Cr12和Cr12MoV一般用作冷作模具钢,其在锻造之后常采用什么热处理工艺作为预先

题型:单项选择题

问题:

Cr12和Cr12MoV一般用作冷作模具钢,其在锻造之后常采用什么热处理工艺作为预先热处理工艺()。

A.等温球化退火

B.调质处理

C.高温回火

D.正火

考点:机械工程模具制造工艺学模具制造工艺学题库
题型:单项选择题

读短文,判断正(√)误(×)。

      Lisa and Mary are good friends. They are planning a trip together. Lisa wants to go to sunny Australia! It's

so warm there. She can swim all day. She has a new bathing suit (游泳衣) and sunglasses. But Mary doesn't like

swimming. She likes skating. So she is going to Canada. It's winter there now. She can skate all day. She has

winter coats and some new ice skates (滑冰鞋).

( ) 1. Seasons in Australia and Canada are the same.

( ) 2. Lisa and Mary are going to Canada.

( ) 3. Lisa likes swimming.

( ) 4. Lisa has a new bathing suit and sunglasses.

( ) 5. It's warm in Australia.

题型:单项选择题

Among the crises that face humans ________ the lack of natural resources.

A.is

B.are

C.is there

D.are there

题型:单项选择题

根据《UCP600》,信用证金额、单价、数量前如有“about”、“circa”或类似意义字样者,所容许的差额不超过( )。

A.5%
B_8%
C.3%
D.10%

题型:单项选择题

痞满的主要病机在于()

A.胃失和降

B.脾失升清

C.腑气不通

D.中焦气机阻滞

E.肝气横逆

题型:单项选择题

快硬水泥的特点是,凝结硬化快,早期强度增长率高。

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