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
2024-10-10
8
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 method of welding is the simplest for the welders to operate?
选项
A、Fusion welding.
B、Gas welding.
C、Pressure welding.
D、Spot welding.
答案
C
解析
细节题。从文章第二段第一句“The simplest method of welding two pieces ofmetal together is known as pressure welding.”可知,加压焊(pressure welding)操作起来最简便,所以[C]是正确答案。
转载请注明原文地址:https://tihaiku.com/zcyy/3794689.html
相关试题推荐
Thereareanumberofmethodsofjoiningmetalarticlestogether,depending
I’vewrittenbeforeaboutSherryTurkle’snewbook,AloneTogether:WhyWeE
I’vewrittenbeforeaboutSherryTurkle’snewbook,AloneTogether:WhyWeE
Mr.Wells,togetherwithallthemembersofhisfamily,______forEuropethisaf
Atthepartywefoundthatshygirl______hermotherallthetime.A、dependingo
Whousedtolivetogetherinanextendedfamily?[br][originaltext]Thefa
Whousedtolivetogetherinanextendedfamily?[originaltext]Thefamilyi
______indicatethattherearemoreboysthangirlsattendingschool.A、NumbersB
Pheumoniaissaid______thenumber-twokillerofchildrenoverthepastfewyears
______ismentionedabove,thenumberofthestudentsinseniorhighschoolsisi
随机试题
[originaltext]M:HelloHeather.I’mlookingforyou!W:WhatcanIdoforyou,
Thisprogramcanhelpfreshmenmakeasuccessful______intocollegelife.A、tran
[originaltext]M:IhadthoughttodropinandfindoutexactlywhereIwentwro
[originaltext]Goodafternoon,everyone!IwonderifyouknowthatAmerican
判断男性生殖力的主要指标不包括A.精液量 B.精子活动率 C.异形精子数
【教学过程】 环节一:课堂导入 多媒体导入:展示电磁起重机的工作原理示意图。 教师提问:电磁起重机的本质是什么?(通电螺线管。) 教师引导:简单的通电螺
癫痫局灶性(部分性)发作可选择的药物是A.卡马西平 B.苯巴比妥 C.苯妥英
2020年1月1日,甲公司向银行借入资金500万元,期限3年,
银行承兑汇票的承兑银行,应当按照票面金额向出票人收取()的手续费。A:千分之一
(2017年真题)电渗井点降水的井点管应()。A.布置在地下水流上游侧 B.布
最新回复
(
0
)