首页
登录
职称英语
There are a number of methods of joining metal articles together, depending
There are a number of methods of joining metal articles together, depending
游客
2023-11-12
41
管理
问题
There are a number of methods of joining metal articles together, depending on the type of metal and the strength of the joint which is required. Soldering gives a satisfactory joint for light articles of steel, copper or brass, but the strength of a soldered joint is rather less than a joint which is brazed, riveted or welded. These methods of joining metal are normally adopted for strong permanent joints.
The simplest method of welding two pieces of metal together is known as pressure welding. The ends of metal are heated to a white heat—for iron, the welding temperature should be about 1 , 300℃—in a flame. At this temperature the metal becomes plastic. The ends are then pressed or hammered together, and the joint is smoothed off. Care must be taken to ensure that the surfaces are thoroughly clean first, for dirt will weaken the weld. Moreover, the heating of iron or steel to a high temperature causes oxidation, and a film of oxide is formed on the heated surfaces. For this reason, a flux is applied to the heated metal. At welding heat, the flux melts, and the oxide particles are dissolved in it together with any other impurities which may be present. The metal surfaces are pressed together, and the flux is squeezed out from the centre of the weld. A number of different types of weld may be used, but for fairly thick bars of metal, a vee-shaped weld should be employed. It is rather stronger than the ordinary butt weld.
The heat for fusion welding is generated in several ways, depending on the sort of metal which is being welded and on its shape. An extremely hot flame can be produced from an oxyacetylene torch. For certain welds an electric arc is used. In this method, an electric current is passed across two electrodes, and the metal surfaces are places between them. The electrodes are sometimes made of carbon, but more frequently they are metallic. The work itself constitutes one of them and the other is an insulated filler rod. An arc is struck between the two, and the heat which is generated melts the metal at. the weld. A different method is usually employed for welding sheets or plates of metal together. This is known as spot welding. Two sheets or plates are placed together with a slight overlap, and a current is passed between the electrodes. At welding temperature, a strong pressure is applied to the metal sheets. The oxide film, and any impurities which are trapped between the sheets, are squeezed out, and the weld is made. [br] Which of the following statements can NOT be inferred from the first paragraph?
选项
A、Different methods of joining metal articles determine different strength of the joints.
B、Soldering can’t produce strong permanent joints.
C、Soldering produces a satisfactory joint for light articles of steel, copper or brass.
D、The strength of the joint which is brazed, riveted or welded is much more than the joint which is soldered.
答案
B
解析
推理题。第一段末句说“These methods of joining metal are normally adoptedfor strong permanent joints.”其中these methods包括soldering(钎焊),故[B]与原文不符,是正确答案。
转载请注明原文地址:https://tihaiku.com/zcyy/3180124.html
相关试题推荐
Usingextremelydifferentdecoratingschemesinadjoiningroomsmayresultin__
ControlanUniversityLogisticNumber,BoycottSchoolFeesRiseOve
ControlanUniversityLogisticNumber,BoycottSchoolFeesRiseOve
Xenonhasanumberofapplications,______maybementioneditsuseinflashlamp
Collegecosts【C1】______quiteabit,dependinguponthetypeofschool【C2】___
Collegecosts【C1】______quiteabit,dependinguponthetypeofschool【C2】___
Collegecosts【C1】______quiteabit,dependinguponthetypeofschool【C2】___
Collegecosts【C1】______quiteabit,dependinguponthetypeofschool【C2】___
Collegecosts【C1】______quiteabit,dependinguponthetypeofschool【C2】___
Collegecosts【C1】______quiteabit,dependinguponthetypeofschool【C2】___
随机试题
WhichofthefollowingisNOTcorrect?A、Polysemyisthephenomenonthatthesame
Howdidthemantravelabroad?In______car.[br][originaltext](11)Aman
AgriculturalNewsFoodandAgricultureinTwenty-fiveYea
不属于抗组胺的药物是A.雷尼替丁 B.法莫替丁 C.奥美拉唑 D.盐酸西替
糖皮质激素禁用于创伤修复期是因为A.抑制蛋白质合成 B.促进胃酸分泌 C.抑
2020年,F省全年粮食产量502.32万吨,比上年增加8.42万吨,增长1.7
Ibelieveyouhave______someimportant
小学德育的组成部分包括政治教育、思想教育、道德教育和__________。
某人从市场上买回冬虫夏草服用后,出现头晕、呕吐等症状。经专家鉴别为亚香棒虫草,被
关于组织和组织工具的说法,正确的有()。A.合同结构图能够反映项目所有工作任务
最新回复
(
0
)