【判断题】渗碳钢的合金调质钢的含碳量一般<0.25%。< /div>
【单选题】常用渗碳钢一般为低碳钢或低碳合金钢,含碳量要求在()。
【单选题】为增加钢件表层的含碳量和一定的碳浓度梯度,将钢件放在含碳的介质中加热并保温,使活性碳原子渗入表层的热处理工艺称为渗碳。渗碳用钢一般采用含碳量为()的低碳钢或低碳合金钢
【单选题】•Read the passage about the job of store assistants. •Choose the correct word A, B, C or D from below the passage to fill each gap. •For each question (19-33) , mark one letter (A, B, C or D) on your ...
【简答题】choose the correct answer for the sentences in column A
【简答题】什么叫渗碳钢?为什么一般渗碳用钢的含碳量都比较低?合金渗碳钢常含有哪些元素?它们对钢的组织与性能有何影响?
【单选题】Complete the diagram below. Choose the correct letter A-E from the box below. Write your answers in boxes 19-23 on your answer sheet.