Material of stock headers and x-pipe: Incoloy 800.
04-03-2013, 03:26 AM
#16
Racer
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Material engineers - what are the differences between inconel and 321? Is there a test to identify one from the other? Spark, magnetism, hardness, something easy and definitive.
Welders - surely someone has welded up a set of these headers with success. What filler rod or mig wire did you use?
Welders - surely someone has welded up a set of these headers with success. What filler rod or mig wire did you use?
04-03-2013, 03:35 AM
#17
Drifting
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I am in a boring meeting at work right now so don't have a lot of time. I suggest you read/search Inconel on Wikipedia first, then you will have a very good idea what it is and why it was invented. It is considerably different than 321 SS. As posted early, if you use Inconel 625 filler rod you will be safe, as it is compatible with most all SS.
My above statement has now been proved incorrect, I wanted to edit in case somebody read this in the future and did not make it to the end. The newer/better filler rod is alloy 50 or C22 filler rod.
My above statement has now been proved incorrect, I wanted to edit in case somebody read this in the future and did not make it to the end. The newer/better filler rod is alloy 50 or C22 filler rod.
Last edited by URG8RB8; 04-04-2013 at 12:56 AM. Reason: I was using obsolete information, getting old!
04-03-2013, 06:25 AM
#18
Burning Brakes
Thread Starter
Ok So I went and got the headers tested and this is the composition of the pipes and flanges.
Exhaust port flanges: ss304
Other flanges: Mild steel.
Heat shields: ss304
Tubes and collectors, crossover Incalloy 800 group.
The main chemical composition is
Cr (Cromium): 19.05
Fe (iron): 45.75
Ni (Nickel): 30
Monell: 0.029
Zn (Zinc): 3.79
This comes up as Incoloy 800 series alloy according to this table http://www.painc.com/chemical_composition.htm.
No wonder people have trouble repairing these once they crack They are surely assuming it is a lesser alloy and using inadeqaute cleaning and the wrong filler materials:
To make matters worse it is diffucult to work with aged components:
These are the recommended filler materials:[quote]
INCOLOY alloy 800 has good weldability by all welding processes. Material to be welded must be thoroughly clean, and the proper joint designs must be used. [...]
For (TIG) gas-tungsten-arc, gas-metal-arc, and submerged-arc welding, INCONEL Filler Metal 82 is recommended. Alloy 625 has been extensively used for welding dissimilar joints in austenitic and duplex steels. Use of this filler metal has caused problems and has been discontinued. Alloy 59 or C22 filler metals has replaced Alloy 625 as the filler of choice.
Perhaps this should be made a sticky?
Exhaust port flanges: ss304
Other flanges: Mild steel.
Heat shields: ss304
Tubes and collectors, crossover Incalloy 800 group.
The main chemical composition is
Cr (Cromium): 19.05
Fe (iron): 45.75
Ni (Nickel): 30
Monell: 0.029
Zn (Zinc): 3.79
This comes up as Incoloy 800 series alloy according to this table http://www.painc.com/chemical_composition.htm.
No wonder people have trouble repairing these once they crack They are surely assuming it is a lesser alloy and using inadeqaute cleaning and the wrong filler materials:
From TWI.co.uk http://www.twi.co.uk/technical-knowl...alloys-part-1/
The most serious cracking problem with nickel alloys is hot cracking in either the weld metal or close to the fusion line in the HAZ (heat affected zone) with the latter being the more frequent. Both weld metal and HAZ cracking are generally the result of contamination by grease, oil, dirt, etc left behind following inadequate cleaning;. [...] .Machining or vigorous stainless steel wire brushing followed by thorough degreasing with a suitable solvent is necessary prior to welding, with the welding taking place within about eight hours to reduce the risk of contamination. Any heat treatment must be carried out using sulphur-free fuel or by using electric furnaces. Components that have been in service and require weld repair may need to be ground or machined prior to degreasing to remove any contaminants that have become embedded in the surface in or adjacent to the weld repair area. Remember that if mechanical wire brushing is carried out AFTER the degreasing operation or during welding the compressed air from air powered tools contains both moisture and oil and the cleaned surfaces may be therefore be re-contaminated.
Porosity can be a problem with the nickel alloys, the main culprit being nitrogen. As little as 0.025% nitrogen will form pores in the solidifying weld metal. Quite light draughts are capable of disrupting the gas shield and atmospheric contamination will occur resulting in porosity. Care must be taken to ensure that the weld area is sufficiently protected and this is particularly relevant in site welding applications. [...G]as purity and the efficiency of the gas shield must be as good as possible. It goes without saying that gas purging of the root is essential when depositing a TIG root pass. [...] A small amount of hydrogen (up to 10%) added to the argon shield gas has been found to reduce the problem.
The most serious cracking problem with nickel alloys is hot cracking in either the weld metal or close to the fusion line in the HAZ (heat affected zone) with the latter being the more frequent. Both weld metal and HAZ cracking are generally the result of contamination by grease, oil, dirt, etc left behind following inadequate cleaning;. [...] .Machining or vigorous stainless steel wire brushing followed by thorough degreasing with a suitable solvent is necessary prior to welding, with the welding taking place within about eight hours to reduce the risk of contamination. Any heat treatment must be carried out using sulphur-free fuel or by using electric furnaces. Components that have been in service and require weld repair may need to be ground or machined prior to degreasing to remove any contaminants that have become embedded in the surface in or adjacent to the weld repair area. Remember that if mechanical wire brushing is carried out AFTER the degreasing operation or during welding the compressed air from air powered tools contains both moisture and oil and the cleaned surfaces may be therefore be re-contaminated.
