Influence of Boron on the Hot Ductility of TWIP steels The WritePass Journal

Influence of Boron on the Hot Ductility of TWIP steels 1.0 Introduction Influence of Boron on the Hot Ductility of TWIP steels 1.0 Introduction2.0 Literature Review3.0 Aim Method of Contribution3.1 Gannt Chart Project4.0 ReferencesRelated 1.0 Introduction The demand for crude steel has increased worldwide according to World Steel Association the steel production in 2010 was 1414 million tones.   This shows an increase 15% when compared to the total in 2009 where production was 1229 tonnes. What is interesting is that China accounted for 44% of this total, if China was excluded the annual total increased by 20% when we compare this to 2009.   The steel production in December for 66 countries increased by 7.8% to 116 million tonnes [1]. To meet these production demands, casting is engaged as the chosen fabrication process as it is more economically viable for high production rates than forming operations.   In particular, the technique of continuous casting is favored as a primary hot-rolling operation that produces slabs or thin sheets of steel.   These are a convenient entity that can then undergo secondary metal-forming operations. The conventional way to improve the strength and impact behavior of steel is to add small amounts of micro-alloying elements such as Al or in our case B to benefit grain.  Ã‚   Micro-alloying additions enable tensile strengths of over 500 MPa to be achieved [2] as the micro-alloys formed fine precipitates that would attach the austenite grain boundaries from moving as well as to provide strengthening via precipitation hardening.   It is important to note that these beneficial mechanical properties engineered into steels are only applicable to the finished product, where the steel is employed at room temperature as automobiles.   This point is applicable before the finished steel is even utilized, as at the high temperatures of the continuous casting operation, the steel has undesirable properties. Over the past forty years, the difficulty in casting some steels has led to great efforts in understanding the science behind the cracking processes.   The continuous casting process can to some degree be simulated using a simple laboratory hot tensile test.   Investigating the hot ductility of the steel under these laboratory conditions does give great insight into the viability of producing continuous cast steel free from transverse cracking.   It has been quantified that after straining a steel sample to failure, a ductility displayed as a reduction of area (R of A) value of greater than 40 % will allow for successful casting in industry [3].   These findings are further enforced with visual probing techniques such as microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).   These allow insights into the influence of grain size, precipitation hardening, cooling rates, strain rate and composition on crack propagation which are all import ant in explaining failure modes and preventing failure.   New steel types need to be tested under laboratory conditions before steel companies have the confidence for mass production in industry. 2.0 Literature Review 3.0 Aim Method of Contribution The major problem with TWIP steels is the difficult in casting it; this is because during the continuous casting operation, the cast has to be straightened as it is being cast in a curved mould.   The straightening process puts the surface and the edges of the slabs into tension and this causes cracks and this can be propagated easily into fragile steel grades this is what TWIP falls into. The aim of the project is to do a hot ductility test in which a tensile specimen is melted and then cooled to the straightening temperature which ranges from 1000-700 °C as used in the commercial casting operation.   Following this the specimen is strained to failure by using the strain rate used in the unbending operation as this is a good indicator of a steels likely hood to crack. There have been indications that that by adding a small amount of boron in our case (0.001%) that this will improve the hot ductility of the new TWIP steels and this would make them easier to cast [3] As mentioned the experiment involves the ductility test in which a tensile specimen is melted and then cooled to the straightening temperature which ranges from 1000-700 °C from this we will get a hot ductility curve.   Following this I will perform microscopically and scanning electron microscope examination of the fractured surfaces to find out the mechanism of this improvement. I have 12 specimens which have been provided by POSCO. The machine used for the tensile test is the Hounsfield Tensometer which is situated at City University. 3.1 Gannt Chart Project 4.0 References [1] ISSB: World Steel Review (Iron Steel Bureau, February 2011) [2] Abu Shousha, R., I: Hot Ductility of Steels (PhD thesis, City University) [3] – Discussions with   Prof B.Mintz

