-
最新消息
1-2
the benefits
of civilization which we enjoy today are
essentially
due to the
improved quality of products available to us
.
文明的好处我们享受今天本质上是由于改进质量的产品
提供给我们。
the
improvement
in
the
quality
of
goods
can
be
achieved
with
proper
design
that
takes
into
consideration the functional
requirement as well as its manufacturing aspects.
提高商品的质量可以达到与适当
的设计
,
考虑了功能要求以及其制造方面。
The design
process that would take proper care of the
manufacturing
process as well would be
the ideal one. This would ensure a better product
being made available at an economical
cost.
设计过程中
,
将采取适当的照顾的生产过程将是理想的一个。这将确保更好的产品被使可
得到一个经济成
本。
Manufacturing is involved in turning
raw materials to finished products to be used for
some purpose.
制
造业是参与将原材料到成品用
于某些目的。
In the present age there have
been increasing demands on the product
performance
by
way
of
desirable
exotic
properties
such
as
resistance
to
high
temperatures,
higher
speeds
and
extra
loads.
在现在的时代已经有越来越多的产品性能要求的理想的异国情调的性能如耐高温
< br>,
更高的速度和额
外的负载
Th
ese in turn would require a variety of new
materials and its associated
processing.
这些反过来需要各
< br>种新材料及其相关的处理
Also,
exacting
working conditions that are desired in the modern
industrial operations
make large
demands on the manufacturing industry.
这些反过来需要各种新材料及其相关的处理。同时
,
严格的
工作环境
,
需要在
现代工业操作使大型制造业的需求
.
Further, the economics of the
manufacturing operation is a very important
consideration.
此外
,
经济学
的生产操作是一个非常重要的考虑因素。
To
be
viable
in
the
modern
environment,
a
product
has
to
be
competitively priced
besides having the functional and aesthetic
appeal.
是可行的在现代环境中
,
一个产品必须具
有价格竞争力除了具有功能性和审美情趣。
Therefore, it is necessary
for the engineer to give a proper thought to
various aspects of
manufacturing.
因此
,
它是必要的让工程师给适当的认为制造业的各个方面。
Manufacturing
processes
is
a
very
fundamental
subject
since
it
is
of
interest
not
only
to
mechanical
engineers but
also to those from practically every discipline of
engineering.
制造过程是一个非常基本的主题
,
因
为它是有趣的
,
不仅机械工程师但同样从几乎每个学科的工程。
It is so because
engineering as a whole is meant
for
providing various materials for human
consumption.
它是如此因为工程作为一个整体是
用来提供各种材料供
人类食用
For
various
products
such
as
plant
machinery
required
for
chemical,
civil,
electrical,
electronic,
textile,
etc., the manufacturing process forms a
vital ingredient.
对于不同的产品
,
如植物机械所需的化工、土木、电气、
电子
、纺织等
,
生产过程形成一个至关重要的因素
< br>.
A detailed understanding of the
manufacturing processes is thus essential for
every engineer.
详细了解
生产流程是必不可
少的每个工程师这样。
This
helps
him
appreciate
the
capabilities,
advantages
and
also
the
limitations
of the various
manufacturing processes.
这有助
于他欣赏能力、优势和局限性
,
各生产工序。
< br>
This in
turn helps in
the proper design of any product required for
him.
这反过来有助于正确的设计的任何产品需要他。
Firstly, he would be able to assess the
feasibility of manufacturing from his
designs.
首先
,
他将能够评估制造的可
行性从他的设计。
He may also find out that there more
than one process available for manufacturing a
particular
product and so he can make a
proper choice of the process which would require
the lowest manufacturing cost and
would
deliver the product of desired quality.
他可能也发现有超过一种过程用于生产特定的产品
,
所以他可
以使
一个适当的选择过程
,
需要最低的
制造成本和交付产品的期望质量。
He may also modify his
design slightly to suit
the particular
manufacturing process he chooses.
也可以修改自己的设计稍微适应特定的制造过程他选择
.
< br>
Manufacturing
is
defined
by
the
Merriam
Webster
online
dictionary
as
to
make
into
a
product
suitable to use.
制造业是梅里厄姆
-
韦伯斯特词典定义的在线词典使成一个产品适合使用。
Manufacturing
remained as a craft
till the first industrial revolution towards the
end of the 18
century with
low volumes and single-piece
productions.
制造业仍然作为一个工艺直到第一
次工业革命对
18
世纪末的低
量和单件
生产。
It
required
highly
skilled
craftsmen
to
individually
produce
the
pieces
and
fit
them
when
the
assembly
was
required.
