CR700/980DP dual-phase steel is a high-strength steel used in automobile manufacturing with a dual-phase structure. It consists of cold rolling and heat treatment process, through the control of the microstructure of the steel, it has high strength and good plasticity at the same time. Among them, CR stands for “cold rolling”, 700 and 980 represent yield strengths of 700MPa and 980MPa respectively, and DP stands for “dual phase”, which means that the microstructure of steel is composed of two different grains. This kind of steel is widely used in automobile body, door, roof and other parts, which can improve the safety and energy-saving performance of automobiles.

What is the chemical composition of CR700/980DP dual phase steel?

Carbon (C): usually between 0.10% and 0.15%, controlling the carbon content can adjust the hardness and strength of steel.

Silicon (Si): Between 0.50% and 1.50%, it has an effect on the toughness and strength of steel.

Manganese (Mn): Between 1.50% and 2.50%, it can increase the yield strength and hardness of steel.

Phosphorus (P): Generally controlled below 0.10%, high phosphorus content will affect the cold workability of steel.

Sulfur (S): Generally controlled below 0.03%, high sulfur content will affect the hot workability and plasticity of steel.

Chromium (Cr): Between 0.50% and 1.50%, it can improve the strength and corrosion resistance of steel.

Molybdenum (Mo): Between 0.10% and 0.50%, it can improve the strength and toughness of steel.

Aluminum (Al): Between 0.01% and 0.10%, it can improve the corrosion resistance and thermal stability of steel.

What are the mechanical properties of CR700/980DP dual phase steel?

High yield strength: The yield strength of CR700/980DP dual-phase steel is usually between 700 MPa and 980 MPa, which is several times higher than ordinary low alloy steel or ordinary carbon steel.

Good ductility and toughness: Despite its high strength, CR700/980DP dual phase steel has excellent ductility and toughness. This means that the steel remains intact even when subjected to impact or deformation.

Good weldability: CR700/980DP dual-phase steel has good weldability, and various common welding methods can be used, such as arc welding, laser welding, plasma welding, etc.

High fatigue life: Due to the structural characteristics of dual-phase steel, CR700/980DP dual-phase steel can still maintain high strength and toughness under high cyclic loads, and has a long fatigue life.

These excellent mechanical properties make CR700/980DP dual-phase steel widely used in the automotive industry, especially in body structures, doors and roofs, which can improve the safety and energy-saving performance of automobiles.

What is the manufacturing process of CR700/980DP dual phase steel?

Raw material preparation: select high-quality pig iron, scrap steel and other raw materials, and carry out precise proportioning to ensure that the content of alloy elements meets the requirements.

Smelting and refining: Putting raw materials into blast furnaces for smelting and refining to remove impurities and undesirable elements and control the proportion of ingredients.

Converter refining and casting: Through converter refining, the composition of molten steel is further controlled, and then continuous casting is performed on the casting machine to obtain steel slabs of required thickness and width.

Hot rolling and cold rolling: the steel slab is sent to the hot rolling mill for hot rolling, then cooled and reprocessed, and finally cold rolled steel plate is obtained.

Annealing: Annealing is performed on cold-rolled steel sheets to restore their plasticity and ductility and to obtain the desired dual-phase structure.

Final rolling and cutting: The annealed steel plate is sent to the final rolling unit for final rolling, and then cut and cut to length to obtain the final CR700/980DP dual-phase steel plate.

What are the advantages of CR700/980DP dual phase steel?

Excellent Strength and Toughness: Due to the design of its dual-phase structure, CR700/980DP dual-phase steel has very high yield strength and excellent ductility and toughness. This allows it to retain its shape under high stress conditions without being prone to plastic deformation or fracture.

Good corrosion resistance: CR700/980DP dual-phase steel has good corrosion resistance and can resist oxidation, corrosion and other environmental factors, so it can be used in harsh climates or operating conditions.

Lightweight: Compared with traditional low-alloy steel or carbon steel, CR700/980DP dual-phase steel has higher strength, and thinner plates can be used to meet the same strength requirements, thereby achieving lightweight automobiles.

