Monday, October 8, 2007
Sunday, June 10, 2007
Questions we are Frequently Asked
Questions we are Frequently Asked
Some of the frequently asked questions we get asked are presented below:
What are the marks shown on the head of a bolt?
When tightening stainless steel bolts - they tend to seize - what's happening?
I can't find the shear strength of a fastener in the specification,can you help?
What is the best way to check the torque value on a bolt?
What are the benefits of fine threaded fasteners over coarse threaded fasteners?
What methods are available for calculating the appropriate tightening torque for a bolt.
Does it matter whether you tighten the bolt head or the nut?
How do you select a fastener size for a particular application?
Does using an extension on a torque wrench change the abliity to achieve the desired torque value?
Is it okay to use a mild steel nut with a high tensile bolt?
Should I always use a washer under the bolt head and nut face?
What is the torque to yield tightening method?
How do metric strength grades correspond to the inch strength grades?
What is the difference between a bolt and a screw?
Are the use of a thin nut and a thick nut effective in preventing loosening?
Is there some standard that states how much the thread should protrude past the nut?
What are the marks shown on the head of a bolt?
head of a bolt. The manufacturer's mark is a symbol identifying
the manufacturer (or importer). This is the organisation that
accepts the responsibility that the fastener meets specified 
requirements. The grade mark is a standardised mark that identifies
the material properties that the fastener meets. For example
307A on a bolt head indicates that the fastener properties
conform to the ASTM A307 Grade A standard. The bolt head shown
at the side indicates that it is of property class 8.8 and
ML is the manufacturer's mark.
Both marks are usually located on the top of the bolt head,
most standards indicating that the marks can be raised or
depressed. Raised marks are usually preferred by manufacturers
because these can only be added during the forging process
whereas depressed marks can subsequently added (possibly with
illegitimate marks).
We have a problem when tightening stainless steel bolts - they tend to seize - whats happening?
Stainless steel can unpredictably sustain
galling (cold welding). Stainless steel self-generates an
oxide surface film for corrosion protection. During fastener
tightening, as pressure builds between the contacting and
sliding, thread surfaces, protective oxides are broken, possibly
wiped off, and interface metal high points shear or lock together.
This cumulative clogging-shearing-locking action causes increasing
adhesion. In the extreme, galling leads to seizing - the actual
freezing together of the threads. If tightening is continued,
the fastener can be twisted off or its threads ripped out.
If galling is occurring than because of high friction the
torque will not be converted into bolt preload. This may be
the cause of the problems that you are experiencing. The change
may be due to the surface roughness changing on the threads
or other similar minor change. To overcome the problem - suggestions
are:
1. Slowing down the installation RPM speed may possibly solve
or reduce the frequency of the problem. As the installation
RPM increases, the heat generated during tightening increases.
As the heat increases, so does the tendency for the occurrence
of thread galling.
2. Lubricating the internal and/or external threads frequently
can eliminate thread galling. The lubricants usually contain
substantial amounts of molybdenum disulfide (moly). Some extreme
pressure waxes can also be effective. Be careful however,
if you use the stainless steel fasteners in food related applications
some lubricants may be unacceptable. Lubricants can be applied
at the point of assembly or pre-applied as a batch process
similar to plating. Several chemical companies, such as Moly-Kote,
offer anti-galling lubricants.
3. Different combinations of nut and bolt materials can assist
in reducing or even eliminating galling. Some organisations
specify a different material, such as aluminium bronze nuts.
However this can introduce a corrosion problem since aluminium
bronze is anodic to stainless steel.
I can't find the shear strength of a fastener in the specification,
can you help?
Bolted shear joints can be designed as
friction grip or direct shear. With friction grip joints you
must ensure that the friction force developed by the bolts
is sufficient to prevent slip between the plates comprising
the joint. Friction grip joints are preferred if the load
is dynamic since it prevents fretting.
