Nihard residual stress
Nihard residual stress
(OP)
We are considering having rings 44 inch diameter cast from one of the nihards, then machined to create moderately accurate labyrinth grooves and a few tapped holes, and finally two saw cuts made to remove a section to allow installation.
One of the concerns is residual stress levels that would make the ring "spring" when saw cut. I see ASTM A532 -93a includes stress relieving as an option for both "hardened" and "as cast", without mentioning a process or resulting hardness. NIhard's low ductility (often described as NIL) makes installation of this part risky, and even more so if it must be spread to line up bolt holes.
Are we concerns justified?
thanks
Dan T
One of the concerns is residual stress levels that would make the ring "spring" when saw cut. I see ASTM A532 -93a includes stress relieving as an option for both "hardened" and "as cast", without mentioning a process or resulting hardness. NIhard's low ductility (often described as NIL) makes installation of this part risky, and even more so if it must be spread to line up bolt holes.
Are we concerns justified?
thanks
Dan T





RE: Nihard residual stress
Ask your vendor what stress relief he uses. If he doesn't know off the top of his head maybe you should search further.
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Plymouth Tube
RE: Nihard residual stress
NiHard4 is generally heat treated at higher temperatures and air cooled and may have a temper applied.
RE: Nihard residual stress
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"The richer we have become materially, the poorer we have become morally and spiritually." Martin Luther King Jr
RE: Nihard residual stress
You can thenuse a hand ginder and have an easy fit.
_____________________________________
"The richer we have become materially, the poorer we have become morally and spiritually." Martin Luther King Jr