它需要高度熟练的工匠来单独生产件和适
合他们的需要时组装。。
This
was
a slow and expensive process , but in
the absence of any machines, that was the only
thing that was
possible.
这是一个缓慢而昂贵的过程
,
但在缺乏任何机
器
,
这是唯一可能的。
The
availability
of
the
steam
engine
and coal-fire furnaces made the invention of a
number of steam-power driven machinery to
greatly increase the manufacturing
capacity.
蒸汽引擎的可用性和煤火熔炉使发明一种数量的全局驱动
机械制造能力大大增加。
A large number of
inventions related to machine tools took place
during this
th
period and
continued into the 19
century.
< br>大量的发明与机床发生在这一时期
,
持续到
19
世纪。对十九世
纪末的发明电力和更好的工程材
料、生产操作变得更有效率。
Towards the end of the
19
century with the
invention of electricity and better
engineering materials, manufacturing operations
became more
productive.
The
developments
in
the
automobiles
at
the
beginning
of
the
20
century
are
instrumental
in the growth of a variety of
manufacturing methods and practices.
对十九世纪末的发明电力和更好
的工程材料、生产操作变得更有效率
。汽车的发展在
20
世纪初期是工具性成长的各种生产方法和实
践。
。
There are a
large number of processes available to the
engineer for manufacture.
有大量的流程
提供给工程师制造。
These processes can be broadly classified into
four categories.
这些过程可以
大致分为四类
Casting processes forming processes
fabrication processes material removal
processes
铸造工艺成形过程工艺制备材料去除的过程
These
are
the
only
processes
where
liquid
metal
is
used.
这些是唯一使用过程中
,
液态金属。
Casting is also one of the oldest known
manufacturing processes.
铸
造是一个已知的最古老的制造过程。它需要准备一个腔通常在耐火材料类似于最终对象是。<
/p>
It required
preparation of a
cavity usually in a refractory material to
resemble closely the final object to
be
made.
它需要准备一个腔通常在耐火材料类似于最终对象是。
Molten metal is poured into this
refractory mould cavity and is allowed
to solidify.
金属熔液注入这耐火模腔和允许巩固。凝固后的对
象被删除从模具。
The object after
solidification is removed from the
mould.
凝固后的对象被删除从
模具。
Casting processes are universally used for
manufacture of a wide variety of products.
铸
造过程是普遍用于制造各种各样的产品
The
principal process among these is sand casting
where sand is
used as the refractory
material.
其中的主要过程是砂铸
,
砂用作耐火材料。
The process is equally
suitable for the production of a very
small batch as well as on a very large
scale.
这个过程同样
适用于生
产的一个非常小的批量以及一个非常
大尺度。
Some of the other casting processes for
specialized needs
are
一些其他的铸造工艺专业需
求
Shell-mould casting.
壳型铸造
permanent-mould
casting
硬模铸造
Precision-
investment.
精密的
投资
casting
die-casting
铸造压铸
Plaster-mould
casting.
石膏型铸造
Centrifugal
casting
离心铸造
These
are solid state manufacturing
processes involving minimum amount of
material wastage
and
faster
production.
这些都是固态制造过程涉及最少的材料损耗和更快的生产。
In
a
forming
process,
the metal may be
heated to a temperature, which is slightly below
the solidus temperature and then
a
large force is applied such that the material
flows and takes the desired shape.
在成形过
程中
,
金属可能被加热到一个温度
,<
/p>
略低于固相线温度
,
然后一个大力量是应
用的材料流和需要所需的形状。
The
desired
shape is controlled by means of a set of tools
called dies, which may be completely closed
or partially closed during manufacture.
所需的形状是通过控制的一组工具称为死亡
,
< br>这可能是完全封闭
或部分封闭在制造。
These
processes are normally used for large-scale
production rates. These are
generally
economical and in many cases improve the
mechanical properties too.
这些过程通常用于大
规模的生产速度。这些通常是经济和在许多情况下改善机械性能太
<
/p>
th
th
th
S
ome of the metal forming processes are rolling
,extrusion ,drop forging ,wire drawing ,press
forging ,sheet
metal operations ,upset
forging .
一些金属成形过程是轧制、挤压、落锤锻造
,
拉丝
,
按锻造、金属板操作、顶锻
These
are
secondary
manufacturing
processes
where
the
starting
raw
materials
are
processed
by
any
of
the
previous
manufacturing processes described .