With direct shear joints the shank of the
bolts sustain the shear force directly giving rise to a shear
stress in the bolt. The shear strength of a steel fastener
is about 0.6 times the tensile strength. This ratio is largely
independent of the tensile strength. The shear plane should
go through the unthreaded shank of a bolt if not than the
root area of the thread must be used in the calculation.
What is the best way to check the torque value on a bolt?
There are three basic methods for the checking
of torques applied to bolts after their installation; namely,
taking the reading on a torque gauge when:
1. The socket begins to move away from
the tightened position in the tightening direction. This method
is frequently referred to as the "crack-on" method.
2. The socket begins to move away from
the tightened position in the un- tightening direction. This
method is frequently referred to as the "crack-off"
method.
3. The fastener is re-tightened up to a
marked position. With the "marked fastener" method
the socket approaches a marked position in the tightening
direction. Clear marks are first scribed on the socket and
onto the joint surface which will remain stationary when the
nut is rotated. (Avoid scribing on washers since these can
turn with the nut.) The nut is backed off by about 30 degrees,
followed by re-tightening so that the scribed lines coincide.
For methods 1. and 2. the breakloose torque
is normally slightly higher than the installation torque since
static friction is usually greater than dynamic friction.
In my opinion, the most accurate method is method 3 - however
what this will not address is the permanent deformation caused
by gasket creep. An alternative is to measure the bolt elongation
(if the fastener is not tapped into the gearbox). This can
be achieved by machining the head of the bolt and the end
of the bolt so that it can be accurately measured using a
micrometer. Checking the change in length will determine if
you are losing preload.
The torque in all three methods should
be applied in a slow and deliberate manner in order that dynamic
effects on the gauge reading are minimised. It must always
be ensured that the non- rotating member, usually the bolt,
is held secure when checking torques. The torque reading should
be checked as soon after the tightening operation as possible
and before any subsequent process such as painting, heating
etc. The torque readings are dependent upon the coefficients
of friction present under the nut face and in the threads.
If the fasteners are left to long, or subjected to different
environmental conditions before checking, friction and consequently
the torque values, can vary. Variation can also be caused
by embedding (plastic deformation) of the threads and nut
face/joint surface which does occur. This embedding results
in bolt tension reduction and affects the tightening torque.
The torque values can vary by as much as 20% if the bolts
are left standing for two days.
What are the benefits of fine threaded fasteners over coarse threaded fasteners?
The potential benefits of fine threads are:
1. Size for size a fine thread is stronger
than a coarse thread . This is both in tension (because of
the larger stress area) and shear (because of their larger
minor diameter).
2. Fine threads have also less tendency
to loosen since the thread incline is smaller and hence so
is the off torque.
3. Because of the smaller pitch they allow
finer adjustments in applications that need such a feature.
4. Fine threads can be more easily tapped
into hard materials and thin walled tubes.
5. Fine threads require less torque to
develop equivalent bolt preloads.
On the negative side:
1. Fine threads are more susceptible to
galling than coarse threads.
2. They need longer thread engagements
and are more prone to damage and thread fouling.
3. They are also less suitable for high
speed assembly since they are more likely to seize when being
tightened.
Normally a coarse thread is specified
unless there is an over-riding reason to specify a fine thread,
certainly for metric fasteners, fine threads are more difficult
to obtain.
What methods are available for calculating the appropriate tightening
torque for a bolt?
A high bolt preload ensures that the joint
is resistant to vibration loosening and to fatigue. In most
applications, the higher the preload - the better (assuming
that the surface pressure under the nut face is not exceeded
that is).
The preload is related to the applied torque
by friction that is present under the nut face and in the
threads. The torque value depends primarily on the values
of the underhead and thread friction values and so a single
figure cannot be quoted for a given thread size.
The stress that is often quoted is often
taken as the direct stress in the bolt as a result of the
preload. It is normally calculated as preload divided by the
stress area of the thread. Typical values vary between 50%
to 80% of the yield strength of the bolt material, in many
applications a figure of 75% of yield is used. Our TORKSense
program uses this approach and further details on this is
presented in the help file that comes with the demo program
that is available for download from our web site. (This program
also provides large databases on thread, bolting materials
and nut factors.)
