EDDS Steel Grade: Properties and Key Applications

Extra Deep Drawing Steel (EDDS) is a specialized category of low-carbon steel designed primarily for applications requiring exceptional formability and deep drawing capabilities. Classified under the broader category of deep drawing steels, EDDS is characterized by its low carbon content, typically ranging from 0.03% to 0.08%, which enhances its ductility and reduces the risk of cracking during the forming process. The primary alloying elements include manganese, phosphorus, and sulfur, which play crucial roles in defining the steel's mechanical properties and performance during fabrication.

The most significant characteristics of EDDS include its excellent elongation properties, high drawability, and superior surface finish. These attributes make it particularly suitable for manufacturing complex shapes and components in industries such as automotive and appliance manufacturing. The main advantages of EDDS are its ability to undergo extensive deformation without failure, its good weldability, and its compatibility with various surface treatments. However, common limitations include lower strength compared to higher carbon steels and susceptibility to corrosion if not properly treated.

Historically, EDDS has played a vital role in the development of lightweight automotive components, contributing to fuel efficiency and performance improvements. Its market position is strong, particularly in sectors that prioritize formability and surface quality.

Alternative Names, Standards, and Equivalents

Standard Organization	Designation/Grade	Country/Region of Origin	Notes/Remarks
UNS	G10080	USA	Closest equivalent to AISI 1008
AISI/SAE	1008	USA	Minor compositional differences to be aware of
ASTM	A1008/A1008M	USA	Standard specification for cold-rolled steel sheets
EN	1.0330	Europe	Equivalent to DC01, suitable for deep drawing
JIS	SPCC	Japan	Similar properties, but with different testing standards
ISO	3574	International	Specifies cold-rolled low carbon steel sheets

The table above highlights various standards and equivalents for Extra Deep Drawing Steel. It is essential to note that while these grades may be considered equivalent, subtle differences in composition and mechanical properties can significantly impact performance in specific applications. For instance, the presence of sulfur in some grades can enhance machinability but may also affect weldability.

Key Properties

Chemical Composition

Element (Symbol)	Percentage Range (%)
Carbon (C)	0.03 - 0.08
Manganese (Mn)	0.30 - 0.60
Phosphorus (P)	≤ 0.04
Sulfur (S)	≤ 0.05
Iron (Fe)	Balance

The primary role of key alloying elements in EDDS is as follows:
- Carbon (C): Low carbon content enhances ductility and formability, reducing the risk of cracking during deep drawing.
- Manganese (Mn): Improves strength and hardenability, contributing to the overall toughness of the steel.
- Phosphorus (P): While it can improve strength, excessive phosphorus can lead to brittleness; thus, it is kept at low levels.
- Sulfur (S): Enhances machinability but can negatively affect weldability if present in high amounts.

Mechanical Properties

Property	Condition/Temper	Typical Value/Range (Metric)	Typical Value/Range (Imperial)	Reference Standard for Test Method
Tensile Strength	Annealed	270 - 350 MPa	39 - 51 ksi	ASTM E8
Yield Strength (0.2% offset)	Annealed	150 - 220 MPa	22 - 32 ksi	ASTM E8
Elongation	Annealed	30 - 45%	30 - 45%	ASTM E8
Reduction of Area	Annealed	50 - 70%	50 - 70%	ASTM E8
Hardness (Brinell)	Annealed	60 - 80 HB	60 - 80 HB	ASTM E10
Impact Strength (Charpy)	-20°C	30 - 50 J	22 - 37 ft-lbf	ASTM E23

The combination of these mechanical properties makes EDDS particularly suitable for applications involving complex mechanical loading and structural integrity requirements. Its high elongation and reduction of area values indicate excellent formability, allowing for the production of intricate shapes without compromising the material's integrity.

Physical Properties

Property	Condition/Temperature	Value (Metric)	Value (Imperial)
Density	-	7.85 g/cm³	0.284 lb/in³
Melting Point/Range	-	1425 - 1540 °C	2600 - 2800 °F
Thermal Conductivity	20°C	50 W/m·K	34.5 BTU·in/h·ft²·°F
Specific Heat Capacity	20°C	460 J/kg·K	0.11 BTU/lb·°F
Electrical Resistivity	20°C	0.0000175 Ω·m	0.000011 Ω·ft
Coefficient of Thermal Expansion	20-100°C	11.5 x 10⁻⁶/K	6.4 x 10⁻⁶/°F

Key physical properties of EDDS have practical significance in its common applications:
- Density: The relatively low density contributes to lightweight designs, essential in automotive applications for improved fuel efficiency.
- Thermal Conductivity: Adequate thermal conductivity allows for effective heat dissipation in components subjected to thermal cycling.
- Coefficient of Thermal Expansion: A low coefficient minimizes dimensional changes during temperature fluctuations, ensuring tight tolerances in manufactured parts.

