#1 original 304 1/4x20 bolt

This is the 304 ss bolt before the start of the experiment

#2

Another shot of bolt before starting

#3 start

Start of experiment, bolt submerged in HCl, time 0hr

#4 close up submerge

Close up of submerged bolt

#5 15 minutes

15 minutes after bolt was submerged in Hydrochloric Acid

#6 15 minute close-up

Close-up of bolt 15 minutes after submersion

#7 12 hours later

12 hours later after submersion of 304 s/s bolt in HCl

#7 solution

This shows the resultant green colored solution created 12 hours after the bolt was submerged

#8 residue

Close-up of residue 12 hours after bolt submersion

#9 corroded bolt

12 hours after submersion, the bolt is severely corroded, a black "smut" has coated the bolt.

#10 comparison

Corroded bolt compared side by side to an indentical original un-treated 304 s/s bolt

#11 comparison

Corroded bolt compared side by side to an indentical original un-treated 304 s/s bolt

#12 rinsed bolt

Here is the resulting bolt 12 hours after submersion in HCl and rinsed with clean water. Note: "smut" was rubbed off by water and handling. Dull grey finish.

#13 Electropolished Bolt

Bolt after electropolishing, all black and grey discoloration removed and passive layer re-generated. While reduced in size by the corrosion effect of the HCl. The bolt now has a higher corrosion resistance than a brand new un-treated bolt. Note the bright and smooth surface created by electropolishing.

#14 comparison

Comparitive shot of the electropolished bolt to an un-treated identical original. Note the difference is size due to the corrosive nature of Hydrochloric Acid on 304 s/s.

#15 comparison

#16 compare

# 17, Hydrochloric Acid, Muratic Acid, HCl

Pic of the Hydrochloric Acid used for the experiment