根除黄毒 靠运营商自律远远不够

日前，随着央视对手机贩黄事件的系列报道，“手机涉黄”已成媒体和整个社会关注的热门话题。网络色情早已有之，手机贩黄尚属新鲜事物，为何此事披露后会引起社会如此强烈的反响？12月2日，天安信通总裁高建波，通信评论员、移动通信运营观察家刘权和刘东凯三位做客人民网无线频道，与手机网民一起，就手机涉黄事件与广大手机网友展开深入交流。

　　根除黄毒 “自律+监管”并举

　　我国电信管理条例的第五十七条中规定，任何组织或者个人不得利用电信网络传播淫秽、色情等内容，违反这一规定的，应当受到行政处罚。淫秽色情内容充斥于手机终端，行政机关有权对传播了色情淫秽内容的运营商进行行政处罚。

　　中国移动总裁王建宙总裁对此宣布，中国移动将追加1亿元专项资金进行技术攻关，坚定不移地打击手机WAP色情网站。目前，中国移动共封堵手机色情网站 564个。对此通信评论员刘权发表了自己的看法，他认为只靠中国移动的自律是不够的，国家在这方面应该多给一些支持和鼓励，这样才能给青少年更严密的保护，从而让家长放心。

　　“这是一个集中全社会的力量共同努力的一件事。对于政府来讲，除规范之外还应该有个切实可行的措施，只有大家共同行动起来，才能把这件事情做好。今后应加大力度开发绿色终端以保证青少年上网安全。”高建波说。

　　比起绿色终端的引进，刘东凯更加强调监管。政府的监管有时候轻有时候重，并没有连贯性，而很多政策出台后，也没有细则的处罚措施。如果能够明确的量刑，有强有力的处罚力度或措施，就会有更多的人引以为戒。

　　孩子上网被制止对产业链发展影响巨大

　　“对于3G甚至是4G，手机上网是重要的一个功能，也是未来盈利的一个焦点。”通信评论员刘东凯从运营者的角度来看待这个问题。“但调查发现，作为家长为了使孩子远离黄毒的危害，只能关闭孩子手机上网的功能，而这对整个产业链发展的打击是非常巨大的。”

　　中国移动在今日已经成为全球第一大运营商，从3G的运营到4G的投入，未来的市场前景非常广泛，手机因涉黄而因小失大，对于商家亦是饮鸩止渴。

　　国外保护青少年各自有方 pneumatic cylinders-auto bearings-automotive bearings-china manufacturer

　　美国就专门制定了《儿童色情内容防治法》来维护未成年人网上权益。日本在2009年4月1日颁布实施的《保证青少年安全安心上网环境的整顿法》要求，世界最大电信服务商——日本的NTTDOCOMO已自动为未成年人提供包括“时间受限”和“网络受限”的上网过滤服务。

　　高建波提议：“应该从国家、政府的角度，从国家立法的角度给出详细的界定范围，应该是从更高的角度来界定什么是黄色网站，如何防止涉黄。”

　　曾担任过中国互联网反垃圾邮件小组组长的李欲晓介绍，美国、英国、日本、澳大利亚等国家，率先制定了相关法律，保护个人信息，惩治网络侵权，而我国在这方面还比较滞后。“信息和网络是跨行业、跨部门的，只有通过法律才可能协调好各方利益。我们应该加速信息社会规范和法律的研究和制定。”

2008年的最后一封日志

东升，西落，岁月如梭
寒冬风起兮上班忙，岁月匆匆兮人感伤。
　　腰酸背疼兮累断肠，起早贪黑兮为住房。
　　烟雾缭绕兮心惆怅，交朋结友兮路宽广。
　　人贫志贵兮终坚强，富贵荣华兮放一旁。

本着善始善终的原则，是该我写08年最后一封日志的时候了。沉思了好久，不知道该说些什么，比较疲惫。还是说点什么吧，我的08愿望没能实现，但我一直努力着，目标正一步步接近，我该享受这个过程。整个过程伴随着压力、怀疑、信任、鼓励！压力磨练着我、怀疑监督着我、信任支持着我、鼓励推动着我！这些都是我 08收获最宝贵的东西！08我成熟了很多，懂得了爱，懂得了相依为命！08我要感谢的人很多，他们用一双双眼睛注视着我，鼓励着我前进！我会记住他们的，我会报答他们的！前面的路还是不平坦的，我一颗探索的心始终在，看成败人生豪迈，只不过是从头在来！
沧桑历尽古根盘，
屹立高涯鸟瞰攀。
弄月筛风迎旭日，wind turbines home wind turbine small wind turbine wind energy wind power
虚怀若谷耐严寒。

