Paul, Is there any effect on the metallurgy of the liner due to the
heating during the welding process that could adversely affect the apex seal
sealing and or wear? Joe Berki Limo EZ I can't detect any. The apex seals
cannot seal in this area as they are wide open on both sides as they
pass over the intake port. That is why the differential pressure from
chamber to chamber is zero in this area. Tig welding is a very
localized heating process. Obviously the steel must be heated to
melting temperature but a few hundreds of an inch away the aluminum is
not melted. This process flies in the face of intuition. The metal has
a worse time of it down by the peripheral exhaust ports where the heat
can be 1800 F for thousands of hours. Paul Lamar ...No rotor no motor.
Paul, I do question the fact that the welding process causes the inclusion of chromimum. The hard chrome process which coats the liner will be fused into the weld. This could cause a brittle weld. There may not be enough inclusion to be a big factor but very small amounts can change the metalurgy. I'm not chemically astute enough to tell you how much might be needed to cause a problem. Bill Jepson  Yes it changes the 304 Stainless Steel or mild steel to chrome molly :) If you start with 4130 tubes you get chrome chrome molly :)
What do you get when you weld mild steel to SS?
Answer: No problems:)
What do you get when you weld mild steel to 4130?
Answer: No problems:)
There is near zero load on the tube and it never gets over 200 F if that.
We are not talking about stressing the part to 65,000 psi. It will be lucky to see 600 psi.
Paul Lamar ...No rotor no motor.
Paul, I'm sure when they put the Chromimum in Chrome Moly they do it
in a vacuum remelt furnace. Even when you tig a weld there is
signifigant
chance of oxidation. I may be being overly fretful, but I am always
concerned with the "unintended consequences" factor of a mod like that.
I would suggest that the tube be trimmed back from the face of the
housing slightly and that the weld be more of a tiny fillet. I know the
material is thin, so I don't suggest a lot. .020-.030 using a small
amount
of filler if needed.
Bill Jepson


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