Deep etching on steel

A. ferric chloride naturally reduces to ferrous chloride as the process takes place. You may notice your etchant is efficient initially, then its performance fails. It is important to keep the percent ferric chloride high and is easiest to do this with ORP control feeding oxidizer to your etchant. We find a sodium chlorate based product amenable to our process. In addition to the ferric chloride content, the acid content is also key, as this will keep your metals in solution. These prolong bath life. If you are in a production setting, it is imperative to implement regeneration, or the cost of this process is high.

A. Hi,

I think the problem lies with the concentration of the ferric chloride and also please check the timing of the process in the chemicals. ferric chloride is used in etching processes (about 3 minutes) to clean away impurities off the metal parts prior to inspection in some processes in the industry.

Regards,

A. Some solutions for SS etching:

460 gms iron chloride/ 1 lit water, 50 °C temp.
or
250-300 gms nitric acid + 250-300 gms HCl/1 lit water,38 °C temp.
or
350 gms iron nitrate/1 lit water, 50 °C temp.

A. I suspect your problem is with the ferric chloride conditions. For stainless steels it should be between about 35 and 48 baumé and between 35 and 55 C. According to some work by David Allen on the optimum etching of 304, it should be 32 baumé and 50 °C - this gives an etching rate of 38um/min. You need to keep the Fe(II) levels down and if you want to use some of the suggestions above, they may help too.

A. Hi, S. As a regular reader you may know that the etching of different materials is done with different solutions, and that we have threads about etching each of these. If you are speaking of etching as a way of "engraving" patterns, rather than etching for surface texture or for metallographic examination, though, a fairly versatile approach that will be applicable to most of these metals is Cermark laser etching. The marking solution is put on the part, a laser reacts it, turning the desired areas black, and then the marking solution is washed off.

Good luck.

Regards,

A. Hi again, cousin.

The information you seek seems to me to already be on this page then. If there is something that you didn't understand, please try to express your question in terms of the answers already offered, because I am not seeing the difference between your question and the previous questions which were answered, and going in circles won't move us forward :-)

Thanks and Regards,

A. Sure, no problem. HCl and HNO3 are for regular steel. FeCl3 for SST and Nital for m.s.

A. Johnson: ferrous chloride will not work. What you want is ferric chloride ⇦ this on eBay or Amazon [affil links] .

A. ferric chloride is the only practical way to deep etch most stainless steels.
However simple immersion will not work. It is usual practice to spray the solution.