Q345C

Q345C Steel Properties and Introduction

Q345C 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 (datasheet tested with 16mm diameter steel bars or steel plates). According to GB/T 1591 – 2008, Q345 material has 5 quality grades: Q345A, Q345B, Q345C, Q345D and Q345E. “Q” is the first letter of Chinese Pinyin: “qu fu dian”, which means Yield Point, “345” is short for 345 MPa. For datasheet and specification, please see the tables below.

Q345 steel weldability, cold & hot workability and corrosion resistance are good. Widely used in bridges, ships, boilers, pressure vessels, petroleum storage tanks, lifting transport machinery and other high-load welded structural parts.

Table-1, Chemical Composition of Q345C Steel

		Chemical Composition Content (≤%)	≥%
Steel Grade	Quality Grade	C	Si	Mn	P	S	Nb	V	Ti	Cr	Ni	Cu	N	Mo	B	Als
Q345	Q345A	0.20	0.50	1.70	0.035	0.035	0.07	0.15	0.20	0.30	0.50	0.30	0.012	0.10	–	–
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%.

Table-2, Q345 Mechanical Properties

		Mechanical Properties: Yield Strength (≥ N/mm2)
Steel Grade	Quality Grade	Ø ≤16	16 < Ø ≤ 40	40 < Ø ≤ 63	63 < Ø ≤ 80	80 < Ø ≤ 100	100 < Ø ≤ 150	150 < Ø ≤ 200	200 < Ø ≤ 250	250 < Ø ≤ 400
Q345	Q345A	≥345	≥335	≥325	≥315	≥305	≥285	≥275	≥265	–
Q345B
Q345C
Q345D	≥265
Q345E

Notes: Ø = Thickness or wire diameter in mm;

1 MPa = 1 N/mm2

		Mechanical Properties: Tensile Strength (N/mm2)
Grade	Quality Level	Ø ≤ 40	40 < Ø ≤ 63	63 < Ø ≤ 80	80 < Ø ≤ 100	100 < Ø ≤ 150	150 < Ø ≤ 250	250 < Ø ≤ 400
Q345	Q345A	470 – 630	470 – 630	470 – 630	470 – 630	450 – 600	450 – 600	–
Q345B
Q345C
Q345D	450 – 600
Q345E

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

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)

Q345 Equivalent

China

USA

Germany

Japanese

France

UK

ISO

Standard

Grade

Standard

Grade

Standard

Grade (steel number)

Standard

Grade

Standard

Grade (steel number)

Standard

Grade (steel number)

Standard

Grade

GB/T 1591 – 2008 (Year)

Q345A

ASTM A529/A529M; ASTM A572/A572M; ASTM A588/A588M; ASTM A678/A678M; ASTM A808/A808M

Grade 50; Grade 50; Grade B; Grade D; A808M

DIN EN 10025-2; DIN 17100

S355JR (1.0045), E355 (1.0060); St52-3

JIS G3135

SPFC590

NF EN 10025-2

S355JR (1.0045), E355 (1.0060);

BS EN 10025-2

S355JR (1.0045), E355 (1.0060);

ISO 630-2

S355C, S355D (S355)

GB/T 1591 – 2008

Q345B

Ditto

Ditto

Ditto

Ditto

JIS G3135

SPFC 590

Ditto

Ditto

Ditto

Ditto

ISO 630-2

S355C, S355D (S355)

GB/T1591 – 2008

Q345C

Ditto

Ditto

DIN EN 10025-2; DIN 17100

S355J0 (1.0553), E335 (1.0060); St52-3

JIS G 3135

SPFC590

NF EN 10025-2

S355JO (1.0553), E335 (1.0060)

BS EN 10025-2

S355JO (1.0553), E335 (1.0060)

ISO 630-2

S355D (S355)

GB/T 1591 – 2008

Q345D

ASTM A656/A656M; ASTM A529/A529M

Type 7; 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

NF EN 10025-2; NF EN 10025: 1993

S355J0 (1.0553), E335 (1.0060); S355J2G3 (1.0570)

BS EN 10025-2; BS EN 10025: 1993

S355J0 (1.0553), E335 (1.0060); S355J2G3 (1.0570)

ISO 630-2

S355D (S355)

GB/T 1591 – 2008

Q345E

ASTM A656/A656M; ASTM A529/A529M

Type 7; 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

NF EN 10025-2; NF EN 10025: 1993

S355J2 (1.0553), S355K2 (1.0596), E335 (1.0060); S355J2G4 (1.0577), S355K2G3 (1.0595), S355K2G4 (1.0596)

BS EN 10025-2; BS EN 10025: 1993

S355J2 (1.0553), S355K2 (1.0596), E335 (1.0060); S355J2G4 (1.0577), S355K2G3 (1.0595), S355K2G4 (1.0596)

Notes: Q345 steel has been replaced byQ355 in the latest version of GB standard “GB/T 1591 – 2018”, the previous version is “GB/T 1591 – 2008”.