【简答题】A woman is standing at a bus stop at noon. A van pulls up. A young man hops out of the van, grabs the woman's purse, gets back into the van, and it drives off. _______1_______. He is admiring the full...
【简答题】有两个含碳量为 1.2%的碳钢薄试样,分别加热到780 °C 和 860 °C 并保同时间,使之达到平衡状态,然后以大于 V K 的冷却速度至室温。试问: ( 1)哪个温度加热淬火后马氏体晶粒较粗大? ( 2)哪个温度加热淬火后马氏体含碳量较多? ( 3)哪个温度加热淬火后残余奥氏体较多? ( 4)哪个温度加热淬火后未溶碳化物较少? ( 5)你认为哪个温度加热淬火后合适?为什么?