Hard Chrome Anodes? STEEL?

In my experience, steel anodes have their use but can be problematic.  The main problem stems from the fact that the steel is consumed during the process.  The steel is not inert like the tin/lead anodes.  As the current is passed through the steel, it dissolves the steel.  This can cause contamination of the chrome bath if used frequently.  Also, as the steel is being consumed, the dimensions of the anode are changing.  The anode gets smaller, and presumedly farther from the part, which limits the amount of current it can pass (without modifying the voltage).  It is also likely that the steel piece will become deformed and can cause uneven plating.  In rare cases, it can also become so thin that it will bend under its own weight and touch the work piece, causing a short.

I've used steel anodes before, but only until I could get something better.  In a job shop, you may not have that luxury.  But then again, you should expect to have more problems than a captive shop while running virtually every conceivable part under the sun.

I'd be pretty impressed if you could remove dissolved iron with an electromagnet like this one.  People use a similar principle when they filter their chrome with a porous pot, but there the contaminated solution is contained. 

The dissolved steel anode won't create iron filings or small pieces, but instead it will dissolve as iron ions (Fe+2, Fe+3) in the bath.  These cations might be attracted to an electromagnet, but can and will quickly dissociate away.

Oh!!! This is getting good!! I am typing and Dustin's lighting up the board too!! It is going to be a Happy New Year after all!!!!!

My thoughts exactly on the dissolved iron contaminants, filtration for the insoluble(s) and porous pot for the "tri-" and other "stuff". But most of all, if you going to "knowingly" contaminate your bath, and it makes good sense to do so from a costs perspective. You need to know what thresholds you can remain productive with, meaning, buy yourself a porous pot, be aware of the iron levels in your bath and re-consider the use of steel vs. lead/tin, lead or other aux. anodes.

Peace.

It will vary depending upon who you talk to.  I've got more experience with decorative chrome where 2opg of metallic contamination (zinc, copper, nickel, iron, lead, etc) is generally considered on the high end and as you get higher than 3 or 4opg your plating range gets much smaller.  For hard chrome, this is much less of a problem due to the (usually) lower chrome/sulfate ratio and (usually) higher current densities.

To directly answer your question: it is up to the plater to determine what levels are acceptable.  As your metallic contamination levels grow, the chrome deposit will become more impure, leading to potential failures in the field.  Personally, I'd invest in a porous pot (or multiple pots) to maintain the metallics less than 2opg total.

Lead anodes form an insoluble lead peroxide film on their surface when a current is applied.  This is the "chocolate brown" film that you sometimes hear described.  This layer also protects the underlying lead metal from attack from the chrome bath.  As the current is removed and the anodes are allowed to sit in the bath, the peroxide layer breaks down.  The lead is then exposed to the chrome bath.  Lead chromates can form, which are inhibitors to current flow.  They can form a crusty, flaky deposit that is yellow in color and can be very stubborn to remove.  There are specific descalers for this problem available from your chemical supplier.  Recent research has shown that an excess of mist-suppressant can increase the problem of the chromate scale.

The tin in the anodes makes the anodes more rigid.  Over time, a pure lead anode will bend in the direction toward the work piece.  Old school platers just rotated their anodes or hammered them back into shape.  Now, tin and or antimony is used at around 5-8% to prevent or minimize this. 

Steel/iron anodes will not form the protective peroxide layer and are therefore subject to rapid attack by the chrome bath.