这些是二次制造过程的起始原料处理前面的任何制造过程描述。
It
essentially, envolves joining pieces
either permanently or temporarily so that they
would perform the necessary
function. <
/p>
它从本质上讲
,envolves
加入碎
片要么永久或暂时如此
,
他们将执行必要的功能。
The
joining
can
be
achieved by either or
both of heat and pressure and/or a joining
material.
的加入可以达到的一种或两种热量和
压力和
/
或加入材料。
Many of the steel structural
constructions we see are first rolled and then
joined together by
a fabrication proces
s.
许多钢结构建筑
,
我们看到的是第
一卷
,
然后连接在一起的工艺过程。
Some of the processes of interest in
this category are gas welding, cold welding,
electric arc welding, brazing,
electric
resistance welding, soldering, thermit welding.
一些感兴趣的过程都属于这一类气体焊接、冷焊接、电弧焊、钎焊、电阻焊、钎焊、铝热焊。
These are
also
secondary manufacturing processes where the
additional unwanted material is
removed
in
the
form
of
chips
from
the
blank
material
by
a
harder
tool
so
as
to
obtain
the
final
desired
shape.
这些是二次制造工艺<
/p>
,
额外的不必要的材料去除的形式的芯片从空白材料的困难
,
得到了工具最终想要的形状。
Material
removal
is
normally
the
most
expensive
manufacturing
process
because
more
energy
is
consumed
and also, a lot of
waste material is generated in the process.
材料去除的通常是最昂贵的制造过程
,
因为更多的能
量消耗
,
同时
,
大量的废弃物产生的过程。
Still this is widely used
because it delivers very
good
dimensional accuracy and good surface finish.
这仍是广泛使用的
,
因为它提供了非常良好的尺
寸精
度和良好的表面光洁度。
It
also
generates
accurate
contours.
Material
removal
processes
are
also
called
machining processes.
它还生成精确的轮廓。材料去除过程也称为加工过程。
The
various
processes
in
this
category
are
turning,
grinding,
drilling,
broaching,
shaping
and
planning,
sowing,
milling.
各种流程在这个类别是车削、磨削、钻孔、扩孔、塑造和规划、播种
、铣削。
All
these
manufacturing
processes
have
been continuously
developed so as
obtain better products
at a reduced
cost.
所有这些制造工艺不断发展
,
获得更好的产品在降低成本。
Of
particular
interest
is
the
development
of
computer
and
their
effect
on
the
manufacturing
processes.
特别感兴趣的是计算机的发展及其影响制造过程。
The advent of computers has remarkable
difference to most of the above manufacturing
processes.
电脑的出现有
显著差异
,
最上面的制造过程。
They have
contributed greatly to both automation and
designing the process.
他们作
出了巨
大贡献两个自动化和设计过程
An important
responsibility of the engineer is to choose a
manufacturing process, which makes the required
quality
of a product to the
specifications and at the lowest cost
possible.
工程师的一个重要职责是选择一个以尽可
能低
的成本制造出所需质量的产品的制造过程。
To
fulfil
both
the
conditions,
one
would
have
to
do
a
break-even
analysis of the
various processes suitable for the production of
the given object.
为了实现这两方面的目
标，工程
师必须针对给定的目标对不同的制造过程做出适当的盈亏平衡分析，
In the break-even analysis, two
types of costs are considered:
在盈亏平衡分析中要考虑两方面的成本，
Fixed cost relates to the initial
investment on the equipment and tools required for
the process. This cost would be
constant and
does
not vary
with
quantity
produced.
固定成本与制造
过程相关联的所有设备和工具的投资是固
定成本，固定成本是固定的，不以产量而异，另
一方面是可变成本，因实际产量不同而有差别。
Variable cost on the other hand, varies
with the actual number of objects made. This takes
into account the raw
material
required,
energy
consumed,
labour
cost,
cost
of
special
toolings,
cost
of
tools
used
and
other
administrative overheads. requirement
of these are directly proportional to the quantity
produced.
可变成本计算进的所需原材料消耗、能量消耗劳动力成本、特殊工
具成本和其他的行政管理费用，这些通常和
产量是成比例的
The same is shown in graphical form in
Fig. ly, as the quantity of produced decreases.
This is due to the
fact that the fixed
cost associated with the production remains
constant.