The Meaning of Nani in Japanese

The Meaning of 'Nani' in Japanese The word nani  Ã¤ ½â€¢ (㠁 ªÃ£  «) in Japanese means what. And depending on the situation, you might, instead, use  nan (㠁 ªÃ£â€šâ€œ). Which term you use depends on the context, in particular, whether you are speaking or writing formally or informally. The sentences below are listed first in a transliteration of the Japanese phrase or sentence, followed by the spelling in Japanese characters- using  kanji,  hiragana, or  katakana  as appropriate- followed by the translation in English. Where indicated, click on the link to bring up a sound file and hear how to correctly pronounce the word or sentence in Japanese. Using Nani or Nan in a Sentence Nani is the more formal and polite term to use when asking a question, as in: Nani  wo  suru  tsumori  desu ka? (㠁 ªÃ£  « ã‚’ 㠁™ã‚‹ 㠁 ¤Ã£â€šâ€šÃ£â€šÅ  㠁 §Ã£ â„¢ 㠁‹)   What do you intend to do? or What are you planning to do? In more casual situations it would  be  fine to use nan. As a general rule,  if the word following what begins with a syllable from the t, n, and d groups, use nan, as in: Nandeshou? (㠁 ªÃ£â€šâ€œÃ£  §Ã£ â€"ょ㠁†) What do you want? More on Using Nan vs. Nani Nan is used before  particles.  A particle is a word that shows the relationship of a word, phrase, or clause  to the rest of the sentence.  Particles are added to the end of sentences to  express the speaker  or writers  emotions, such as doubt, emphasis, caution, hesitation, wonder, or admiration. You might use  nan   with a phrase such as /㠁 ®, /㠁 § (which means of the and is pronounced no de)  and verb da/desu (打㠁 §Ã£ â„¢ ), meaning it is hitting or it is striking. Nani is used before: /㠁‹ (meaning or and pronounced as ka)  and /㠁 « (meaning into a and pronounced as ni). Be careful when you use nan because, for example, if you use  nan  before ka  (/㠁‹), which means or, it would sound like the word nanka  (㠁 ªÃ£â€šâ€œÃ£ â€¹), which means things like. Another example would be if you were to use  nan with  ni (/㠁 «), it would be nanni  (㠁 ªÃ£â€šâ€œÃ£  «), meaning why, but this sounds very much like nannimo  (㠁 ªÃ£â€šâ€œÃ£  «Ã£â€šâ€š), which translates as nothing at all. Using Nani or Nan in Context You might use  nani  or  nan  in a restaurant. Depending on whether you are at a formal business luncheon or a casual eatery, you might use either of these terms. For example, at fast food eatery you might say: Osusume wa nan desu ka.  (㠁Šå‹ §Ã£â€š Ã£  ¯Ã¤ ½â€¢Ã£  §Ã£ â„¢Ã£ â€¹) What do you recommend?Are wa nan desu ka. (㠁‚ã‚Å'㠁 ¯Ã¤ ½â€¢Ã£  §Ã£ â„¢Ã£ â€¹Ã£â‚¬â€š) What is that?   If you are at a more formal eatery, but you dont know what to order, you might ask a fellow diner: Nani ga oishii desu ka. (ä ½â€¢Ã£ Å'㠁Šã â€žÃ£ â€"㠁„㠁 §Ã£ â„¢Ã£ â€¹Ã£â‚¬â€š) What is good? If you are traveling on a train and need to ask for help from a stranger or train conductor, that would be considered a more formal situation in Japan. Thus, you would use  nani  and might say: Tsugi  wa  nani  eki  desu ka.  (æ ¬ ¡Ã£  ¯Ã¤ ½â€¢Ã© §â€¦Ã£  §Ã£ â„¢Ã£ â€¹Ã£â‚¬â€š) What is the next station? However, if you are traveling with a friend, you might use   the informal  nan, as in: Nan-ji  ni  demasu  ka.  (ä ½â€¢Ã¦â„¢â€šÃ£  «Ã¥â€¡ ºÃ£  ¾Ã£ â„¢Ã£ â€¹Ã£â‚¬â€š)   What time does it leave?