Good processability: CR700/980DP dual-phase steel has good processability and can be subjected to various processing operations, such as stamping, bending, welding, etc., making it easy to process and form in the automobile manufacturing process.

Energy saving and environmental protection: Compared with traditional low-alloy steel or carbon steel, the lightweight of CR700/980DP dual-phase steel can reduce vehicle fuel consumption and carbon dioxide emissions, which is conducive to energy saving and emission reduction.

What are the disadvantages of CR700/980DP dual phase steel?

Higher price: Since its manufacturing process is more complicated than traditional low-alloy steel or carbon steel, the price of CR700/980DP dual-phase steel is relatively high, which increases the cost of automobile production.

Prone to stress corrosion cracking: In humid environments, CR700/980DP duplex steel may suffer from stress corrosion cracking, which may affect its service life and safety.

Difficulty in processing: CR700/980DP dual-phase steel has high strength and ductility, so high-strength cutting and stamping equipment is required during processing, which increases production difficulty and cost.

High requirements for material surface treatment: CR700/980DP dual-phase steel is prone to oxidation, pollution and corrosion during the production process, so the requirements for surface treatment are relatively high, and advanced cleaning, rust prevention and spraying technologies are required.

What are the applications of CR700/980DP dual-phase steel in automobile manufacturing?

Body structure: CR700/980DP dual-phase steel has high strength and excellent ductility, and can be used in the manufacture of automobile body structures to improve the strength and rigidity of the body, thereby improving the safety and comfort of the car.

Parts such as doors and roofs: CR700/980DP dual-phase steel has the characteristics of light weight and can be used to manufacture parts such as doors and roofs to reduce body weight, improve fuel economy and reduce carbon emissions.

Engine covers and hoods: CR700/980DP duplex steel can be used to manufacture hoods and hoods, improving the strength and stiffness of components while reducing weight, improving fuel economy and reducing carbon emissions.

Chassis and suspension system: CR700/980DP dual-phase steel can be used to manufacture chassis and suspension system components, improve the strength and stiffness of components, reduce weight, and improve suspension performance and handling performance.

Wheels: CR700/980DP dual-phase steel can be used to manufacture wheel parts such as hubs, improve the strength and rigidity of parts, reduce weight at the same time, and improve the handling performance and fuel economy of cars.

What is the heat treatment process of CR700/980DP dual-phase steel?

Hot rolling: CR700/980DP dual-phase steel sheet is hot-rolled at high temperature to form the desired thickness and shape.

Air cooling: Place the hot-rolled CR700/980DP dual-phase steel sheet in the air to cool naturally, so that its temperature gradually drops below room temperature to form a preliminary structure.

Superheated annealing: heat the cooled CR700/980DP dual-phase steel plate to above 800°C, hold it for a certain period of time and then gradually cool it to form a coarse-grained structure.

Recrystallization annealing: heat the CR700/980DP dual-phase steel plate after overheating annealing to about 650°C, hold it for a certain period of time, and then gradually cool it to form a fine-grained structure.

Quenching and bainite transformation treatment: The CR700/980DP dual-phase steel sheet after recrystallization annealing is quenched, and then bainite transformation treatment is performed to form a structure with a dual-phase structure.

Aging treatment: The CR700/980DP dual-phase steel plate after quenching and bainite transformation treatment is subjected to aging treatment to make its structure more stable and have better mechanical properties.

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Our company’s CR700/980DP dual-phase steel product is a high-strength, high-toughness, high-corrosion-resistant steel, which is widely used in automobiles, electrical appliances, construction and other fields. It has excellent mechanical properties and good weldability, which can meet the requirements of different industries for material performance and quality. Our company has advanced production equipment and technology, which can guarantee product quality and delivery time. If you are interested in our products, please feel free to contact our sales team, we will provide the most professional service and the most suitable solution to provide you with high-quality CR700/980DP dual-phase steel products.