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GB/T 700 Q235D Carbon Steel Plate

Q: What are the weldability characteristics of high-strength low-alloy steel plates?

High-strength low-alloy steel plates offer excellent weldability. As their carbon content is typically low (below 0.2%), they present a lower risk of cracking during welding compared to standard high-strength steel plates and generally do not require complex preheating treatments.

Q: Why are high-strength low-alloy steels the preferred choice in construction and automotive manufacturing?

The key advantage of high-strength low-alloy steels is weight reduction. As they offer greater strength, thinner sheets can be used to withstand the same loads, thereby reducing the overall weight of the structure; in the automotive sector, this leads to improved fuel efficiency.

Q: What is high-strength low-alloy steel (HSLA)?

High-strength low-alloy steel (HSLA) is a type of steel in which small amounts of alloying elements (such as niobium, vanadium, titanium or copper) are added to enhance its mechanical properties. Compared to traditional carbon steel, it offers higher yield strength and better corrosion resistance whilst maintaining good weldability and formability.

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GB/T 700 Q235D Carbon Structural Steel Plate has medium strength and good low-temperature impact toughness (-20°C). It is mainly used in building structures in cold regions, engineering machinery, low-temperature containers/pipelines, and other fields.

Standard :
GB/T 700
Grade :
Q235D
Thickness :
3 - 100 mm
Width :
1500 - 2500 mm
Length :
3000 - 12000 mm

Special thickness, width, and length can be negotiated separately.
We also provide customized processing services.If you have any questions, please contact us.

Overview

GB/T 700 Q235D is a carbon structural steel known for its "medium strength + low-temperature resistance," with its core advantage being impact toughness at -20°C.

Q235D steel plate is a carbon steel plate of better quality within the Q235 series, offering excellent low-temperature impact toughness. It is a commonly chosen material for industrial structures and outdoor equipment in cold regions.

Grade	Q235D
Standard	GB/T 700: Chinese Standard Code - Carbon Structural Steel
Classification	Hot-rolled Structural Steel
Delivery Conditions	Hot-rolled
Approval By Third Party	ABS, DNV, GL, CCS, LR , RINA, KR, TUV, CE
Weldability	Good weldability
Machinability	Good machinability (Easily undergoes cold working such as shearing, stamping, and bending.)
Surface Quality	Default surface in hot-rolled condition. Additional treatments such as Shot Blasting, Sandblasting, Painting and Galvanized can be required upon request.
Quality Control	Provide Certificate of Quality

Chemical Composition

Grade	Q235D
Element	C	Si	Mn	P	S
Content (max, %)	0.17	0.35	1.40	0.035	0.035

* A carbon content of ≤0.17% ensures the weldability and toughness of the steel, preventing increased brittleness due to excessive carbon levels.

* The content of harmful impurities sulfur (S) and phosphorus (P) is strictly controlled to ≤0.035% in order to reduce the hot shortness and cold brittleness of the steel.

Mechanical Properties

Grade	Thickness (t) [mm]	Yield Strength (ReH) [min, MPa]	Tensile Strength (Rm) [MPa]	Elongation (A) [min, %]	Impact Energy (KV) [min]
Q235D	t ≤ 16	235	370 - 500	26	27J at -20°C
	16 < t ≤ 40	225	370 - 500	25	27J at -20°C
	40 < t ≤ 60	215	370 - 500	24	27J at -20°C
	60 < t ≤ 100	215	370 - 500	23	27J at -20°C
	100 < t ≤ 150	195	370 - 500	22	27J at -20°C
	150 < t ≤ 200	185	370 - 500	21	27J at -20°C

* As the thickness of the steel increases, the yield strength gradually decreases, and it must pass the impact test at -20°C.

Applications

Q235D Structural Steel Plate is primarily used for structural components with specific low-temperature performance requirements:

1. Building structures in cold regions: steel columns, steel beams, bridge components, and high-rise steel structural frames for industrial plants.

2. Outdoor engineering machinery: structural parts (e.g., frames, booms) of loaders and excavators operating in low-temperature environments.

3. Low-temperature containers/pipelines: non-pressure shells of low-temperature storage equipment, outdoor conveying pipelines (e.g., heating pipeline supports).

4. Shipbuilding and offshore engineering: ship deck supports in cold offshore areas, secondary structures of marine platforms (requiring auxiliary anti-corrosion treatment).

5. Agricultural machinery: agricultural equipment (e.g., tractor chassis) in cold regions, which must withstand low temperatures and impact loads during winter.

Other Information

Difference In Quality Grades

Quality Grade	Impact Test Requirements	Sulfur (S) Content	Phosphorus (P) Content	Applicable Scenarios
Q235A	No impact test required	≤ 0.050%	≤ 0.045%	Static structures, non-load-bearing structures
Q235B	Impact test at room temperature (20°C)	≤ 0.045%	≤ 0.045%	General structural components in room temperature environments
Q235C	Impact test at 0°C	≤ 0.040%	≤ 0.040%	Structural components in slight low-temperature environments
Q235D	Impact test at -20°C	≤ 0.035%	≤ 0.035%	Structural components in low-temperature environments

* The core differences between different quality grades of Q235 steel plates lie in the impact test requirements and the content of harmful elements (Phosphorus and Sulfur).

International Standard Equivalent Materials

Grade	Standard	Yield Strength (min, MPa)	Tensile Strength (MPa)	Impact Energy (KV) [min]
Q235D	GB/T 700 (China)	235	375-500	27 J at -20°C
S235J2	EN 10025-2 (Europe)	235	360-510	27 J at -20°C

* Grade equivalences are only approximate, actual mechanical properties and chemical composition should be compared.

FAQ

Q1:

What are the weldability characteristics of high-strength low-alloy steel plates?

High-strength low-alloy steel plates offer excellent weldability. As their carbon content is typically low (below 0.2%), they present a lower risk of cracking during welding compared to standard high-strength steel plates and generally do not require complex preheating treatments.

Q2:

Why are high-strength low-alloy steels the preferred choice in construction and automotive manufacturing?

The key advantage of high-strength low-alloy steels is weight reduction. As they offer greater strength, thinner sheets can be used to withstand the same loads, thereby reducing the overall weight of the structure; in the automotive sector, this leads to improved fuel efficiency.

Q3:

What is high-strength low-alloy steel (HSLA)?

High-strength low-alloy steel (HSLA) is a type of steel in which small amounts of alloying elements (such as niobium, vanadium, titanium or copper) are added to enhance its mechanical properties. Compared to traditional carbon steel, it offers higher yield strength and better corrosion resistance whilst maintaining good weldability and formability.