上海第三天

时间好快，第三天了，开心的日子总是过的那么快，一样睡到自然醒，阳光依旧明媚，心情依旧灿烂，收拾好行头，出发......
今天的人似乎比组天要多，还在乱走，逛啊，买啊，但一张100块的假钞把我原本好好的心情搞的极烂，好好的，让我损失几天工资，很伤心......
一阵伤心劲过去，又开始乱走，边逛边吃，小日子很是悠哉，饶有兴致的走到南京路，走到外滩，怎么跟10年前一样没有一点变化呢，还是那些破楼，那个破钟，时间敲响6点，“卡擦”，让时间永远停留在傍晚六点......
继续前行，南京路步行街，好多人头，正是我想要的那种多，好好享受了把被埋没在人群中的乐趣，一直都喜欢这种感觉......
逛累了，打道回府，这次换坐地铁了，上海人民抢占地铁的实力还一如既往的强劲，三秒之内空荡荡的地铁立马塞满了人，哈，还是跟以前一样的感觉，一拥而入，一挤而出，恍惚间已到达目的地，只是不再有以前终于的感觉，只是，只是......
宝贝，玩够了吗？疯够了吗？记得该回家了......die castingwind generators

继续无题

一个奇怪的梦，熟悉的人，奇怪的关系，醒来后唏嘘不已。
若这梦是真实的，那现实井然的秩序会变成怎样，里面的人还会继续原来的关系吗？
不过仔细想想，这个梦还是有一定真实性的，至少它反应了人的一些内在心理，这些在客观世界里因为某种道德的或者价值观的束缚而无法得以表达的心理，在虚拟的梦境里却可以肆意地扩大、甚至变得夸张。
梦里的我是一个旁观者，看着身边熟悉的人之间的关系突然变得陌生，才觉得它的奇怪。
实际上，也许我的内心早就洞察了他们的心理，所以，做了这样一个梦。合肥搬家公司 合肥搬家 合肥网站建设

Britain ambitious expansion of offshore wind power generation

United Kingdom Ministry of Energy and Climate Change (Department for Energy and Climate Change), said a study in the next decade, the sea will be the new 5000-7000 wind turbines to produce 25 billion kilowatts of electricity, equivalent to 25 large-scale burning coal power plants. These new capacity coupled with the planned construction of 80 billion watts of electricity, the British offshore wind power generation up to a total of 33 billion watts.


The British Government has announced that by 2020, the British at sea (offshore) wind power generation sufficient to meet the needs of all families. Of geology, birds and marine life for up to one year of research, the conclusion even more than the festival Carbon Fund (Carbon Trust) the company's prediction. Festival Carbon Fund established by the British Government, is designed to help businesses reduce carbon emissions, the company last year said that the British offshore wind power generation to meet the total 29 billion watts.



But energy companies E. ON companies have believed that Britain's largest sea (offshore) wind power project "London Front Line" (London Array) the economic outlook for the current "can not be optimistic about."



E. ON spokesman艾米丽海默尔(Emily Highmore), said the company "is committed" in the "London line array" and the Humber is located in another 300 million瓦海on wind power projects, but the company should not "guarantee" They will continue to advance. E. ON Company third offshore wind power projects located in England and Scotland between索尔威Bay (Solway Firth), currently under construction.



海默尔said: "The sea wind power generation has been, and in the future will be very expensive. We should not have been convinced that it will continue. However, we believe that this is an excellent project to help the British Government to meet its renewable energy goals very important. "



海默尔also said that, E. ON companies hope that the British Government's offshore wind power generation to financial support doubled. She said: "We think, 330 billion watts is an ambitious goal, only if we solve the wind generator capital, such as grid access and planning issues, it could become a reality."



Carbon Fund section of the report also urges the British Government, for the developers to provide more low-cost sea wind power generation sites, to promote R & D investment in order to enhance efficiency and improve the National Grid.



Carbon Fund strategy section manager Tom Jennings (Tom Jennings) said that many of the recommendations have been implemented, but required a more detailed, for example, in the planning regulations. Jennings said: "The short-term cost-effectiveness appears to be very weak, but as long as the cost of reducing the long term, they should be attractive."



Carbon Fund section of the report also says that, if successful, sea and land-based wind power can make the UK the overall carbon dioxide emissions 14 percent and create 70,000 jobs, and can supply both domestic and export markets the United Kingdom

CRY CRY CRY

我发觉自己越来越没用了，碰到点挫折就会哭鼻子，最近事情来得个烦，碰到很难沟通的人，或是态度很不好的人，特别是语气很不好的时候，我竟会很想哭，我在想是不是好久没有掉眼泪了，积在眼睛里的泪太多了，还是我越来越脆弱了。我一直以来以THICK-FACE自居，怎么会变成现在这个样子啊。真搞不东自己啊。 automotive bearings automotive bearings Pneumatic Cylinders hydraulic valves 鹅肥肝

