Q355 Steel: Q355B Q355C Q355D Properties & Equivalent

Q355 Steel: Q355B, Q355C, Q355D

Q355 steel is a low alloy high strength structural steel commonly used in China, which replaced Q345. The material has a minimum yield strength of 355 MPa (51 ksi) and a tensile strength of 470-630 Mpa (68-91 ksi). According to GB/T 1591 -2018, Q355 has 3 steel grades: Q355AR, Q355M and Q355N, and these steel grades are indicated by the suffix letters B, C, D, E, F for quality grades.

Q355: Q355B, Q355C and Q355D.

Q355M: Q355MB, Q355MC, Q355MD, Q355ME, Q355MF

Q355N: Q355NB, Q355NC, Q355ND, Q355NE, Q355NF

Meaning (Designation)

“Q” is the abbreviation of Chinese Pinyin: “Qufu”, which means Yield Strength;
“355” indicates the minimum yield strength 355 MPa for steel diameter or thickness ≤16mm;
“AR” refers to As-Rolled, the symbol can be omitted/removed when the delivery condition is hot rolled;
“M” means Thermomechanically rolled;
“N” means Normalized or normalized rolled;
B, C, D, E and F indicate quality grades.

Note: AR, M and N refers to the delivery conditions.

Q355 Steel Properties

The tables below show Q355 material properties, datasheet and specifications such as chemical composition, and physical and mechanical properties.

Chemical Composition (Hot rolled)

Hot rolled steel chemical composition based on heat analysis.

Chemical Composition (Heat Analysis), %, ≤
Steel Grade	Quality Grade	C	Si	Mn	P	S	Cr	Ni	Cu	N
Q355	Q355B	0.24	0.55	1.6	0.035	0.035	0.30	0.30	0.40	0.012
	Q355C	0.20			0.030	0.030				0.012
	Q355D	0.20			0.025	0.025				–

Note: For quality grades C & D, Carbon content (C)-

C ≤0.20% when thickness/diameter ≤40mm (1.57 in.);
C ≤0.22 when thickness/dia. >40mm (1.57 in.);

Normalized or normalized rolled steel

Chemical Composition (Heat Analysis), %
Steel Grade	Quality Grade	C, ≤	Si, ≤	Mn	P, ≤	S, ≤	Cr, ≤	Ni, ≤	Cu, ≤	Mo, ≤	N, ≤	Nb	V	Ti	Al, ≥
Q355N	Q355NB	0.20	0.5	0.90-1.65	0.035	0.035	0.30	0.50	0.40	0.10	0.015	0.005-0.05	0.01-0.12	0.006-0.05	0.015
	Q355NC	0.20			0.030	0.030
	Q355ND	0.20			0.030	0.025
	Q355NE	0.18			0.025	0.020
	Q355NF	0.16			0.020	0.010

Thermomechanically rolled steel

Chemical Composition (Heat Analysis), %
Steel Grade	Quality Grade	C, ≤	Si, ≤	Mn, ≤	P, ≤	S, ≤	Cr, ≤	Ni, ≤	Cu, ≤	Mo, ≤	N, ≤	Nb	V	Ti	Al, ≥
Q355M	Q355MB	0.14	0.5	1.60	0.035	0.035	0.30	0.50	0.40	0.10	0.015	0.01-0.05	0.01-0.10	0.006-0.05	0.015
	Q355MC				0.030	0.030
	Q355MD				0.030	0.025
	Q355ME				0.025	0.020
	Q355MF				0.020	0.010

Notes:

For bars and sections, the P and S content can be 0.005% higher.
For Ti content, can be up to 0.20%.

Carbon Equivalent (CEV)

Based on smelting analysis, steel delivered in hot rolled state.

