Cobalt Interlayed TiN-coated Tungsten Carbide Cutting Tool’s Performance Ⅵ

3. Results and discussion

3.1. Coating characterization

Fig. 2 shows the thickness of the Co interlayer as a function of sputter time at fixed Co sputter  current of 0.4 A. The thickness of Co interlayer linearly increased from 0.027 μm to 0.160 μm with increasing the sputter time from 10 to 60 min. This result reflects that our hybrid coating system enables an easy control of Co interlayer in synthesis of TiN/Co/WC-Co systems. After deposition of Co interlayer, the TiN coatings were deposited under condition shown in Table 1 by AIP method. The thickness of TiN was approximately 2.5μm. Additionally ,the micro-indentation hardness of the TiN coating layers were found to almost constantly maintain from 27 GPa to 30 GPa at approximately 0.027 μm of thickness of Co interlayer. However, the hardness of TiN having Co interlayer linearly decreased with further increase in the thickness of Co interlayer. This effect is related to a change in the mean free path of Co, which is defined as the thickness of Co in the WC-Co system.

图片锚文本

 

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The Dos and Don’ts of Tungsten Darts Etiquette

Violations of tungsten darts etiquette result in less fun being had and fewer games being played. If you do any of these things, please stop! If your friends do these things, slap them and tell them what’s up.  Friends don’t let friends ruin darts for others. Those who know are responsible for the future habits of those who don’t.

DO be a good sport. People playing tungsten darts are looking to have fun.

DON’T talk to someone throwing unless they are your teammate, and they are okay with being talked to while at the line. If you don’t know, ask them before their next throw.

DON’T talk loudly next to or behind someone throwing. Some doing this are oblivious, while others do it intentionally to get an edge. All tungsten darts players should discourage this even if they are not involved in the match.

DO move smoothly and deliberately without hesitation while retrieving tungsten darts. If you have a bounce-out into a neighboring lane, you can either waiting at the line for them to finish or get low and reach for it like a ninja.
DON’T ever turn and watch someone throw while you are walking back from pulling your tungsten darts. Walk straight and silently until you completely pass their field of vision before turning around to watch.

DON’T stand in the thrower’s field of view. If you can’t avoid it, don’t make sudden moves. In those cases, print a map (from linked article) and give it to your bartender.

DO stand still while chalking steel tip matches. Sudden movements may result in tungsten darts thrown at you. If the player throwing is on an opposing team, it is unsportsmanlike.

DON’T distract games in progress. If you are practicing on a board adjacent to players in a league or tournament match, be considerate and change to a further board when practical.

DO learn the fist-bumping culture of where you are playing and participate. Some bump every player on every throw, some only bump their teammate, some only bump great turns, some only bump before and after matches, and some never bump.  Going against the culture of the bar and its players is impolite. Fist bumps encourage camaraderie and remind everyone that they are playing a game for fun, even when money is on the line.

DON’T practice on other boards if involved in a league or tournament match. Muscle memory is a huge factor and extra throws are typically considered an unfair advantage. One generally acceptable exception is when a participating player goes to the bathroom and everyone is left waiting.

DO play at a reasonably quick pace. Use the bathroom before and after matches. Stay near the tungsten darts area, pay attention to the game, and minimize the time that others are waiting on you.

 

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Characteristics and Classification of China’s Tungsten Deposits

The first tungsten deposit in China was discovered in 1908, and since the end of 1920s, the annual output of tungsten in China has averagely made up 40 percent of the total annual tungsten output of the world.

The basic geological characteristics of China’s tungsten deposits might be summarized as wide in distribution ,numerous in production place, large in size ,rich in grade, complex in associated components and varied in ore deposit types. In addition, China’s tungsten resources are famous in the world for its highly developed quartz vein type tungsten deposits.

The classification of tungsten deposits depends mainly on the research level of their geneses. Polynary metallogenic should serve as the major basis for this classification, and whether the ore-prospecting prognostic information can be provided or not is also a principle for classification.

China’s tungsten deposits can be classified into rock-controlled tungsten deposits and stratabound ones. The former is further divided into two subclasses, i.e., crust-derived tungsten deposits and tungsten deposits from mixed crust-mantle sources, and the latter also into two subclasses , namely, reworked tungsten deposits and superimposed ones, with the addition of modern supergene tungsten deposits. Finally, these deposits are divided into a number of types according to ore-forming process. A simplified classification is given in the paper.

