未登录,请登录后再发表信息
最新评论 (0)

课堂上教你焊接

Welding... with Class

音乐
[MUSIC PLAYING]
在工业过程中 焊接极其重要
Fusion welding is an incredibly important industrial process
我们要连接材料
for joining materials.
小到椅子 大的摩天大楼 都要用到焊接
It’s used to build everything from chairs to skyscrapers.
但它的原理真的十分简单
At its core it’s a really simple process.
你只需把两种材料组合到一起
You bring two pieces of metal close together.
加热它们 直到融化融合
You heat them up until they melt and fuse.
然后冷却它们 使它们单独成型
And then you cool them, so that they solidify.
看看你的周围 我敢打赌你会看见许多的焊接品
Take a look around you and I bet you’ll see a lot of welds.
焊接
Weld.
现在的焊接技术已相当发达
Today’s welding techniques are very high tech.
但焊接的理念却没再更新
But the idea of welding isn’t new.
因为古人缺乏
Because ancient civilizations lacked the technology
直接使用大型材料的技术
to directly make large metal objects,
他们使用一种称为锻焊的技法将
they used a technique called forge welding to join together
更小的材料焊接到一起
smaller pieces of metal.
在锻焊技术里 两块材料被连接
In forge welding two pieces of metal are brought into contact,
加热到白热状态
heated up until they’re white hot,
然后再被锤炼到一起
and then hammered together.
十二世纪初 大型材料生产的新型技术
In the 1100s, new methods of mass producing metal
发展起来 焊接变得没那么重要
were developed and welding became less important.
如果人们想要一件合金制品 他们只需融化金属
If people wanted a metal object, they would melt the metal
然后直接将材料倒进模具里铸造
and make the object directly by casting it into a mold.
二战前 当
It wasn’t until World War II, when
敌人想要为大型物品焊接钢材
armies wanted to join steel plates for massive objects
如飞机和战舰 这使焊接
like airplanes and battleships, that welding became essential
又非常重要起来
again.
如果你正在设法焊接 有
If you’re designing a weld, there
一些重要的参数你
are several important parameters you
必须记住 热源强度
have to keep in mind– the intensity of the heat
它被定义为每一单位面积输出的能量
source, which is defined as the power input per unit area.
热被输入到每一单位长度的焊接材料上
The heat input per unit length of the weld,
这与热源强度
which is related to the heat source intensity
以及你移动热源有多快的关系密切
and how quickly you move the heat source.
防护焊接时的活性气体的方法
The method of shielding the weld from reactive gases
如大气中的氢,氧 以及氮
in the atmosphere like hydrogen, oxygen, and nitrogen that
它们都可能影响焊接品的强度
can affect the weld’s strength.
所有的变量都要根据
All of these variables are determined
焊接时的几何构图 以及你要结合的
by the geometry of your weld and the type of materials
材料类型
you’re trying to join.
回到第一种参数
Going back to the first parameter,
热源的类型大致分三种
there are three general categories of heat sources
你必须明白
that you should know about.
按照逐渐增加的强度次序 他们分别
In order of increasing intensity they
是依靠碳氢化合物燃烧的气体来源
are gas sources that rely on the combustion of hydrocarbons,
以及在金属上产生极热等离子体的弧光源
arc sources that generate a piping hot plasma
还有高能电波源
above the metal, and high energy beam sources
如 电子束以及激光
like electron beams and lasers.
电子束与激光可以促成最好的焊接
Electron beams and lasers can generate the nicest welds.
但需要昂贵的设备
But they require expensive equipment.
因而电弧光源是
So arc sources tend to give the best balance between quality
质量与费用的最佳平衡
and cost.
让我们来看看燃烧型焊接
Let’s start by looking at a combustion welding
技术 它依靠
technique that relies on the chemical reaction
乙炔与氧之间的化学作用
between acetylene and oxygen.
[哼唱]
[HUMMING]
氧乙炔型焊接依靠
Oxyacetylene welding relies on the energy released
从乙炔以及氧气燃烧释放的能量
from the combustion of acetylene and oxygen
将其氧化为二氧化碳与水蒸气
