Stainless Steel Pipe Fittings

Manufacturer | Stockist | Exporter — Bangalore, India

Product Overview

Bombay Metal Corporation is a leading manufacturer, stockist, and exporter of Stainless Steel Pipe Fittings, serving industrial buyers across India and international markets. Our fittings are precision-engineered to meet the most demanding piping system requirements — from ambient-temperature water lines to high-pressure, high-temperature petrochemical loops and corrosive chemical process pipework.

We supply three primary fitting connection types: Buttweld Fittings (ANSI / ASME B16.9), Socket Weld Fittings (ASME B16.11), and Threaded / Screwed Fittings (ASME B16.11). Within each connection type, the full range of fitting geometries is available — elbows, tees, reducers, caps, couplings, unions, crosses, and stub ends — ensuring complete piping system coverage from a single supplier.

All fittings are manufactured and tested in accordance with ASTM A403 / A182, ASME SA403 / SA182, MSS SP-43, MSS SP-79, and MSS SP-83 standards. Material Test Certificates (MTC) in accordance with EN 10204 3.1 are provided as standard. Third-party inspection by TUV, SGS, BV, or LLOYDS is available on request.

Available Fitting Types:  Elbows (45°, 90°, 180°)  |  Equal & Reducing Tees  |  Concentric & Eccentric Reducers  |  Pipe Caps  |  Stub Ends (Lap Joints)  |  Couplings  |  Unions  |  Crosses  |  Outlet Fittings (Weldolets, Sockolets, Threadolets)

Connection Standards:  ANSI/ASME B16.9 (Buttweld)  |  ASME B16.11 (Socket Weld & Threaded)  |  MSS SP-43  |  MSS SP-79  |  MSS SP-83

Material Standards:  ASTM A403  |  ASME SA403  |  ASTM A182  |  ASME SA182

Size Range:  ½” NB to 48″ NB  (DN 15 to DN 1200)

Wall Thickness / Schedule:  SCH 5S, 10S, 20, 40S, 80S, 120, 160, XXS

Available Grades

Every grade below is held in ready stock across common sizes and schedules. Specialty sizes and non-standard schedules are sourced within short lead times.

Grade 304 / 304L / 304H Pipe Fittings

Grade 304 is the most widely specified stainless steel globally, offering a proven balance of corrosion resistance, weldability, formability, and cost. The 304L variant reduces carbon to 0.03% maximum, eliminating sensitisation risk in heavy-section welded assemblies without post-weld annealing. Grade 304H, with its higher carbon range, provides superior creep strength for sustained elevated-temperature service and is the mandatory specification for high-temperature pressure piping under ASME code.

Applications — 304 / 304L / 304H Fittings

• Food and dairy processing pipelines — hygienic elbows, tees, and reducers
• Pharmaceutical and biotech process lines conforming to GMP / FDA requirements
• Domestic and commercial potable water distribution systems
• Chemical process lines handling dilute acids, alkalis, and organic solvents
• HVAC and cryogenic distribution systems
• Pulp and paper plant process pipework
• High-temperature boiler and superheater pipework (304H)
• General-purpose fabrication and structural piping applications

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Grade 309 / 309S Pipe Fittings

Higher chromium (23%) and nickel (13%) contents make Grade 309/309S an outstanding high-temperature grade. The elevated alloy content builds a thicker, more tenacious oxide scale that resists spalling at temperatures where 304 would break down rapidly. Grade 309S is preferred for welded fittings as the reduced carbon content minimises sensitisation.

Applications — 309 / 309S Fittings

• Furnace gas recirculation and combustion air ducting fittings
• Kiln and annealing furnace process piping
• High-temperature heat exchanger nozzles and connecting elbows
• Flue gas and stack liner piping systems
• Thermal oxidiser and incinerator process connections
• Boiler flue gas desulphurisation (FGD) ducting connections

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Grade 310 / 310S / 310H Pipe Fittings

Grade 310/310S is the premium heat-resistant grade with the highest chromium (25%) and nickel (20%) content in the standard austenitic stainless range. It performs reliably at temperatures up to 1150°C, where most other grades fail. Grade 310H, with its higher carbon level, is specifically approved for elevated temperature pressure service under ASME Section VIII. Its exceptional oxidation and sulphidation resistance makes it indispensable in thermal processing industries.

