Alternative coating to Titanium Nitride? 2

[ManOfSteel8357]

Hi All,

I have a rather complex part that has a long cylindrical protrusion in the shape of a drill bit. This drill bit section will be used to drill through thick sections of steel when the part is in service. Currently, the part is made of 1022 and case hardened to 50-53 with an effective case depth of 0.009". We are exploring the possibility of applying a ceramic coating to the drill bit portion in order to increase the drilling capabilities of the tip. It was suggested that we use a titanium nitride coating, however due to the unusual shape of the part and the high volume needed, this does not appear to be a feasible approach (titanium nitride coating requires individual fixturing in order to apply the electrical arc, and this can be costly). Is there a ceramic coating that we can use that can be applied in batch? Ideally we are looking for a coating that will give us a hardness anywhere between 70-90 HRC. At this point, it doenst matter if the coating is applied to the entire part if the process is done in batch (such as dipping), since this will decrease cost and not require fixturing. Any ideas would be greatly appreciated at this point.

Thanks,
Steel

 

[KENAT]

Look into DLC (Diamond Like Coating).

I can't remember (and may not have known enough originally) if it addresses all your points but might be worth some time investigating.

There are different DLC processes, and flavors of coating so you may need to look more than one place.

We've talked to Sulzer Metco a few times, but it hasn't gone anywhere yet.

http://www.sulzer.com/en/Products-and-Services/Coating-Services/DLC-Coatings

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[Maui]

PVD coatings such as TiN are not a practical option for your application - the required temperatures are in the neighborhood of 930 F, which would be too high for 1022. If you attempted to PVD coat one of your tools the case would temper back below your aim hardness range. A diamond like coating (DLC) probably wouldn't hold up well if you are using this tool to drill into ferrous based alloys such as steel, although they could work well if you were drilling into a different material such as aluminum.

What prompted the original investigation into coatings? How exactly have the parts not been performing to expectations? Are the tools simply wearing out too quickly, or are they breaking?

Maui

http://www.EngineeringMetallurgy.com

 

[ManOfSteel8357]

Thanks for the comments Maui and kenat. To answer your question Maui, the issue isn't wearing out or breaking of the bit, but it's more a function of speed. The competitors part is able to drill through 1/4" steel plates much quicker than our part, and also requires less load behind the drill. I know that drill through speed is a function of other variables not just tip hardness, but we are looking into researching new ways to make our product better. Another point of interest, these parts only need to drill into place once and then they are set, so wear and durability isnt necessarily a hug deal. That being said, do you think DLC could be a viable option? Is this relatively comparable in price to say, a heat treat process?

 

[Maui]

Based on what you described, DLC may be a viable option. The cost depends in part on how complicated it is to coat your components, and the process that is ultimately selected. It may be worthwhile to contact a qualified supplier and request a quote.

Maui

http://www.EngineeringMetallurgy.com

 

[ornerynorsk]

Sounds like toolbit geometry is worth investigating.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[TVP]

I agree with ornerynorsk, you should investigate optimizing the tool geometry for your application. Any chance you could split this into multiple pieces so that the drill section could be made out of a proper tool material (HSS, cemented carbide, etc.)?