Just one last dance

Just one last dance....oh baby...just one last dance
We meet in the night in the Spanish café
I look in your eyes just don't know what to say
It feels like I'm drowning in salty water
A few hours left 'til the sun's gonna rise
tomorrow will come an it's time to realize
our love has finished forever
how I wish to come with you (wish to come with you)
how I wish we make it through
Just one last dance
before we say goodbye
when we sway and turn round and round and round
it's like the first time
Just one more chance
hold me tight and keep me warm
cause the night is getting cold
and I don't know where I belong
Just one last dance
The wine and the lights and the Spanish guitar
I'll never forget how romantic they are
but I know, tomorrow I'll lose the one I love
There's no way to come with you
it's the only way to do
Just one last dance
before we say goodbye
when we sway and turn round and round and round
it's like the first time
Just one more chance
hold me tight and keep me warm
cause the night is getting cold
and I don't know where I belong
Just one last dance
Oh,Baby
Just one last dance
before we say goodbye
when we sway and turn round and round and round
it's like the first time
Just one more chance
hold me tight and keep me warm
cause the night is getting cold
and I don't know where I belong
Just one last dance
before we say goodbye
when we sway and turn round and round and round (When we sway turn around)
it's like the first time(hold my tight oh my love)
Just one more chance
hold me tight and keep me warm
cause the night is getting cold(the night is getting cold)
and I don't know where I belong(don't know where I belong)
Just one last dance
Just one last dance
Just one more chance
Just one last dance
Over... wind generators wind turbine 合肥汽车租赁 合肥租车 尿毒症 风力发电机 风力发电机

听见夏天的离开

见--听见夏天的离开我在某年某月醒过来
我想我等我期待未来却不能因此安排
阴天傍晚车窗外未来有一个人在等待
向左向右向前看爱要拐几个弯才来
我遇见谁会有怎样的对白
我等的人他在多远的未来
我听见风来自地铁和人海
我排著队拿著爱的号码牌
我往前飞飞过一片时间海
我们也曾在爱情里受伤害
我看著路梦的入口有点窄
我遇见你是最美丽的意外
总有一天我的谜底会解开

歌词 写的真的是很不错哦! die casting aluminum die casting oil paintings solar lamp

有点迷茫

突然间就那么想念校园时光,突然间就那么想念曾经的在一起的朋友们,没来由就回流泪,我还以为这么几年来,对校园里的一切会被淡淡遗忘,可是,还是想念起来,原来什么都没忘.
或许是夏天这个季节太特殊,总让我想到离别,所以真的特别想念曾经干净简单的一切.有时候走在街上,看见小情侣们手牵手一起逛街,就会想到曾经的我们,幸好,KF还一如既往的陪在我身边,让我可以唯一延续对校园时光的眷恋,让我至少还有依靠和寄托.也会不经意间就会想起和他的曾经,那么纯粹,那么简单,那么单纯.呵呵,想起这些,依旧会发自内心的笑.
其实很羡慕姗姗,青青还有宝华他们,这些家伙还能有事没事时常聚一聚,一群姐妹淘可以逛街,喝茶,聊天，可以肆无忌惮,让我羡慕,曾经也不顾一切的冲到她们那里,想要跟她们一起安定下来,可是被KF一个电话,一句话就拉了回来,感情啊;
现在的我,还是一如既往的孤单,甚至比以前孤单千百倍,在这个工作的地方,没有亲人,没有朋友,虽然也有一帮好同事在一起疯,可是,的确没有曾经那种感觉,找不到,也许校园真的不能与社会相比,社会上的人,总不得不让我提防三分,我不喜欢与人争吵,也不喜欢与人太亲近,幸好这个习惯还不赖.
我是个不能轻易让自己难过的人,所以还是觉得应该追随KF,他在哪里,我就去哪里,所以赶紧跟领导交了辞职报告,以前也老想着要走，可是看看工资还不错,而且领导也对我不赖的分上,觉得留在这里也不错,不知道为什么这次特别坚决,也许是因为夏天?
die casting aluminum die casting oil paintings solar lamp呵呵,把工作交接了,再休息半个月,想想这种日子是我向往的,可是,领导至今还不死心,没有让我交接的意思,就这么把我留着,哼,我才不管,哪天提出辞职,一个月交接期到了就立马走人,随便她交接不交接.

Ductile Iron Casting

Ductile iron, a synthetic metal material that was invented in the middle of the twentieth century, is one of the types of iron used to make cast iron. In general, ductile iron has a higher tensile strength than grey iron, the kind of iron traditionally used to make cast iron products. Ductile iron, as its name suggests, is more ductile than traditional iron materials, which tend to be more brittle and prone to fracture under high tensile stress.

Ductile iron is commonly used to make cast iron pipes, like those used in water and sewer lines. Ductile iron is used for a variety of applications in many different industries. These industries include, but are not limited to agriculture, automotive, irrigation, ventilation, hydraulics, and manufacturing.

