【单选题】【消耗次数:1】
在锻造过程中,引起钢产生热脆的元素是()
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相关题目
【单选题】 在碳素钢中加入某些合金元素(锰、硅、钒、钛等),用于改善钢的性能或使其获得某些特殊性能的钢称为( )。
①  结构钢
②  高碳钢
③  普通钢
④  合金钢
【单选题】 钢中的杂质元素主要为硫和
① 
② 
③ 
【判断题】 钢中的硫可增加钢的热脆性,磷可增加钢的冷脆性( )。
①  正确
②  错误
【判断题】 钢中的硫可增加钢的热脆性,磷可增加钢的冷脆性( )。
①  正确
②  错误
【判断题】 锰对钢的性能产生一系列不良的影响,是一种有害元素。
①  正确
②  错误
【单选题】 下列关于钢材有害元素氧、硫、磷说法有误的一项是( )。
①  硫化物夹杂于钢中,具有强烈的偏析作用,会降低钢材的各种机械性能
②  磷含量提高,钢材的强度提高,塑性和韧性显著下降
③  磷的偏析较严重,使钢材的冷脆性降低,可焊性降低
④  氧有促进时效倾向的作用,使钢的可焊性变差
【判断题】 钢含磷较多时呈热脆性,含硫较多时呈冷脆性。
①  正确
②  错误
【多选题】 钢中()为有害元素。
① 
② 
③ 
④ 
⑤ 
【判断题】 锻造时,金属加热温度越高,锻造过程中越不易被打裂。
①  正确
②  错误
【单选题】 钢中硫和氧的含量超过限量时,会使钢材()。
①  变软
②  热脆
③  冷脆
④  变硬
随机题目
【单选题】 If the doctor had been available, the child ____________.
①  would not die
②  could not have died
③  might not die
④  should not have died
【单选题】 If Mary _______shopping this afternoon, please ask her to write a shopping list first.
①  will go
②  goes
③  went
④  has gone
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①  spend
②  spends
③  take
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①  whom they are waiting for
②  who they are waiting
③  whom are they waiting for
④  who are they waiting
【单选题】 Tom ________ more than twenty pounds on the novel.
①  spent
②  paid
③  cost
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①  of
②  into
③  to
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①  in
②  at
③  on
④  to
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①  discovered
②  invented
③  found
④  developed
【单选题】 ____ you know, David has been well lately.
①  Which
②  As
③  What
④  When
【单选题】 The garden _______while the Greens were away from home.
①  took good care of
②  was taken good care
③  was taken good care of
④  was taking good care