It is important to note that it does not
take into account the torsional stress as a result of the
tightening torque. High friction values can push the actual
combined stress over yield if high percentages are used. (The
tensile stress from the preload coupled with a high torsional
shear stress from the torque due to thread frictional drag
results in a high combined stress.) The percentage yield approach
works well in most practical circumstances but if you are
using percentage of yield values over 75% then you could be
exceeding yield if high friction values are being used.
One way to over come this limitation is
to use the percentage of yield based upon the combined effects
of the direct stress (from the bolt preload) and the torsional
stress (from the applied torque). Using this approach to specify
torque values is more logically consistent and can reduce
the risk of the yield strength of the bolt being exceeded
- especially under high thread friction conditions. A figure
of 90% of yield is typically used here when the combined stress
(usually calculated as the Von-Mises stress) from the direct
and torsional stresses is calculated. Our Torque and BOLTCALC
programs uses this approach and a copy of the demo program
can be downloaded from our web site. The help file provided
with the demo program does provide additional information
on this topic.
Does it matter whether you tighten the bolt head or the nut?
Normally it will not matter whether the
bolt head or the nut is torqued. This assumes that the bolt
head and nut face are of the same diameter. If they are not
then it does matter.
Say the nut was flanged and the bolt head
was not. If the tightening torque was determined assuming
that the nut was to be tightened then if the bolt head was
subsequently tightened instead then the bolt could be overloaded.
Typically 50% of the torque is used to overcome friction under
the tightening surface. Hence a smaller friction radius will
result in more torque going into the thread of the bolt and
hence being over tightened.
If the reverse was true - the torque determined
assuming that the bolt head was to be tightened then if the
nut was subsequently tightened - the bolt would be under tightened.
There is also an effect due to nut dilation
that can, on occasion, be important. Nut dilation is the effect
of the external threads being pushed out due to the wedge
action of the threads. This reduces the thread stripping area
and is more prone to happen when the nut is tightened since
the tightening action facilitates the effect. Hence if thread
stripping is a potential problem, and for normal standard
nuts and bolts it is not, then tightening the bolt can be
beneficial.
How do you select a fastener size for a particular application?
When selecting a suitable fastener for
a particular application there are several factors that must
be taken into account. Principally these are:
1. How many and what size/strength do the
fasteners need to be? Other than rely upon past experience
of a similar application an analysis must be completed to
determine the size/number/strength requirements. A program
like BOLTCALC can assist you with resolving this issue.
2. The bolt material to resist the environmental
conditions prevailing. This could mean using a standard steel
fastener with surface protection or may mean using a material
more naturally corrosion resistant such as stainless steel.
The general underlying principle is to
minimise the cost of the fastener whilst meeting the specification/life
requirements of the application. Each situation must be considered
on its merit and obviously some detailed work is necessary
to arrive at a detailed recommendation.
Does using an extension on a torque wrench change the abliity to
achieve the desired torque value?
If you use an extension spanner on the
end of a torque wrench, the torque applied to the nut is greater
than that shown on the torque wrench dial.
If the torque wrench has a length L, and
the extension spanner a length E (overall length of L+E) than:
TRUE TORQUE= DIAL READING X (L+E)/L
i.e the torque will be increased.
Is it okay to use a mild steel nut with a high tensile bolt?
Nut thickness standards have been drawn
up on the basis that the bolt will always sustain tensile
fracture before the nut will strip. If the bolt breaks on
tightening, it is obvious that a replacement is required.
Thread stripping tends to be gradual in nature. If the thread
stripping mode can occur, assemblies may enter into service
which are partially failed, this may have disastrous consequences.
