If you’re designing lightweight, crash-resistant parts—especially for the automotive industry—DP 590 dual phase steel is a game-changer. As a key advanced high-strength steel, it blends exceptional tensile strength with great formability, making it perfect for balancing safety and fuel efficiency. This guide covers everything you need to know to use it effectively.
What makes DP 590’s properties unique?
DP 590’s unique performance comes from its dual microstructure: soft ferrite for formability and hard martensite for strength. This combination allows it to handle high stress while stretching without cracking.
Chemical composition
The alloy elements are carefully balanced to create its dual-phase structure.
| Element | Composition Range (%) | Key Role |
|---|---|---|
| Carbon (C) | 0.06 – 0.10 | Promotes martensite formation, balances strength and ductility |
| Manganese (Mn) | 1.20 – 1.60 | Enhances hardenability, helps form ferrite-martensite mix |
| Silicon (Si) | 0.15 – 0.35 | Strengthens ferrite, acts as deoxidizer |
| Chromium (Cr) | 0.10 – 0.30 | Improves corrosion resistance, refines grain structure |
| Aluminum (Al) | 0.01 – 0.06 | Controls grain size, boosts formability |
| Titanium (Ti) | 0.01 – 0.05 | Prevents grain growth, enhances fatigue strength |
| Sulfur (S) | ≤ 0.015 | Kept low to avoid brittleness |
| Phosphorus (P) | ≤ 0.025 | Limited to prevent cold brittleness |
Physical properties
These traits affect how DP 590 behaves in manufacturing and real-world use.
- Density: 7.85 g/cm³ – thinner gauges enable lighter designs
- Melting point: 1,450–1,480°C – compatible with standard forming processes
- Thermal conductivity: 42 W/(m·K) at 20°C – manageable for stamping
- Thermal expansion: 12.5 μm/(m·K) – low expansion for precision parts
- Magnetic properties: Ferromagnetic – useful for automated handling
Mechanical properties
DP 590’s mechanical strength is its biggest advantage, especially for safety-focused parts.
| Property | Typical Value |
|---|---|
| Tensile strength | 590 – 700 MPa |
| Yield strength | 340 – 440 MPa |
| Elongation | ≥ 20% |
| Hardness (Vickers) | 170 – 210 HV |
| Impact toughness | ≥ 40 J at -40°C |
| Fatigue strength | ~300 MPa |
| Bending strength | ≥ 650 MPa |
A global automaker faced problems with mild steel side impact beams. They were heavy at 3.5 kg each and had low tensile strength at 350 MPa, causing excessive cabin intrusion in crashes. Switching to DP 590 solved both issues. The new beams weighed 2.2 kg each—37% lighter. Cabin intrusion dropped by 40% in crash tests. Fuel efficiency improved by 2% per vehicle.
Other key properties
- Corrosion resistance: Good. Resists mild moisture and road salts. Use zinc coating for automotive underbody parts.
- Formability: Excellent. Soft ferrite allows stamping into complex shapes like door rings and bumpers.
- Weldability: Very good. Low carbon minimizes cracking. Use standard MIG/MAG welding processes.
- Machinability: Fair. Hard martensite can wear tools. Use carbide inserts with cutting fluid.
- Impact resistance: Strong. Absorbs energy in crashes, ideal for safety components.
Where is DP 590 used?
DP 590’s mix of strength, formability, and lightweight potential makes it a top choice for high-strength, safety-critical applications.
Automotive industry (primary use)
Car manufacturers rely on DP 590 to meet crash safety and fuel efficiency goals.
- Body-in-white (BIW): Door frames, roof rails, and floor pans. A European automaker switched to DP 590 for BIW parts, cutting vehicle weight by 8% while improving crash test scores.
- Bumpers: Front and rear bumpers use DP 590’s impact resistance to absorb collision energy.
- Side impact beams: Door beams reduce injury risk in side crashes. Tensile strength of 590–700 MPa prevents cabin intrusion.
- Suspension components: Control arms and knuckles use DP 590’s fatigue strength of ~300 MPa to withstand road vibrations.
- Roll cages: Racing cars use DP 590 roll cages—lightweight yet strong enough to protect drivers.
Structural components
Beyond automotive, DP 590 is used for lightweight, strong structures.
- Lightweight frames: Delivery vans and small trucks use DP 590 frames, improving fuel economy.
