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Mitsu turbine housings. Cast Steel?

E

EivlEvo

Active member
Joined
Sep 11, 2012
Squad.

I thought I remembered reading that the Mitsu/Volvo turbine housings (exhaust side) were all cast steel? Anyone able to confirm this?

Trying to figure out if I need to heat up the grill or just scrub and weld?
 
But these people are all suggesting that it's cast iron no? I'd wholly agree there and my rig setup would be way different. But if the housings are cast steel then maybe I can dig into it...

I'm really probably way overthinking this. I have the angled flange 19T and am trying to sort out the 4th bolt. I was intending to weld a stud in there to go through the manifold and bolt from the other side. I'm mostly worrying about compression loads... I suspect the three usable studs would be plenty to keep the turbo locked in place no?
 
Why take the risk, just heat it up and weld it. I've welded a vband to a mitsu housing using 309L filler. Preheat and slow cool down did the trick. It welded like cast iron.
 
Take a grinder to it and watch the sparks. I've welded to them both with and without heat, and haven't had an issue...although I swap stuff pretty frequently so I can't say conclusively how long it would last without preheat.
 
The turbine housing and the exhaust manifold are cast steel. I learned this when trying to get a broken stud removed from the turbine housing. The cast steel was harder than a tap.
 
lummert said:
The turbine housing and the exhaust manifold are cast steel. I learned this when trying to get a broken stud removed from the turbine housing. The cast steel was harder than a tap.
Click to expand...

I personally wouldn't bet a whole nickel on that...Turbine housing for hi-po allpications have a GOOD chance of being cast in "ni-resist" iron alloy..

Cast steel is a bitch to cast--expensive and more viscous meaning hard to pour into complicated shapes--like turbine housings---and thinner parts will cool rapidly leading to internal stresses...
It has its place but think "impact" ---where higher strength and "toughness" is needed..

https://www.esterer-giesserei.de/en/services/materials/cast-steel-gsgx/

Ni-resist is used in some hi-po applications for turbine housing because while it has high--maybe 20%+ nickle ----it is still cast iron base alloy which means dirt cheap..

As for manifolds..boring ordinary cast iron.. cost and lack of need for impact resistance..

Ni-Resist / austenitic cast iron (EN-GJLA/EN-GJSA)
High resistance to corrosion and not magnetisable
If one needs high resistance to corrosion, e.g. against the influences of sea water or against alkaline mediums, then the material Ni-Resist is highly suitable.
Further Ni-Resist, also called austenitic cast iron, is non-scaling, resistant to erosion and is not magnetisable.

The reason for these characteristics is the high share of nickel of more than 20 per cent.

Thus, Ni-Resist is often used in the areas of food industry, shipbuilding and medical engineering.
Examples for construction parts made of this material are pumps, valves, furnace parts, sockets, piston rings, compressors,------> turbo-charger casings<-------, exhaust manifolds. <----(maybe)

Details on the physical values of the materials we produce from Ni-Resist (austenitic cast iron) are available in the data sheet Ni-Resist/austenitic cast iron (EN-GJSA).pdf, which is available for you as a Download-file.
Click to expand...

Sure iron might seem weird after heating and cooling and oxidizing...but I think its the oxidizing that makes the surface so hard.

And this is not merely opinion, I spent several whole days talking across the desk from heads of several turbocharge manufacturers discussing manufacture of my favorite turbine housing. THEY brought up Ni-resist before I got to it in my discussion notes.
 
EivlEvo said:
Squad.

I thought I remembered reading that the Mitsu/Volvo turbine housings (exhaust side) were all cast steel? Anyone able to confirm this?

Trying to figure out if I need to heat up the grill or just scrub and weld?
Click to expand...

Cast iron is generally less than 2% weight Carbon, and cast steels are generally anything over that. 2-3% carbon by weight is the start of "cast steels".

To answer your questions, the turbine housing is most likely cast steel of some sort. You will want to still preheat it, and probably post weld heat it and let it cool down slowly. You may get lucky (and a lot of people have) or you may not. Castings can often have areas with large amounts of carbon in them (carbon segregation), and these carbon rich areas are much more prone to cracking from mechanical loads or welding. The carbon rich areas are also REALLY hard, and can be near impossible to drill/cut through unless using abrasives, EDM, or carbide tooling.

So... clean it up and remove and rust/scale from the weld area with an abrasive wheel (not just a wires wheel!). Heat it up to 400+ degrees, and use low carbon rod such as 309L. BTW, that's what makes 309L so good at welding cast materials... low carbon content. Then heat it back up again to a uniform temp and keep it there for a while. Then wrap it in a fiberglass welding blanket or bury it in a large bucket of sand to cool it slowly and reduce the chances of it cracking.

Fun time in the garage if your bored: You can actually take a steel/iron casting and polish the surface, and then use an etchant (naval jelly works) to see the large areas of carbon in the metal (if there are any). There are different etchants for showing different elements and microstructures. It's pretty cool. You can also use it to see weld penetration. There's a cool write up on it here: http://www.weldingtipsandtricks.com/macro-etch.html

The reason that cast iron/steels get harder on the surface is carbon enrichment when the material is at an elevated temperature, a "natural" way of carburizing/case hardening. "Carbon migration" is another term that's used to describe this.

