渗碳后，由于工件表面含碳量提高，所以不需要淬火即可获得高硬度和高耐磨性。（） 

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SQL Error: select id,body,options from ***_enewstiku where sourceid='24891' and id < 2124446 and id<>'2124446' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='24891' and id > 2124446 and id<>'2124446' order by id asc limit 5