The development and application of high-strength steels are crucial pathways for automotive lightweighting. So, what are the classifications of automotive steels? Follow HAIFEI Energy Storage Welding to explore the details.
HAIFEI Energy Storage Welding: What Are the Classifications of Automotive Steels?
| Material & Grade | Color Code (RGB) | Weight Percentage (%) | Sub-Classifications |
|---|---|---|---|
| Mild Steel | R153, G204, B255 | ||
| High-Strength Steel (HSS) | R051, G102, B255 | HSIF, BH HSLA, CMn Nb DP, TRIP TWIP TBF, Q&P |
|
| Advanced High-Strength Steel (AHSS) | R255, G153, B204 | ||
| Stainless Steel | R051, G051, B153 | ||
| Ultra-High-Strength Steel (UHSS) | R204, G153, B255 | CP MS |
|
| Hot-Stamped Steel | R128, G000, B128 | ≥1700MPa | 1500MPa Grade |
Capacitor discharge spot welders provide a high-strength and reliable welding method for spot welding high-strength steel and hot-formed steel, as well as for nut projection welding in the automotive manufacturing industry. Notably, nut projection welding eliminates the need for subsequent tapping of threads.
Specifically for welding a nut onto hot-formed steel sheet: The nut features projections (small raised points). During welding, these projections crush and melt, fusing the nut to the hot-formed steel sheet.
Thermal Challenge:
Hot-formed steel plates exhibit high strength, requiring greater energy for fusion welding. However, the projections (raised points) on the nuts have relatively low strength. Applying excessive pressure prematurely crushes these projections before fusion occurs, resulting in failed welds.
Solution:
This necessitates capacitor discharge (CD) spot welding technology. It delivers:
Instantaneous Energy Release: Stored electrical energy is discharged in a single, ultra-short pulse (typically 3-10 milliseconds).
High-Current Pulse: This rapid discharge generates an extremely high-intensity current pulse.
Surface Breakdown & Fusion: The intense pulse instantly breaks down the surface of the hot-formed steel and melts the nut projections simultaneously under controlled force.
Controlled Collapse & Bonding: The molten projections collapse, forging a metallurgical bond between the nut and the steel plate before excessive deformation occurs.
