Q390C High Strength Steel

1. Standard and Nomenclature

Standard: Complies with China's national standard GB/T 1591-2018 (Low-Alloy High-Strength Structural Steel).

Naming Convention:

Q: Represents "Yield Strength" (pinyin: Qūfú qiángdù).

390: Minimum yield strength of 390 MPa.

C: Indicates impact test at 0°C (impact toughness grades: A=no test, B=+20°C, C=0°C, D=-20°C, E=-40°C).

2. Chemical Composition (Typical Values, %)

Element	Content Range	Role
C	≤0.20	Balances strength; lower carbon improves weldability and toughness.
Si	0.20–0.55	Strengthens ferrite, enhancing hardness and strength.
Mn	1.00–1.60	Improves strength, wear resistance, and hot-working performance.
P	≤0.030	Harmful; high levels cause cold brittleness (strictly controlled).
S	≤0.025	Harmful; high levels cause hot brittleness (strictly controlled).
V	0.02–0.20	Microalloying element; forms carbides/nitrides to refine grains.
Nb	0.015–0.060	Inhibits austenite grain growth, improving weldability.
Ti	0.02–0.20	Refines grains, enhances toughness, and reduces cold cracking risk.

3. Mechanical Properties

Plate Thickness (mm)	Yield Strength ReL (MPa) ≥	Tensile Strength Rm (MPa)	Elongation A (%) ≥	Impact Energy KV2 (J) ≥ (0°C, Longitudinal)
≤16	390	490–650	20	34
16–40	370	470–630	19	34
40–63	350	450–610	18	34
63–80	330	430–590	17	34

 

 

 

 

 

 

4. Key Characteristics

High Strength & Toughness:

Yield strength ≥390 MPa, suitable for heavy-load structures.

Excellent impact resistance at 0°C (KV2 ≥34J), reducing brittle fracture risks in cold climates (e.g., northern China).

Weldability & Machinability:

Low carbon equivalent (CE ≤0.45%) enables easy welding (arc welding, gas shielded welding) with crack-resistant joints.

Suitable for cold/hot processing (cutting, bending, stamping) for complex component fabrication.

Corrosion Resistance & Economy:

Alloying elements (e.g., Cu, P in some grades) enhance atmospheric corrosion resistance.

Reduces steel usage and structural weight compared to lower-strength grades, cutting costs.

 

 

 

 

 

Why Choose Us?
We take pride in our ability to provide custom solutions for our customers' unique needs.
We analyze and compare the previous products and the current technical situation of our Q390C High Strength Steel, and develop new technical specifications and processes.
Our customers trust us to deliver high-quality Cold-rolled Steel products on time and on budget.
We strictly implement the warm and thoughtful after-sales service, adhere to the development of good professional ethics.
We offer a wide range of Cold-rolled Steel products to meet diverse customer needs.
We adhere to the customer-centric and brand-oriented business philosophy, and continue to provide customers with reliable and excellent products and services.
Our factory is committed to upholding the highest standards of safety and quality.
All staff of our company and all departments work together to combine business management, professional technology, quantitative statistical methods and ideological education.
Our Cold-rolled Steel products are known for their durability and reliability.
Relying on the superior conditions and strong advantages of mass production, we are able to meet the different needs of our customers.

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