Porosity can be a problem with the nickel alloys, the main culprit being nitrogen. As little as 0.025% nitrogen will form pores in the solidifying weld metal. Quite light draughts are capable of disrupting the gas shield and atmospheric contamination will occur resulting in porosity. Care must be taken to ensure that the weld area is sufficiently protected and this is particularly relevant in site welding applications. [...G]as purity and the efficiency of the gas shield must be as good as possible. It goes without saying that gas purging of the root is essential when depositing a TIG root pass. [...] A small amount of hydrogen (up to 10%) added to the argon shield gas has been found to reduce the problem.
The sensitivity of the age hardened alloy to cracking causes problems when attempts are made to repair items, particularly when these have been in high temperature service and additional precipitation on the grain boundaries has occurred.
Little can be done to overcome this problem apart from a full solution heat treatment but this is often not possible with a fully fabricated component. If repair is to be attempted, small weld beads and controlled low heat input welds are recommended.
Little can be done to overcome this problem apart from a full solution heat treatment but this is often not possible with a fully fabricated component. If repair is to be attempted, small weld beads and controlled low heat input welds are recommended.
INCOLOY alloy 800 has good weldability by all welding processes. Material to be welded must be thoroughly clean, and the proper joint designs must be used. [...]
For (TIG) gas-tungsten-arc, gas-metal-arc, and submerged-arc welding, INCONEL Filler Metal 82 is recommended. Alloy 625 has been extensively used for welding dissimilar joints in austenitic and duplex steels. Use of this filler metal has caused problems and has been discontinued. Alloy 59 or C22 filler metals has replaced Alloy 625 as the filler of choice.
Perhaps this should be made a sticky?
Last edited by bebbetufs; 04-03-2013 at 07:20 AM.
04-03-2013, 07:40 AM
#19
Rennlist Member
Hey, great work and thanks for posting this. Very interesting!
04-03-2013, 07:56 AM
#20
Drifting
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Very nice, good job on the research! Interesting find on not using 625 filler rod anymore also! Yes, sticky is in order. Very valuable information here.
04-03-2013, 11:33 AM
#22
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Wow, I'm surprised Porsche went to the trouble and expense of using inconel.
My welding advice in another thread is wrong then.
My welding advice in another thread is wrong then.
04-03-2013, 03:44 PM
#23
Burning Brakes
I had heard this before and it probably goes a long way to explaining the cost of a factory replacement set of headers and crossover which is probably something in the region of $4,000 if my pounds to dollars conversion is right. I went through 4 sets of used headers before I found a mint set with a matching crossover that was not warped and had no cracks.
04-03-2013, 04:52 PM
#24
Burning Brakes
Thread Starter
That is not an option for me. I can't have 4 set sent across the pond only to find all of them cracked. I guess I must learn to repair them myself when mine crack from all the bending I subjected them to to make them match the outlet ports.
04-03-2013, 05:55 PM
#26
Burning Brakes
I am sure you are right there, I was very patient and I guess good used headers will be very rare in Norway.
04-03-2013, 10:22 PM
#27
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WOW. I guess they are. That explains the weird skin on the puddles I was making with the Tig Welder. This furthered my readings into thinking that they actually might be Inconel. But that was silly thinking and there was no way they would be made out of this. I guess there was a way. I used stainless rod. a lot of it. It seemed to hold up.
04-03-2013, 10:37 PM
#28
Drifting
Besides Robstah there is some great info in this thread.
Sean
04-03-2013, 11:02 PM
#29
Rennlist Member
[quote=bebbetufs;10355093]Ok So I went and got the headers tested and this is the composition of the pipes and flanges.
Exhaust port flanges: ss304
Other flanges: Mild steel.
Heat shields: ss304
Tubes and collectors, crossover Incalloy 800 group.
The main chemical composition is
Cr (Cromium): 19.05
Fe (iron): 45.75
Ni (Nickel): 30
Monell: 0.029
Zn (Zinc): 3.79
This comes up as Incoloy 800 series alloy according to this table http://www.painc.com/chemical_composition.htm.
No wonder people have trouble repairing these once they crack They are surely assuming it is a lesser alloy and using inadeqaute cleaning and the wrong filler materials:
To make matters worse it is diffucult to work with aged components:
These are the recommended filler materials:
Just saved this in my off-line info! Thank You!
Exhaust port flanges: ss304
Other flanges: Mild steel.
Heat shields: ss304
Tubes and collectors, crossover Incalloy 800 group.
The main chemical composition is
Cr (Cromium): 19.05
Fe (iron): 45.75
Ni (Nickel): 30
Monell: 0.029
Zn (Zinc): 3.79
This comes up as Incoloy 800 series alloy according to this table http://www.painc.com/chemical_composition.htm.
No wonder people have trouble repairing these once they crack They are surely assuming it is a lesser alloy and using inadeqaute cleaning and the wrong filler materials:
To make matters worse it is diffucult to work with aged components:
These are the recommended filler materials:
INCOLOY alloy 800 has good weldability by all welding processes. Material to be welded must be thoroughly clean, and the proper joint designs must be used. [...]
For (TIG) gas-tungsten-arc, gas-metal-arc, and submerged-arc welding, INCONEL Filler Metal 82 is recommended. Alloy 625 has been extensively used for welding dissimilar joints in austenitic and duplex steels. Use of this filler metal has caused problems and has been discontinued. Alloy 59 or C22 filler metals has replaced Alloy 625 as the filler of choice.
Perhaps this should be made a sticky?
For (TIG) gas-tungsten-arc, gas-metal-arc, and submerged-arc welding, INCONEL Filler Metal 82 is recommended. Alloy 625 has been extensively used for welding dissimilar joints in austenitic and duplex steels. Use of this filler metal has caused problems and has been discontinued. Alloy 59 or C22 filler metals has replaced Alloy 625 as the filler of choice.
Perhaps this should be made a sticky?