Tungsten deposits are distributed all over 29 provinces, municipalities and autonomous regions of China. With 30° north latitude as the boundary, this paper divides China into North China and South China and differentiates sixteen metallogenic belts which are described in detail.

 

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American Darts History

There are many theories about how darts found its way across the Atlantic; the most popular being that the Pilgrim Fathers took the game with them – and indeed played it - on the Mayflower when they sailing into self-imposed, permanent exile in the ‘New World’ back in 1620.

One darts writer, Keith Turner, challenged the ‘facts’ back in 1980 in his book Darts - The Complete Book of the Game and stated that he could find no evidence to support the theory. Keith added, “In view of their beliefs and code of living it is extremely unlikely that they played any other sort of games either.” Their credo would simply not have allowed it.

Determined came as no surprise to me that the Curator of Exhibits replied that he could find no evidence whatsoever to support such a theory stating “We have researched this in depth and have to confess that we have found no mention or hint of this in our records.” More recently, to close the book on this, Dan William Peek (2001) undertook research with The Pilgrim Society and knocked the ‘fact’ back into the realms of fiction.
It was Dan who set out on an epic journey to seek out the true history of the sport of darts in America. His book To the Point: The Story of Darts in America is an essential work and should be read by anyone interested in darts ‘across the pond.’ It is not my intention here to lift sections of Dan’s work into this article.

When the Americans joined the Second World War, they ‘invaded’ Britain and thousands were stationed in towns and villages up and down the country. One of the activities that appealed to the ‘Yanks’ whilst they were ‘over here’ was visiting the local pub and what did they find in the pub? Yes, darts. A great number of those servicemen and women took darts back home with them and helped spread the word of darts in the post-war years across North America.

American Darts Organization With the coming of the British Darts Organization and the World Darts Federation in the 1970s, darts went well and truly international. In the USA the lead was taken by the late, much-lamented Tom Fleetwood who founded the American Darts Organization (ADO) and with his wife Della and many other colleagues worked great things for US darts for many years.
In addition to Dan William Peek, who has researched the broad history of the sport of darts in the USA, there are a few enthusiasts out there that have recorded the history of their own darts organizations. One of these is Ed Otjen who, in 1999, wrote an 18-page history of the Twin City Darts Association especially to celebrate the TCDA’s 25th Anniversary and was presented at the special Anniversary Dinner in the fall of that year.

Nowadays, tungsten darts have popularized between darts fans. Because tungsten darts are made of high-density metal, so they’re smaller than other materials darts (in the same weight), in the mean time, tungsten darts is environment-friendly.

 

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Experimental Research on Ferro-Molybdenum-Tungsten Ore Processing

Tungsten is an important alloying element in high-speed and other tool steels, and is used to a lesser extent in some stainless and structural steels. Tungsten is often added to steel melts as ferrotungsten, which can contain up to 80% tungsten. World ferrotungsten production is dominated by China, which in 2008 exported 4,835 t (gross weight) of the alloy. Ferrotungsten is relatively expensive, with the prices around $31–44 per kilogram of contained tungsten.
 
Major producers of ferromolybdenum are Chile (16,918 t), China (40,000 t) and the United States which accounted for about 78% of world production of molybdenite ore in 2008, whereas Canada, Mexico and Peru accounted for the remainder. Molybdenite concentrates are roasted to form molybdic oxide, which can be converted into ferromolybdenum, molybdenum chemicals, or molybdenum metal. Although the United States was the second leading molybdenum-producing country in the world in 2008, it imported more than 70% of its ferromolybdenum requirements in 2008, mostly for the steel industry (83% of ferromolybdenum consumed).
 
Aiming at some ferro-molybdenum-tungsten ore from a metal mine in Heilongjiang province, two processing flowsheets are compared, one of which is iron magnetic separation-total sulphur molybdenum floatation-tungsten floatation and the other is total sulphur molybdenum floatation-iron magnetic separation-tungsten floatation. The experiment results show that the indices of the latter are obviously higher than those of the former. The closed-circuit tests obtain molybdenum concentrate, iron concentrate and tungsten concentrate at the grades of 51.69 %,68.22 % and 56.82 %.Meanwhile, the recovery rates are respectively 90.19 %,97.97 % and 73.21 %.The floatation tungsten concentrate is treated by acid pickling to remove phosphonium and carbonate, and its final concentrate is 70.99 %.


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