into carbon dioxide and water.
化学反应有以下两步
The chemical reaction follows two step
能在燃烧过程中可见
that can be seen in the flame itself.
第一步是 乙炔和氧的分解
The first is the decomposition of acetylene and oxygen
氧化为一氧化碳和氢
into carbon monoxide and hydrogen.
这需要大约总热量的2/3
This accounts for about 2/3 of the total heat
释放以及发生在这个小圆锥上 在这里温度能
released and occurs in this tiny cone, where temperatures can
达到3500摄氏度
reach 3,500 degrees Celsius.
这很大 外圈是蓝焰
This larger, light blue flame is the outer envelope.
在这里 一氧化碳和第一步产生的氢
And here the carbon monoxide and hydrogen from the first step
以及来自大气中氧互相作用形成二氧化碳
react with oxygen from the air to form carbon dioxide
以及水蒸汽
and water.
这个次要的氧化扮演了一个重要的角色
This secondary combustion plays the important role
一旦它开始吸收所有的氧它就开始在维护焊接
of protecting the weld since it sucks up all the oxygen
环境了
from the environment.
我们现在有一个关于化学过程的想法
Now that we have an idea about the chemistry,
让我们沿着缝隙焊接
let’s weld along a seam.
你开始焊接 通过融化一些材料
You start to weld by melting some of the materials you
你尝试着把它同一种叫做焊池的液体金属池里进行粘结
are trying to join into a liquid metal puddle call a weld pool.
然后你沿着焊池移动
You then move the weld pool along the line
你想要粘结的这条线路
that you want the join.
随着你向前移动 金属就被焊接为
As you move forward, the metal re-solidifies
一个固定结合
into a solid joint.
这个结合有三个独立的部分 熔化带
This joint has three separate parts– the fusion zone,
热作用区 以及基层金属
the heat-affected zone, and the parent metal.
一个完美的焊接要求熔化
An ideal weld is designed so that the fusion
带以及热作用区与基础金属
zone and the heat-affected zone resemble the parent
尽可能的尽可能的相似
metal as closely as possible.
这是由于许多工程材料
This is because many engineering materials
有独特的微小结构设计
have a specifically-designed microstructure.
通过加热材料 让它融化
By heating the material up, allowing it to melt,
我们准许这些原子移动以及这个微小结构
we are allowing those atoms to move and the microstructure
的改变
to change.
这个能够对材料性能产生不利影响
And this can have a detrimental effect
如机械强度
on the material’s properties like mechanical strength.
工业上最重要的焊接技术是
The most industrially-important welding techniques
电弧光焊接技术 就如它的名字意义一样
are the arc welding techniques that, like their name implies,
它依靠电弧产生热
rely on an electric arc to generate heat.
在电弧光焊接里 你制作一个电路
In arc welding you make a circuit
这样电流能够在电焊条
so that current can flow between the welding
和通过接地半成品形式的半成品之间流动
electrode and your work piece by grounding your work piece
以及为你的电焊条提供电势能
and applying a potential to your electrode.
在你的半成品与电焊条之间的电压
The voltage between your work piece and the electrode
通常是在10伏特左右
is normally around 10 volts.
以及电流有上百多安培
And the current is in the hundreds of amperes,
因而总能量接近于上千多的
so that the total power is on the order of thousands
瓦特
of watts.
给你一些对比,普通的日光灯
To give you some comparison, your average fluorescent light
泡消耗十几瓦特
bulb consumes tens of watts.
大都数的能量作为在电弧内以及电弧周围的热被产生
Most of this power is generated as heat in and around the arc.
从电弧焊接以及气焊的背后概念看
From looking at the concepts behind arc welding
我已经给你了
and oxy-fuel welding, I’ve given you
焊接工作原理的概念
a sense of how welding works.
希望你能学到一些东西
I hope you’ve learned something.
记住 眼睛要远离美丽的焊接
And remember to keep an eye out for beautiful welds
未来
in the future.
诨名
[HUMMING]
音乐
[MUSIC PLAYING]

发表评论

译制信息
视频概述
听录译者

收集自网络

翻译译者

收集自网络

审核员

自动通过审核

视频来源

https://www.youtube.com/watch?v=xdF94yE6d9g

相关推荐