相同的显示在图形化的形式在图
1.1<
/p>
。通常
,
作为生产的数量减少。这是由于
这样的事实
,
即固定成本与生产有关
保
持不变。
If the engineer has to
make a choice between two different processes for
manufacturing the same component, he
may first estimate the fixed costs and
variable costs for both the processes and then
plot the total cost curves for
both as
in Fig.
如果一位工程师必须制造同一产品的两种不同工艺做出选择，
他必须首先估计两种工艺的总的固
定成本和可变成本，然后绘制总成本曲
线，
The point where both these curves
intersect is called the break-even
point.
这些曲线的交点叫做盈亏平衡点，
It
implies
that
the
first
process
will
be
economical
if
the
quantity
of
production is less than that of the
break-even point, that while beyond it the second
process is economical.
这意味
着如果
产量比盈亏平衡点低第一种工艺是经济的，如果产量超过该点那么，第二种是经济的。
The break-even quantity, n,
can also be obtained by equating the
total costs in both the processes.
保本量
,n,
也可以把获得的总成本的过程。<
/p>
This would give
a positive value when a fixed and variable costs
are lower than the other process, then the latter
process is always uneconomical whatever
may be the production quantity.
这将给一个积极的
价值当一个固定和
可变成本是低于其他过程
,
< br>那么后者过程总是不经济的任何可能的生产数量。
The manufacturing of a component may
involve more than one process or more variants of
the same process.
制
造一个组件可能会涉
及到多个进程或更多的变种相同的过程。
In
the
first
case,
it
is
necessary
to
consider
the
costs of all the processes while
computing the total cost for each of the processes
在第一种情况下
,
有必要考虑成
本的所有工序
,
同时计算总成本的每个过程<
/p>
The deformation caused in a
material is of two types, elastic and
plastic.
在材料中引起的变形可以分为
两种类型，弹性变形和塑性变形
Elastic deformation
is that part of the deformed material which when
the applied
load is removed, would
spring back to its normal shape.
弹性变形是指
材料上所施加的载荷被移除后能恢复原来
形状的变形。
Plas
tic deformation is on the other hand , permanently
set in a material and cannot be regained.
，塑性
变形是另一方面，永久的不可回复的变形。
Tensile strength is
measured by a tensile test carried out on a
universal testing machine.
拉应力通过在一
种通用的测试机上实施的测试实验测得。
This involves
the preparation of a test specimen as per standard
shown in
Fig.2.1
包括图
2.1
所示作为标准的样本的准备。
The standard specimen can be either
rectangular or cylindrical.
样
本可以是矩形的也可以是圆柱形的，
Rectangular is
generally used for plate-type
specimens.
矩形的通常被用于板
式样本，
Care has to be taken to see that the
specimen is prepared in a way such that the
surface is smooth and
without any deep
cracks or nicks.
必须保证样本的表面是平滑的、没有任何裂缝或刻痕
。
The
tensile
testing
machine
consists
of
a
heavy
test
frame
with
a
lower
fixed
beam,
and
an
upper
crosshead which is the
moving beam used to apply the tensile force on the
specimen as shown in Fig2.2.
拉伸试验机
由一个带有一个较低的横梁和一个在样本上施加拉力的联杆器的巨大测试机
架组成。
The
specimen
is
mounted
between two grips ,one attached to the
fixed beam and the other attached to the
crosshead.
样本只能装在两个抓
爪间，一个附加在
横梁上，另一个附加在连杆器上，
An extensometer is
attached to the specimen to measure the
elongation of the test specimen as the
force is being applied .
当施加
负载时一个伸长仪被加到样品上来测量测试
样本的伸长量。
Th
en a uniformly increasing tensile load is applied
on the specimen.
然后一个均匀增加的载荷被施
加到样本上，
The movement of the crosshead
relative to the fixed beam generates strain within
the specimen and a
corresponding
load.
连杆器和横梁的相对运动在样本上形成张力和一个相应的载荷。
As the load increases, the
specimen initially gets elastically
elongated. As can be noted from Fig2.1, the
central portion is smaller compared to
the gripping section.
随着载荷的增加，样本首先产生弹性变形，如图
2.1
所示，相比之下中心部分比引人瞩目的
区域要小。
On further elongation, the specimen
starts necking at some point (within the gauge
marks) when the
material goes beyond
the elastic range.
继续加载荷，当材料超过弹性范围样本在一些
点处会变窄。
The reduced
width of
he specimen would be reduced under the force of
the load and finally develop fractures when the
test is
completed.
在载荷的作用下样本
减少的宽度会减少，当测试结束时样本会最终断裂。
If
the
necking
does
not
happen within the gauge
marks, the test need to be repeated with a
different specimen.
