Chemical composition and mechanical properties of SA553, an American grade of  pressure vessel steel.

SA553 Approximate Grade Lookup Table

SA553 Chemical Composition

Type I II III
C,≤① 0.13 0.13 0.13
Mn，≤ Smelting Analysis② 0.9 0.9 0.9
Finished Product Analysis③ 0.98 0.98 0.98
P,≤① 0.015 0.015 0.01
S,≤① 0.015 0.015 0.01
Si，≤ Smelting Analysis 0.15-0.40② 0.15-0.40② 0.15-0.30①
Finished Product Analysis 0.13-0.45③ 0.13-0.45③ -
Ni，≤ Smelting Analysis 8.50-9.50 7.50-8.50 6.50-7.50①
Finished Product Analysis 8.40-9.60 7.40-8.60 -
Mo① ... ... 0.10-0.30
Nb④，≤① ... ... 0.03

①Both smelting analysis and finished product analysis are applicable.

②If the total aluminum content is 0.030% or higher, or if the acid-soluble aluminum content is 0.025% or higher, the silicon content may be less than 0.15%.

③If the total aluminum content is 0.030% or higher, or if the acid-soluble aluminum content is 0.025% or higher, the silicon content may be less than 0.13%.

④Cb and Nb are the same element, their names are interchangeable, and both names can be used in the A01 standard.

SA553 Mechanical Properties

Tensile strength(Mpa) 690-825
Yield strength(0.2% residual deformation) MPa ≥ 585
Elongation (gauge length 2 in. or 50 mm), %① ≥ 20

①For adjustments to elongation, please refer to the A20/A20M standard.