Aluminum Castings china

Aluminum casting is a metal forming process in which molten aluminum metal is put under pressure and injected into a die. Aluminum die casts are lightweight alloys that have good corrosion resistance, mechanical properties, high thermal and electrical conductivity and strength at high temperatures. Aluminum alloys possess high dimensional stability for complex shapes and thin walls.

Aluminum casting is efficient and economical and offers a wide range of durable shapes and components. Little or no machining is required after a part is die cast, because the process provides very close tolerances for even complex shapes. Aluminum castings can also be easily plated or finished. Aluminum castings are dimensionally stable and heat resistant.

Aluminum castings are commonly used in the production of hardware and tools because of their great resistance to corrosion and high temperatures, as well as their conductivity. In addition, aluminum castings are used in applications requiring the production of intricate part features and components.

sand casting Molding box and materials

A multi-part molding box (known as a casting flask, the top and bottom halves of which are known respectively as the cope and drag) is prepared to receive the pattern. Molding boxes are made in segments that may be latched to each other and to end closures. For a simple object¡ªflat on one side¡ªthe lower portion of the box, closed at the bottom, will be filled with prepared casting sand or green sand¡ªa slightly moist mixture of sand and clay. The sand is packed in through a vibratory process called ramming and, in this case, periodically screeded level. The surface of the sand may then be stabilized with a sizing compound. The pattern is placed on the sand and another molding box segment is added. Additional sand is rammed over and around the pattern. Finally a cover is placed on the box and it is turned and unlatched, so that the halves of the mold may be parted and the pattern with its sprue and vent patterns removed. Additional sizing may be added and any defects introduced by the removal of the pattern are corrected. The box is closed again. This forms a "green" mold which must be dried to receive the hot metal. If the mold is not sufficiently dried a steam explosion can occur that can throw molten metal about. In some cases, the sand may be oiled instead of moistened, which makes possible casting without waiting for the sand to dry. Sand may also be bonded by chemical binders, such as furane resins or amine-hardened resins.

Chills

To control the solidification and metallurgical structure of the metal, it is possible to place metal plates¡ªchills¡ª in the mold. The associated rapid local cooling will form a finer-grained structure and may form a somewhat harder metal at these locations. In ferrous castings the effect is similar to quenching metals in forge work. The inner diameter of an engine cylinder is made hard by a chilling core. In other metals chills may be used to promote directional solidification of the casting. In controlling the way a casting freezes it is possible to prevent internal voids or porosity inside castings.

Cores

To produce cavities within the casting¡ªsuch as for liquid cooling in engine blocks and cylinder heads¡ªnegative forms are used to produce cores. Usually sand-molded, cores are inserted into the casting box after removal of the pattern. Whenever possible, designs are made that avoid the use of cores, due to the additional set-up time and thus greater cost.
Two sets of castings (bronze and aluminium) from the above sand mold
Two sets of castings (bronze and aluminium) from the above sand mold

With a completed mold at the appropriate moisture content, the box containing the sand mold is then positioned for filling with molten metal¡ªtypically iron, steel, bronze, brass, aluminium die casitng, magnesium alloys, or various pot metal alloys, which often include lead, tin, and zinc. After filling with liquid metal the box is set aside until the metal is sufficiently cool to be strong. The sand is then removed revealing a rough casting that, in the case of iron or steel, may still be glowing red. When casting with metals like iron or lead, which are significantly heavier than the casting sand, the casting flask is often covered with a heavy plate to prevent a problem known as floating the mold. Floating the mold occurs when the pressure of the metal pushes the sand above the mold cavity out of shape, causing the casting to fail.
Left:- Corebox, with resulting (wire reinforced) cores directly below. Right:- Pattern (used with the core) and the resulting casting below (the wires are from the remains of the core)
Left:- Corebox, with resulting (wire reinforced) cores directly below. Right:- Pattern (used with the core) and the resulting casting below (the wires are from the remains of the core)

After die casting, the cores are broken up by rods or shot and removed from the casting. The metal from the sprue and risers is cut from the rough casting. Various heat treatments may be applied to relieve stresses from the initial cooling and to add hardness¡ªin the case of steel or iron, by quenching in water or oil. The casting may be further strengthened by surface compression treatment¡ªlike shot peening¡ªthat adds resistance to tensile cracking and smooths the rough surface.oil painting,Oil Painting Reproduction

Design requirements

The part to be made and its pattern must be designed to accommodate each stage of the process, as it must be possible to remove the pattern without disturbing the molding sand and to have proper locations to receive and position the cores. A slight taper, known as draft, must be used on surfaces perpendicular to the parting line, in order to be able to remove the pattern from the mold. This requirement also applies to cores, as they must be removed from the core box in which they are formed. The sprue and risers must be arranged to allow a proper flow of metal and gasses within the mold in order to avoid an incomplete casting. Should a piece of core or mold become dislodged it may be embedded in the final casting, forming a sand pit, which may render the casting unusable. Gas pockets can cause internal voids. These may be immediately visible or may only be revealed after extensive machining has been performed. For critical applications, or where the cost of wasted effort is a factor, non-destructive testing methods may be applied before further work is performed.

