How do you create pitted corrosion on steel with acid?

[DSC]

Hi there,

Wondering if anyone knows how to create pitting in steel with acid as the only method I know takes about 20 years and burying steel in the ground, not very ideal so was looking towards acid as I've heard of other people using it as an oxidizing agent to create corrosion on steel but have never found the recipe or what they used to create the corrosion. I've got some phosphoric acid but the internet says that's not very good at corroding steel.

I know there's tons of acids out there so was hoping that somebody on here would know which one is best at corroding steel.

Many Thanks

 

[Bystander]

You want it in less than twenty years? Iron boilers pit fairly quickly, can't give you time to mean pit dimensions as a function of water hardness or treatments. Hibachis and other cast iron barbecue grills pit in a matter of maybe one or two seasons. What time frame are you looking to achieve? This is for antiquing, or artistic purposes?

 

[DSC]

You want it in less than twenty years? Iron boilers pit fairly quickly, can't give you time to mean pit dimensions as a function of water hardness or treatments. Hibachis and other cast iron barbecue grills pit in a matter of maybe one or two seasons. What time frame are you looking to achieve? This is for antiquing, or artistic purposes?

More antiquing than artistic and was hoping for the steel to pit as quickly as possible, ideally a week as it'll be on multiple objects but can be between a month or two, depending on how many objects are going at the same time.

 

[Borek]

Bystander is definitely right about high temperature speeding up the process. Keeping it hot, wet (preferably wet with sea or salt water) and with access to the fresh air is the most obvious approach.

I am not saying there are no faster alternatives using some more corrosive chemicals, but nothing obvious comes to mind. I mean - if you put it in the acid, effect will be different, as corrosion is not just a dissolution on the surface, it is more about electrochemical cells developing on the surface and to some effect following material structure.