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| Mr.Yokoo |
: |
The answer is simple. That's because there
are no other materials other than tin-lead
solder. Actually, it is not necessary to change
the materials. The tin-lead solder provides
a relatively low melting temperature and the
cost is low. It can thoroughly flow into even
a narrow gap. It can spread well and get wet
well. The strength is also perfect. At present,
from an environmental point of view, we've
begun to use lead-free solder or solder containing
no lead. But, such lead-free solder is inferior
to tin-lead solder in convenience. |
| Hikaru |
: |
Tin-lead solder is very advantageous, isn't
it? |
| Mr.Yokoo |
: |
That's right, Wataru. |
| Hikaru |
: |
No. I'm Hikaru···. |
| Mr.Yokoo |
: |
Sorry. Age makes me so forgetful. Anyway,
Tin-lead solder is commonly used now. In particular,
eutectic solder, or an alloy containing tin
of 63% and lead of 37%, will melt instantaneously
at a relatively low temperature of 183ºC and
hardens instantaneously. Because of these
characteristics, we prefer using eutectic
solder. |
| Hikaru |
: |
What is the advantage of instantaneous hardening? |
| Mr.Yokoo |
: |
You have many questions, indeed. You need
to study on your own!
Well, I must teach you because you are in
the training period today. |
| Hikaru |
: |
Thank you very much. |
| Mr.Yokoo |
: |
Pure substance, or a substance without any
other substance mixed in, has three states:
solid, liquid and gas. However, when two or
more substances are mixed, the states of solid
and liquid simultaneously exist because the
temperature at which the mixture starts melting
is different from the temperature at which
it completely melts.
Soldering must fill solder into a gap between
target metals. But, if the melting start temperature
is different from the melting completion temperature,
the solder may not have completely melted,
although it looks melted. It's a semi-melted
state. Do you understand what I've explained
until now? |
| Hikaru |
: |
Yes, I think I understand it. |
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