Quench cooling a crank???

DaviesDJ · Post by **DaviesDJ** » Wed Dec 18, 2013 1:03 pm

While grinding the leading edge of my counterweights for my track project last week (prior to the Landy chg going) - I was thinking about old methods of iron hardening- if I used my home blowtorches to heat my crank right up to glowing hot and then quenched them in water (like medieval sword makers) would this increase their hardens and strength to any significant amount?? I also cosidered passing a strong current through it is this state to line up the metallic bond "sea" and restore a uniform grain??? Is this done at all??

Cheers

Dave

Post by **katanaman** » Wed Dec 18, 2013 2:17 pm

http://www.inductoheat.com/pdf/97.pdf

kiwicar · Post by **kiwicar** » Wed Dec 18, 2013 8:14 pm

Hi Mr DJ
I think the first thing you need to make sure of is what is the crank actually made of, Cast iron, Cast Nodular iron, cast steel. within these general terms what grade, there were 4 grades of cast steel/ iron used on A series cranks that I know of, I know that there are 2 grades of nodular iron used on chevy cranks and some cast steel OEM cranks (ignoring the forged ones) before you decide to heat treat it sort out what it is you are about to treat. From memory "ordinary" cast iron is best treated to a general clean up to remove any remaining casting sand and chilled foundry crud, bearing surfaces masked and then shot peened with steel shot then nitrided, steels are generally shot peened with lead and parkerised. steels can be case hardened by raising the carbon content through induction heating, a blow tourch would not heat enough of the crank at any time or for long enough, you need about 12 hours to get about a thou of an inch with raised carbon levels then quenched in lead or oil depending on how hard you want the surface.
Stuff like the EN 45 can be heat treated without further carbon enrichment. EN45 is used for making modern swords by those who want serious swords, but these are steels usually given a forging process when used for cranks, and for swords come to think of it.
Best regards
Mike

bigaldart · Post by **bigaldart** » Wed Dec 18, 2013 9:57 pm

Whatever you do, DO NOT Nitride a cast iron crank, especially a Rover crank! We had two done by mistake, they were supposed to be tuftrided. Net result was lots of engine changes that year, crank had over 10 thou wear on the journals after two passes. The best treatment is Tuftriding followed by shot peening the fillet radii. We still have one of the originals we had done this way, over 20 years ago and still standing up to our abuse. If I couldn't get the tuftriding done then I would still get the shot peening done.

Alan

kiwicar · Post by **kiwicar** » Thu Dec 19, 2013 6:23 am

Hi
OK the memory is not so good, tuftride iron, nitride steel ones, but most of all find out what material you are actually dealing with!
best regards
Mike

DaviesDJ · Post by **DaviesDJ** » Thu Dec 19, 2013 8:35 am

Great, many thanks, think u should read a little more about this. Shot peening seems completely logical and always intended to do this. Thanks for that article it is fascinating!

Thanks mr kiwi!

Wotland · Post by **Wotland** » Thu Dec 19, 2013 12:55 pm

Another solution is cryogenic treatment.

Cheap and good result.

mgbv8 · Post by **mgbv8** » Thu Dec 19, 2013 5:35 pm

Andy at 195 below does this for about £10 per kilo....

Give Andy a call to discuss the pro's and cons.

http://www.195below.co.uk/