I haven't heard of Ni-Resist before, so I did some searching and found this interesting PDF with info: https://www.nickelinstitute.org/Tec...ionsofNi_ResistandDuctileNi_ResistAlloys.aspx

On page 19 they have a picture of some turbine housings with the material they were cast in (D-2 and D-5s). If you scroll on down to page 22, you'll see that the C Max (carbon max) is 3% and 2.3%, placing them as "Cast Steels".
Pretty interesting paper.
 
Culberro brings some good info to this thread. Especially regarding the location of high carbon areas in the casting (of which I was unaware).

I knew that welding Mitsubishi housings was a similar afair to welding cast iron. <strike>I was not aware of the</strike> I apparently have forgotten that there is a carbon content distinction between cast iron and cast steel.

My only concern is that I was taught (in materials Engineering class) that quenching was supposed to be followed by tempering for cast iron and cast steels. Is this one of those areas where real world application (i.e. welding already cast parts vs casting a new piece) deviates from textbook knowledge?

---

Also, I learned something new from Mr. Vanlandingham :cheers:
 
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culberro said:
I haven't heard of Ni-Resist before, so with info:
Click to expand...

Then perhaps, rather than talk about what you "imagine is likely", you should talk directly with the people who make turbochargers?

https://garrett.honeywell.com/upgradegbh/contact-us/
Click to expand...

Or even easier
https://www.turbotechnics.com/contact/

Contact details
Area Contact
Enquiries: enquiries@turbotechnics.com
+ 44 1604 705050
Click to expand...

They were very helpful when I spoke with them..and the guy who was competition liason gave me the direct line to a colleague who worked under him when they at Garrett UK when were developing the marelous TB3403

Or you could just keep on out-googling people and then telling us what you have figured out.
 
John V said:
Thank you..I thought this was common knowledge.:omg:
Click to expand...

I've just started welding (at 42 yrs old...), so I am learning a lot.

Being an amateur, I do not have years of accumulated knowledge in this area.

I've only had the pleasure of above average machine shops doing work for me and entertaining my endless barrage of questions ;-)
 
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John V said:
Then perhaps, rather than talk about what you "imagine is likely", you should talk directly with the people who make turbochargers?



Or even easier


They were very helpful when I spoke with them..and the guy who was competition liason gave me the direct line to a colleague who worked under him when they at Garrett UK when were developing the marelous TB3403

Or you could just keep on out-googling people and then telling us what you have figured out.
Click to expand...

Haha, no googling required except to find an article on etching for carbon and on the Ni-Resist, and that was just to find out the composition. But I’m sure you knew what that was already...

My experience in steel and iron castings comes from me being a design engineer and testing engineer at a steel foundry for 3 years. Working primarily in prototyping and developing new steel castings.
 
I mig welded a 2.5" to 3" v band adapter directly to my China bay/emusa turbo with 7170?? wire whatever is normal wire for carbon steel and it hasn't fallen off or cracked yet. I can't remember if I preheated it but I think I did.
 
VB242 said:
I mig welded a 2.5" to 3" v band adapter directly to my China bay/emusa turbo with 7170?? wire whatever is normal wire for carbon steel and it hasn't fallen off or cracked yet. I can't remember if I preheated it but I think I did.
Click to expand...

There are plenty of these cases out there. But it's less about whether yours cracked and more about whether it could crack I guess.

As many knowledge bases point out... a lot comes down to "it won't crack if you hit this spot in the metal and it's this metallic content, but if it's THIS metallic content, it might crack"

So to speak.
 
John V said:
I personally wouldn't bet a whole nickel on that...Turbine housing for hi-po allpications have a GOOD chance of being cast in "ni-resist" iron alloy..

Cast steel is a bitch to cast--expensive and more viscous meaning hard to pour into complicated shapes--like turbine housings---and thinner parts will cool rapidly leading to internal stresses...
It has its place but think "impact" ---where higher strength and "toughness" is needed..

https://www.esterer-giesserei.de/en/services/materials/cast-steel-gsgx/

Ni-resist is used in some hi-po applications for turbine housing because while it has high--maybe 20%+ nickle ----it is still cast iron base alloy which means dirt cheap..

As for manifolds..boring ordinary cast iron.. cost and lack of need for impact resistance..



Sure iron might seem weird after heating and cooling and oxidizing...but I think its the oxidizing that makes the surface so hard.

And this is not merely opinion, I spent several whole days talking across the desk from heads of several turbocharge manufacturers discussing manufacture of my favorite turbine housing. THEY brought up Ni-resist before I got to it in my discussion notes.
Click to expand...

This is a TD05-12B with -89 manifold.
 
lummert said:
The turbine housing and the exhaust manifold are cast steel. I learned this when trying to get a broken stud removed from the turbine housing. The cast steel was harder than a tap.
Click to expand...

This is my finding on a TD05-12b and -89 exhaust manifold. later models may be different.
 
Id also say its most likely a high nickel content based cast iron over a cast steel. no reason to use steel over a nickel-iron for this kind of app.

The alloy John mentioned is very popular in the industry for these types of applications.
 
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