Stainless Steel Machined Hydraulic Fittings
• SS 316 CNC Machining

Request a Quote

Contact Stainless Steel Fittings India for competitive pricing on SS 316 and SS 304 milled parts. Send your drawings (STEP/DWG/PDF) for a detailed quote within 24 hours. Price: US$ 11.50 / kg — bulk discounts available on orders above 500 kg. Email or call our engineering team for DFM support and delivery scheduling.