问题 问答题

常用减少焊接残余应力的工艺措施有哪些

答案

参考答案:(1)采用合理的焊接顺序和方向。
1)先焊收缩量较大的焊缝,使焊缝能较自由地收缩。
2)先焊错开的短焊缝,后焊直通长焊缝。
3)先焊工作时受力较大的焊缝,使内应力合理分布。
(2)降低局部刚性。
(3)锤击焊缝区法。
(4)预热法。
(5)加热减应区法。

阅读理解

Dear Tom,

How are you? I’m in a new school in China this term. And I’m writing to you in my school now. This school is big and nice. There are more than two thousand students in my school. I like the teachers. They are all kind to me. And they can speak English well. So there is no problem to talk with them. My classmates are very friendly. They teach me Chinese and I teach them English.

We have many subjects at school. I like Chinese, music, PE and more. And my favorite subject is art. It’s really interesting. And my art teacher is very fun. He can draw well. I don’t like math. It’s too difficult. After school, I like playing basketball with my new friends. What a fun time to play with them!

We have no classes on weekends. I often go to movies with my parents. Sometimes I stay at home and watch TV. My parents want me to learn Chinese. Sometimes I go shopping. The food is so delicious in Chengdu. I like the food. And the people are very friendly. I love China. I love Chengdu.

Please write to me soon!

Yours                                      Jack

小题1:Jack writes this letter to __________.

A. pen pal            B. old friend          C. parents

小题2:Jack is in a ____________.

A. English school        B. Chinese school        C. small school

小题3:Jack’s teachers _____________.

A. teach him English     B. only teach him Chinese   C. are good to him

小题4:Jack help his new classmates with _________.

A. English          B. Chinese          C. music

小题5:Jack likes _________ after school.

A. playing basketball       B. swimming        C. going shopping

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