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
50
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] What is the best title for the passage?
选项
A、Welding
B、Soldering
C、Fusion Welding
D、Pressure Welding
答案
A
解析
主旨题。本文主要介绍了焊接(welding)的四种方式:pressure welding,fu—sion welding,spot welding,gas welding,故[A]是正确答案。
转载请注明原文地址:http://tihaiku.com/zcyy/3180128.html
相关试题推荐
Theystoodchattingtogetheraseasilyandnaturallyas______.A、itcouldbeB、
Thegovernmenthasreducedthenumberof$100notesin______.A、circulationB、su
Alargenumberoflocalpeopleareanxiousaboutthe______impactthatthemotorw
Xenonhasanumberofapplications,______itsuseinflashlampsforhighspeedp
Let’sgotothemoviestogether,______?A、willyouB、shallweC、won’tyouD、shoul
AsaChinesesayinggoes,"Many______makelightwork".Solet’sworktogether.A
Thescientistwroteanumberofbooks,but______bookswerenovels.A、lasttwohis
Whyonlinebillpaysaferthantraditionalmethods?[br][originaltext]Many
Whyonlinebillpaysaferthantraditionalmethods?[originaltext]Manypeopl
TheUniversityofSouthernCaliforniahasthelargestnumberofinternationalst
随机试题
Itisnotpolitetoarriveatadinnerpartymorethan15to20minuteslate
Thewaypeopleholdtothebeliefthatafunfilled,painfreelifeequalsha
Forthispart,youareallowed30minutestowriteashortessay.Youshouldsta
根据我国相关法律规定,劳动者享有的权利包括:A.享有平等就业和选择职业的权利
核准制与行政审批制相比,具有的特点主要有()。A:增强了保荐机构的责任 B:
“凡事预则立,不预则废。”这一古训的哲学方法论意义是指( )。A.正确认识事物
目前我国银行开办的外币存款业务币种包括()。A:英镑 B:卢布 C:新加坡元
A.牙髓炎 B.牙龈萎缩 C.根尖炎 D.牙龈炎 E.牙槽脓肿后牙修复体
地下工程水泥砂浆防水层的养护时间至少应为( )。A.7d B.14d C.2
毒簟中毒在临床上可分为六期的是哪一型A.胃肠炎型 B.神经精神型 C.溶血型
最新回复
(
0
)