Lead Brass
Purpose：Observe
the microstructure of lead brass. Lead brass exhibits excellent machinability,
mechanical properties, and resistance to cold/hot pressure processing, making
it ideal for soldering and welding. It is widely used in structural components
such as screws, washers, gaskets, bushings, nuts, and nozzles. Samples undergo
cutting (TableCut200), mounting (FLEX-PRESS fully automatic modular hot
mounting machine), grinding/polishing (Alpha610), and etching with a ferric
chloride-hydrochloric acid aqueous solution to observe the microstructure (MN80
metallographic microscope).
Basic
Guide：
Cutting：1.Use
a silicon carbide cutting wheel. Refer to the Trojan Cutting Guide for specific models.
2.Select
pulse mode for cutting, with a recommended maximum cutting speed ≤0.25 mm/s.
Mounting：Use
high-edge-retention cold/hot mounting resin.
Grinding：1.Begin
with P400 silicon carbide sandpaper/lapping films/diamond grinding discs until
the sample surface is flat
and cutting damage is fully removed. 2.Continue fine grinding with P800, P2000
sandpaper or a POS disc + 9 µm diamond polishing suspension.
3.Clean
the sample, sample holder, and hands after each grinding step.
Polishing：1.Clean
the polishing cloth, sample holder, and hands before polishing. Repeat cleaning
after each step.
2.Do
not mix polishing disks with different
abrasive particle sizes.
3.Rinse
the sample surface with alcohol and dry with a blower to remove water residue.
4.After
each polishing step, inspect under a metallographic microscope to ensure
scratch size matches the abrasive grit and direction is random.
5.Clean
polishing cloths with running water and a soft brush after use, then air-dry.
6.Dedicate
polishing cloths used for lead brass exclusively to such samples.
7.If
surface protrusions remain after polishing, regrind and repolish while reducing
polishing time with silica + ZN suspension.