Essential improvements of the foundry technology

An increasing demand for castings in the growing car and machine building industry during and after the World War One and Two, stimulated new inventions in mechanization and later automation of the sand casting process technology. The bottleneck for a faster casting production was not only the molding speed, but also slow molding sand preparation in the slow sand mixers, slow core manufacturing processes and slow metal melting rate in the cupola furnaces. In 1912 sand slinger was invented by the American Company Birdsley & Piper. In 1912 the first sand mixer with individually mounted revolving plows was marketed by Simpson Company. In 1915 first experiments started with bentonite clay in stead of simple fireclay as bonding additive to the molding sand. This increased tremendously the green and dry strength of the moulds. In 1918 the first fully automated foundry fabricating hand grenades for the U.S. Army. In 1930 first high-frequency coreless electric furnace was installed in the U.S. In 1924 Henry Ford sets record producing 1 million cars, consuming one-third of the total casting production in the U.S. In 1943 ductile iron was invented by adding magnesium to the widely used grey iron. In 1940 thermal sand reclamation was applied for molding and core sands. In 1952 D-process was developed for making shell molds with fine, pre-coated sand. In 1953 hotbox core sand process was invented by thermally curing cores. In 1954 a new core binder - water glass hardened with CO2 from the ambient air, was applied.

Investment casting From Wikipedia

Investment casting, also called lost-wax casting, is one of the oldest known metal-forming techniques. From 5,000 years ago, when beeswax formed the pattern, to today’s high-technology waxes, refractory materials and specialist alloys, the castings allow the production of components with accuracy, repeatability, versatility and integrity in a variety of metals and high-performance alloys. Lost foam casting is a modern form of investment casting that eliminates certain steps in the process.


Inlet-outlet cover of a valve for a nuclear power station produced using investment castingThe process is generally used for small castings, but has produced complete aircraft door frames, steel castings of up to 300 kg and aluminium castings of up to 30 kg. It is generally more expensive per unit than die casting or sand casting but with lower equipment cost. It can produce complicated shapes that would be difficult or impossible with die casting, yet like that process require little surface finishing and only minor machining.

Cast iron

Cast iron production in addition to the proper choice of ingredients to be gifted to the organization, the heat treatment is further adjust and improve the matrix structure to enhance the performance of a cast iron important ways. Iron and steel heat treatment of the heat being buried in common, but also different. Cast iron heat treatment in general can not improve the original graphite in the shape and distribution. The grey cast iron, because flake graphite caused by the effects of stress concentration of iron play a leading role in the storm, the gray iron impose the enhanced effect of heat treatment are far less ductile iron and steel as significant. Guyou iron main heat treatment process for annealing, normalizing, and so on. For ductile iron, as a spherical graphite, the base of the fragmented role greatly reduced, through heat treatment will be based organizations to fully play its role, which can significantly improve the mechanical properties of the ball. Therefore, ductile iron like steel, its heat treatment process are annealed, normalizing, conditioning, multi-quenching, induction heating and hardening the surface, such as chemical heat treatment.

The cast iron heat treatment process:

1. Annealing elimination of stress due to uneven casting thickness, heating, cooling and phase transition process will produce stress and stress. Also in large parts of its processed within easy residual stress, all of which are necessary to eliminate stress. Annealing is usually to stress the heating temperature of 500 ~ 550 ?鏍╫lding time for 2 ~ 8 h, and then furnace cold (gray iron) or air-cooled (ductile iron). Using this technology can eliminate the stress of casting 90 to 95 percent, but the cast iron organization does not change. If the temperature exceeds 550 ?鏍痳 holding time is too long, it will cause graphite, to reduce the casting strength and hardness.

2. Elimination of the high-temperature casting white graphite annealing casting cooling, surface and thin cross sections, often produce white. White hard and brittle organizations, poor processing performance, easily peeling off. Annealing to be used (or normalizing) approach to the fight against white organizations. Annealing Process: heated to 550-950 ?鏍﹏sulation 2 ~ 5 h, then cold to furnace 500-550 ?鏍磑air-cooled. In high-temperature insulation, high outbound cementite and eutectic cementite divided into graphite and A, in the subsequent cooling process for the second cementite and eutectoid cementite also decomposition, in the process of graphite. As cementite of decomposition, resulting in hardness decline, thereby enhancing the cutting of.

