What is meant by the viscosity index or viscosity index (VI) is a number that indicates the range of changes in the viscosity of a hydraulic fluid associated with changes in temperature.<\/span> Thus the viscosity index is used as a basis in determining the characteristics of the hydraulic fluid viscosity related to temperature changes.<\/span> Regarding the viscosity index is specified in DIN ISO 2909. Hydraulic fluid is said to have a high viscosity index when the viscosity changes little (stable) over a relatively large temperature changes.<\/span><\/p>\n

Or it can be said that the hydraulic fluid can be used in a range of temperature changes significantly.<\/span> Hydraulic fluids, especially hydraulic oil is expected to have a viscosity index (VI) = 100. In fact, most of the hydraulic oil given additional ingredients (additives), called “VI improvers” to increase the VI becomes higher than 100. Hydraulic oil with high viscosity index also called multigrade oils ,<\/span> To determine the viscosity change is noticed Ubbelohde ‘s viscosity – temperature diagram below (figure 3).<\/span>
\n<\/a>
\n Figure 3. Ubbelohde ‘s viscosity -temperature diagrams<\/span><\/p>\n

Hydraulic fluid must have certain characteristics in order to meet the requirements in carrying out its functions.<\/span> Characteristics or attributes required include:<\/span>
\n A. Viscosity (Viscosity) pretty.<\/strong><\/span>
\n Hydraulic fluid must have sufficient viscosity in order to fulfill its function as a lubricant.<\/span> If the viscosity is too low, the oil film is formed to be very thin and is unable to withstand friction.<\/span><\/p>\n

B. Viscosity Index are good.<\/strong><\/span>
\n With good viscosity index, the viscosity of hydraulic fluid used on the system will be stable with temperature changes work quite volatile.<\/span><\/p>\n

C. Fireproof (non-flammable)<\/strong><\/span>
\n Hydraulic systems often operate in places that tend to arise or adjacent fire with fire.<\/span> It is therefore necessary fire-resistant fluids.<\/span><\/p>\n

D. No foaming (foaming)<\/strong><\/span>
\n When many foamy hydraulic fluid will result in a lot of air bubbles trapped in the hydraulic fluid so that there will be compressable and will reduce the power transfer.<\/span> In addition, the presence of foam was terjilat possibility of fire will be greater.<\/span><\/p>\n

E. Hold cold<\/strong><\/span>
\n The meaning is that the cold-resistant hydraulic fluids not easily freeze when operating in cold temperatures.<\/span> Freezing or melting point that is desired by the hydraulic fluid ranged between 100-150 C below the temperature at the beginning of the engine is operated (start-up).<\/span> This is to anticipate the block (blocked) by hydraulic fluid that freezes.<\/span><\/p>\n

F. Resistant to corrosion and wear resistant.<\/strong><\/span>
\n Hydraulic fluids should be able to prevent corrosion due to corrosion does occur then the construction will not be easy to wear in other words, the machine will last.<\/span><\/p>\n

G. De mulsibility (Water separable)<\/strong><\/span>
\n What is meant by de-mulsibility is the ability of a hydraulic fluid to separate water from hydraulic fluids.<\/span> Why water must be separated from the hydraulic fluid, because the water will cause corrosion when it comes to metal.<\/span><\/p>\n

H. Minimum Compressibility<\/strong><\/span>
\n In teorotis fluid is uncompressible (can not be compressed).<\/span> But the fact of hydraulic fluid can be compressed up to 0.5% by volume for each pressure 80 bar.<\/span> Therefore, it is required that a hydraulic fluid to be relatively compressible or if compressible possibility is very small.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

What is meant by the viscosity index or viscosity index (VI) is a number that indicates the range of changes in the viscosity of a hydraulic fluid associated with changes in temperature. Thus the viscosity index is used as a basis in determining the characteristics of the hydraulic fluid viscosity related to temperature changes. Regarding …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1406],"tags":[1555,1558,1559,1562,1557,1556,1560,1563,1564,1561],"class_list":["post-1464","post","type-post","status-publish","format-standard","hentry","category-english","tag-viscosity-index","tag-viscosity-index-astm-d2270","tag-viscosity-index-calculator","tag-viscosity-index-chart","tag-viscosity-index-formula","tag-viscosity-index-improver","tag-viscosity-index-meaning","tag-viscosity-index-motor-oil","tag-viscosity-index-of-water","tag-viscosity-index-table"],"_links":{"self":[{"href":"https:\/\/www.tneutron.net\/mesin\/wp-json\/wp\/v2\/posts\/1464","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tneutron.net\/mesin\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tneutron.net\/mesin\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tneutron.net\/mesin\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tneutron.net\/mesin\/wp-json\/wp\/v2\/comments?post=1464"}],"version-history":[{"count":1,"href":"https:\/\/www.tneutron.net\/mesin\/wp-json\/wp\/v2\/posts\/1464\/revisions"}],"predecessor-version":[{"id":3080,"href":"https:\/\/www.tneutron.net\/mesin\/wp-json\/wp\/v2\/posts\/1464\/revisions\/3080"}],"wp:attachment":[{"href":"https:\/\/www.tneutron.net\/mesin\/wp-json\/wp\/v2\/media?parent=1464"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tneutron.net\/mesin\/wp-json\/wp\/v2\/categories?post=1464"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tneutron.net\/mesin\/wp-json\/wp\/v2\/tags?post=1464"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}