Manufacturer, Supplier & Exporter of ASTM A335 P91 Spool

ASTM A335 P91 is a high‑performance ferritic alloy steel (9Cr‑1Mo‑V) developed specifically for high-temperature, high-pressure applications. Its alloying elements — chromium, molybdenum, vanadium, and sometimes niobium — give it excellent creep strength, oxidation resistance, and mechanical stability under cyclic thermal stress. This makes P91 ideal for critical components in power plants such as superheaters, reheaters, headers, and boiler piping systems..

Riddhi Siddhi Impex, a known supplier in the alloy‑steel pipe industry, would be a logical source for P91 spools — even if specific public catalogues for “P91 spools” are limited. Given their scale and network in supplying Cr‑Mo alloy pipes, they are capable of sourcing or fabricating P91 in spool form, working with reliable mills to meet the stringent chemical and mechanical requirements that P91 demands.

In the Indian context, demand for P91 spools is growing strongly in cities with heavy thermal power infrastructure — places like Mumbai, Delhi, Bengaluru, Hyderabad, Chennai, Kolkata, Pune, Ahmedabad, and Vadodara. These cities host large-scale power plants, refineries, and process industries, and P91’s superior temperature and pressure capability make it very attractive for modern, efficient boiler designs and high‑temperature piping systems..

ASTM A335 P91 Spool is a high-performance ferritic alloy steel pipe, commonly used in high-temperature and high-pressure environments. Its chemical composition, which includes Chromium (Cr), Molybdenum (Mo), Vanadium (V), and sometimes Niobium (Nb), provides excellent creep strength, thermal stability, and oxidation resistance. This makes it a preferred choice in superheater and reheater piping, boiler tubes, and other critical power plant applications where standard carbon steel pipes cannot withstand operational conditions..

Riddhi Siddhi Impex is a reputed manufacturer and supplier of ASTM A335 P91 spools in India. They specialize in delivering high-quality spools that comply with ASTM A335 / ASME SA335 standards. With a robust supply chain and direct tie-ups with steel mills, Riddhi Siddhi Impex ensures material traceability, quality certifications, and adherence to strict mechanical and chemical specifications for P91. Their services extend to prefabricated spools, custom lengths, and end preparations suitable for welding and assembly in industrial setups..

ASTM A335 P91 Spool

Specification

Product Name	ASTM A335 P91 Spool
Manufacturer	Riddhi Siddhi Impex
Material	Alloy Steel (Chromium-Molybdenum-Vanadium-Niobium)
Standard	ASTM A335 / ASME SA335
Size Range	1/2” NB to 48” NB
Wall Thickness	Sch 10 to XXS
Length	Cut Length / Random Length / Custom
End Preparation	Beveled End (BE), Plain End (PE)
Form	Seamless, Welded (ERW, SAW)
Applications	Power plants, Boilers, Superheaters, Heat Exchangers, Petrochemical Piping

Chemical Composition

Element	Content (%)
Carbon (C)	0.08–0.12
Manganese (Mn)	0.30–0.60
Chromium (Cr)	8.0–9.5
Molybdenum (Mo)	0.85–1.05
Vanadium (V)	0.18–0.25
Niobium (Nb)	0.06–0.10
Silicon (Si)	0.20–0.50
Phosphorus (P)	0.015 Max
Sulfur (S)	0.010 Max

Mechanical Properties

Property	Value
Tensile Strength	585 MPa min
Yield Strength (0.2% offset)	415 MPa min
Elongation	20% min
Hardness	≤ 250 HB
Impact Toughness	High at 20°C

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	A335 P91
UNS	K91560
EN	1.4903 / X10CrMoVNb9-1
DIN	17MoV6-2

Equivalent Standards

Standard	Description
ASTM A335 / ASME SA335	Specification for Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service
EN 10216-2	Seamless Steel Tubes for Pressure Purposes
DIN 17175	Seamless Steel Tubes for High-Temperature Applications

Other Types

Type	Description
ASTM A335 P11	Low alloy steel pipe for moderate temperature and pressure applications
ASTM A335 P22	Chromium-molybdenum steel for medium temperature and high-pressure service
ASTM A335 P91	High chromium-molybdenum-vanadium steel for high-temperature, high-pressure applications
ASTM A335 P92	Advanced alloy steel for ultra-supercritical power plants

In India, the demand for P91 spools is concentrated in cities with heavy thermal power infrastructure. Major markets include Mumbai, Delhi, Bengaluru, Hyderabad, Chennai, Kolkata, Pune, Ahmedabad, Vadodara, Surat, and Nagpur, where power plants, refineries, and chemical industries require high-temperature resistant piping solutions. The strategic importance of P91 in supercritical and ultra-supercritical power plants makes it a critical material in India’s energy sector expansion and modernization projects..

Frequently Asked Questions (FAQs)

Q1: What are the primary applications of ASTM A335 P91 Spools?

A1: They are used in superheaters, reheaters, boiler piping, heat exchangers, and high-temperature pressure piping systems.

Q2: Can Riddhi Siddhi Impex supply custom lengths and end preparations?

A2: Yes, custom spool lengths, beveling, and plain ends are available as per project requirements.

Q3: What is the maximum operating temperature for P91 spools?

A3: ASTM A335 P91 can operate safely up to 600–650°C depending on pressure conditions and welding treatments.

Q4: Are P91 spools available in all major Indian cities?

A4: Yes, they are available in Mumbai, Delhi, Bengaluru, Hyderabad, Chennai, Kolkata, Pune, Ahmedabad, Surat, Vadodara, Nagpur, and other domestic cities.