Properties and application of low alloy high strength Q390 steel plate

Q390 steel plate is a low alloy high strength structural steel. Similiar material: Q420, Q460, Q500, Q550, Q690, Q890, Q960. The steel grade is composed of three parts: Chinese phonetic alphabet representing yield strength, yield strength value and quality grade symbol, such as Q390C. Q390B-Z15 Q390B-Z25. When the demander requires the steel plate to have the performance in the thickness direction, a symbol representing the performance level in the thickness direction (Z direction) shall be added after the above specified grade.

Chemical composition of Q390 steel plate (mass fraction) (%)

Grade	C	Mn	Si	P	S	V	Nb	Ti	Al	Cr	Ni
A	≤0.20	1.00-1.60	≤0.55	≤0.045	≤0.045	0.02-0.20	0.015-0.060	0.02-0.20	-	≤0.30	≤0.70
B	≤0.20	1.00-1.60	≤0.55	≤0.040	≤0.040	0.02-0.20	0.015-0.060	0.02-0.20	-	≤0.30	≤0.70
C	≤0.20	1.00-1.60	≤0.55	≤0.035	≤0.035	0.02-0.20	0.015-0.060	0.02-0.20	≥0.015	≤0.30	≤0.70
D	≤0.20	1.00-1.60	≤0.55	≤0.030	≤0.030	0.02-0.20	0.015-0.060	0.02-0.20	≥0.015	≤0.30	≤0.70
E	≤0.20	1.00-1.60	≤0.55	≤0.025	≤0.025	0.02-0.20	0.015-0.060	0.02-0.20	≥0.015	≤0.30	≤0.70

Mechanical properties of Q390 steel plate [tensile strength] (σb/MPa)：370-580
Q390 steel plate elongation (δ5/%)

Grade	δ5/%
Q390A	≥19
Q390B	≥19
Q390C	≥20
Q390D	≥20
Q390E	≥20

Q390 steel plate yield point (σs/MPa)

Thickness (diameter, side length)/mm	≤16	>16-35	>35-50	>50-100
σs/MPa	≥390	≥370	≥350	≥330

Q390 steel plate impact absorption energy (Akv (longitudinal)/J)

Temperature	+20	0	-20	-40
Q390A
Q390B	≥34
Q390C		≥34
Q390D			≥34
Q390E				≥27

Q390 steel plate has good comprehensive mechanical properties, good weldability, cold and hot working properties and corrosion resistance. Grade C, D and E steels have good low-temperature toughness. Q390 steel is applied to ships, boilers, pressure vessels, oil tanks, bridges, power plant equipment, lifting and transportation machinery and other welding structures with high loads.