Chemical composition and mechanical properties of SA387 Grade91 Type2, an American grade of  pressure vessel steel.

SA387 Grade91 Type2 Approximate Grade Lookup Table

SA387 Grade91 Type2 Chemical Composition

Element Analysis Category Grade91 Type2
C Smelting Analysis 0.08-0.12
Finished Product Analysis 0.06-0.15
Mn Smelting Analysis 0.30-0.50
Finished Product Analysis 0.30-0.50
P,≤ Smelting Analysis 0.02
Finished Product Analysis 0.02
S,≤ Smelting Analysis 0.005
Finished Product Analysis 0.005
Si Smelting Analysis 0.20-0.40
Finished Product Analysis 0.20-0.40
Cr Smelting Analysis 8.00-9.50
Finished Product Analysis 8.00-9.50
Mo Smelting Analysis 0.85-1.05
Finished Product Analysis 0.80-1.05
Ni Smelting Analysis 0.2
Finished Product Analysis 0.2
V Smelting Analysis 0.18-0.25
Finished Product Analysis 0.16-0.27
Nbᴮ Smelting Analysis 0.06-0.10
Finished Product Analysis 0.05-0.11
B,≤ᶜ 0.001
N Smelting Analysis 0.035-0.070
Finished Product Analysis 0.035-0.070
N/Al ≥4.0
Al,≤ᶜ 0.02
Ti,≤ᶜ 0.01
Zr,≤ᶜ 0.01
W,≤ᶜ 0.05
Cu,≤ᶜ 0.1
Sb,≤ᶜ 0.003
As,≤ᶜ 0.01
Sn,≤ᶜ 0.01

A:For steel plates with a thickness greater than 5 inches (125 mm), the carbon content in the finished product analysis should not exceed 0.17%.

B:Cb and Nb are interchangeable and commonly used names for the same element, and both names are applicable to the (ASTM) "A101" standard.

C:Both smelting analysis and finished product analysis are applicable.

SA387 Grade91 Type2 Mechanical Properties

Tensile properties of Class II steel plates

Tensile strength(MPa) 585-760
Yield strength (0.2% residual deformation), MPa ≥ 415
Elongation (gauge length 8 in. or 200 mm), %≥ ...
Elongation (gauge length 8 in. or 50 mm), %≥ 18
Reduction of area,% ...

①Not applicable to annealed steel sheets

②For adjustments to elongation, please refer to the A20/A20M standard.

③Measurement using a round sample.

④Determination using flat specimens.

*Grade 91 steel plate is only applicable to Category 2 steel plates, see Section 1.3 — Translator's note