Hence, the potential of thread stripping of both the internal
and external threads must be avoided if a reliable design
is to be achieved. When specifying nuts and bolts it must
always be ensured that the appropriate grade of nut is matched
to the bolt grade.
The standard strength grade (or Property
Class as it is known in the standards) for many industries
is 8.8. On the head of the bolt, 8.8 should be marked together
with a mark to indicate the manufacturer. The Property Class
of the nut matched to a 8.8 bolt is a grade 8. The nut should
be marked with a 8, a manufacturer's identification symbol
shall be at the manufacturer's discretion.
Higher tensile bolts such as property class
10.9 and 12.9 have matching nuts 10 and 12 respectively. In
general, nuts of a higher property class can replace nuts
of lower property class (because as explained above, the 'weakest
link' is required to be the tensile fracture of the bolt).
Should I always use a washer under the bolt head and nut face?
Our opinion is that plain washers are best
avoided if possible and certainly, a plain washer should not
be used with a 'lock' washer. It would partly negate the effect
of the locking action and secondly could lead to other problems
(see below). Many 'lock' washers have been shown to be ineffective
in resisting loosening.
The main purpose of a washer is to distribute
the load under the bolt head and nut face. Instead of using
washers however the trend as been to the use of flanged fasteners.
If you compute the bearing stress under the nut face it often
exceeds the bearing strength of the joint material and can
lead to creep and bolt preload loss. Traditionally a plain
washer (that should be hardened) is used in this application.
However they can move during the tightening process (see below)
causing problems.
Research indicates that the reason why
fasteners come loose is usually caused by transverse loadings
causing slippage of the joint. The fastener self loosens by
this method. When using impact tightening tools there is a
large variability in the preload achieved by the fastener.
The tightening factor is between 2.5 and 4 for this method.
(The tightening factor is the ratio of max preload to min.
preload.) Software such as our BOLTCALC program allow for
this by basing the design on the lowest anticipated preload
that will be achieved in the assembly. Because of changes
in the thread condition itself - different operators etc.
it could be that lower values of preload are being achieved
even though the assemblies may appear to be identical.
One problem that can occur with washers
is that they can move when being tightened so that the washer
can rotate with the nut or bolt head rather than remaining
fixed. This can affect the torque tension relationship.
What is the torque to yield tightening method?
Torque to yield is the method of tightening
a fastener so that a high preload is achieved by tightening
up the yield point of the fastener material. To do this consistently
requires special equipment that monitors the tightening process.
Basically, as the tightening is being completed the equipment
monitors the torque verses angle of rotation of the fastener.
When it deviates from a specified gradient by a certain amount
the tool stops the tightening process. The deviation from
a specified gradient indicates that the fastener material
as yielded.
The torque to yield method is sometimes
called yield controlled tightening or joint controlled tightening.
How do metric strength grades correspond to the inch strength grades?
Some details on conversion guidance between
metric and inch based strength grades is given in section
3.4 of the standard SAE J1199 (Mechanical and Material Requirements
for Metric Externally Threaded Steel Fasteners).
Metric fastener strength is denoted by
a property class which is equivalent to a strength grade.
Briefly:
Class 4.6 is approximately equivalent to
SAE J429 Grade 1 and ASTM A307 Grade A
Class 5.8 is approximately equivalent to
SAE J429 Grade 2
Class 8.8 is approximately equivalent to
SAE J429 Grade 5 and ASTM A449
Class 9.8 is approximately 9% stronger
than equivalent to SAE J429 Grade 5 and ASTM A449
Class 10.9 is approximately equivalent
to SAE J429 Grade 8 and ASTM A354 Grade BD
For information there is no direct inch
equivalent to the metric 12.9 property class.
What is the difference between a bolt and a screw?
Historically the difference between a bolt
and a screw was that the screw was threaded to the head whereas
the bolt had a plain shank. However I would say that now this
could cause you a problem if you made this assumption when
specifying a fastener. The definition used by the Industrial
Fastener Institute (IFI) is that screws are used with tapped
holes and bolts are used with nuts.