Applications — 310 / 310S / 310H Fittings

• High-temperature furnace process gas and flue gas piping connections
• Cement, lime, and mineral processing kiln gas ducting
• Fired heater and cracking furnace transfer line fittings
• Continuous annealing and heat treatment plant piping
• Chemical reformer piping operating above 900°C
• Nuclear fuel reprocessing facility high-temperature lines
• Coke oven and coal gasification plant process connections

Grade 316 / 316L / 316Ti Pipe Fittings

The addition of 2–3% molybdenum is the defining feature of Grade 316/316L. Molybdenum dramatically raises resistance to pitting and crevice corrosion in chloride-bearing media, making 316 the standard specification wherever salt water, chlorinated process streams, or halide chemicals are present. Grade 316L eliminates weld sensitisation risk, while 316Ti — titanium-stabilised — is the preferred choice when the fitting must be welded and will see sustained service in the sensitisation temperature range (425–850°C).

Applications — 316 / 316L / 316Ti Fittings

• Marine and offshore platform process and utility piping
• Subsea and splash-zone piping systems
• Chemical plant process lines handling chlorides, sulphuric acid, and phosphoric acid
• Pharmaceutical process lines requiring FDA-compliant, crevice-corrosion-resistant fittings
• Coastal desalination plant process and brine piping
• Food processing — brine, pickling, and vinegar handling lines
• Pulp bleaching and paper process lines
• Nuclear plant secondary coolant and auxiliary piping (316L)
• Heat exchanger inlet/outlet connections handling seawater cooling
• Petrochemical sulphur recovery and acid gas handling systems

Grade 317 / 317L Pipe Fittings

Grade 317/317L carries a higher molybdenum content (3–4%) than 316, pushing the pitting resistance equivalent (PRE) to approximately 30 — making it suitable for more aggressive chloride and acid environments where 316 would corrode unacceptably. Grade 317L, with reduced carbon, is the standard welded-fitting specification. It is the go-to grade for FGD scrubber systems and aggressive chemical process pipework.

Applications — 317 / 317L Fittings

• Flue gas desulphurisation (FGD) scrubber inlet, outlet, and recirculation piping
• Textile dyeing and finishing plant process lines
• Chlorinated solvent handling systems
• Pulp bleaching circuits — particularly chlorine dioxide stages
• Chemical plant lines handling concentrated chlorides and sulphuric acid
• Pharmaceutical manufacturing where 316L does not meet corrosion requirements

Grade 321 / 321H Pipe Fittings

Titanium stabilisation in Grade 321 scavenges carbon before it can combine with chromium at grain boundaries, making it immune to sensitisation and fully resistant to intergranular attack in the 425–900°C range. This makes 321 fittings ideal for systems that operate continuously or cycle through the sensitisation zone. Grade 321H provides enhanced creep rupture strength for long-term high-temperature pressure service.

Applications — 321 / 321H Fittings

• Refinery and petrochemical process piping operating in the sensitisation temperature range
• Jet engine exhaust gas lines and thermal management piping
• Expansion loop and bellows connections in high-temperature piping
• Heat exchangers operating between 425°C and 870°C
• Aircraft and aerospace thermal-protection system connections
• Power boiler superheater and reheater connecting fittings (321H)

Grade 347 / 347H Pipe Fittings

Grade 347 uses niobium (and tantalum) as the stabilising element rather than titanium. Niobium is a stronger carbide-former than titanium and provides slightly better creep strength at high temperature, making 347 a preferred alternative to 321 in some refinery and petrochemical applications. Grade 347H is specifically ASME code-approved for pressure vessels and high-temperature piping, offering superior long-term creep strength.

