1.What are the microstructure and core properties of special cold-rolled precision stamping steel?
Spherical carbides (cementite) are small, uniform, and spherical in distribution, and the spheroidization rate is usually required to be ≥90%, or even ≥98%.
It has good plasticity, high strength, low and stable yield strength ratio, and uniform performance throughout the steel coil.
2.What are the microstructure and core properties of ordinary cold-rolled coils?
Carbides may be in the form of lamellar or network structures, which can easily become the initiation point of cracks during stamping.
Its performance is primarily designed for general forming and has not been specifically optimized for the demanding conditions of fine blanking.
3.What kind of cold-rolled coils are suitable for fine stamping?
Specialized fine-stamping steel grades: Steel mills have specially developed series of fine-stamping steel. For example:
Carbon steel: such as C75S, SAE1074, 50Mn, 65Mn, etc.
Alloy steel: such as special grades containing elements like Cr, Mn, Ti, etc., to meet the needs of higher strength or more complex parts.
Low-carbon steel: such as the DC01-C series (DC01-C390, DC01-C590, etc.), these are grades explicitly marked as "fine-stamping material" or "fine-stamping steel for cold forming," and their performance indicators (such as n-value, r-value) have been specially designed and certified.
4.What is the special end-to-end production process?
Precise composition design: Strict control of the content of elements such as C, Mn, Cr, and Si ensures hardenability and final performance.
Crucial spheroidizing annealing: This is the core step that imparts superior properties to fine-stamped steel. Through long-duration (e.g., ≥480 minutes) and specific temperature (e.g., 700-750℃) bell-type annealing, carbides are transformed into uniform spherical shapes.
High-precision dimensional control: High-end fine-stamped parts require extremely small thickness deviations in cold-rolled fine-stamped steel (e.g., ≤10µm) to ensure stable stamping gaps.
Definitive thickness application range: Fine-stamping is not only suitable for thin plates. Through special production processes, the thickness of cold-rolled fine-stamped steel can reach 12.5 mm, directly replacing heavy parts that traditionally require machining from solid bars, significantly reducing costs.
5.What are the conclusions and recommendations?
If you are a trader or processor: When procuring cold-rolled coils for fine blanking, do not order only ordinary cold-rolled coils. You must specify "fine blanking steel" from the steel mill, providing a specific grade (e.g., C75S) and performance requirements (e.g., spheroidization rate, yield strength range).
If you are a technician: When designing fine blanking parts or selecting materials, you should refer to the relevant material standards (e.g., specific grades of EN 10139, EN 10130) or confirm with the steel mill's technical department to ensure that the microstructure and mechanical properties of the selected cold-rolled coils fully meet the requirements of the fine blanking process.