Q345 Steel, Q345A Q345B Q345C Q345D Q345E Equivalent, Specification, Chemical Composition, Properties

Q345 Steel Properties

Q345 steel is a Chinese GB standard Low Alloy High Strength Structural Steel, material density is 7.85 g/cm3, tensile strength is 470-630 Mpa, and yield strength is 345 MPa, it has better properties than Q235. According to GB/T 1591 – 2008, Q345 material has 5 quality grades: Q345A, Q345B, Q345C, Q345D and Q345E.

Q345 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.

Meaning & Designation

“Q” is the first letter of Chinese Pinyin: “qu fu dian”, that means Yield Point, “345” is the minimum value of yield strength 345 MPa for steel thickness ≤16mm.

Datasheet and Specification

Datasheet and specification are listed in the tables below, including chemical composition, machenical properties, etc.

Chemical Composition of Q345 Steel

Based on melting analysis.

		Chemical Composition Content (≤%)
Steel Grade	Quality Grade	C	Si	Mn	P	S	Cr	Ni	Mo	Cu	Ti	N	Nb	V	B	Als, ≥
Q345	Q345A	0.20	0.50	1.70	0.035	0.035	0.30	0.50	0.10	0.30	0.20	0.012	0.07	0.15	–	–
	Q345B				0.035	0.035
	Q345C				0.030	0.030										0.015
	Q345D	0.18			0.030	0.025
	Q345E				0.025	0.020

Notes: The P and S contents of profiles and bars can be increased by 0.005%, and the upper limit of Grade A steel can be 0.0045%.

Material Q345 Mechanical Properties

		Mechanical Properties: Yield Strength (≥ MPa)
Steel Grade	Quality Grade	d ≤16	16< d ≤ 40	40 <d ≤ 63	63 <d≤ 80	80 < d ≤ 100	100 < d ≤ 150	150 < d ≤ 200	200 < d ≤ 250	250 < d ≤ 400
Q345	Q345A	345	335	325	315	305	285	275	265	–
	Q345B
	Q345C
	Q345D									265
	Q345E

Notes:

• d= Thickness or wire diameter in mm;
• 1 MPa = 1 N/mm2

		Mechanical Properties: Tensile Strength (MPa)
Grade	Quality Level	d≤ 40	40 <d ≤ 63	63 <d ≤ 80	80 <d≤ 100	100 < d≤ 150	150 < d ≤ 250	250 < d ≤ 400
Q345	Q345A	470-630	470-630	470-630	470-630	450-600	450-600	–
	Q345B
	Q345C
	Q345D							450 – 600
	Q345E

		d mm, Elongation (≥%)
Grade	Quality Level	d≤40	40 <d ≤ 63	63 < d≤ 100	100 <d≤ 150	150 < d ≤ 250	250 <d ≤ 400
Q345	Q345A	20	19	19	18	17	–
	Q345B
	Q345C	21	20	20	19	18
	Q345D						17
	Q345E

Charpy Impact

Charpy (V-notch) impact test temperature and impact absorption energy (KV₂/J), thickness (t).

Quality	Temperature, °C (°F)	12-150 (mm)	150<t≤250 (mm)	250<t≤400 (mm)
Q345B	20 (68)	≥34J	≥27J	–
Q345C	0 (32)
Q345D	-20 (-4)			27J
Q345E	-40 (-40)

Material Q345 Equivalent

Q345 steel: Q345A, Q345B, Q345C, Q345D, Q345E equivalent to US ASTM, European Germany DIN, British BS, France NF, Japan JIS, and ISO Standard (For Reference).

Notes: Q345 steel has been replaced by Q355 in the latest version of GB standard “GB/T 1591 – 2018”, the previous version is “GB/T 1591 – 2008”.

Low Alloy Structural Steel Q345 Equivalent
China		US	Germany		Japanese		ISO
Standard	Grade	Standard	Standard	Grade (steel number)	Standard	Grade	Standard	Grade
GB/T 1591 – 2008 (Year)	Q345A	ASTM A529 Grade 50; ASTM A572 Grade 50; ASTM A588 Grade 50; ASTM A678 Grade 50			JIS G3135	SPFC590	ISO 630-2	S355C, S355D (S355)
GB/T 1591 – 2008	Q345B		DIN EN 10025-2; DIN 17100	S355, S355JR (1.0045), E355 (1.0060); St52-3	JIS G3135	SPFC 590	ISO 630-2	S355C, S355D (S355)
GB1591 – 2008	Q345C		DIN EN 10025-2; DIN 17100	S355J0 (1.0553), E335 (1.0060); St52-3	JIS G 3135	SPFC590	ISO 630-2	S355D (S355)
GB 1591 – 2008	Q345D	ASTM A656 Grade 50; ASTM A529 Grade 50	DIN EN 10025-2; DIN EN 10025: 1993; DIN 17100	S355J0 (1.0553), E335 (1.0060); S355J2G3 (1.0570); St52-3	JIS G 3135	SPFC590	ISO 630-2	S355D (S355)
GB/T 1591 – 2008	Q345E	ASTM A656/A656M Grade 50; ASTM A529/A529M Grade 50; ASTM A808 Grade 50	DIN EN 10025-2; DIN EN 10025: 1993	S355J2 (1.0553), S355K2 (1.0596), E335 (1.0060); S355J2G4 (1.0577), S355K2G3 (1.0595), S355K2G4 (1.0596)	JIS G3135	SPFC 590

Tags: Q345A steel, Q345B steel, Q345C steel, Q345D steel, Q345E steel

Related material: SS400 Steel, SUJ2 Steel, 304 Stainless Steel