		CEV (Mass fraction ≤%); Nominal thickness or diameter (d)
Steel Grade	Quality Grade	≤ 30	30 < d ≤ 63	63 < d ≤ 150	150 < d ≤ 250	250 < d ≤ 400
Q355	Q355B	0.45 (CEV)	0.47	0.47	0.49	–
	Q355C					–
	Q355D					0.49

Q355 Material Mechanical Properties

Notes:

1 MPa = 1 N/mm2
1 GPa = 1 kN/mm2

Q355 steel mechanical properties are listed in the data sheet below, including yield strength, tensile strength and elongation, etc.

Yield Strength

Yield Strength (≥ MPa), Thickness or Dia. (d) mm
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
Q355	Q355B	355	345	335	325	315	295	285	275	–
	Q355C									–
	Q355D									265
Q355N	All									–

Yield Strength (≥ MPa), Thickness or Dia. (d) mm
Steel Grade	Quality Grade	d≤16	16< d ≤40	40 < d ≤63	63 < d ≤ 80	80< d ≤ 100	100< d≤ 120
Q355M	All	355	345	335	325	325	320

Tensile Strength

Tensile Strength, MPa; Dia. (d) mm
Steel Grade	Quality Grade	d≤100	100< d ≤250	250< d ≤400
Q355	Q355B	470-630	450-600	–
	Q355C			–
	Q355D			450-600
Q355N	All			–

Tensile Strength, MPa; Dia. (d) mm
Steel Grade	Quality Grade	d≤40	40< d ≤63	63< d ≤100	100< d ≤120
Q355M	All	470-630	450-610	440-600	430-590

Elongation

Elongation (%); Dia. (d) mm; (Hot rolled)
Sample direction	d≤40	40< d ≤63	63< d ≤100	100< d ≤150	150< d≤ 200	250< d ≤400
Transverse	20	19	18	18	17	17
Vertical	22	21	20	18	17	17

Charpy Impact

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

Quality Grade	Temperature, °C (°F)	Longitudinal Impact Energy (J), ≥	Transverse Impact Energy (J), ≥
Q355B, Q355MB, Q355NB	20 (68)	34	27
Q355C, Q355MC, Q355NC	0 (32)	34	27
Q355D	-20 (-4)	34 (Only for thickness ≥250mm)	27 (for thickness ≥250mm)
Q355ND, Q355MD	20 (68)	55	31
	0 (32)	47	27
	-20 (-4)	40	20
Q355NE, Q355ME	20 (68)	63	40
	0 (32)	55	34
	-20 (-4)	47	27
	-40 (-40)	31	20
Q355NF, Q355MF	20 (68)	63	40
	0 (32)	55	34
	-20 (-4)	47	27
	-40 (-40)	31	20
	-60 (-76)	27	16

Physical Properties

Density: 7850 kg/m3 (0.284 lb/in3)

Melting point: 1450-1530 °C (2640-2800 °F)

Features and Applications

Q355 steel has good mechanical properties, good weldability, hot and cold processing properties and corrosion resistance. Can be used to manufacture ships, boilers, pressure vessels, petroleum storage tanks, bridges, power station equipment, lifting transport machinery and other higher load welded structural parts.

Q355 Steel Equivalent Grade

Q355 carbon steel equivalent material is listed in the table below including European EN standard (German DIN EN, British BSI, French NF…), ISO, Canada CSA (Canadian Standards Association), Australian/New Zealand and Indian IS standard.

China		ISO		European Union		Canada		Australian/New Zealand		Indian
Standard	Grade	Standard	Grade	Standard	Grade (Material Number)	Standard	Grade – SI (Imperial)	Standard	Grade	Standard	Grade
GB/T 1591 -2018	Q355B	ISO 630-2	S355B	EN 10025-2	S355, S355JR (1.0045)	CSA G40.20-13/G40.21-13	350W (50W); 345WM (50WM)	AS/NZS 3679.1	Grade 350; 350L0; 350L15	IS 2062	E350 (Fe 490)
	Q355C		S355C		S355J0 (1.0553)
	Q355D		S355D		S355J2 (1.0577)