CE ESTE OŢELUL?

Oţelul reprezintă o familie extinsă de metale. Acesta nu este un element, ca aluminiul ori aurul, ci un aliaj. Toate tipurile de oţel sunt aliaje ce conţin fier, carbon şi alte elemente, cum sunt nichelul, cromul ori tungstenul. În funcţie de procentul de carbon adăugat aliajului, oţelul va fi mai dur sau mai moale.
Procentul de carbon variază între 0,25% şi 1,50%; cu cât procentul de carbon este mai mare, cu atât aliajul va fi mai dur.

Iată câteva exemple de instrumente cu duritate diferită, în funcţie de procentul de carbon:
- foarfece ori cuţit, 1,4% carbon;
- topor, 1% carbon;
- zalele unui lanţ, 0,05% carbon.

RĂCIREA ŞI DURITATEA OŢELULUI

Modul în care se face răcirea oţelului determină cât de dur şi casant este acesta. O răcire treptată va produce oţel mai puţin dur decât o răcire bruscă.

CE ÎNSEAMNĂ "STAINLESS STEEL"?

Pe mai toate cuţitele veţi găsi acestă inscripţie, "stainless steel"; este asigurarea producătorului că nu vă va rugini cuţitul. În mod obişnuit oţelul "stainless steel" conţine fier, carbon, crom şi nichel. După definiţie, oţelul necoroziv (inoxidabil), "stainless steel", conţine un minimum de 11% crom.

CE ESTE "HIGH SPEED STEEL"?

Este posibil să fi observat, dacă aţi cumpărat, de exemplu, burghie pentru o bormaşină ori discuri pentru polizor, că pe unele este menţionat că acestea conţin high speed steel. Ce înseamnă acest lucru? Este semnul că puteţi folosi burghiul ori discul pe metal, căci vor rezista la temperaturile foarte mari ce se dezvoltă la frecarea metal pe metal.

source: www.scientia.ro

Most Expensive Knife

In 1966, a twenty-something named Buster Warenski decided that he’d like to make his own knife. Forty years later, he is considered one of the greatest knife makers of the last century. At the age of thirty, he became one of the handful of knife makers to join the Knifemakers Guild. He ended up serving two terms as the guild’s president.

His Legacy Series of four 18k gold knives includes the most expensive modern knife in the world—Gem of the Orient. Designed for a Japanese customer, the knife’s jade and gold filigree handle is encrusted with 153 emeralds (10 carats) and nine diamonds (5 carats). In all, the knife was made with 28 ounces of gold. Supposedly, it took Warenski 10 years to make.

The world’s most expensive modern knife was originally sold for $1.2 million. The buyer, in turn, put Gem of the Orient up for sale for $2.1 million.

Source:http://most-expensive.net/knife-moder

Most Expensive Swiss Army Knife

Don’t bring this one on your next camping or fishing trip. Victorinox Swiss Army is producing these stunningly outrageous knives more likely to sit on a shelf than in the pocket of an outdoorsman…or Macgyver.

The shells of the most expensive Swiss Army knife are made of pure platinum 950. The inset lengthwise has 430 dazzling diamonds bringing the total weight to close to 4 carats.

All of the tools included with the expensive knives are engraved with diamonds too, except for the tweezers. If you were to buy the most expensive Swiss Army Knife in the world, it would also include a solid gold or platinum chain and a chic Bonfort case. Oh yeah, and it would cost you $70,000 US.

Swiss Army knives are world famous for their innovations in knife craftsmanship. They produce all kinds of knives from simple to extremely lavish. Other Swiss Army knives with interesting features include a knife with a USB flash drive and one that doubles as an MP3 player. These knives might be for you if you’re in the market for a cool knife but don’t have $70 grand to blow.
PRODUCT DETAILS OF PLATINUM SWISS ARMY KNIFE
Large Blade
Small Blade
Nail File and Nail Cleaner
Scissors
Orange-Peeler with Screwdriver
Ring
Tweezers

source:http://most-expensive.net