3. Ductile iron is the iron fireballs normalizing the purpose is to be pearlite matrix organization, and refined grains, uniform organizations, to enhance the mechanical properties of casting. Sometimes the ball is normalizing iron surface hardening in the organization of preparation, normalizing at low temperature and high temperature normalizing normalizing. High-temperature normalizing temperature generally no more than 950 ~ 980 ?娆爈ow-temperature heat to a total of normalizing the general presentation of the temperature range 820 ~ 860 ?娈燗fter normalizing for the general need to deal with four to eliminate at normalizing the stress.

4. Ductile iron quenching and tempering in order to improve the mechanical properties of ductile iron, heated to Afc1 general casting more than 30 ~ 50 ?鏍ˋfc1 heating A representative of the end of a temperature), the insulation after quenching oil, be martensite . In order to appropriately lower after quenching the residual stress, the general should be quenched tempered, low-tempered organizations to increase tempering Markov for residual bainite with spherical graphite. This wear-resistance organizations, and demand for high wear resistance, high-strength parts. Tempering temperature in the temperature of 350-500 ?鏍ter tempering tempering troostite organizations to increase spherical graphite, applicable to the requirements of good wear resistance, a certain validity of the stability and flexibility in thick pieces. High-temperature tempering temperature of 500-60 D ?娆燼fter tempering tempering Soxhlet for organizations to increase spherical graphite, a good combination of strength and toughness of the comprehensive performance, wide application in production.

5. Ball and the use of multi-quenching ductile iron, such as the temperature can be quenched high-intensity, and both plastic and good toughness. Multi-quenching heating temperature of the main consideration so that the original choice of organizations of all A, non-residual F, but also to avoid A grain growth. The general Afc1 heating temperature above 30 ~ 50 ?娆爏uch as temperature temperature of 0 ~ 350 ?鏍磑 ensure access to a comprehensive mechanical properties of the bainite organizations. Mg-Al-iron, and other rare earth temperature quenched ?覡b = 1200 ~ 1400MPa, ??k = 3 ~ 3.6J/cm2, HRC = 47 ~ 51. It should be noted, such as temperature quenched with a tempering process.

6. Hardening the surface of certain items in order to improve the surface hardness, wear resistance and fatigue strength, the surface can be quenched. Ductile iron and gray iron castings to the surface can be quenched. The general high (in) frequency induction heating and hardening the surface, hardening the surface contact.

7. Chemical heat treatment requirements for wear-resistant surface or anti-oxidation, corrosion resistance of the castings, steel can be used similar to the chemical heat treatment process, such as soft chloride gas, chloride, boronizing, seepage, such as sulfur treatment.

About China Sand Casting

Sand casting is one of the most popular and simplest types of casting that has been used for centuries. Sand casting allows for smaller batches to be made compared to permanent mold casting and at a very reasonable cost. Not only does this method allow manufacturers to create products at a low cost, but there are other benefits to sand casting, such as very small size operations. From castings that fit in the palm of your hand to train beds (one casting can create the entire bed for one rail car). Sand casting also allows most metals to be cast depending on the type of sand used for the molds.

Sand casting requires a lead time of days for production at high output rates (1-20 pieces/hr-mold) and is unsurpassed for large-part production. Green (moist) sand has almost no part weight limit, whereas dry sand has a practical part mass limit of 2300-2700 kg. Minimum part weight ranges from 0.075-0.1 kg. The sand is bonded together using clays (as in green sand) or chemical binders, or polymerized oils (such as motor oil). Sand can be recycled many times in most operations and requires little additional input.

Aluminum Die Casting Technical Introduction

Die-casting is similar to Permanent mold castings except that the metal is injected into the mold under high pressure of 10-210Mpa (1,450-30,500) psi . This results in a more uniform part, generally good surface finish and good dimensional accuracy, as good as 0.2 % of casting dimension. For many parts, post-machining can be totally eliminated, or very light machining may be required to bring dimensions to size.

Die-casting can be done using a cold chamber or hot chamber process

1.In a cold chamber process, the molten metal is ladled into the cold chamber for each shot. There is less time exposure of the melt to the plunger walls or the plunger. This is particularly useful for metals such as Aluminum, and Copper (and its alloys) that alloy easily with Iron at the higher temperatures.

2.In a hot chamber process the pressure chamber is connected to the die cavity is immersed permanently in the molten metal. The inlet port of the pressurizing cylinder is uncovered as the plunger moves to the open (unpressurized) position. This allows a new charge of molten metal to fill the cavity and thus can fill the cavity faster than the cold chamber process. The hot chamber process is used for metals of low melting point and high fluidity such as tin, zinc, and lead that tend not to alloy easily with steel at their melt temperatures.

