annealing stainless steel tube

kiwicar · Post by **kiwicar** » Sat Sep 06, 2008 12:27 pm

Any one know what I need to do to soften the stuff so I can expand the ends of the tube with a tube expander ? The stainless is in the form of mandrell exhaust bends and have work hardened as a result of the bending process (well I assume it must have as if you tried to bend it in this state it would shatter!!)
Mike

Seight-V8 · Post by **Seight-V8** » Sat Sep 06, 2008 4:33 pm

hiya,

We use 1089degc for stainless steel formed parts at work.

But for annealing you will need to do it in a vaccum otherwise you will end up with lots of oxide & discolouration on the surface, which can alter the grain structure of the metal.

You could stress relieve it at lower temperatures but this would not relieve 100% of the stresses.

Best maybe to talk to someone who has made some stainless exhaust and has come across this problem.

As i dont think this is something you could do at home.

scott

kiwicar · Post by **kiwicar** » Sun Sep 07, 2008 2:11 am

not somthing I can tackle here. looks like time for a long handle on the pipe expander spanner!
Mike

stevieturbo · Post by **stevieturbo** » Sun Sep 07, 2008 7:35 am

Why are you expanding it ?

Eliot · Post by **Eliot** » Sun Sep 07, 2008 11:07 am

stevieturbo wrote:Why are you expanding it ?

my thoughts too.

kiwicar · Post by **kiwicar** » Sun Sep 07, 2008 4:50 pm

so I can make a couple of slip joints in the manifolds I am building. If I make it all in one welded piece I will never get it off again

. I am doing a full cross over job 8 into 4 into2 into1 into 2.
Mike

stevieturbo · Post by **stevieturbo** » Sun Sep 07, 2008 8:17 pm

Get flanges cut and bolt it together.

Slip joints are one massive PITA

Ian Anderson · Post by **Ian Anderson** » Mon Sep 08, 2008 8:00 am

Cross over - now you're talking but should be 4 into 1 with 2 and 3 on each side crossd over

I have slip joints and they leak
Reseal them and withing 100 miles blown the seals out again

Now they just leak a bit all the time as I'm tired of filling!

But I intend to get flanges done and a slightly longer silencer to try get on track as it's too noisy at the moment!

Ian

kiwicar · Post by **kiwicar** » Mon Sep 08, 2008 9:15 am

OK so anyone want to buy a pipe expander? flanges it is

Ian the set up is to join them into pairs firing 360 apart (ie 4 and 7) then immediatly join the paired ones to ones firing 180 relative to those, then join the resulting two into one big collector for about 6" before splitting into two to go into the silencers. It is basically like a Nascas SB" try Y collector set up but with the cross over of the cylinder banks, Oh and it all sits above the gearbox so I can boil the oil in that

.
Mike

Ian Anderson · Post by **Ian Anderson** » Mon Sep 08, 2008 9:45 am

Sounds interesting
Do you have a Before dyno sheet so you can compare to the After to see how much you gained?

An yes the heat they make is amazing!
It is definately worth having them ceramic coated as the ceramic reduces the heat lost but that will set you back about £300 - £400 for the headers and collectors.
Or Make sure you have a load of heatmat on the Exhaust side of the cover
Strangely Mild steel will reduce the heat transfer into the air around your gearbox (And probably allow you to use your (chest) expander)

Ian

kiwicar · Post by **kiwicar** » Mon Sep 08, 2008 9:59 am

Hi Ian
can't do a before/ after as I am still building the engine and car

. working on calculalations and lots of reading off hotrod/ carcraft and looking at the design of the Nascar exhausts in various places.
Mike

Eliot · Post by **Eliot** » Mon Sep 08, 2008 10:25 pm

stop messing around with fancy pipes - slap a wanging great turbo in there

kiwicar · Post by **kiwicar** » Tue Sep 09, 2008 2:18 pm

Actually a wanging great turbo in there would solve the problem of fitting in the 90 degree bend I need to do at the back of the car to be able to route the exhaust back under the car and get a silencer or two in there. Trouble is I recon I'm going to blow the cr*p out my gearbox as it is even without the trubo

.
Mike

IainB · Post by **IainB** » Tue Sep 09, 2008 3:20 pm

A nice Bullseye BW S475 can be had for under $500....brand new

I can pass you contact details if your interested

kiwicar · Post by **kiwicar** » Tue Sep 09, 2008 4:21 pm

I don't need a Bl**dy turbo I need a stronger gearbox!!!

Mike