EDD Steel: Properties and Key Applications in Deep Drawing

Extra Deep Drawing (EDD) Steel is a specialized category of low-carbon steel designed primarily for deep drawing applications. This steel grade is characterized by its excellent formability and ductility, making it ideal for producing complex shapes without cracking or deforming. EDD steel typically contains low levels of alloying elements, which contribute to its unique properties. The primary alloying elements include manganese, phosphorus, and sulfur, which enhance its mechanical properties while maintaining a low carbon content.

The most significant characteristics of EDD steel include high elongation, good drawability, and a fine-grained microstructure. These properties allow for the production of thin-walled components with intricate geometries, such as automotive body panels and household appliances. The advantages of EDD steel include its ability to be formed into complex shapes with minimal risk of failure, as well as its cost-effectiveness in mass production. However, its limitations include lower strength compared to higher carbon steels and susceptibility to corrosion if not properly treated.

Historically, EDD steel has played a crucial role in the automotive and appliance industries, where the demand for lightweight and durable components has driven its development and use. Its market position remains strong due to ongoing innovations in manufacturing processes and material treatments that enhance its performance.

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	Low carbon steel with good formability
ASTM	A1008	USA	Specification for cold-rolled steel sheets
EN	1.0330	Europe	Equivalent to DC01 in EN standards
JIS	SPCC	Japan	Similar properties, used in automotive applications
ISO	1010	International	General-purpose low-carbon steel

The table above outlines various standards and equivalents for EDD steel. While many of these grades are considered equivalent, subtle differences in chemical composition and mechanical properties can influence selection for specific applications. For instance, while AISI 1008 and EN 1.0330 share similar characteristics, the specific manufacturing processes and quality control measures may vary, impacting performance in critical applications.

Key Properties

Chemical Composition

Element (Symbol and Name)	Percentage Range (%)
C (Carbon)	0.06 - 0.12
Mn (Manganese)	0.30 - 0.60
P (Phosphorus)	≤ 0.04
S (Sulfur)	≤ 0.05
Fe (Iron)	Balance

The primary alloying elements in EDD steel play crucial roles in defining its properties. Carbon, while kept low, is essential for enhancing strength and hardness. Manganese contributes to improved ductility and toughness, while phosphorus and sulfur are controlled to minimize brittleness and ensure good formability.

Mechanical Properties

Property	Condition/Temper	Typical Value/Range (Metric - SI Units)	Typical Value/Range (Imperial Units)	Reference Standard for Test Method
Tensile Strength	Annealed	270 - 350 MPa	39 - 51 ksi	ASTM E8
Yield Strength (0.2% offset)	Annealed	160 - 220 MPa	23 - 32 ksi	ASTM E8
Elongation	Annealed	30 - 50%	30 - 50%	ASTM E8
Hardness (Brinell)	Annealed	70 - 90 HB	70 - 90 HB	ASTM E10
Impact Strength (Charpy)	-20°C	30 - 50 J	22 - 37 ft-lbf	ASTM E23

The mechanical properties of EDD steel make it particularly suitable for applications requiring high formability and moderate strength. The combination of good elongation and yield strength allows for effective deep drawing processes, ensuring structural integrity under mechanical loading.

Physical Properties

Property	Condition/Temperature	Value (Metric - SI Units)	Value (Imperial Units)
Density	-	7.85 g/cm³	0.284 lb/in³
Melting Point	-	1425 - 1540 °C	2600 - 2800 °F
Thermal Conductivity	20°C	50 W/m·K	34.5 BTU·in/(hr·ft²·°F)
Specific Heat Capacity	20°C	0.49 kJ/kg·K	0.12 BTU/lb·°F
Electrical Resistivity	20°C	0.000017 Ω·m	0.00001 Ω·in

Key physical properties such as density and thermal conductivity are significant for applications where weight and heat dissipation are critical. The relatively low density of EDD steel makes it advantageous for lightweight structures, while its thermal properties ensure effective heat management in manufacturing processes.

Corrosion Resistance

Corrosive Agent	Concentration (%)	Temperature (°C/°F)	Resistance Rating	Notes
Atmospheric	-	-	Fair	Risk of rusting without protective coating
Chlorides	3-5	20-60 °C (68-140 °F)	Poor	Susceptible to pitting corrosion
Acids	10-20	20-40 °C (68-104 °F)	Poor	Not recommended for acidic environments
Alkaline	5-10	20-60 °C (68-140 °F)	Fair	Moderate resistance, but protective measures advised

EDD steel exhibits moderate corrosion resistance, particularly in atmospheric conditions. However, it is susceptible to pitting in chloride environments and should not be used in acidic applications without protective coatings. Compared to stainless steels, EDD steel's corrosion resistance is significantly lower, making it less suitable for harsh environments.

