BS 1501 621B

Grade 621B has long been superseded by EN10028 but as our clients still make reference to this chrome moly grade, we have included details here, which should be used for cross reference purposes.
621B is a chrome moly steel for use in pressurised vessels and boilers found commonly in the oil and gas industry. The material has good tensile and yield strength and is designed to operate in higher working temperatures. 621B has good weldability and corrosion resistance.
Please refer to the technical information below for this particular steel grade.
 

Mechanical Properties of 621B

GradeThickness (mm)Tensile StrenthYield StrengthElongation (A)
620B<75515/69034018
>75 <100500/67032016
>100 <150490/65031016

Chemical Composition of 621B

 %
Carbon (C)0.09/0.17
Silicon (Si)0.50/0.80
Manganese (Mn)0.40/0.65
Phosphorus (P)0.025
Sulphur (S)0.015
Chromium (Cr)1.00/1.50
Molybdenum (Mo)0.45/0.60
Nickel (Ni)0.30
Others0.32