时间：2024-07-16 访问量：1418
1.Steel for car body exterior panels
Steel used for automobile body exterior panels is mainly used to manufacture parts such as front, rear, left, and right exterior panels, engine hood panels, and trunk lid panels. It should have good formability, corrosion resistance, dent resistance, and good weldability. The exterior panels of automobile bodies are often coated with plates to meet anti-corrosion requirements. In order to improve their resistance to dents, baking hardened steel, high-strength IF steel, and high formability cold-rolled annealed duplex steel (such as DP450) are commonly used. Galvanized sheets are commonly used, including hot-dip galvanized sheets, hot-dip galvanized iron sheets, electroplated galvanized sheets, and electroplated galvanized nickel sheets.
2. Steel for the interior panels of the vehicle body
Through the exterior panel of the car, we can see that the shape of the parts on the body panel is more complex, which requires the steel used for the body panel to have higher formability and deep drawing performance. Therefore, the body panel is mostly made of IF steel with excellent stamping formability and deep drawing performance, and a small amount of high-strength IF steel is used. Its coating requirements are similar to those of the exterior panel.
3. Body structural components of automobiles
Going further inside, we can see the structural components of the car body, as shown in the following picture. It is closely related to the safety and lightweighting of automobiles. Therefore, the selection of materials requires both high strength and high plasticity. Advanced High Strength Steel (AHSS) is commonly used in vehicle structural components due to its excellent strong plastic bonding, good collision characteristics, and higher fatigue life. For example, it has been widely used in key areas such as the front and rear bumper frames, A-pillars, and B-pillars. In the event of an impact, especially in front and side impacts, it can effectively reduce cockpit deformation and protect the safety of drivers and passengers. Advanced automotive high-strength includes duplex steel, martensitic steel, phase change induced plasticity steel, duplex steel, and quenched ductile steel. The typical mechanical properties are shown in Appendix 1 at the end of the article.
二、Alloy structural steel for automobiles
After understanding the steel used for the exterior and skeleton of cars, let's continue to learn about the alloy structural steel hidden inside the car body. Mainly including: quenched and tempered steel and non quenched and tempered steel for shafts, steel for gears, steel for various springs, and steel for various high-strength standard components.
1. Shaft type quenched and tempered steel and non quenched and tempered steel
On your beloved car, various axles are great contributors. As soon as cars start running, they are subjected to significant stress. The front axle is subjected to bending fatigue stress, the crankshaft is subjected to bending and torsional composite stress, the transmission shaft is subjected to torsional fatigue stress, and the connecting rod is subjected to asymmetric tensile and compressive stress... In order to ensure their healthy and safe operation, quenched and tempered steel for shafts usually contains certain alloy elements, which not only guarantees hardenability (the ability to ensure that the strength of each part of the part section meets the requirements of the part), but also improves impact toughness. At present, there are quenched and tempered steels such as 40Cr and 42CrMo used for crankshafts, S45C, SCM4, SCM6, SAE1045 commonly used for automotive half shafts, and 40Cr and S48C commonly used for automotive connecting rods. Non quenched and tempered steels such as 12Mn2VBS and 35MnVN have also been widely used in steering knuckles and engine connecting rods.
2. Steel for gears
Gears are also important components for transmitting power in automobiles, and the performance requirements for gear steel are: high crush resistance and resistance to pitting and peeling; Good impact resistance and bending ability; Appropriate hardenability, hardened layer depth, and core hardness; Good process performance and machinability; And deformation and dimensional stability. Gear steel includes Cr Mo series such as SCM420 and SCM822, Cr Ni Mo series, and Ni Mo series.
3. Steel for springs
Springs are widely used and come in various varieties in automobiles. They are a basic structural component, mainly used for suspension spring steel and valve spring steel. In light or heavy trucks, the amount of spring suspension used is generally 100-500kg. The performance requirements for spring steel are: high elastic limit and relaxation resistance, good hardenability and appropriate hardenability, high fracture toughness and strain fatigue life, good metallurgical process performance and formability, certain wear resistance and corrosion resistance. At present, the steel used for suspension springs mainly includes Si Mn series, Mn Cr series, Cr-V series, Mn-Cr-B, etc.
4. Steel for various high-strength standard components
In recent years, high-strength standard components have gradually increased in automotive applications, and riveting steel is one of them. It requires good processability, machinability, strength performance, fatigue performance, and delayed fracture ability under high strength. ADF1 developed in China is used to manufacture 14 grade high-strength bolt steel.