Heat Resistance

Property/Limit	Temperature (°C)	Temperature (°F)	Remarks
Max Continuous Service Temp	400 °C	752 °F	Performance may degrade above this limit
Max Intermittent Service Temp	500 °C	932 °F	Short-term exposure acceptable
Scaling Temperature	600 °C	1112 °F	Risk of oxidation at elevated temperatures

At elevated temperatures, EDD steel maintains its structural integrity up to approximately 400 °C (752 °F). Beyond this, the risk of oxidation and degradation increases, necessitating careful consideration in applications involving heat exposure.

Fabrication Properties

Weldability

Welding Process	Recommended Filler Metal (AWS Classification)	Typical Shielding Gas/Flux	Notes
MIG	ER70S-6	Argon + CO2 mix	Good penetration, minimal distortion
TIG	ER70S-2	Argon	Clean welds, requires skill
Spot Welding	-	-	Suitable for thin sheets

EDD steel 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 enhance the mechanical properties of the weld zone.

Machinability

Machining Parameter	EDD Steel	Benchmark Steel (AISI 1212)	Notes/Tips
Relative Machinability Index	60	100	Moderate machinability
Typical Cutting Speed (Turning)	30 m/min	50 m/min	Use sharp tools for best results

EDD steel has moderate machinability, making it suitable for various machining operations. Optimal conditions include using sharp tools and appropriate cutting speeds to minimize tool wear and achieve desired surface finishes.

Formability

EDD steel excels in formability, allowing for cold and hot forming processes. Its low yield strength and high elongation make it ideal for deep drawing applications, where complex shapes are required. The steel can be bent with relatively small radii, and its work hardening characteristics allow for increased strength during forming.

Heat Treatment

Treatment Process	Temperature Range (°C/°F)	Typical Soaking Time	Cooling Method	Primary Purpose / Expected Result
Annealing	600 - 700 °C (1112 - 1292 °F)	1 - 2 hours	Air or water	Reduce hardness, improve ductility
Normalizing	850 - 900 °C (1562 - 1652 °F)	1 hour	Air	Refine grain structure

Heat treatment processes such as annealing and normalizing are critical for optimizing the microstructure of EDD steel. Annealing reduces hardness and enhances ductility, while normalizing refines the grain structure, improving overall mechanical properties.

Typical Applications and End Uses

Industry/Sector	Specific Application Example	Key Steel Properties Utilized in this Application	Reason for Selection (Brief)
Automotive	Body panels	High formability, moderate strength	Lightweight, complex shapes
Appliance	Refrigerator shells	Excellent drawability, corrosion resistance	Durable, cost-effective
Packaging	Beverage cans	Thin-walled, high elongation	Efficient material usage

EDD steel is widely used in industries such as automotive, appliances, and packaging due to its excellent formability and cost-effectiveness. Its ability to be formed into complex shapes makes it a preferred choice for applications requiring lightweight and durable components.

Important Considerations, Selection Criteria, and Further Insights

Feature/Property	EDD Steel	AISI 1010	AISI 304	Brief Pro/Con or Trade-off Note
Key Mechanical Property	Moderate strength	Low strength	High strength	EDD is more formable than 1010 but less strong than 304
Key Corrosion Aspect	Fair resistance	Poor resistance	Excellent resistance	EDD is less suitable for corrosive environments compared to 304
Weldability	Good	Fair	Good	EDD is easier to weld than 1010 but requires care
Machinability	Moderate	Good	Fair	EDD is less machinable than 1010 but better than 304
Formability	Excellent	Good	Fair	EDD excels in forming compared to both alternatives
Approx. Relative Cost	Low	Low	Higher	EDD is cost-effective for mass production
Typical Availability	High	High	Moderate	EDD is widely available in various forms

When selecting EDD steel, considerations include its mechanical properties, corrosion resistance, and cost-effectiveness. While it offers excellent formability and is suitable for many applications, its limitations in strength and corrosion resistance should be weighed against alternatives like AISI 304 stainless steel for specific environments. The choice of material ultimately depends on the specific requirements of the application, including mechanical loading, environmental exposure, and manufacturing processes.