TheNeedForZ Posted March 3, 2006 Share Posted March 3, 2006 I plan to produce a set of titanium piston pins. They will need surface treatment. So far I know two treatments for the ti surface, one being casidium coating, the other being titanium nitride. I know all it takes to nitride titanium is 800 degrees celsius and pure nitrogen, but I am looking for places that will do the nitriding. Thanks Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted March 8, 2006 Author Share Posted March 8, 2006 bump Quote Link to comment Share on other sites More sharing options...
MatMan Posted March 8, 2006 Share Posted March 8, 2006 Does Ti have the same shear properties as steel? IIRC, Ti is actually a "softer" metal than most low carbon, high speed steels. I undertand the nitriding process, that would make the pin more wear resistant, but I am not sure it would have a great affect on the shear properties. Quote Link to comment Share on other sites More sharing options...
AK-Z Posted March 9, 2006 Share Posted March 9, 2006 Does Ti have the same shear properties as steel? IIRC, Ti is actually a "softer" metal than most low carbon, high speed steels. I undertand the nitriding process, that would make the pin more wear resistant, but I am not sure it would have a great affect on the shear properties. That what my thought on Ti. My impression is that it iis dent resistent for the most part, but when a piece is left in an area that it has to flex, say at an edge of a table, it will flex with time and hold the shape that its been flexed. I don't think its a good idea to use TI in engine internals inless its been cryo (sp?) treated, and even then the effect of said process is only temporary dure to the heat tha it would be seeing. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted March 9, 2006 Author Share Posted March 9, 2006 I asked for places that can do nitride coating or casidium coating on titanium. Please keep the hearsay to a minimum. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted March 9, 2006 Share Posted March 9, 2006 Then why do they make titanium connecting rods? Quote Link to comment Share on other sites More sharing options...
Phantom Posted March 9, 2006 Share Posted March 9, 2006 Contact Advanced Metallurgical Technology in Ft Worth, TX. (817) 921-5100 and ask for 'Frankie'. She owns the place and has a 37 Ford coupe with a blown 454 in it, custom paint, Italian leather & chrome everywhere. She has about $100k in it. If she can't help you she'll know who can. She'll also be willing to tell you if you're on the right track or not with the process you want to perform. Tell her Bill Davis said to call. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted March 9, 2006 Author Share Posted March 9, 2006 Thanks for the info buddy! Quote Link to comment Share on other sites More sharing options...
MatMan Posted March 9, 2006 Share Posted March 9, 2006 Then why do they make titanium connecting rods? Mostly because of a mass savings. Correct me if I am wrong, but I don't believe connecting rods have a shear force applied to them, mostly axial forces. Besides, it seems everyone's on a Titanium kick these days, even with hammers (which is really not a good idea because of the tendency of Ti to spall). As for the hearesay comment, I was taught in Metallurgy that Ti is a soft metal on it's own, that's why it is normally alloyed with Vanadium and Aluminum. Sure it's strength (tensile) to weight is good, but it's shear strength is not in the same class as high speed steels. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted March 10, 2006 Author Share Posted March 10, 2006 well dr_hunt wasn't really asking "why do they make ti rods", he was just trying to make a point to AK-Z, who doesn't know titanium engine parts exists. In fact Diablo, some modern Ferrari's and Porsche GT3 all have titanium con rods, not to mention race cars. The purpose of the coating is NOT for wear resistance. It is to prevent titanium from friction welding with other metal. People that use free floating steel pins never needed any wear resistance because the pin is oiled and is free to move inside the rod and pin bosses to change the load bearing surface. Ditto for titanium wrist pins. The ti alloy I bought(in fact I won the auction just hours ago) is 6AL4V so it is not a pure element. I never said anything about making ti rods, I said I am going to make piston pins. Shear load has nothing to do with piston pins or con rods. Ti has lower shear resistance than HSS...I dunno if this is useful to me, but I'll keep that in mind. At least I learned something so thanks for that. Since you attended metallurgy, can you help me out and tell me something about 6Al4V titanium? compare it to steel that might be used in stock piston pins? Thanks Quote Link to comment Share on other sites More sharing options...
boodlefoof Posted March 10, 2006 Share Posted March 10, 2006 I don't have any experience using titanium, but looked into it briefly a few months ago while planning my spaceframe. I ultimately decided that it was too cost prohibitive to justify building a frame out of it... but here are a few things I learned. These are from memory, so may not be exactly accurate... they are also generalizations not dealing with any specific alloy in particular. Titanium conducts heat very poorly compared with other metals. It also doesn't expand and contract with heat as much as other metals. Titanium is also very corrosion resistant. The melting point for Ti is roughly 2x hotter than steel. Overall Ti is over 50% lighter than steel and is still stronger than steel. You can also MIG weld Ti. Quote Link to comment Share on other sites More sharing options...
johnc Posted March 10, 2006 Share Posted March 10, 2006 Sunbelt in Sugar Hill Georgia also sends stuff out for Nitriding: 770-932-0160 Quote Link to comment Share on other sites More sharing options...
MatMan Posted March 10, 2006 Share Posted March 10, 2006 I am not sure how a wrist pin would not encounter shear as a function of the downforce placed upon it by the piston during the power stroke, as well as the upward thrust placed upon it by the connecting rod on the power/exhaust strokes. This site doesn't mention shear, but is an excellent write-up on the alloy you wish to use. http://www.key-to-metals.com/Article86.htm This one's pretty good for steels: http://www.crucibleservice.com/eselector/general/generalpart4.html Surprisingly to me, this steel is touted as an excellent substrate for the TiAlV coating for corrosion resistance. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted March 10, 2006 Author Share Posted March 10, 2006 Thanks for the help guys Here's why I wouldn't worry about shear load : There is a gap between the rod pin boss and piston pin boss. --------|..|------------|..|-------- ----------------------------------- .piston pin . ----------------------------------- --------|..|------------|..|-------- piston........rod pin boss.....piston pin boss...........................pin boss So if the pin is overloaded, it will bend before it is sheared. Since aftermarket titanium pin makers use the "same dimension" approach without problem, I will not have problems(bending or breakage) as long as I use the same approach. Quote Link to comment Share on other sites More sharing options...
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