Q420B Low Carbon Alloy Plate

 

 

 

Q420B Low Carbon Alloy Plate

1. Material Overview

Q420B is a low-alloy high-strength structural steel conforming to GB/T 1591-2018.

 

Q: Denotes yield strength (Qu in Pinyin).

420: Minimum yield strength of 420 MPa (for thickness ≤16mm).

B: Quality grade specifying impact toughness at ambient temperature (20°C).

 

Characterized by high strength, good plasticity, and weldability, this plate is widely used in high-load structural components such as large bridges, high-rise buildings, heavy machinery, and wind power equipment.

2. Core Properties

Mechanical Properties (Typical Values, Subject to Standards)

Thickness (mm)	Yield Strength (ReL, MPa)	Tensile Strength (Rm, MPa)	Elongation (A, %)	Impact Energy (V-Notch, 20°C, J)
≤16	≥420	520–680	≥18	≥34
16–40	≥400	500–660	≥18	≥34

Process Performance

Weldability: Low carbon equivalent (CEV) allows welding without preheating for most applications (thicker sections or cold environments may require evaluation).

Workability: Suitable for hot-rolling, cold-rolling, and cutting; excellent cold bending performance.

Corrosion Resistance: Better than ordinary carbon steel but requires surface protection (e.g., painting, hot-dip galvanizing) for long-term exposure to corrosive environments.

 

 

 

 

3. Chemical Composition (for Thickness ≤16mm, %)

Element	Content Range	Role Description
C	≤0.20	Low-carbon design ensures plasticity and weldability, reducing cold cracking tendency.
Mn	1.00–1.60	Enhances strength and hardenability; moderate manganese improves toughness.
Si	≤0.55	Deoxidizer that boosts strength but may reduce plasticity and toughness if excessive.
P	≤0.035	Strict control minimizes cold brittleness.
S	≤0.035	Strict control reduces hot brittleness and welding crack risks.
Nb/V/Ti	Trace	Fine-grain strengthening (microalloying allowed by standards, but Q420B typically 不含 these elements).

 

 

 

 

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 Q420B Low Carbon Alloy Plate, 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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