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Basics of Coolant Management

Industrial Lubricants are always a vast and interesting subject to discuss and share. Broadly Industrial Lubricants can be discussed in two verticals – one is of course Factory, Plant & Machinery [ FPM ] products like Hydraulics, Gear Oils, Compressor Oils, etc. Another is Lubricants used in processing. In the later segment, one of the most sensitive portfolios is water extendable cutting coolants used in metal processing industries. Many technical publications and in-depth experiences are shared for the maintenance of cutting coolants. However, today's effort is to address the basics of maintenance of Soluble cutting coolants either mineral based conventional high oil content products or new generation semi-synthetic products. Before going into maintenance practices let us have a quick look at the composition and chemistry of Cutting coolants. New generation cutting oils are a complex combination of Lubricity components blended with Emulsifiers, Co-emulsifiers, Corrosion Inhib

Relation Between Friction, Wear & Lubricants

(R.S) What is Friction:-   Friction is the resistance to motion and wear is the loss of material as a result of friction, contact fatigue and corrosion. Reducing friction is a key objective of lubrication, but there are many other benefits of this process. Lubricating films can help prevent corrosion by protecting the surface from water and other corrosive substances. Different Types of Friction:- Sliding Friction:-  The term sliding friction refers to the resistance created by two objects sliding against each other. This can also be called kinetic friction. Sliding friction is intended to stop an object from moving.    Rolling Friction:-  In simple words Rolling friction is the force resisting the motion when a body rolls on a surface.     Also there some more types of friction is there like Boring Friction, Mix of Sliding & Rolling Friction, Internal Friction of a deform-able body. Majorly in all types of application, we can see these types of friction & the main purpose of

Can Lubricants Increase Friction?

  Lubricants like any types of greases & oils usually used to reduce the effect (heat generated when the surface move) of friction or we can say that its decrease the friction between surfaces in mutual contact rather increasing friction. A good lubricants or proper lubrication process does not only reduce friction but also it has multi functional tasks mentioned below. 1st & for most lubricants used to separate or lubricate two moving surfaces. 2nd A good lubricant or if you have selected proper lubrication process then lubricants can be a good sealant & can be used for sealing process. 3rd one of the major role of lubricants is to reduce the heat generated by two moving surfaces in mutual contact. Lubricants can act as coolant. Last but not the least Lubricating oils & greases can also protect material from different types of foreign particles, which can damage the materials like bearing, gears etc. & protects from oxidization and corrosion. To clarify how lubrica

Reliable Lubrication Solution for Caster Application in Steel Making Plants

In this article we are going to describe one of the vital application of steel making plants. You can understand the criticality of the application by knowing that companies are claim caster is the heart of steel plants. As this application describe as heart of steel making plants, then its also critical as human heart. As study says approx 75 to 80% of application breakdown due to bearing failure is happened due to improper lubricants selection & improper lubrication. Selection of Lubricants & lubrication process is not as simple as it looks like. As we have stated that Caster application is the heart of steel making plants then here proper lubrication & proper lubricants selection is undoubtedly a very important task for application engineers & maintenance peoples.

There are mainly 3 types continues casters we can see in mainly all integrated steel plants as per the end products & caster criticality.

  1. Billet Caster
  2. Bloom Caster
  3. Slab Caster

As per criticality Slab Casters are the most critical continues caster application in steel plants.For decades lubrication scientists & tribologists are doing research & studies to find permanent solution for line clogging issues & as a after effect of line clogging caster rolls bearing failure. Majorly all majorly steel making plants  are facing this issues resulting high down time of application, production failure & considerable man hour loss. To avoid these type of problem modern continuous casting process (CCP) segments are equipped with multiple split rollers, additionally increased number of lubrication points but that is not enough for completely avoid caster rolls bearing failure due to improper lubrication &improper lubricants selection.

Now a days casting machines have multiple & separate automatic & centralized lubrication system to lubricate different types of caster application machine elements, mostly rolls bearing. These centralized lubrication systems pump a relatively small amount of grease at frequent intervals to the bearing. The grease quantity is typically less than 5cc (0.15 oz.), but the frequency is typically 6 to 10 times per hour. This frequent cycle can keep the bearing full with new grease while also clear out old grease and contaminants.

Operational Criticality:-

The bearings which are located at run out table area in continues casting machine are continuously exposed to high radiation heat (considering exit billet  temp is more than 900°C). The bearing temp can go up to more than 150°C, which is not favorable condition for both bearing lubrication and lubrication method.

In Slab Caster application, machine elements mostly bearings & grease lines are exposed to higher radiation temperature because of higher slab width and greater slab thickness & that is the reason of lubrication line clogging or you can say solidification of grease inside the pipeline. Due to grease chocking inside the grease pipe line, lubricants not able to reach the lubrication points. When rolls bearing starving for lubrication for prolonged period of time, the result is early premature bearing failure & system shutdown.

There is a way to fight with this kind of problem. Normally anyone can avoid this problem by using high temp grease with frequent or shorter lubrication cycle but these will increase the lubricants consumption drastically as well as lubrication cost will also increase uncontrollably. Also frequent roll jamming and caster segment replacement is also increase the cost which can not controlled by using non effective high temp lubricants.

An alternative is the air-oil system; The Air Oil system uses compressed air to drive a film of oil through distribution pipes to the bearings. These systems can operate continuously to keep fresh required grease flowing while clearing out the old grease and contaminants. Modern air-oil systems can operate with significantly reduced lubricant consumption.

Common problem faced by the customer:-

Because of continuous expose to high temp,the problems are as follows:
  • The grease feed line (from distributor to bearing) clogs very frequently because of hardening of grease inside the narrow pipe, which leads to frequent replacement / cleaning of the pipes.
  • The grease inside the bearings sometimes gets hardened which also attracts premature bearing failure.
  • Because of lubrication starvation inside the bearing, the problem can occur.
  • Bearing life can be shortened because of improper or inadequate lubrication.

Required properties of the grease:- 

  1. Should not harden at higher temperature. 
  2. Should be able to reduce wear on the bearings. 
  3. Reduces lubricant consumption.

Lubricants / Greases for Caster Application in Major Steel Plants:-

For applications operating at very high temperatures, the type of lubrication used must also be evaluated. If the caster application temperatures exceed the lubricants temp rating then the effectiveness of the lubrication will be compromised and that will be the reason of increased friction in the rolls bearings used in caster. This increased friction increases wear and reduces the life of the bearing components.

You probably know the importance of THICKNERS for any types of grease making. Actually without thickner it is like not possible to make a grease from a oil. Because to make any grease first we need to take lubricating oil (Mineral or Synthetic), then in certain temp we need to mix thickners ( lithium, lithium complex, calcium or aluminium complex soap), additives & solid lubricants to make lubricating grease from a lubrication oil. You can read basic difference between Lubricating grease vs lubricating oil article.

Polyuria thickened greases is also very popular in some types of certain applications. In past & recent years, polyurea thickened greases have gained popularity particularly in steel mill & continuous castors applications. Greases used in caster application should have good thermal stability as well as good load carrying capacity. So, some polyurea based greases with added extreme-pressure (EP) ad-ditive packages provide good load-carrying capability without degrading the thermal stability of the grease at high temperatures. Also polyuria based greases have value added properties like excellent corrosion protection; good mechanical, oxidation and high-shear stability, low wear, low volatility and low oil bleed.
 

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