Die casting molds (called dies in the industry) tend to be expensive as they are made from hardened steel-also the cycle time for building these tend to be long. Also the stronger and harder metals such as iron and steel cannot be die-cast

Common Alloys in Die Casting

Aluminum, Zinc and Copper alloys are the materials predominantly used in die-casting. On the other hand, pure Aluminum is rarely cast due to high shrinkage, and susceptibility to hot cracking. It is alloyed with Silicon, which increases melt fluidity, reduces machinability. Copper is another alloying element, which increases hardness, reduces ductility, and reduces corrosion resistance.

Aluminum is cast at a temperature of 650 ºC (1200 ºF). It is alloyed with Silicon 9% and Copper about 3.5% to form the Aluminum Association 380 alloy (UNS A03800). Silicon increases the melt fluidity, reduces machinability, Copper increases hardness and reduces the ductility. By greatly reducing the amount of Copper (less than 0.6%) the chemical resistance is improved; thus, AA 360 (UNS A03600) is formulated for use in marine environments. A high silicon alloy is used in automotive engines for cylinder castings, AA 390 (UNS A03900) with 17% Silicon for high wear resistance. Common aluminum alloys for die casting are summarized as follows:

Material	Silicon	Copper	Tensile Strength MPa (ksi)	Properties
AA 380 (UNS A03800)	8.5 %	3.5 %	324 (47)	Fair easy to fill
AA 384 (UNS A03840)	11 %	4 %	331 (48)	Easy to fill
AA 386 (UNS A03860)	9.5 %	0.6 %	317 (46)	Good corrosion resistance
AA 390 (UNS A03900)	17 %	4.5 %	283 (41)	Good wear resistance

Zinc can be made to close tolerances and with thinner walls than Aluminum die casting, due to its high melt fluidity. Zinc is alloyed with Aluminum (4%), which adds strength and hardness. The casting is done at a fairly low temperature of 425 ºC (800 ºF) so the part does not have to cool much before it can be ejected from the die. This, in combination with the fact that Zinc can be run using a hot chamber process allows for a fast fill, fast cooling (and ejection) and a short cycle time. Zinc alloys are used in making precision parts such as sprockets, gears, and connector housings.

Copper alloys are used in plumbing, electrical and marine applications where corrosion and wear resistance is important.

Minimum wall thicknesses and minimum draft angles for die casting are :

Material	Min. Thickness mm (in)	Min. Draft Angle (º)
Aluminum alloys	0.9 mm (0.035 in)	0.5
Zinc alloys	0.6 mm (0.025 in)	0.25
Copper alloys (Brass)	1.25 mm (0.050 in)	0.7

Die-castings are typically limited from 20 kg (55 lb) max. for Magnesium, to 35 kg (77 lb) max. for Zinc. Large castings tend to have greater porosity problems, due to entrapped air, and the melt solidifying before it gets to the furthest extremities of the die-cast cavity. The porosity problem can be somewhat overcome by vacuum die casting

From a design point of view, it is best to design parts with uniform wall thicknesses and cores of simple shapes. Heavy sections cause cooling problems, trapped gases causing porosity. All corners should be radiused generously to avoid stress concentration. Draft allowance should be provided to all for releasing the parts-these are typically 0.25º to 0.75º per side depending on the material.

Casting and other technology

p>Casting often use a variety of metal materials, coke, wood, plastic, gas and liquid fuels, such as modeling materials. Have the necessary equipment used in various metal smelting furnace, a Mixer with the various Mixer, a shape-made batteries used in various molding machine, machine-made batteries, cleaning up the castings used for loading sand, Shot Blasting Machine And so on. Casting is also available for special machinery and equipment, and many transportation and material handling equipment.

Casting and other technology have different characteristics, mainly wide adaptability, needed materials and equipment, pollution of the environment. Casting will have dust and harmful gases and noise pollution to the environment, compared to other machinery manufacturing processes to become more serious, need to take measures to control.

Casting product development requirements of the trend is casting a better overall performance, higher accuracy and less headroom and clean the surface. In addition, the requirements of energy-saving society and restore the natural environment of the call also getting higher and higher. To meet these requirements, the new cast alloy will be developed, the new smelting technology and new equipment will be corresponding.

Casting the mechanized production continuously improve the degree of automation in the same time, to be more flexible production development, to expand the volume and variety of different production adaptability. Conserve energy and raw materials of new technologies will be giving priority to the development, have little or no pollution of the new equipment, new technology will be the first attention. Quality control technology in all stages of testing and nondestructive testing, stress determination, there will be new development.

Die casting materials

The main die casting alloys are: zinc, aluminium, magnesium, copper, lead, and tin. Specific dies casting alloys include: ZAMAK, zinc aluminum, AA 380, AA 384, AA 386, AA 390, and AZ91D magnesium. The following is a summary of the advantages of each alloy:

Zinc: the easiest alloy to cast; high ductility; high impact strength; easily plated; economical for small parts; promotes long die life.