Applications — 347 / 347H Fittings

• Refinery atmospheric and vacuum distillation column process piping
• Hydrocracker and hydrotreater high-temperature piping fittings
• High-temperature boiler superheater connecting fittings (347H)
• Petrochemical transfer lines operating above 500°C
• Chemical reactor feed and effluent piping operating in the sensitisation range
• Power generation — steam headers and turbine leads (347H)

Grade 409 Pipe Fittings

Grade 409 is a titanium-stabilised ferritic grade with the lowest alloy content in the stainless range. It offers adequate oxidation resistance at moderate temperatures, good formability, and is primarily chosen on the basis of cost. Its ferritic microstructure makes it magnetic and not heat-hardenable. Corrosion resistance is limited to mildly corrosive and dry environments.

Applications — 409 Fittings

• Automotive exhaust system elbows, tees, and flex connections
• Catalytic converter inlet and outlet piping connections
• Agricultural and construction equipment mild-environment process connections
• Bus and railway vehicle exhaust system fittings
• Muffler and heat shield connecting elbows

Grade 410 Pipe Fittings

Grade 410 is the workhorse martensitic stainless grade. Unlike austenitic grades, 410 can be heat-treated to a wide range of hardness and strength levels. In the annealed condition it is ductile and machinable; after hardening and tempering it achieves very high tensile strength and hardness. It offers moderate corrosion resistance, suitable for mild environments such as fresh water, steam, food acids, and mild chemicals, but is not recommended for chloride or reducing acid service.

Applications — 410 Fittings

• Steam turbine and compressor process piping connections
• Pump and valve body fittings in mild-corrosion environments
• Oil and gas wellhead fittings and flow control connections
• Petrochemical column fittings where moderate corrosion and high strength are required
• Mining and mineral processing pipe connections subject to abrasion and mild corrosion
• General-purpose process fittings in dilute acid and alkaline service

Grade 446 Pipe Fittings

Grade 446 is a high-chromium ferritic stainless grade with exceptional oxidation and sulphidation resistance, outperforming even Grade 310S in sulphur-bearing atmospheres. Its very high chromium content (up to 27%) builds an extremely stable oxide scale, making it the preferred ferritic choice for extreme-heat applications. It is magnetic in all conditions and cannot be hardened by heat treatment.

Applications — 446 Fittings

• Furnace gas and combustion product piping operating above 1000°C
• Kiln and calciner process gas connections in sulphur-bearing atmospheres
• Burner nozzle and flame-tube connecting fittings
• Heat treatment and annealing furnace gas ducting fittings
• Petroleum refinery heater and reformer process connections in sulphur service
• Boiler and fired heater ash handling and flue gas piping connections

Grade 904L Pipe Fittings

Grade 904L is a super-austenitic stainless steel engineered specifically for resistance to strong reducing acids — most notably sulphuric acid across all concentrations and temperatures. Its very low carbon content (≤ 0.02%), combined with high nickel (up to 28%), high molybdenum (4–5%), and a copper addition (1–2%), delivers outstanding resistance to sulphuric acid, phosphoric acid, acetic acid, and chloride pitting and crevice attack. It is the material of choice for sulphuric acid plant internals and handling lines.

Applications — 904L Fittings

• Sulphuric acid plant process piping — absorption towers, coolers, and transfer lines
• Phosphoric acid processing and fertiliser plant process piping
• Seawater desalination plant high-pressure feed and brine distribution
• Offshore platform seawater injection and cooling piping
• Chemical plant processes handling hot concentrated reducing acids
• Pharmaceutical plant multi-purpose process lines requiring ultra-low carbon specification
• Oil and gas sour service process connections where H2S and CO2 co-exist
• Pulp bleaching plant piping exposed to mixed acid and chloride environments

Size Charts

Buttweld Fittings — Standard Dimensions (ASME B16.9)

90° Long Radius Elbow — Key Dimensions (ASME B16.9)

Socket Weld & Threaded Fittings — Size Range (ASME B16.11)

Custom sizes, non-standard schedules, and special-end preparations (bevel end, plain end, threaded, grooved) are available on request.

Technical Details

Chemical Composition (%) — Quick Reference

Mechanical Properties — Quick Reference

Applicable Standards & Specifications

Industry Applications

Stainless Steel Pipe Fittings from Bombay Metal Corporation are found across a broad spectrum of process industries. The table below maps key sectors to the grade most commonly specified:

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