如果断裂没有在标准刻度
< br>内发生，测试需要用不同的样本重新做。
During the test ,
a record is maintained of the load and the
corresponding
elongation.
在测试中应持续记载载荷和相应的伸长量。
The
stresses and strains are calculated from the above
data
and plotted in a diagram as shown
in Fig.2.3.
应力和张力可以由上述数据计算并被绘制成图
< br>2.3
所示图标。
It
can be observed that there is a limit up to which
the applied stress is directly proportional to the
induced
strain.
可以观察到所施加的力和诱发的张力直接成比例，
This
is represented by the linear portion of the curve
up
to A which is termed as the
proportional limit.
这一点可以有延伸到
A
点的线性曲线表示，
A
点叫做比例
极限。
The
end
of
this
linear
portion
is
the
yield
point
of
the
material
above
which
the
material
starts
plastically
by
the
bow-shaped portion of
the cube.
线性部分的终点叫做屈服点，在屈服点以上材料开始弹性变形，拱
形曲线表明
在弹性范围内，应力与张力之间没有明显的线性关系。
Finally, the specimen breaks when the force of
the applied
load goes beyond the limit
that can be borne by the material.
最终样本在
所施加载荷超过材料所能承受的极限时发
生断裂。
The
proportional
limit
is
often
difficult
to
calculate,
therefore,
two
practical
measurements,
offset
yield
strength (OYS) and
yield by extension under load (EUL), were
developed to approximate the proportional limit. <
/p>
比例
极限通常难以计算，
因此，
两种特殊的测量方法，
补偿屈服应力和延伸屈服被发展用于近似代替比例
极限。
Point
B represents the
offset yield strength and is found by constructing
a line X-
B parallel to the curve in the elastic
region.
点
b
通过在弹性范围内构造一条平行线
x-b
表示补偿屈服
应力。
Line X-B is offset a strain amount
O-X that is
typically 0.2% of the guage
length.
X-B
线补偿了拉伸长度
O-X
所表示的的应力的
0.2%
。
Point C represents the yield
strength by extension under load and is
found by constructing a vertical line Y-C.
点
C
通过在在载荷下的拉伸量并构
成曲线
Y-C
来表示屈服应力。
L
ine Y-C is offset a strain amount O-Y that is
typically 0.5% of the guage length.
Y-C
线补
偿拉伸长度
O-Y
所表示的应力的
0.5%
。
T
he ultimate tensile strength , or peak stress, is
represented by the point C.
最终的拉伸应力或顶点应力由点
D
表示。
Total elongation, which includes both
elastic and plastic deformation, is
the
amount
of
uniaxial
strain
at
fracture
and
is
depicted
as
strain
at
the
point
cent
elongation
at
break
is
determined by removing the fractured
specimen from the grips;
总伸长
量，包括弹性变形和塑性变形，是断裂时
的单轴应变，
由
Z
点的应变表示。
fitting the broken ends together and
measuring the distance between guage
marks.
断裂点的单一伸长量由移动抓爪间的断裂样本决定。
Per cent elongation at break reports
the amount of plastic
deformation only.
The guage length used for measurement is reported
with the result.
他和断裂点相配合来测量定
位刻度间的距离。
Similar tests can
also be conducted for measuring the compression
and shear strength.
Hardness is a very important property
since the manufacturing depends on it to a great
extent.
硬度是非常
重要的性
能，因为制造在很大程度上依赖与他，
Hardness
is the resistance offered by a material
indentation. Moh
的
scale of
hardness is based on ten standard minerals as
shown in Table 2.1.
硬度是材料对压力的抵抗力莫氏硬度
测量基于表
2.1
所示的十种标准矿物。
It can be measured by the indentation
made by a harder material. .
通常可以
由一种坚硬的材料造成的压痕来测量。
The indentation
made depends upon the applied load, the sharpness
of the
indentor and the time for which
the applied load is maintained
压痕取决于所施加负
载，
压痕的清晰度取决于负载应
用的时间。
There are a number of indentation
tests to measure the hardness of a material
normally.
同场还有许
多硬度测试方法来测量材料的
硬度。
These usually involve a ball, a cone
or a pyramid of a harder material which is
indented into the material under test
with a specified load.
这些测试方法通常是在指定的负载下
把由坚硬的材料
制成的团块、
圆锥体或球椎体压入材料，
The permanent indentation thus made is
measured to give an indication of
the
hardness on the given scale
for the tes
ts.
