焊接 翻译

Welding

There are a number of methods of joining meta l articales together,dep ending on the type of meta l and the strength of the joint which is reqired. Soldering gives a satisfactory joint for light articles of steel,copper or brass. but the strength of a soldeing is rather less than a joint which is brazed,ri veted or welded.These methods of jointing meta l are normally adopted for srtong permanent joint.

The simplest method of welding two pieces of meta l toghter is known as pressure welding.The ends of meta l are heated to a white heat-for iorn, the welding temperature should be about 1300℃-in a flame.At this tempera ture the meta l becomes plastic.The ends are then pressed or hammered tog ether,and the joint is stoothed off.Care must be taken to ensure that the su rface 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 firm of oxide is formed on the heated surfaces.For this reason,a flux is applied to the heated meta l.At welding heat,the flux meta ls,and oxide particles are dissolved in it together with any other imputities,and the flux is squeezed out from the center of the weld.A number of different types of weld may be used ,but for fairly thick bars of meta l,a vee-shaped weld should norm ally be employed.It is rather stonger than the ordinary butt weld.

The heat of fusion welding is generated in several ways,depending on the sort of meta l which is being welded and on its shape.An extremely h ot flame can be produced from an oxyacetylene torch. For certain welds a n electric arc is used. In this method,an electric current is passed across t wo electrodes,and the meta l surface are placed between them.The electrodes are sometimes made of carbon,but more frequently they are meta lllic. The work itself constitutes one of them and the other is an insulated filler rod. An arc is stuck between the two ,and the heat which is generated melts t he meta l at the weld. A different method, known as spot welding, is usual

ly employed for welding sheets of meta l toghter. Spot welding requires bot h an electric current and a forging pressure to produce the weld. The two sheets to be spot welded are griped between copper electrodes through whi ch a heavy current is passed; fusion occurs at the spots where the electrod es are thus applied. meta ls of low electrical resistence will be different to spot weld, whereas those of high resistance,such as stainless will produce a spot weld readily.

焊接

连接金属的方法很多，其分类方法取决于金属的类型和所需求的焊点的强度。软铅焊使轻钢件、铜件或黄铜件的焊点非常好。但是软铅焊焊点的强度要远小于铜焊、铆接或焊接的焊点强度。这些连接金属的方法通常用于焊接高强度的永久焊点。

把两块金属焊接在一起的的最简单的方法就是压力焊。用火焰把金属端部加热至白热状态---对铁而言焊接温度大约为1300℃。在此温度下，金属变成为塑性的。之后金属端部就会被施压或锤击而结合在一起，并且焊点会被抹平。要注意的是确保金属表面首先是要完全清洁的，因为污污会使焊缝的强度减弱。此外，把铁或钢加热到较高的温度会引起氧化，在加热表面会形成一层氧化物。由此，常在加热金属中加入一种助熔剂。在焊接温度，助熔剂熔化了，氧化物颗粒以及其它可能出现的杂质都会熔化于助熔剂。可能会用到许多种不同的焊接方法，但是对于相当厚度的金属棒，通常要开V型坡口，它的强度要大于普通的对焊焊缝。

熔焊的热度有几种来源，取决于被焊金属的种类及其形状。氧乙炔焊炬可能会产生极其热的火焰，对于某些焊缝来说可能会用到电弧，在此方法中，电流通过两个电极，并且金属表面被置于两电极之间。电极有时是用碳作成的，但是通常由金属作成，工件由其中的一个电极构成，而另外一个是绝缘填充棒。电弧在此两者之间产生，产生的热量会使金属在接焊处熔化。一种不同的方法，比如说点焊，常用来把金属片焊在一起。点焊需要电流及锻压来产生焊缝。将被焊接的两片金属被固定在有强大电流通过的铜电极两端。所输送的焊条在焊点处熔化，低电阻的金属很难应