- Safety barriers: Highway crash barriers use DP 590’s bending strength of ≥650 MPa to bend on impact without breaking, redirecting vehicles safely.
How is DP 590 manufactured?
DP 590’s dual-phase structure is created through precise steelmaking and heat treatment.
Steelmaking and heat treatment
- Steelmaking: Electric arc furnace (EAF) is most common. Alloy elements like manganese, chromium, and aluminum are added to reach target composition.
- Cold rolling: Steel is rolled to thin gauges of 1–3 mm for automotive use.
- Inter-critical annealing: Heated to 750–800°C, converting part of the ferrite to austenite.
- Rapid cooling: Quenched in water or air. Austenite transforms to martensite, creating the dual-phase structure.
- Tempering (optional): Heated to 200–300°C to reduce residual stress for suspension components.
Forming and machining
- Stamping: Most common for automotive parts. High-pressure presses shape DP 590 into door rings, bumpers, or body panels. Elongation of ≥20% lets it stretch without cracking.
- Cold forming: Used for simple parts like brackets. Bending or rolling creates shapes without heating.
- Cutting: Laser or plasma cutting is preferred. Avoid oxy-fuel, which can damage the dual-phase structure.
- Welding: MIG/MAG welding with low-carbon filler metals works best. Preheat to 100–150°C to prevent cracking.
How does DP 590 compare to other materials?
Understanding how DP 590 stacks up helps with material selection for high-strength applications.
| Material | Tensile Strength | Elongation | Cost vs. DP 590 | Best For |
|---|---|---|---|---|
| DP 590 | 590–700 MPa | ≥ 20% | 100% | Automotive safety parts like beams and BIW |
| Mild steel (SPCC) | 300–400 MPa | ≥ 30% | 85% | Low-stress parts like inner panels |
| HSLA H340LA | 340–440 MPa | ≥ 25% | 90% | Structural parts like frames |
| UHSS 22MnB5 | 1,500–1,800 MPa | ≥ 10% | 180% | Ultra-safe parts like A-pillars |
| 6061 aluminum | 310 MPa | ≥ 16% | 300% | Very lightweight parts like hoods |
| Carbon fiber | 3,000 MPa | ≥ 2% | 1,000% | High-end parts like racing car bodies |
Key takeaways:
- DP 590 offers the best balance of strength, formability, and cost for most automotive safety parts
- It’s lighter than mild steel when using thinner gauges
- It’s cheaper than aluminum or carbon fiber composites
Conclusion
DP 590 dual phase steel delivers an excellent balance of strength, formability, and cost for safety-critical applications. Its ferrite-martensite microstructure provides tensile strength up to 700 MPa while maintaining elongation above 20% for complex stamping. For automotive body structures, side impact beams, and lightweight frames where crash safety and weight reduction matter, it offers proven reliability at a reasonable cost.
FAQ
Can DP 590 be used for EV battery enclosures?
Yes. Its tensile strength of 590–700 MPa and impact resistance protect batteries from crashes. Pair it with a corrosion-resistant coating like galvannealing to prevent rust from road salts.
Is DP 590 more expensive than mild steel?
Yes, but only by 10–15%. The weight savings of 30–40% for the same strength reduce fuel costs or EV range anxiety, making it a better long-term value. For high-volume production, the cost difference is even smaller.
Can DP 590 be welded to other steels?
Absolutely. It welds well to mild steel or HSLA steel using standard MIG/MAG welding. Use filler metals with low carbon content like ER70S-6 and avoid overheating to keep the dual-phase structure intact.
What’s the difference between DP 590 and DP 800?
DP 590 offers lower tensile strength at 590–700 MPa but higher elongation at ≥20%, making it more formable. DP 800 has higher strength at 800–920 MPa but lower elongation at ≥14%, making it better for simpler, higher-stress parts like A-pillars.
Does DP 590 require special stamping equipment?
Standard high-pressure presses of 1,000–1,500 tons work well. Its elongation of ≥20% prevents cracking during deep drawing. No special heating or cooling equipment is needed, unlike UHSS grades.
Discuss Your Projects with Yigu Rapid Prototyping
At Yigu Rapid Prototyping, we supply DP 590 dual phase steel for automotive safety parts and lightweight structures. Our material meets global standards, and we offer custom stamping, welding, and coating services. Contact us to discuss your next lightweight, crash-resistant project.