偶测量这些所产生的永久压痕来在测试给定的范围内对材料的硬度
做出指示。
Some precautions
that need to be taken during the use of Brinell
test are that the surface of the material
whose hardness is being tested should
be smooth and even, and there is enough material
underneath the indentation
and on all
sides to give a proper value for the
indentation.
一些预防措施
,
需要在使用布氏硬度试验是材料的表面
的硬度测试应光滑
、均匀
,
并有足够的材料在压痕和在各方面给予适当的缩进值。
The
Brinell
hardness
of
steel
is
roughly
related
to
the
tensile
strength
of
the
material
utilizing
the
following empirical relationship for
plain carbon steels.
这个布氏硬度的
钢大致与抗拉强度的材料利用以下实证关
系碳素钢。
It may be noted that these conversions
are only approximate.
可以指出
,<
/p>
这些转换只是近似。
Also, the
actual relationship depends upon the
chemical composition of the alloy as well as the
heat treatment process.
同时
,<
/p>
实际的关系取决于合金的化学成分和热处理工艺。
Compara
tive values for these are given in Table
2.2.
比较值在
表
2.2
中给出了这些。
There are
number of indentation tests to measure the
hardness of a material normally.
通常还有许多硬度测试方法来测量材料的硬度
These
usually
involve
a
ball,
a
cone
or
a
pyramid
of
a
harder
material
which
is
indented
into
the
material
under
test
with
a
specified
load.
The
permanent
indentation
thus
made is measured to give an indication
of the hardness on the given scale for the tests
这些测试方法通常是在指定
的负载下把由坚硬的材料制成的团块、圆
锥体或球椎体压入材料，偶测量这些所产生的永久压痕来在测试给定
的范围内对材料的硬
度做出指示。
The most commonly
used tests are the following:
最常用的测试有以下几种
Brinell hardness test where a sphere
(usually of diameter 10+0.01mm) made of steel or
tungsten Carbide is
indented with a
gradually applied load at right angles to the
specimen surface and the indentation diameter made
on the specimen
measured.
验
Then the Brinell
hardness number, BHN is given by
布氏强度是通过
施加
90°
的压力在
用钢或钨化物做成
的试件表面
,
然后测试试件上压痕直接来获得的
BHN=2p/D[D-
√
D2-d2]
Where
P is the applied load in kg,
D
is the diameter of the ball in mm, and
d is the
diameter of the indentation in mm
其中，
P
是所施加的载荷千克，
D
是球的直径
,
毫米，
和
d
为压痕
的直径，用
mm
表示
The applied
load P is based on the hardness of the specimen
material being tested.
所施加的载荷
P
是根据被测试
的样品材料硬度
Some
precautions that need to be taken during the use
of Brinell tests are that the surface of the
material
whose
hardness
is
being
tested
should
be
smooth
and
even,
and
there
is
enough
material
underneath
the
indentation and on all
sides to give a proper value for the indentation.
贝氏硬度的测试使用过程中要采取某些预
防措施，需要被测试的
材料的硬度，表面应是光滑和均匀的，并且压痕下应该有足够的材料，下面的压痕和各
侧
面，应该有一个适当的压痕值
The
Brinell hardness of steel is roughly related to
the tensile strength of the material utilizing
thefollow ing
empirical
relationship
for
plain
carbon
steels.
普通钢和布氏硬度相关的抗拉强度可利用下面的经验公式来
表达
Tensile strength (in MPa
= 3.55 x BHN when
BHN<
≤
175
Tensile strength (in MPa)= 3.38 x BHN
when BHN > 175
It may be noted that these
conversions are only approximate. Also, the actual
relationship depends upon the
chemical
composition of the alloy as well as the heat
treatment process. Comparative values for these
are given in
Table 2.2.
可能需要注意的是这些转化都是相互的。当然，实际关系依赖于合金化学成分和热处理工艺，这
些
比较值如
2.2
所示
Rockwell
tests
utilize
the
principle
that
the
depth
of
penetration
of
the
indentor
is
proportional
to
the
material
hardness.
洛氏硬度运用的规律是压痕仪的渗透深度和材料的硬度成正比的
Thus,
the
hardness
measurement is
faster compared to other methods.
这样的硬度的测试和其他的方法相比快得多
In the
Rockwell
test,
a
sphero-conical
diamond
cone
of
120angle
and
a
spherical
apex
of
0.2-mm
radius
is
used
to
make
the
indentation, and the depth of the
indentation, t, is used as a criterion to
calculate the hardness number.
