E550(DD,E) Low Alloy High Strength Steel

 

The designation E550(DD,E) is commonly used in European standards (e.g., EN 10149-2 for hot-rolled products or EN 10210 for structural hollow sections), though specific interpretations may vary slightly by standard. Here's a breakdown:

 

E: Indicates high-strength structural steel (often used for thermomechanically rolled or quenched and tempered steel).

550: Represents the minimum yield strength (≥550 MPa) for specified thicknesses (typically ≤16 mm).

DD/E: Denotes the quality 等级 (impact toughness):

DD: Not a standard designation in EN 10025-2; may be a manufacturer-specific or project-specific code.

E: In EN 10025-2, quality grades for impact testing are A, B, C, D, E (with decreasing impact temperatures). Grade E requires impact testing at -40°C with a minimum absorbed energy (e.g., ≥27 J).

 

Note: Always refer to the specific standard or manufacturer's technical documentation for exact definitions, as sub-grades (e.g., DD) may relate to additional requirements like weldability or chemical composition.

2. Chemical Composition (Typical Range)

Low alloy high-strength steels like E550 typically contain:

 

Carbon (C): ≤0.18% (to balance strength and weldability).

Manganese (Mn): 1.0–1.6% (improves strength and hardenability).

Silicon (Si): 0.15–0.50% (deoxidizer, enhances strength).

Microalloying Elements:

Niobium (Nb), Vanadium (V), or Titanium (Ti): 0.01–0.10% (grain refinement, strength improvement via precipitation hardening).

Molybdenum (Mo) or Chromium (Cr): Sometimes added in higher-strength grades (e.g., for quenched and tempered steels) to boost hardenability.

Sulfur (S) and Phosphorus (P): ≤0.035% ( to minimize brittleness and improve ductility).

 

Example (EN 10149-2):

 

Element	C	Mn	Si	P	S	Nb	V	Ti
Max %	0.12	1.60	0.55	0.025	0.015	0.05	0.10	0.03

 

 

 

 

 

 

 

 

 

 

 

 

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 E550(DD,E) Low Alloy 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.

Hot Tags: e550(dd,e) low alloy high strength steel, China e550(dd,e) low alloy high strength steel suppliers, factory, CR180BH, CR1 Steel, CR240LA, Low carbon High strength, HR500LA, CR210IF