Typical chemical composition (mass fraction)?
A: C≤0.15%, Mn≤0.60%, P≤0.100%, S≤0.025%; internal controls vary among steel mills, please refer to the quality certificate.
Typical mechanical properties in the annealed state?
A: Yield strength ≥130 MPa, tensile strength 270–410 MPa, elongation after fracture δ5≥28%; specific details are subject to the batch quality certificate.
Hardness grading and range?
A: Annealed S: HV≈85–110; 1/8H: HV≈95–130; 1/4H: HV≈115–150; 1/2H: HV≈135–185; H: HV≥170; Follow standards and steel mill internal controls.
Why do yield plateaus and yield elongations occur?
A: Low-carbon steel often exhibits a yield plateau after annealing, which can easily lead to Lüders bands during stamping. This can be eliminated or mitigated through leveling; a leveled state is preferable for deep-drawn parts.
What is the impact of a high yield strength ratio on stamping?
A: A high yield strength ratio increases the risk of cracking and reduces the forming limit. For complex shapes, batches with low yield strength ratios and high elongation and r/n values should be selected, or upgraded to SPCD/SPCE.