洛氏硬度
的测试是用一个成
120°
的金刚石球锥和直径为
0.2mm
的球形顶总来压痕，
压痕深
度
t
则用来作为计算硬度的一个
标准<
/p>
The Rockwell hardness number (R) is
given by
洛氏硬度值可以从下列式得出
R = 100-500 t
Depending on the load used
for indentation there are a number of scales, A,
B, C, etc., available in Rockwell
tests.
依据压痕所加负载，适用于洛氏硬度测试的一系
列数据范围可为
A.B,C,
等，
Th
ese
are
used
for
materials
with
different
hardnesses.
这些都是用于不同硬度的材料
In
the
Rockwell
B
test.
a
steel
ball
of
0.06t5-inch
diameter is used
with a load of l00kg.
在洛氏
B
测试。
0.06t5
英寸直径的钢球用
l00kg
负载
This test is normally used
for low and
medium carbon steels. It should not be used for
materials whose hardness is above RB l00.
< br>这种测试
通常用于低，中碳钢。但它不允许测试硬度以上的材料
< br>For materials with hardness above this value, Rockwell C
test (30 RB corresponds to O
RC) is more generally used.
对于材料的硬度高于此值
，通常用于洛氏
C
测试（
30
RB
对应到
O
RC
），
This is the fastest way
of measuring hardness because the hardness can
directly be read from the
scale on the
Rockwell tester.
这是最快的方式，因为硬度可从洛氏硬度计上的刻
度直接读取硬度测量值。
Besides, there are other tests
available such as Vicker's and Knoop hardness
tests to measure hardness over
a small
area. In Vickers hardness test, a square base
pyramid diamond indentor having
136°
betweern the opposite
faces is used.
此外，在某些小范围内可以使
用维氏硬度努氏硬度在维克硬度测试中，与
136°
的的相反面
三角锥
压痕仪一个平面方面内进行测试，
The Vickers hardness number (VHN) is
calculated by
维氏硬度值通过下式计算
VHN
=
1.854L/D2
where
L
is
the
applied
load
in
kg
which
is
normally
about
30
kg,
though
provision
up
to
120kg
would
Be
available
on
the
testing
machine for harder
materials, and D is the measured average diagonal
of the indentation in mm
其中
L<
/p>
是所施
加的负载（公斤），通常是约
30
公斤，虽然对较硬的材料增加到
120
千克中对测试仪来说也是可行的，
D
表示压痕对角线长度，用<
/p>
mm
表示
The scleroscope
uses a different principle to measure the hardness
which is based on the rebound height
of
a ball from the specimen.
肖式硬度计用一个不同的规则
来测试材料硬度，
它是基于从试件弹回的小球的高度
来的
The harder the material, the
higher is the height to which the ball rebounds. <
/p>
材料的硬度越高，小球弹回的
高度也越高
Because of
these hardness tests being conducted under
arbitrary conditions, it is difficult to have any
proper
correlation between the
different scales An
approximate
relationship of these
hardness values is presented in
Table 2.2 merely as a guideline
由于这些
硬度是在变化的条件下进行导出的，
不同尺度之间很难有任何适当的
关联性
The
hardness
values
are
normally
represented
as
200
BHN,
32Rc
,etc.
Representaive
values
of
some
commonly used materials are presented
in Table2.3
硬度值通常表示为
200 BHN
，
32Rc
，等。一些常用的代表性材
料硬度值如
Table2.3
It is
the measure of the amount of plastic deformation a
material can undergo under tensile forces without
fracture. In quantitative terms it is
normally measured as the ratio of elongation of
the material at fracture during
the
tensile test to the original length, expressed as
a percentage.
延展性是对一种材料在拉力作用下不断裂所能
承受的弹性变形量的估量。材料到断裂时的伸长量与原始长度的比例定量地表示成一种百分关系
The final value of elongation
obtained during the tensile test immediately after
the fracture could be taken
as the
ductility .
材料在拉伸试验中突然断裂时的拉伸估计值可以被做延展性
Since the elongation is dependent upon
the gauge length chosen for the tensile test, the
length needs to be
specified
along
with
the
elongation
values.
Alternatively, it may also be expressed as the
ratio of reduction in cross-sectional area in the
fractured specimen to the original
cross-section area.