Obviously a standard 'bolt' can be used
in a tapped hole or with a nut. The IFI maintain that since
this type of fastener is normally used with a nut then it
is a bolt. Certain short length bolts are threaded to the
head - they are still bolts if the main usage is with nuts.
Screws are fastener products such as wood screws, lag screws
and the various types of tapping screws. The IFI terminology
and definition has been adopted by ASME and ANSI.
Are the use of a thin nut and a thick nut effective in preventing loosening?
I had been of the opinion that when two
nuts were being used to lock a thread, the thicker of the
two nuts should go next to the joint. I had this as one of
the 'tips for the day' on some software and a couple of years
ago was taken to task that this was wrong. The thin nut he
said should go next to the joint.
My reasoning was that nut heights had been
decided by establishing the least height that would ensure
that the bolt would break before the threads started to shear.
So if you wanted to get the maximum preload into the fastener
then the thick nut should go first so that thread stripping
was prevented. If you put the thin nut first, the preload
would be limited by the thread stripping (whose failure may
not be obvious at the time of the nuts were tightened). Putting
the thin nut on top of the thick nut, I thought, would assist
in preventing the thick nut self-loosening. I had also seen
that
using two nuts was a popular method on old machinery - and
the ones that I had seen all had the thin nut on top of the
thick nut.
The correct procedure, I was told, was
to put the thin nut on first, tighten it to 30% or so of the
full torque and then tighten the thick nut on top of it to
the full torque value. You have to take care that the thin
nut does not rotate when you are tightening the thick nut.
The tightening of the thick nut would impose a preload on
the joint equivalent to that which would be obtained from
100 - 30 = 70% of the tightening torque (approximately anyway).
The idea is that the bolt threads engaging on the thin nut
disengage so that the thick nut takes the preload by taking
up the backlash on the threads of the thin nut. The thin nut
being jammed (hence the alternative name - jam nut) against
the thick
nut. This helps to prevent self-loosening and improves the
fastener's fatigue performance by modifying the load distribution
within the threads. Doing it the other way, thin nut on top
of the thick nut, does not jam the parts together sufficiently.
Two years on and I am still unconvinced.
I am still asked the two nut question but I always tend to
recommend other more modern ways of locking the threads. I
think that the reasons that I am not easy with the method
is that it is too reliant upon the skill of the person tightening
the joint. There is also the amount of backlash in the threads
(you could strip the threads of the small nut if it was a
tight fit) and the preload will be down on what it could be
as well.
Is there some standard that states how much the thread should protrude past the nut?
There are some building codes that stipulates that there must
be at least one thread protruding through the nut. However
it is common practice to specify that at least one thread 
pitch must protrude across a range of industries. Typically
the first few pitches of the thread can be only partially
formed because of a chamfer etc.
Nut thickness standards have been drawn
up on the basis that the bolt will always sustain tensile
fracture before the nut will strip. If the bolt breaks on
tightening, it is obvious that a replacement is required.
Thread stripping tends to be gradual in nature. If the thread
stripping mode can occur, assemblies may enter into service
which are partially failed, this may have disastrous consequences.
Hence, the potential of thread stripping of both the internal
and external threads must be avoided if a reliable design
is to be achieved. When specifying nuts and bolts it must
always be ensured that the appropriate grade of nut is matched
to the bolt grade.
In cases of when a threaded fastener is
tapped into a plate or a block it is usually the case that
the fastener and block materials will be of different strengths.
If the criteria is adopted that the bolt must sustain tensile
fracture before the female thread strips, the length of thread
engagement required can be excessive and can become unrealistic
for low strength plate/block materials. Tolerances and pitch
errors between the threads can make the engagement of long
threads problematical.
In summary the full height of the nut is
to be used if you are to avoid thread stripping. Have a look
at information on the website on the BOLTCALC program and
thread stripping - there is a tutorial/presentation available
from the website.