Corrosion Resistance

Corrosive Agent	Concentration (%)	Temperature (°C)	Resistance Rating	Notes
Chlorides	3-10	20-60	Fair	Risk of pitting corrosion
Sulfuric Acid	1-5	20-40	Poor	Not recommended
Sodium Hydroxide	1-10	20-60	Fair	Risk of stress corrosion cracking
Atmospheric	-	-	Good	Requires protective coating

EDDS exhibits varying levels of resistance to different corrosive environments. In atmospheric conditions, it performs reasonably well, but it is susceptible to pitting corrosion in chloride-rich environments. The presence of sulfuric acid can lead to rapid degradation, making it unsuitable for applications involving strong acids. Compared to other steel grades, such as AISI 304 stainless steel, which offers excellent corrosion resistance, EDDS is less favorable in highly corrosive settings. However, its formability often outweighs these limitations in applications where corrosion resistance is not the primary concern.

Heat Resistance

Property/Limit	Temperature (°C)	Temperature (°F)	Remarks
Max Continuous Service Temp	300	572	Suitable for moderate temperatures
Max Intermittent Service Temp	400	752	Short-term exposure only
Scaling Temperature	600	1112	Risk of oxidation beyond this limit

At elevated temperatures, EDDS maintains its mechanical properties up to a certain limit but can experience oxidation and scaling beyond 600 °C. This can lead to surface degradation and loss of mechanical integrity, particularly in applications involving high-temperature exposure. Proper surface treatments and coatings can mitigate these effects, enhancing the steel's performance in thermal environments.

Fabrication Properties

Weldability

Welding Process	Recommended Filler Metal (AWS Classification)	Typical Shielding Gas/Flux	Notes
MIG	ER70S-6	Argon + CO2	Good fusion and penetration
TIG	ER70S-2	Argon	Excellent control
Stick	E7018	-	Requires preheat

EDDS is generally considered to have good weldability, particularly with MIG and TIG processes. Preheating may be necessary to avoid cracking, especially in thicker sections. Post-weld heat treatment can further enhance the properties of the weldment, reducing residual stresses and improving ductility.

Machinability

Machining Parameter	[EDDS]	AISI 1212	Notes/Tips
Relative Machinability Index	70	100	Good machinability, but lower than AISI 1212
Typical Cutting Speed	30 m/min	40 m/min	Adjust for tool wear

EDDS exhibits good machinability, though it is not as favorable as higher machinability grades like AISI 1212. Optimal cutting speeds and tooling should be employed to minimize wear and achieve desired surface finishes.

Formability

EDDS is highly suitable for both cold and hot forming processes. Its excellent elongation properties allow for significant deformation without failure, making it ideal for applications requiring intricate shapes. The steel can be bent to tight radii, and its work hardening characteristics can be managed through controlled processing conditions.

Heat Treatment

Treatment Process	Temperature Range (°C/°F)	Typical Soaking Time	Cooling Method	Primary Purpose / Expected Result
Annealing	600 - 700 / 1112 - 1292	1 - 2 hours	Air	Improve ductility and reduce hardness
Normalizing	800 - 900 / 1472 - 1652	1 hour	Air	Refine grain structure
Quenching & Tempering	850 - 950 / 1562 - 1742	30 minutes	Oil or Air	Increase strength and toughness

Heat treatment processes such as annealing and normalizing are critical for optimizing the microstructure of EDDS. Annealing enhances ductility, while normalizing refines the grain structure, improving overall mechanical properties. Quenching and tempering can be applied to increase strength, but care must be taken to avoid brittleness.

Typical Applications and End Uses

Industry/Sector	Specific Application Example	Key Steel Properties Utilized in this Application	Reason for Selection
Automotive	Body panels	High elongation, excellent formability	Lightweight, complex shapes
Appliance	Refrigerator liners	Good surface finish, deep drawing capabilities	Aesthetic and functional requirements
Packaging	Beverage cans	High drawability, corrosion resistance	Lightweight and durable
Electronics	Enclosures	Good machinability, formability	Precision components

In the automotive sector, EDDS is favored for body panels due to its ability to form complex shapes while maintaining structural integrity. Similarly, in appliance manufacturing, its excellent surface finish and deep drawing capabilities make it ideal for refrigerator liners. The packaging industry benefits from its lightweight nature, while the electronics sector utilizes its machinability for precision enclosures.

Important Considerations, Selection Criteria, and Further Insights

Feature/Property	[EDDS]	[AISI 304]	[SPCC]	Brief Pro/Con or Trade-off Note
Key Mechanical Property	Moderate strength	High strength	Moderate strength	EDDS is less strong but more formable
Key Corrosion Aspect	Fair	Excellent	Good	EDDS is less resistant to corrosion
Weldability	Good	Fair	Good	EDDS has better weldability than AISI 304
Machinability	Good	Fair	Good	EDDS is easier to machine than AISI 304
Formability	Excellent	Fair	Good	EDDS excels in forming applications
Approx. Relative Cost	Moderate	High	Low	EDDS is cost-effective for forming applications
Typical Availability	Common	Common	Common	All grades are widely available

When selecting EDDS for specific applications, considerations such as cost-effectiveness, availability, and mechanical properties are crucial. While EDDS offers excellent formability and weldability, its corrosion resistance is less favorable compared to stainless steels like AISI 304. This trade-off must be evaluated based on the application's requirements. Additionally, the cost of EDDS is generally moderate, making it an attractive option for manufacturers seeking to balance performance and budget.

In summary, Extra Deep Drawing Steel is a versatile material that excels in applications requiring high formability and surface quality. Its unique properties make it a preferred choice in various industries, particularly where complex shapes and lightweight designs are essential.