问题 问答题 简答题

简述滚压模膛的结构分类。

答案

参考答案:

(1)开式:横截面为矩形;模膛制造方便,但聚料作用小,滚压效率低,坯料的表面质量也较低。适于锻件各段截面变化较小的情况。

(2)闭式:横截面为椭圆形;聚料效果好,滚压效率高,坯料表面光滑,但模膛制造较复杂。适用于锻件各部分截面变化较大的情况。

(3)混合式。

(4)不对宽闭式。

(5)不对称式。

填空题
单项选择题

It was two years ago today that the hunting ban came into force, supposedly ending centuries of tradition. However, the law has been an unmitigated failure-not that either side is shouting about it.
It was a nightmare vision that struck fear and loathing into the hearts of millions. When the hunting ban became law, it was said, 16, 000 people would lose their jobs, thousands of hounds would be put down, rotting carcasses would litter the countryside, hedgerows would disappear, riders would face on-the-spot fines, law-abiding people from doctors to barristers would be dragged from their horses and carted off to prison, while dog owners would be prosecuted if their mutt caught a rabbit.
These were just some of the claims as desperate countryside campaigners battled to save their sport in the lead-up to the hunting ban, which Labour rammed into law using the Parliament Act on November 18, 2004.
For many, the fears were real. Others exaggerated as they fought an increasingly aggressive anti-hunting lobby which had rejected acres of independent evidence affirming that hunting is the most humane way of killing foxes. In the battle to"fight prejudice, fight the ban", every emotive argument was deployed.
For its part, the anti-hunting brigade extravagantly claimed that the ban would put an end to the rich parading in red jackets. A senior Labour MP, Peter Bradley, admitted in this newspaper that it was, as many suspected, about "class war". He lost his seat shortly afterwards. But people in red coats did not disappear.
In fact, none of the forecasts came true. What did happen was something nobody had predicted: the spectacular revival and growth of hunting with hounds. In short, the hunting ban has been a failure.
Today, on the second anniversary of the ban’s coming into force on February 18, 2005, new figures show that participation in the sport has never been higher. It is so cheerful that two new packs have been formed, something that has not happened for centuries.
They include the seductively named Private Pack, set up by the financier Roddy Fleming in Gloucestershire. It operates on an invitation-only basis, a sort of hunting private members’ club. This can only mean one thing: like it or not, hunting is cool. Young people are taking it up, enticed by the element of rebellion and the mystique of what actually happens as hunts attempt to keep within the law.

The phase "came into force" underlined in Paragraph 1 is closest in meaning to ______.

A.take effect

B.be popular

C.be forced

D.come into existence