Aluminum: lightweight; high dimensional stability for complex shapes and thin walls; good corrosion resistance; good mechanical properties; high thermal and electrical conductivity; retains strength at high temperatures.

Magnesium: the easiest alloy to machine; excellent strength-to-weight ratio; lightest alloy commonly die cast.

Copper: high hardness; high corrosion resistance; highest mechanical properties of alloys die cast; excellent wear resistance; excellent dimensional stability; strength approaching that of steel parts.

Lead and Tin: high density; extremely close dimensional accuracy; used for special forms of corrosion resistance.

Maximum weight limits for aluminium, brass, magnesium, and zinc castings are approximately 70 pounds (32 kg), 10 lb (5 kg), 44 lb (20 kg), and 75 lb (34 kg), respectively.

The material used defines the minimum section thickness and minimum draft required for a casting as outlined in the table below.

What is Investment Casting?

Investment casting / precision casting or the “lost wax” process has been in use since the construction of the first pyramid. The Egyptians and Chinese used the process in their early history to make jewellery and statues. The investment casting method was largely ignored as an industrial process for the fabrication of parts until the demand for rapidly finished parts during World War II created the need for “near net-shape” components that could readily be put into their final form. At this time new inorganic high temperature ceramic mold binders were developed to industrialize the process applications to include high strength and corrosion resistant materials such as low to high carbon alloy steel, tool steel, stainless steel, and nickel and cobalt base alloys. Aluminum and brass alloys are available also.

It is a process capable of producing intricate shapes weighing from a small fraction of an grams up to 20 Kgs. or more. Some examples would be: aircraft structural parts, components for the automotive industry, military weaponry, jet engines, machinery components, dental appliances, jewelry and many others.

In general, an injection molded wax pattern is used for each part produced which is then encased in multiple layers of ceramic material. The wax pattern is then removed from the ceramic shell mold. The mold is fired in an oven and then molten metal is poured into the cavities left by the evacuated wax pattern. Upon cooling, the resulting precision casting are cleaned and subjected to further processing such as heat treatment. At this point, many parts are in their final form and are ready for use while others may require a small amount of further processing such as machining before reaching their final form.

Why Investment Casting?

FLEXIBILITY IN DESIGNING

Investment casting produces near-net-shape configurations, offering engineers and designers freedom of design in a wide range of alloys. The process is capable of producing precise detail and dimensional accuracy in parts weighing many Kgs or just a few grams.

WIDE CHOICE OF ALLOYS

More than 125 ferrous and nonferrous metals are routinely cast.

TOOLING SET-UP IS ELIMINATED

By offering near-net-shape configuration, fixturing costs are substantially reduced or eliminated.

REDUCE PRODUCTION COSTS & ENHANCE PROFITABILITY

Costly machining operations are reduced and often eliminated. No capital equipment investment is needed to produce parts in-house.

CUT ASSEMBLY OPERATIONS

Several parts can be made as one casting, reducing handling, assembly and inspection costs.

REPRODUCE FINE DETAILS

Splines, bosses, serrations, lettering, holes and even some threads can be cast.

Sand Casting: Introduction

Sand casting is used to make large parts (typically Iron, but also Bronze, Brass, Aluminum). Molten metal is poured into a mold cavity formed out of sand (natural or synthetic). The processes of sand casting are discussed in this section, include patterns, sprues and runners, design considerations, and casting allowance.

The cavity in the sand is formed by using a pattern (an approximate duplicate of the real part), which are typically made out of wood, sometimes metal. The cavity is contained in an aggregate housed in a box called the flask. Core is a sand shape inserted into the mold to produce the internal features of the part such as holes or internal passages. Cores are placed in the cavity to form holes of the desired shapes. Core print is the region added to the pattern, core, or mold that is used to locate and support the core within the mold. A riser is an extra void created in the mold to contain excessive molten material. The purpose of this is feed the molten metal to the mold cavity as the molten metal solidifies and shrinks, and thereby prevents voids in the main casting.

In a two-part mold, which is typical of sand castings, the upper half, including the top half of the pattern, flask, and core is called cope and the lower half is called drag. The parting line or the parting surface is line or surface that separates the cope and drag. The drag is first filled partially with sand, and the core print, the cores, and the gating system are placed near the parting line. The cope is then assembled to the drag, and the sand is poured on the cope half, covering the pattern, core and the gating system. The sand is compacted by vibration and mechanical means. Next, the cope is removed from the drag, and the pattern is carefully removed. The object is to remove the pattern without breaking the mold cavity. This is facilitated by designing a draft, a slight angular offset from the vertical to the vertical surfaces of the pattern. This is usually a minimum of 1?or 1.5 mm (0.060 in), whichever is greater. The rougher the surface of the pattern, the more the draft to be provided.