In terms of maximum protrusion I have not
come across any guidelines on this point other then minimise
to avoid wasting material.
See shortbolting.htm
for more information on this topic.
Hex Head Bolt Markings
Hex Head Bolt Markings
The strength and type of steel used in a bolt is supposed to be
indicated by a raised mark on the head of the bolt. The type of mark
depends on the standard to which the bolt was manufactured. Most
often, bolts used in machinery are made to SAE standard J429, and bolts used in
structures are made to various ASTM
standards. The tables below give the head markings and some of the
most commonly-needed information concerning the bolts. For further
information, see the appropriate standard.
ASTM A325 Type 2 bolts have been discontinued, but are included above because they can be found in existing structures. Their properties can be important in failure investigations.
While the bolts shown above are among the most common in the U.S., the list is far from exhaustive. In addition to the other bolts covered by the SAE and ASTM standards, there are a host of international standards, of which ISO is perhaps the most well known.
Thursday, June 7, 2007
Shapes of screw head
(a) pan, (b) button, (c) round, (d) truss, (e) flat, (f) oval
pan head: a low disc with chamfered outer edge.
button or dome head: cylindrical with a rounded top.
round head: dome-shaped, commonly used for machine screws.
truss head: lower-profile dome designed to prevent tampering.
flat head or countersunk: conical, with flat outer face and tapering inner face allowing it to sink into the material.
oval or raised head: countersunk with a rounded top.
bugle head: similar to countersunk, but there is a smooth progression from the shaft to the angle of the head, similar to the bell of a bugle.
cheese head: disc with cylindrical outer edge, height approximately half the head diameter.
fillister head: cylindrical, but with a slightly convex top surface.
socket head: cylindrical, relatively high, with different types of sockets (hex, square, torx, etc.).
mirror screw head: countersunk head with a tapped hole to receive a separate screw-in chrome-plated cover, used for attaching mirrors.
headless (set or grub screw): has either a socket or slot in one end for driving.
Some varieties of screw are manufactured with a break-away head, which snaps off when adequate torque is applied. This prevents tampering and disassembly and also provides an easily-inspectable joint to guarantee proper assembly.
Differentiation between bolt and screw
A screw, by definition, is not a bolt. A bolt is designed such that a nut (or other turning device) is required for operation. A bolt is not designed to be turned. What most people refer to as a bolt is in fact a 'cap screw', which is designed to be turned (or screwed). Cap screws may, or may not be used with nuts. The distinction is subtle, but significant in the design of the fastener. If threaded all the way to the back of the head, it becomes a 'machine screw'
Wednesday, June 6, 2007
Japanese Industrial Standards
From Wikipedia, the free encyclopedia
This article is about Japanese Industrial Standards in general; see JIS encoding for the character encoding used in representing the Japanese language for computer software and communication.
JIS symbol.
JIS old symbol.
Japanese Industrial Standards (JIS) specifies the standards used for industrial activities in Japan. The standardization process is coordinated by Japanese Industrial Standards Committee and published through Japanese Standards Association.
Deutsches Institut für Normung
From Wikipedia, the free encyclopedia
(Redirected from DIN)
This article is about the German Institute for Standardization. For other uses of "DIN", see DIN (disambiguation).
DIN Deutsches Institut für Normung e.V. (DIN; in English, the German Institute for Standardization) is the German national organization for standardization and is that country's ISO member body.
DIN and mini-DIN connectors, as well as DIN rails are several examples of older DIN standards that are today used around the world. However, there are currently around thirty thousand DIN Standards, covering almost all fields of technology. One of the earliest, and surely the most well-known, is DIN 476, the standard that introduced the A4, etc. paper sizes in 1922. This was later adopted as international standard ISO 216 in 1975.
