Q: What is the typical chemical composition of SPCC (JIS G3141)?
A: C≤0.12%, Mn≤0.50%, P≤0.035%, S≤0.035%, Si≤0.05%, Fe balance; low carbon content ensures formability and weldability.
Q: What are the mechanical properties of SPCC?
A: JIS does not mandate yield strength/tensile strength/elongation requirements; SPCCT requires: tensile strength ≥270MPa, elongation ≥28%; hardness: S-state HRB 50–71, 1/2 hard HRB 74–89, hard HRB ≥85.
Q: Why is tensile strength/yield strength sometimes not guaranteed for SPCC?
A: JIS G3141 only grades hardness; tensile strength requires special marking T (SPCCT); domestic enterprise standards often supplement mechanical requirements.
Q: Does the fluctuation in the yield strength of SPCC affect processing? A: The impact is significant; fluctuations >50MPa can easily lead to inconsistent bending springback. It is recommended to use the S-state or stable batch, and annealing to stabilize the microstructure if necessary.