Manufacturer, Supplier & Exporter of Stainless Steel347 Spool

Stainless Steel 347 Spool is a high-temperature, chromium-nickel austenitic stainless steel stabilized with niobium (columbium). The addition of niobium precludes carbide precipitation, offering outstanding intergranular corrosion resistance and thermal stability in applications where 321 or unstabilized grades may fail. These spools perform reliably under cyclic high-heat service, making them perfect for piping in boilers, furnace systems, exhaust lines, and power-plant connections. In environments that face frequent heating and cooling cycles, the 347 grade retains its strength and resists grain-boundary sensitization better than traditional stainless steels.

Riddhi Siddhi Impex is a renowned manufacturer and stockist of Stainless Steel 347 Spools across India. With decades of experience in stainless steel fabrication, their facility is outfitted with precision welding machines, CNC spool‑fabrication lines, bending equipment, and quality inspection setups. The company ensures that every 347 spool produced meets both national and international standards such as ASTM A312 and ASME SA312, ensuring reliability and safety in high-temperature piping systems..

One of the standout features of Riddhi Siddhi Impex’s offering is the custom spool fabrication of Stainless Steel 347. They provide tailor-made spool assemblies to suit various pipe diameters, wall thicknesses, lengths, bends, fittings, and end connections (flanged, welded, threaded). Their skilled engineering team works closely with clients — especially EPC contractors and industrial fabricators — to design spool sections optimized for installation, thermal expansion, and operational stress. This customized capacity ensures a perfect match between spool design and application requirements, minimizing installation challenges...

Stainless Steel 347 Spools offer significant advantages in high-temperature and cyclic service environments: high creep and rupture strength, resistance to oxidation, and improved grain stability due to niobium stabilization. These make 347 spool assemblies highly suitable for steam lines in power plants, turbine piping, heat exchanger loops, petroleum refinery piping systems, and chemical processing units. Where other stainless grades may experience intergranular corrosion or creep drift, 347 spools retain dimensional stability and mechanical strength over prolonged operation..

Quality assurance is central to Riddhi Siddhi Impex’s process. Each Stainless Steel 347 Spool is subject to rigorous inspections including Positive Material Identification (PMI), non-destructive testing (NDT), radiography or ultrasonic testing of welds, dimensional measurement, and pressure testing as per client needs. Additionally, they provide Material Test Certificates (MTCs) in compliance with EN 10204 or equivalent standards, ensuring full traceability from raw material to finished spool. Their quality commitment guarantees that clients get spools capable of withstanding severe thermal and pressure cycling..

Stainless Steel 347 Spool

Specification

Product Name	Stainless Steel 347 Spool
Manufacturer	Riddhi Siddhi Impex
Material	Stainless Steel 347 (Niobium stabilized)
Standard	ASTM A312, ASME SA312
End Connections	Butt Weld, Flanged, Threaded
Form	Spool, Pipe Sections
Applications	High-temperature piping, boilers, exhaust systems, heat exchangers, chemical and petrochemical plants

Chemical Composition

Element	Content (%)
Carbon (C)	0.08 Max
Chromium (Cr)	17.0 – 19.0
Nickel (Ni)	9.0 – 13.0
Manganese (Mn)	2.0 Max
Silicon (Si)	1.0 Max
Phosphorus (P)	0.045 Max
Sulfur (S)	0.03 Max
Niobium + Tantalum (Nb+Ta)	10 x C – 0.7 Min

Mechanical Properties

Property	Value
Tensile Strength	≥ 515 MPa
Yield Strength (0.2% offset)	≥ 205 MPa
Elongation	≥ 40%
Hardness	≤ 200 HB

Dimension Chart (Nominal)

Nominal Pipe Size (NB)	Outside Diameter (mm)	Wall Thickness (mm)	Length
1/2"	21.3	2.77	Up to 12 m
1"	33.4	3.38	Up to 12 m
2"	60.3	3.91	Up to 12 m
4"	114.3	6.02	Up to 12 m
6"	168.3	7.11	Up to 12 m
10"	273.1	9.27	Up to 12 m
16"	406.4	12.70	Up to 12 m

Equivalent Grades

Standard	Grade
ASTM	A312 TP347 / TP347H
EN	1.4550 / X6CrNiNb18-10
DIN	1.4550
JIS	SUH 347

Equivalent Standards

Standard	Description
ASTM A312	Seamless and Welded Stainless Steel Pipes
ASME SA312	Specification for Stainless Steel Pipe for High Temperature

Other Types of Stainless Steel Spools

Type	Description
SS 304 Spool	General-purpose stainless steel spool for moderate corrosion resistance
SS 316L Spool	Low-carbon molybdenum-grade for high corrosion resistance
SS 321 Spool	Niobium-stabilized for high-temperature service similar to 347
SS 317L Spool	Molybdenum-enriched for better corrosion resistance in aggressive media

As a leading domestic supplier of Stainless Steel 347 Spool, Riddhi Siddhi Impex serves a wide network of industrial and metropolitan locations across India. Their distribution network extends to Mumbai, Delhi, Bengaluru (Bangalore), Hyderabad, Chennai, Kolkata, Pune, Ahmedabad, Surat, Vadodara, Rajkot, Nagpur, Indore, Bhopal, Jaipur, Kanpur, Lucknow, Agra, Varanasi, Amritsar, Chandigarh, Mysuru (Mysore), Udaipur, Jodhpur, Visakhapatnam, Coimbatore, Madurai, Kochi, Thiruvananthapuram, Mangalore, Nashik, Kolhapur, Chandrapur, Akola, Vilayat, Somnath, Dahej, Ankleshwar, Navsari, Valsad, Narmada, and Rajpipla. This comprehensive coverage ensures that industries across India can reliably source 347 spool assemblies for their high-temperature systems..

Frequently Asked Questions (FAQs)

Q1: What are the main applications of Stainless Steel 347 Spool?

A1: It is mainly used in high-temperature piping systems, boilers, chemical plants, heat exchangers, and exhaust systems.

Q2: Can Riddhi Siddhi Impex provide custom spool sizes?

A2: Yes, they offer custom diameters, wall thicknesses, lengths, and end connections to meet specific project requirements.

Q3: What makes SS 347 suitable for high-temperature service?

A3: The niobium stabilization prevents carbide precipitation, improving intergranular corrosion resistance and thermal stability under cyclic high heat.

Q4: In which cities is Stainless Steel 347 Spool available in India?

A4: It is supplied in major cities including Mumbai, Delhi, Bengaluru, Hyderabad, Chennai, Kolkata, Pune, Ahmedabad, Surat, Vadodara, Rajkot, Nagpur, Indore, Bhopal, Jaipur, Kanpur, Lucknow, and more.