GB/T 1591 Q345B steel plate and sheet

There are five quality grades under Q345 series steel  under GB/T 1591: Q345A, Q345B, Q345C, Q345D and Q345E. Density of this steel is 7.85 g/cm3. Q345B GB carbon steel tensile strength is 470-630 MPa; the yield strength is minimum 345 MPa when thickness less than 16mm.

Equivalent to GB/T 1591 Q345B low alloy steel

GB/T 1591-2008	EN 10025-2	DIN 17100	JIS G3135	ISO 630-2
Q345B	S355JR (1.0045)	St52-3	SPFC 590	S355C, S355D

Chemical composition for plates and sheets of Q345B GB low alloy steel (ladle analysis, %)

C max.	Si max.	Mn max.	P max.	S max.	Cr max.	Ni max.	Cu max.	N max.	Nb max.	V max.	Ti max.	Mo max	Al min.
0.20	0.50	1.70	0.035	0.035	0.30	0.50	0.30	0.012	0.07	0.15	0.20	0.10	-

Mechanical properties for plates and sheets of GB/T 1591 Q345B steel

Tensile requirements in different plate thickness (mm)
Q345B grade	t≤16	16-40	40-63	63-80	80-100	100-150	150-200	200-250
Yield strength (≥Mpa)	345	335	325	315	305	285	275	265

Grade	Tensile strength MPa			Elongation % min.
	t≤100	100-150	150-250	t≤40	40-63	63-100	100-150	150-250
Q345B	470-630	450-600	450-600	20	19	19	18	17

Main features of GB/T 1591 Q345B steel plate and sheet
Q345B GB low alloy steel has good weldability, cold & hot workability and corrosion resistance. Widely used in bridges, ships, boilers, pressure vessels, petroleum storage tanks, lifting transport machinery and other high-load welded structural parts.