因为伸长量取决于拉伸试验选择的标距长度
，所以标距长
度须由伸长估计值规定
This is independent of the gauge length
and hence is a more convenient measure for
ductility. it
二者选一
的，
他也可以被表示为断裂样本的代表性区域与原始区域的延伸比率
is also
termed as the ability of a material to
be
drawn
into
wires
since
only
ductile
materials
can
be
drawn into
continuous
wires
without breaking in
between.
Typical values
of
ductilities are given in Table 2.4 for
engineering materials.
也可以表示
为材料被拉成线状的能力，因为只有延展
性材料才可以在不断裂的情况下被拉成线状
Besides the tensile tests,
special forms of ductility testing based on the
desired application can be done
using
the bend test and cupping tests for the purpose of
sheet metal forming applications. More details of
these
tests can be found in
literature.
除了拉伸试验外，特殊的基于所期望
功能的实验可以用弯曲试验，杯状测试来
测试薄片材料的延展性
Brittleness is the property opposite to
that of ductility.
脆性属性延性相反
2.1.4
Toughness
This is the
property which signifies the amount of energy
absorbed by a material at the time of fracture
under
impact
loading.
这是表示材料在冲击载荷下断裂时吸收能量数量的性能。
In
short,
it
is
the
capacity
to
take
impact load.
简言之，就是抵抗冲击载荷的能力。
It can be
considered
as the total
area under the
stress-strain
curve since it is an indication of the
amount of work done on the material without
causing fracture.
韧性可以被看
做应力应
变曲线下方的整体区域，
因为韧性是不引起断裂情况下作用与材料的功的总量。
Thus toughness can be
considered
as a parameter consisting of both strength and duc
tility.
因此韧性可以被看做是应力和延展性的组成
参数
。
Toughness of a material is
measured by means of impact tests, where a notched
bar prepared as per standard
from the
test material, is held in a vice and a weight is
allowed to swing from a known height in such a way
that it
hits the notched bar in its
path and breaks it. Since the material has
absorbed some amount of energy during its
fracture, the swinging mass loses part
of its energy and therefore will not be able to
reach the same height from
where it
started, as shown in Fig. 2.4.
一种材料的韧性可以
通过冲击试验来测得，在这个实验中，一个有测试材
料做成的有凹口的棒被老虎钳夹住，
然后一个重物沿棒的轨道从已知高度摆下并击断他，因为材料在断裂时吸
收了能量，所以
摆动物块失去了一部分能量故而无法达到他的起始高度。如图所示。
2.4
。
The loss in height(h)
multiplied by the weight represents the
energy absorbed by the specimen during fracture,
which can be directly
measured from the
indicator on the tester.
高度损失随样品吸收的能量的增加
而增加，这可以在实验中用显示计
直接测量。
In the Charpy
impact test, the specimen is held between two
grips whereas in the lzod impact test the specimen
is held at one end like a cantilever as
represented in Fig.2.4.
在卡氏冲击实验中，
样品被夹住两端，
而在艾氏冲击
实验中，
样品被如图
2.4
所示像悬臂梁一样只被夹住一端
。
The standard test specimens used in
the Izod and Charpy
impact tests are
made of bars with a square cross section of 10 mm
, the details of which are given in Fig.2.5.
在布
氏与艾氏冲击试验中标准样品被制成具有
10m
m
正方形横截面的棒状具体细节如图
2.5
给出。
The
impact
resistance
is
dependent
upon
the
material
composition
as
well
as
the
heat
treatment
process
given
to
it.
The
annealed
materials
normally
would
have
better
toughness
than
the
corresponding
normalized
or
quenched
specimens.
冲击抗力取决于材料的成分及所用的热处理工艺。煅烧过的样品通常比对应的未煅烧淬火样品具有
< p>更好韧性
Coarse-grained
structures
would
tend
to
have
higher
ductility
compared
to
fine
grain
structure
and
consequently
better
toughness.
粗晶端口通常比细晶断口结构具有更高的塑性和韧性。
Typical
values
of
impact
resistance measured from these tests
are given in Table 2.5 below.
从这些测试中测得的耐
冲击性的典型值在下面
的表
2.5
中给
出。
2.2 RERROUS MATERIALS
We use a
variety of metals, non-metals and their compounds
in our daily life.
我们使用各种金属、非金属及其化
合物在我们的日常生活中。
For
example, a typical automobile may contain the
following materials
例如，一个典
型的汽
车可能含有下列材料
Based on their origin and composition
these materials may be broadly classified as shown
in Fig.2.6.
根据其来源
和组成，这些材料大致可归
类为图
2.6
所示。
Among these,
ferrous materials are by far, used most
extensively because of their better and varied
mechanical