Selecting a high temperature grease – what to look for

When you’re working in a machinery situation the place the temperatures get a little heated, selecting the best grease is a critical determination to get right. How do you make the fitting determination?

The internet has some glorious resources on the market that can assist guide you to making the right decision.

One such resource is the Machinery Lubrication web site, where we discovered a superb primer on all the factors that you’ll want to consider in selecting the correct kind of high temperature grease.

Once you’re working in a machinery situation the place the temperatures get a little heated, choosing the proper grease is a critical decision to get right. How do you make the precise determination?

The internet has some wonderful resources out there that can assist guide you to making the correct decision.

One such resource is the Machinery Lubrication web site, where we discovered a wonderful primer on all the factors that it’s essential consider in selecting the suitable kind of high temperature grease.

deciding on a high temperature greaseWe’ve referenced a lot of that information here.

For the complete article, check out Machinery Lubrication’s web site here.

What To Consider?

There are a lot of criteria to consider when selecting a high-temperature grease for warm, grease-lubricated equipment – oil type and viscosity, oil viscosity index, thickener type, stability of the composition formed by the oil and the thickener, additive composition and properties, ambient temperature, working temperature, atmospheric contamination, loading, speed, relubrication intervals, etc. With the variety of particulars to resolve, the number of greases that should accommodate excessive temperature conditions is a challenging determination, and given potential for incompatibility problems and the high costs for many high-temperature grease, you really have to be selective and discriminating when making the decision of which grease to use.

‘High temperature’ is relative when characterizing temperature conditions. Bearings running in a metal mill roll-out table application could also be exposed to process temperatures of a number of hundreds of degrees, and should expertise sustained temperatures of 250ºF to 300ºF (120ºC to ±150ºC). Automotive assemblers hang painted metal parts on long conveyors and weave them through massive drying ovens to dry painted metal surfaces. Operating temperatures for these gas-fired ovens are maintained round 400ºF (205ºC). You can see that there’s a wide temperature range to consider here.

In these cases, the selection factors differ appreciably. In addition to heat resistance, the grease to be used in a sizzling metal mill application might require exceptional load-carrying capability, oxidation stability, mechanical stability, water wash resistance and good pumpability, and at a value suitable for giant-volume consumption. With all of the essential factors to consider, it is beneficial to have a grease choice strategy.

The place To Start?

A reasonable starting point for choosing a high-temperature grease is to consider the character of the temperatures and the causes of product degradation that are inherent to whatever place you are going to be using it. There’s basic correlation between a grease’s helpful temperature range and the expected value per pound. As an illustration, a fluorinated hydrocarbon-primarily based (type of artificial oil) grease may work effectively as high as 570ºF (300ºC) in space applications but may additionally price hundreds of dollars per pound. How well the grease holds up lengthy-time period is influenced by the causes of degradation, three of which are particularly vital: mechanical (shear and stress) stability, oxidative stability and thermal stability. Oxidative and thermal stresses are interrelated. High-temperature applications will typically degrade the grease by means of thermal stress, in conjunction with oxidative failure occurring if the product is in contact with air. This is similar to what is to be expected with most industrial oil-lubricated applications. Bell Performance’s X-tra Lube Grease provides some advantages in these types of situations because of the residual lubricating power of its additive package, that continues providing lubricating protection after other parts of the grease could have broken down because of these factors in regular use.

What’s In A Grease?

high temperature greaseFor the uninitiated, grease consists of a base oil with a thickener added, plus additional additives thrown in to bulk up sure essential properties of the grease. Think of the whole thing like a sponge – the thickener is the spongy materials that holds the base oil together like a sponger holds liquid.

Base Oils

When deciding on lubricants for oil-lubricated applications, one often begins with the consideration of base oil performance properties. This can be a very good starting level for grease products. Base oils can be subdivided into mineral and synthetic types. Mineral oils are probably the most widely used base oil element, representing approximately ninety five p.c of the greases manufactured. Synthetic esters and PAO (synthetic hydrocarbons) are subsequent, adopted by silicones and some different unique synthetic oils.

The American Petroleum Institute divides base oils into five classes based mostly on their performance limits (Groups I-V). They tend to vary by how well they resist thermal or oxidative break down, and how well they disperse and hold the additives which might be added to the grease product. Generaally speaking, the higher Teams are more resistant but value more.

Mineral and synthetic base oils degrade thermally in conjunction with oxidative degradation if the product is in contact with air. The break level at which the person oil molecules in a highly refined (Group II+, Group III) mineral oil and artificial hydrocarbons will start to unravel, releasing carbon atoms from the molecular chain, is about 536ºF to 608ºF (280ºC to 320ºC). 3,4 The grease manufacturer will choose supplies given their familiarity, and maybe availability, of the raw materials. If the manufacturer makes a particular type of artificial base fluid and is intimately acquainted with the varied destruction mechanisms of that fluid, then it is likely that this type of synthetic base will typically be selected for new product development.

Thickeners

The materials chosen as the grease thickeners may be natural, similar to polyurea; inorganic, reminiscent of clay or fumed silica; or a cleaning soap/complex soap, corresponding to lithium, aluminum or calcium sulfonate complex. The usefulness of the grease over time relies on the entire package collectively, not just one thing like the thickening system or the type of base oil. For example, a silica grease thickener has a dropping point of two,732ºF (1,500ºC) as one excessive example. However, because grease performance depends on a combination of materials, this doesn’t characterize the useful temperature range. Some examples of the kinds of thickeners you will have to choose from could be:

Natural polyurea – gives temperature range limits much like the metal soap-thickened grease, however additionally it has good antioxidation and antiwear properties that come from the thickener itself. Polyurea thickeners would possibly turn into more fashionable but they’re tough to fabricate, requiring the handling of a number of poisonous materials. While the thickener has a high dropping point, the composition begins to thermally degrade at temperatures which limit its usefulness over time at high temperatures.

Calcium sulfonate – much like the polyurea, it possesses inherent antioxidant, rust-inhibiting properties, however in addition has inherent high dropping points and EP/antiwear properties.

For more information on จารบีทนความร้อนสูงยี่ห้อไหนดี review our page.