Q420 Steel Chemical Composition, Properties, Specifications & Equivalent

Q420 Steel Introduction

Q420 steel is a Chinese steel grade of Low Alloy High Strength Structural Steel, Yield Strength is 420 MPa, parameters are tested with 16mm diameter steel bars or steel plates, and tensile strength is 520-680 Mpa, the material density is 7.85 g/cm3. According to GB/T 1591-2008, Q420 has 5 quality levels: Q420A, Q420B, Q420C, Q420D and Q420E. For Q420 steel equivalent, chemical composition and mechanical properties, please see the tables below content.

Features and Uses

Q420 steel has high strength, especially in normalized or normalized plus tempered state, with high comprehensive mechanical properties, can be used in large ships, bridges, power station equipment, medium and high pressure boilers, high pressure vessels, lifting machinery, mining machinery and other large welded structural parts.

Table-1, Chemical Composition of Q420 Steel

		Chemical Composition % (GB/T 1591 – 2008)
Steel Grade	Grade	C (≤)	Si (≤)	Mn (≤)	P (≤)	S (≤)	Nb (≤)	V (≤)	Ti (≤)	Cr (≤)	Ni (≤)	Cu (≤)	N (≤)	Mo (≤)	B (≤)	Als (≥)
Q420	Q420A	0.20	0.50	1.70	0.035	0.035	0.07	0.20	0.20	0.30	0.80	0.30	0.015	0.20	–	–
	Q420B				0.035	0.035										–
	Q420C				0.030	0.030										0.015
	Q420D				0.030	0.025										0.015
	Q420E				0.025	0.020										0.015

		Chemical Composition % (GB/T 1591 – 2018)
Steel Grade	Grade	C (≤)	Si (≤)	Mn (≤)	P (≤)	S (≤)	Nb (≤)	V (≤)	Ti (≤)	Cr (≤)	Ni (≤)	Cu (≤)	N (≤)	Mo (≤)	B (≤)
Q420	Q420B	0.20	0.55	1.70	0.035	0.035	0.05	0.13	0.05	0.30	0.80	0.40	0.015	0.20	–
	Q420C				0.030	0.030

Table-2, Carbon Equivalent Value (CEV)

Steel delivered in hot rolled state (based on smelting analysis)

		CEV (Mass fraction ≤%); Nominal thickness or diameter Ø
Steel Grade	Quality Grade	≤ 30	30 < Ø ≤ 63	63 < Ø ≤ 150	150 < Ø ≤ 250	250 < Ø ≤ 400
Q420	Q420B	0.45 (CEV)	0.47	0.48	0.49	–
	Q420C

Table-3, Q420 Steel Mechanical Properties (Hot rolled)

		Thickness or Dia. (Ø) mm; Yield Strength (≥N/mm2)
Steel Grade	Quality	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
Q420	Q420B	420	410	390	370	370	350	–	–	–
	Q420C

		Dia. (Ø) mm; Tensile Strength (N/mm2)
Steel Grade	Quality Level	Ø≤100	100 < Ø ≤ 150	150 < Ø ≤ 250	250 < Ø ≤ 400
Q420	Q420B	520 – 680	500 – 650	–	–
	Q420C

Table-4, Elongation

		Dia. (Ø) mm; Elongation (%)
Steel Grade	Sample direction	Ø≤40	40 < Ø ≤ 63	63 < Ø ≤ 100	100 < Ø ≤ 150	150 < Ø ≤ 200	250 < Ø ≤ 400
Q420	Horizontal	20	19	19	18	–	–
Q420	Vertical	21	20	20	19	–	–

Q420 steel equivalent to US ASTM, European EN, Germany DIN, Japan JIS, France NF, UK BS and ISO standard (For reference purposes only)

China

USA

Germany

Japanese

France

ISO

Standard

Grade

Standard

Grade

Standard

Grade

Standard

Grade

Standard

Grade

Standard

Grade

Standard

Grade

GB/T 1591 – 2008

Q420A

ASTM A572M,
ASTM A633M

Gr.60,
Gr.E

NF A36-201

E420-1

ISO 4996,
ISO 4951

HS420D
E420CC

GB/T 1591 – 2008

Q420B

ASTM A572M,
ASTM A633M

Gr.60,
Gr.E

DIN EN 10113-2,
DIN EN 10113-3

S420NL,
S420ML

JIS G3124

SEV295,
SEV345

NF EN 10113-2,
NF EN 10113-3

S420NL,
S420ML

BS EN 10113-2,
BS EN 10113-3

S420NL
S420ML

ISO 4996,
ISO 4951

HS420D
E420CC

GB/T 1591 – 2008

Q420C

ASTM A678M,
ASTM A656M

Gr.B,
TyPe7

DIN EN 10113-2,
DIN EN 10113-3

S420NL,
S420ML

JIS G3124

SEV295,
SEV345

NF EN 10113-2,
NF EN 10113-3

S420NL,
S420ML

BS EN 10113-2,
BS EN 10113-3

S420NL
S420ML

ISO 4996,
ISO 4951

HS420D
E420CC

GB/T1591 – 2008

Q420D

ASTM A678M,
ASTM A656M

Gr.B,
TyPe7

DIN EN 10113-2,
DIN EN 10113-3

S420NL,
S420ML

JIS G3124

SEV295,
SEV345

NF EN 10113-2,
NF EN 10113-3

S420NL,
S420ML

BS EN 10113-2,
BS EN 10113-3

S420NL
S420ML

GB/T1591 – 2008

Q420E

ASTM A678M,
ASTM A656M

Gr.B,
TyPe7

DIN EN 10113-2,
DIN EN 10113-3

S420NL,
S420ML

JIS G3124

SEV295,
SEV345

NF EN 10113-2,
NF EN 10113-3

S420NL,
S420ML

BS EN 10113-2,
BS EN 10113-3

S420NL
S420ML

Alloy Steel Structural Steel