About the chemical composition, because factory worry about that it is not totally fit to your custom’s request and cause troubles.
So, they didn’t write it down.
Could you please give me your request, and let me write down?
HG: Qualified
JY: Mechanical Occlusion
PT: General Purpose
FA: General Precision
FB: Higher Precision
FC: Advanced Precision
O: Oiled,
CF-Chromium Free Passivation
R: Organic Coating,
C: Chromate Passivation
CFO: Chromium Free Passivation and Oiled
CO: Chromate Passivation and Oiled
S: Light Zinc
Z: Zero Zinc