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Golden Steel Material is a premier ISO-certified stockist based in Al Jubail. We supply high-performance pipes, fittings, valves, and flanges to the Oil & Gas and Industrial sectors across Saudi Arabia and the GCC.

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+966 54 662 1439
Al Jubail 35526, Saudi Arabia

SA 387 GR.91 CL.1/2 Plates

Material Grade: ASME SA387 Grade 91 (Class 1 & 2)

Alloy System: 9% Chromium - 1% Molybdenum + V & N

Operational Specialty: Advanced Ultra-High Temp Steam Service

Performance Edge: Superior Creep Strength & Thermal Fatigue

Design Class: Optimized for High-Efficiency Power Units

Metallurgical Advantage: Enhanced Resistance to Micro-Cracking

Thickness Range: 6.0 mm to 100 mm

Primary Industries: Supercritical Power Plants, Nuclear, & HRSG

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ASME SA387 Grade 91 Plates represent the pinnacle of Chromium-Molybdenum alloy technology, engineered for the most extreme high-temperature and high-pressure environments. Often referred to as 9Cr-1Mo-V, this grade is a modified version of Grade 9, enhanced with precisely controlled additions of Vanadium, Niobium, and Nitrogen. These micro-alloying elements create a stable martensitic structure that provides exceptional creep-rupture strength, allowing equipment to operate at temperatures where standard alloys would fail. It is the primary choice for supercritical power plants and Heat Recovery Steam Generators (HRSG), where maximizing thermal efficiency is a critical operational requirement.

The technical sophistication of ASME SA387 Gr.91 is available in Class 1 and Class 2, allowing engineers to specify the material based on precise tensile strength and ductility needs. Due to its superior mechanical properties at heat, Grade 91 allows for significantly thinner wall thicknesses in pressure vessel and piping design, which reduces overall weight and minimizes the risk of thermal fatigue during startup and shutdown cycles. This grade is highly resistant to oxidation and corrosion in steam-side applications and is indispensable for advanced petrochemical reactors and nuclear power components. Its high performance relies on rigorous heat treatment and specialized welding protocols, ensuring the highest level of safety and longevity in modern energy infrastructure.

SA 387 GR.91 CL.1/2 Plates Features

» Advanced 9Cr-1Mo-V Chemistry: Micro-alloyed with Vanadium, Niobium, and Nitrogen to create a high-strength martensitic structure that thrives in extreme thermal environments.
» Exceptional Creep-Rupture Strength: Offers significantly higher creep resistance than standard Cr-Mo grades, enabling safe operation at temperatures exceeding 600°C.
» Superior Thermal Fatigue Resistance: Designed to withstand frequent thermal cycling, making it the ideal material for modern Heat Recovery Steam Generators (HRSG) and peaking power plants.
» Leaner Design Efficiency: High allowable design stresses permit reduced wall thicknesses, leading to lower equipment weight, faster welding times, and improved heat transfer.
» High Oxidation & Corrosion Defense: The 9% Chromium content provides a robust protective barrier against high-temperature steam oxidation and aggressive chemical process streams.
» Optimized Ductility: Available in Class 1 and Class 2, providing the flexibility to choose between maximum toughness and higher tensile properties for specialized vessel designs.
» Enhanced Resistance to Micro-Cracking: The refined metallurgical profile is engineered to minimize the risk of Type IV cracking in the heat-affected zone (HAZ) of weldments.
» Critical Steam-Side Performance: Specifically formulated for long-term reliability in supercritical and ultra-supercritical steam cycles, ensuring the longevity of power plant headers and piping.

SA 387 GR.91 CL.1/2 Plates Specification

Standards

ASME Standard: SA387
ASTM Standard: A387
Grade: Grade 91
UNS Number: K90901

Chemistry

Chromium (Cr): 8.00% – 9.50%
Molybdenum (Mo): 0.85% – 1.05%
Vanadium (V): 0.18% – 0.25%
Nitrogen (N): 0.03% – 0.07%

Strength Class

Class 1 Tensile: 585 – 760 MPa
Class 2 Tensile: 620 – 790 MPa
Class 1 Yield: 415 MPa (Min)
Class 2 Yield: 450 MPa (Min)

Processing

Condition: Normalized & Tempered
Normalizing: 1040°C – 1080°C
Tempering: 730°C – 800°C
Structure: Stable Martensitic

Size Range

Thickness: 6 mm to 100 mm
Width: 1500 mm to 3000 mm
Length: 6000 mm to 12000 mm
Edge Condition: Machine Cut / Trimmed

Quality Control

MTC: EN 10204 3.1 / 3.2 IBR
Compliance: NACE MR0175 / MR0103
NDT: Ultrasonic Tested (UT) Level S2
Testing: HIC, SSC, & Charpy V-Notch

SA 387 GR.91 CL.1/2 Plates Detailed Specifications

Property	Specification
Grade	ASME SA 387 GR.91 CL.1/2 Alloy Steel Plate
Width	1000mm-4500mm
Thickness	5mm-150mm
Length	3000mm-18000mm
Supply Condition	As Rolled, Normalized Rolling, Furnace Normalizing, Vacuum Degassing, Simulated Post-Weld Heat Treatment or as per customer requirement.
Impact tested	52° C
Process of Manufacturing	Hot-Rolled (HR)

SA 387 GR.91 CL.1/2 Plates Chemical Composition

A387 GR.91 CL.1 & 2

0.06-0.15 max

0.43 max

0.25-0.66 max

0.012 max

0.16-0.27 max

0.05 max

0.18-0.56 max

0.05-0.11 max

7.90-9.60 max

0.80-1.10 max

0.025-0.080 max

0.025 max

SA 387 GR.91 CL.1/2 Plates Mechanical Properties

Grade	A387 GR.91 CL.1 &2
A387 GR.91 CL.1 &2	Thickness mm	Yield Min Mpa	Tensile Mpa	Elongation Min %
	t≦50	415	585-760	18
	50<t≦200	-	-	-

SA 387 GR.91 CL.1/2 Plates Equivalent Grades

BS	EN	ASTM/ASME	DIN
-	-	SA387-91-2	-

Industrial Locations & Keywords

Industrial Locations & Keywords
Riyadh Industrial Cities (1st, 2nd, 3rd & Sudair)
Jeddah Industrial Cities (1st, 2nd & 3rd)
Dammam Industrial Areas (1st, 2nd & 3rd)
Jubail Industrial City
Yanbu Industrial City
Rabigh Industrial City
Al Khobar Industrial Area
Al Ahsa Industrial City
Madinah Industrial City
Makkah Industrial City
Taif Industrial City
Tabuk Industrial City
Jazan Industrial City
Industrial supplier in Saudi Arabia
Pipe fittings supplier in Jubail / Dammam / Riyadh
Flange and valve supplier Saudi Arabia
Fast delivery industrial materials KSA