DIN is a registered association (e.V.), founded in 1917, originally as Normenausschuss der deutschen Industrie (NADI, Standardisation Committee of German Industry). In 1926 the NADI was renamed Deutscher Normenausschuss (DNA, German Standardisation Committee) in order to indicate that standardization now covered many fields, not just industrial products. In 1975 the DNA was finally renamed DIN. Its headquarters is in Berlin. Since 1975 it has been recognized by the German government as the national standards body and represents German interests at international and European level.
The acronym DIN is often wrongly expanded as Deutsche Industrienorm (German industry standard). This is largely due to the historic origin of the DIN as NADI. The NADI indeed published their standards as DI-Norm (Deutsche Industrienorm, German industry standard). E.g. the first published standard in 1918 was 'DI-Norm 1' (about taper pins). Many people still wrongly associate DIN as an abbreviation for the old DI-Norm naming of standards.
DIN standard designation
The designation of a DIN standard shows its origin (# denotes a number):
DIN # is used for German standards with primarily domestic significance or designed as a first step toward international status. E DIN # is a draft standard and DIN V # is a preliminary standard.
DIN EN # is used for the German edition of European standards.
DIN ISO # is used for the German edition of ISO standards. DIN EN ISO # is used if the standard has also been adopted as a European standard.
Example of DIN standards
See also the list of DIN standards.
DIN 476: international paper sizes (now ISO 216 or DIN EN ISO 216)
DIN 946: Determination of coefficient of friction of bolt/nut assemblies under specified conditions.
DIN 1451: typeface used by German railways and on traffic signs
DIN 72552: electric SFFVGGM numbers in automobiles
DIN 31635: transliteration of the Arabic language.
British Standards
From Wikipedia, the free encyclopedia
BSI Kite Mark Logo - Made up of the letters 'B' & 'S'
BSI British Standards is a division of BSI Group which also includes BSI Management Systems, a management systems registrar and BSI Product Services, a testing organisation. British Standards has a Royal Charter to act as the standards organisation for the UK. It is formally designated as the National Standards Body (NSB) for the UK.
The standards produced are titled British Standard XXXX[-P]:YYYY where XXXX is the number of the standard, P is the number of the part of the standard (where the standard is split into multiple parts) and YYYY is the year in which the standard came into effect. British Standards currently has over 27,000 active standards. Products are commonly specified as meeting a particular British Standard, and in general this can be done without any certification or independent testing. The standard simply provides a shorthand way of claiming that certain specifications are met, while encouraging manufacturers to adhere to a common method for such a specification.
The Kitemark can be used to indicate certification by BSI, but only where a Kitemark scheme has been set up around a particular standard. It is mainly applicable to safety and quality management standards. There is a common misunderstanding that Kitemarks are necessary to prove compliance with any BS standard, but in general it is neither desirable nor possible that every standard be 'policed' in this way.
BSI Group began in 1901 as the Engineering Standards Committee, led by James Mansergh, to standardise the number and type of steel sections, in order to make British manufacturers more efficient and competitive.
Over time the standards developed to cover many aspects of tangible engineering, and then engineering methodologies including quality systems, safety and security.
Another key activity carried out by British Standards is the CE Marking of Medical Devices. The CE 0086 marking can be issued to devices that are found to comply with the Medical Device Directive.
American Iron and Steel Institute
From Wikipedia, the free encyclopedia
The American Iron and Steel Institute (AISI) is an association of North American steel producers. With its predecessor organizations, is one of the oldest trade associations in the United States, dating back to 1855. It assumed its present form in 1908, with Judge Elbert H. Gary, chairman of the United States Steel Corporation, as its first president. Its development was in response to the need for a cooperative agency in the iron and steel industry for collecting and disseminating statistics and information, carrying on investigations, providing a forum for the discussion of problems and generally advancing the interests of the industry.
American National Standards Institute
From Wikipedia, the free encyclopedia
(Redirected from ANSI)
The American National Standards Institute or ANSI (IPA pronunciation: [ænsiː]) is a private nonprofit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international standards so that American products can be used worldwide. For example, standards make sure that people who own cameras can find the film they need for them anywhere around the globe.
