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Looped
11-28-2001, 12:11 PM
Does anyone know what the term “Tuffrided” means when a crankshaft is forged steel & Tuffrided? Is this a temperature-freezing name or is it an additive mixed in with the forged steel???
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Thanks,
Craig

Woodsy
11-28-2001, 01:30 PM
Looped,

Tufftrided is a heat-treatment process used to surface harden a low carbon steel. Basically the steel is immersed in a special salt bath and zapped. Tufftrided is a commercial product, but nitro-carburizing is the actual process. There are three types of Tufftride...

TUFFTRIDE® Q Salt bath nitrocarburising plus oxidative cooling Used to improve wear resistance, running properties, hot strength, corrosion resistance, fatigue strength, rolling fatigue strength and tool life.

TUFFTRIDE® QP Salt bath nitrocarburising plus oxidative cooling and mechanical polishing Used when low roughness, uniform coefficient of friction and metallic shiny surfaces are required.

TUFFTRIDE® QPQ Salt bath nitrocarburising plus oxidative cooling, mechanical polishing and oxidative post treatment Used when low roughness, low coefficient of friction, extremely high corrosion resistance, dark surfaces, attractive appearance and low light reflection are required. “Black chrome” appearance.

Hopes this helps you...

Woodsy :D

Looped
11-28-2001, 02:02 PM
Thanks Woodsy!

Are their places around here that do it on reground cranks or is this done only when the cranks are first made before the chroming and all?

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Woodsy
11-28-2001, 02:24 PM
Looped,

I would call around... I would think they would have to rockwell test (hardness) the crank before they treat it just to be sure it hasn't already been hardened. I would give H&R Racing Engines a call 978-692-1611 in Westford, they might be better able to advise you on this.

Woodsy

PS: I love the animated flag gif... I need that for my avatar!! :D

Klingon
11-28-2001, 09:34 PM
Tuffriding is a commerical name for a process called nitriding. Nitriding is a surface treatment that can harden the surface of the metal to several Rockwell points above chrome. If done long enough it can acheive a depth of .015", deep enough to withstand the first regrind of a crank, usually .010". The first reason to do this is to give the crank a good wearing surface, I have seen cranks in the shop that have gone 100,000+ miles and look perfect. Also keep in mind that these motors are running 70-100 psi oil pressure. The other reason is strength. Porsche sport motors that are running steel rods have them nitrited. This process forms a hardened "shell" on the rod and doing so makes it a stronger unit. By just hardeneding the outer surface it retains some of the advantages of the softer but more forgiving inner core that can take some of the flexing with out cracking/breaking. This is simular to what shot peening a rod does. Most good crank shops have good place that can do the nitriding for them.
Alan :D