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23rd November 2006, 07:50 PM
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#11 |
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Member
Join Date: Mar 2005
Posts: 116
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Hi
retained austenite is alway a problem with high alloys... especially with chromium.. .. I know Achim made a wootz with stainless levels of Cr ... and he did maintain it was tough... so i don't know .... if you reach the temp for martensite finish ... you should have good conversion... that why i like to undercool my blades abit... (just me being paranoid ) with the martensitic wootz.... you don't have an extended soak time as you would with other high alloy steel... I just treat it as a plain carbon steel with a very short 4 min soak at non-mag... ... basically, i don't want the large macro carbides to go into solution... just the steel matrix..... i know its abit bizarre.... just the opposite of modern heat treatments for high alloy steels... in the modern case you want the carbides to be dissolved -- take for example A2 .... with 5% Cr needs 30 to 45 min at 1750 to 1800F for proper heat treat.... -- if you think about it..... part of the forging of the barstock is the growth of these macro carbides........ basically dissolving little ones and adding to the big.. .... through all those heat cycles......... from a black heat up to orange etc also....... alot of the pattern of wootz has to do with how slow the cool time is from liquid charge to solid.... and.... combined with the roast time (anneal ) afterwards.......both time and temperature ... just my opinion 
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