ASTM A387 Grade 91 Class 2

High quality A387 Grade 91 Class 2 – manufactured at some of the world’s finest steel mills, this chrome–molybdenum alloy has excellent resistance to high working temperatures making it ideal for use in the oil, gas, chemical and power generation industry applications. We supply to fabricators who serve these industries on a global basis.
Our plates can be supplied from our own stockholding or directly from the mill – all plates come with mill test certification and individual stampings. Third party testing can be arranged at the customers request.

Chromium & Molybdenum content (according to the ASTM specification):

DesignationNominal Chromium Content (%)Nominal Molybdenum Content (%)
A387 Grade 919.00%1.00%

Tensile Requirements for Class 2 Plates

DesignationRequirementGrade 91
A387 Grade 91Tensile strength, ksi [MPA]85 to 110 [585 to 760]
Yield strength, min, ksi [MPa]/(0.2% offset)60 [415]
Elongation in 8 in. [200mm], min %
Elongation in 2 in. [50mm], min, %18
Reduction of area, min %

Chemical Requirements

Carbon (C)%
Heat Analysis:
Product Analysis:
0.08 - 0.12
0.06 - 0.15
Manganese (Mn)%
Heat Analysis:
Product Analysis:
0.30 - 0.60
0.25 - 0.66
Phosphorus (P)%
Heat Analysis:
Product Analysis:
0.020
0.025
Sulphur (S) (Max)%
Heat Analysis:
Product Analysis:
0.010
0.012
Silicon (Si)%
Heat Analysis:
Product Analysis:
0.20 - 0.50
0.18 - 0.56
Chromium (Cr)%
Heat Analysis:
Product Analysis:
8.00 - 9.50
7.90 - 9.60
Molybdenum (Mo)%
Heat Analysis:
Product Analysis:
0.85 - 1.05
0.80 - 1.10
Nickel (Ni)%
Heat Analysis:
Product Analysis:
0.40
0.43
Vanadium (Vn)%
Heat Analysis:
Product Analysis:
0.18 - 0.25
0.16 - 0.27
Columbium (Nb)%
Heat Analysis:
Product Analysis:
0.06 - 0.10
0.05 - 0.11
Nitrogen (N)%
Heat Analysis:
Product Analysis:
0.030 - 0.070
0.025 - 0.080
Aluminium (Al)%
Heat Analysis:
Product Analysis:
0.02
0.02
Titanium (Ti)%
Heat Analysis:
Product Analysis:
0.01
0.01
Zirconium (Zr)%
Heat Analysis:
Product Analysis:
0.01
0.01