I removed my ~6 months old custom built exhaust system to have the coating redone, only to find out the stainless grade 18/8 bolts/nuts "galled" when I was disassembling; resulting in me having to cut several bolts. I went to Fastnal & Stafford Nut/Bolt to inquire what's best material of construction that will still provide a "bling" in my open bay. No help, except to recommend carbon steel or grade-8 black bolts. For those who have a "shiney" bolt, that stands up to heat cycles w/out risk of galling upon removal; what are you using?? Titanium, Inconel, Hastalloy, etc? And where can you buy them? I need qty = 4 at 3/8" X 1 1/4" and qty 8 at 5/16" X 1 1/4".
Thanks for advise!
exhaust & turbo flange hardware
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madmike
- Posts: 3146
- Joined: Mon Jul 24, 2006 3:11 pm
Re: exhaust & turbo flange hardware
Milk of Magnesia really works on not galling 
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63fiberbuggy
- Posts: 19
- Joined: Sat Nov 23, 2013 1:16 pm
Re: exhaust & turbo flange hardware
Got the answer from a materials engineer...Nitronic® 60 (Alloy 60)
Alloy 60 obtains its galling resistant properties from the additions of manganese and silicon. In most environments, it has better corrosion resistance than 304 Stainless. Generally, its corrosion resistance is not as good as 316 Stainless. Compared to 304 and 316 Stainless, Alloy 60’s yield strength in the annealed condition is almost double. It exhibits decent strength and maintains its anti-galling properties up to 1500° F. In some tests, Alloy 60 has outperformed more expensive cobalt alloys in wear resistance.
Alias(es)
Nitronic 60 (® Armco Inc.)
Primary Resistance
Galling
Specs
ASTM A193 Grade B8S & ASME SA193 (Bolts)
ASTM A194 & ASME SB194 Grade 8S (Nuts)
ASTM A276 (bar)
ASTM A479 (bar)
UNS S21800
W-Nr 1.7440
Typical Tensile Strength (at room temperature in KSI)
115
Typical Chemistry (% by weight)
C .008, Cr 17, Fe 62, Mn 8, Mo .75, N .01, Ni 8.5, Si 4
Alloy 60 obtains its galling resistant properties from the additions of manganese and silicon. In most environments, it has better corrosion resistance than 304 Stainless. Generally, its corrosion resistance is not as good as 316 Stainless. Compared to 304 and 316 Stainless, Alloy 60’s yield strength in the annealed condition is almost double. It exhibits decent strength and maintains its anti-galling properties up to 1500° F. In some tests, Alloy 60 has outperformed more expensive cobalt alloys in wear resistance.
Alias(es)
Nitronic 60 (® Armco Inc.)
Primary Resistance
Galling
Specs
ASTM A193 Grade B8S & ASME SA193 (Bolts)
ASTM A194 & ASME SB194 Grade 8S (Nuts)
ASTM A276 (bar)
ASTM A479 (bar)
UNS S21800
W-Nr 1.7440
Typical Tensile Strength (at room temperature in KSI)
115
Typical Chemistry (% by weight)
C .008, Cr 17, Fe 62, Mn 8, Mo .75, N .01, Ni 8.5, Si 4