ANSI accredits standards that are developed by representatives of standards developing organizations, government agencies, consumer groups, companies, and others. These standards ensure that the characteristics and performance of products are consistent, that people use the same definitions and terms, and that products are tested the same way. ANSI also accredits organizations that carry out product or personnel certification in accordance with requirements defined in international standards.
The organization's headquarters are in Washington, DC. ANSI's operations office is located in New York City.
History
ANSI was formed in 1918 when five engineering societies and three government agencies founded the American Engineering Standards Committee (AESC). The AESC became the American Standards Association (ASA) in 1928. In 1966, the ASA was reorganized and became the United States of America Standards Institute (USASI). The present name, was adopted in 1969.
American Society of Mechanical Engineers
American Society of Mechanical Engineers
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(Redirected from ASME)
“ASME” redirects here. For the magazine editors' society, see American Society of Magazine Editors.
The American Society of Mechanical Engineers (A.S.M.E) is a professional body, specifically an engineering society, focused on mechanical engineering. The ASME was founded in 1880 by Alexander Lyman Holley, Henry Rossiter Worthington, John Edison Sweet and Matthias N. Forney in response to numerous steam boiler pressure vessel failures. The organization is known for setting codes and standards for mechanical devices. The ASME conducts one of the world's largest technical publishing operations through its ASME Press, holds numerous technical conferences and hundreds of professional development courses each year, and sponsors numerous outreach and educational programs.
The organization's stated vision is to be the premier organization for promoting the art, science and practice of mechanical and multidisciplinary engineering and allied sciences to the diverse communities throughout the world. Its stated mission is to promote and enhance the technical competency and professional well-being of its members, and through quality programs and activities in mechanical engineering, better enable its practitioners to contribute to the well-being of humankind. As of 2006, the ASME has 120,000 members.
Core values include:
Embrace integrity and ethical conduct
-Embrace diversity and respect the dignity and culture of all people
-Nurture and treasure the environment and our natural and man-made resources
-Facilitate the development, dissemination and application of engineering knowledge
-Promote the benefits of continuing education and of engineering education
-Respect and document engineering history while continually embracing change
-Promote the technical and societal contribution of engineers
ASME Codes and Standards
ASME is one of the oldest and most respected standards-developing organizations in the world. It produces approximately 600 codes and standards, covering many technical areas, such as boiler components, elevators, measurement of fluid flow in closed conduits, cranes, hand tools, fasteners, and machine tools. (Note that:
A Standard can be defined as a set of technical definitions and guidelines that function as instructions for designers, manufacturers, operators, or users of equipment.
A standard becomes a Code when it has been adopted by one or more governmental bodies and is enforceable by law, or when it has been incorporated into a business contract.)
ASTM International
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(Redirected from ASTM)
History
ASTM International was formed in 1898 in the United States as the American Society for Testing and Materials by a group of scientists and engineers, led by Charles Benjamin Dudley, to address the frequent rail breaks plaguing the fast-growing railroad industry. The group developed a standard for the steel used to fabricate rails. It predates other standards organizations such as BSI (1901), DIN (1917) and AFNOR (1926), but differs from these in that it is not a national standards body, that role being taken in the USA by ANSI. However, it has a dominant role among standards developers in the USA, and claims to be the world's largest developer of standards.
Today, ASTM International supports thousands of technical committees, which draw their members from around the world and collectively maintain more than 12,000 standards. The Annual Book of ASTM Standards consists of 77 volumes.
Standards
The standards produced by ASTM International fall into four categories:
the Standard Specification, that defines the requirements to be satisfied by subject of the standard.
the Standard Test Method, that defines the way a test is performed. The result of the test may be used to assess compliance with a Specification.
the Standard Practice, that defines a sequence of operations that, unlike a test, does not produce a result.
the Terminology Standard, that provides agreed definitions of terms used in the other standards.
The quality of the standard test methods is such that they are frequently used world-wide, even in places where ASTM specifications are not used.