Description:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to hot rolling mills and more particularly, a nano-lubrication system for pilot hot rolling mills.

BACKGROUND OF THE INVENTION
The application of nano-fluids in hot rolling lubrication has not been extensively explored. To delve into this, a basic research project was undertaken to investigate the use of nano-fluids in roll lubrication during hot rolling. The primary objective was to develop stable formulations that offer an innovative and environmentally friendly alternative to traditional lubricants. Experimental trials were conducted in the Experimental Rolling Mill (ERM) to assess the effects of nano-fluids on rolling force, surface roughness, and oxide scale formation. It is important to note that the preparation of nano lubricants requires attention to detail, and the specific steps may vary based on the type of nanoparticles and base lubricant used.

Hence there is a need for the introduction of a novel system that aims to overcome these drawbacks and provide a more efficient solution.

SUMMARY OF THE INVENTION
The following disclosure presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

An object of the present invention is to provide a novel system for nano-lubrication dispersion of nanoparticles in a lubricating fluid.

Another object of the present invention is to provide a novel system for nano-lubrication application in ERM.

Another object of the present invention is to provide a method for nano-lubrication preparation and application for hot rolling application in ERM.

The present application proposes a customized nano-lubrication preparation and application system that has been designed and developed for hot rolling application in ERM. Proper dispersion of nanoparticles in the base lubricant is crucial. Dispersion methods such as sonication, high-shear mixing, are used to achieve a uniform distribution of nanoparticles in the lubricant. Therefore, the effectiveness of nano-lubrication hinges on meticulous control of mixing parameters and the optimization of dispersion techniques. Further, application system varied depending on the end use. In this work, the nano-lubrication application system has developed to carry out hot rolling trials in ERM. Additional laboratories facilities were created to prepare nano-oil mixture and its application system during hot rolling in ERM.

In one aspect of the present invention, a Nano- Lubrication System for Pilot Hot Rolling Mill is provided, wherein the nano-lubrication system is a combination of a nano-lubrication dispersion system and a nano-lubrication application system, the said nano-lubrication dispersion system comprising:
magnetic stirrers for homogenous mixing of nanoparticles in the lubricant;
ultrasonic probe sonicator for thorough mixing of nano-particles with the lubricant by utilizing high-frequency sound waves;
ultrasonic bath sonicator for redispersing nano-sized powders within liquid matrices.

In the other aspect of the invention, a Nano- Lubrication System for Pilot Hot Rolling Mill is provided, wherein the nano-lubrication system is a combination of a nano-lubrication dispersion system and a nano-lubrication application system, the said nano-lubrication application system comprising:
a skid mounted Roll Bite Lubrication (RBL) system; and
one or more spray headers.

In the other aspect of the invention, a method for application of nano-fluids in hot rolling lubrication is provided, said method comprising:
stirring, for breaking down agglomerates of nanoparticles and ensuring their even distribution throughout the lubricant;
mixing of nano-particles with the lubricant by utilizing high-frequency sound waves;
generating a well-dispersed mixture of oil-in-water-based lubricants, infused with nano-particles, and subsequently administering it as a spray onto both the top and bottom rolls of an Experimental Rolling Mill.

Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The above and other aspects, features and advantages of the embodiments of the present disclosure will be more apparent in the following description taken in conjunction with the accompanying drawings, in which:

Figure 1 illustrates the details of the nano-lubrication system according to one implementation of the present invention.
Figure 2 illustrates the magnetic stirrer according to one implementation of the present invention.
Figure 3 illustrates the Ultrasonic Probe Sonicator according to one implementation of the present invention.
Figure 4 illustrates the Ultrasonic Bath Sonicator according to one implementation of the present invention.
Figure 5 illustrates the RBL System for Nano-lubrication according to one implementation of the present invention.
Figure 6 illustrates the Skid Mounted RBL System according to one implementation of the present invention.
Figure 7 illustrates the view of lubrication spraying from nozzles according to one implementation of the present invention.
Figure 8 illustrates Rolling force (Ton) at various lubrication conditions according to one implementation of the present invention.
Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may not have been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE PRESENT INVENTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding, but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments belong. Further, the meaning of terms or words used in the specification and the claims should not be limited to the literal or commonly employed sense but should be construed in accordance with the spirit of the disclosure to most properly describe the present disclosure.

The terminology used herein is for the purpose of describing particular various embodiments only and is not intended to be limiting of various embodiments. As used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising" used herein specify the presence of stated features, integers, steps, operations, members, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, members, components, and/or groups thereof.

The present disclosure will now be described more fully with reference to the accompanying drawings, in which various embodiments of the present disclosure are shown.

The present application proposes a customized nano-lubrication preparation and application system that has been designed and developed for hot rolling application in ERM. Proper dispersion of nanoparticles in the base lubricant is crucial. Dispersion methods such as sonication, high-shear mixing, are used to achieve a uniform distribution of nanoparticles in the lubricant. Therefore, the effectiveness of nano-lubrication hinges on meticulous control of mixing parameters and the optimization of dispersion techniques. Further, application system varied depending on the end use. In this work, the nano-lubrication application system has developed to carry out hot rolling trials in ERM. Additional laboratories facilities were created to prepare nano-oil mixture and its application system during hot rolling in ERM.

Details of the Developed System:
The complete system is divided into two parts as shown in Fig.1, namely, the Nano-lubrication dispersion system and Roll Bite Lubrication Application System for Nano-lubrication at ERM. The experimental investigation was carried out for the hot rolling process by in ERM.

A. Nano-lubrication dispersion system:
The Nano-lubrication dispersion system involves the preparation of a stable and uniform dispersion of nanoparticles in a lubricating fluid. The key goal is to ensure that the nanoparticles are well-distributed and do not agglomerate, allowing them to provide enhanced lubrication properties. The nano-lubrication technique and equipment selected for hot rolling application are as follows:
I. Magnetic stirrers:
Effective stirring is crucial in the first step of the process. It ensures the uniform distribution of nanoparticles in the lubricant, enhancing homogeneity. Homogeneous mixing is essential for the consistent properties and performance of the resulting nano-lubricant. A magnetic stirrer (Fig.2.) is employed for this purpose. It consists of a magnetic field generator and a stir bar. The stir bar is typically a rod-shaped magnet. The magnetic stirrer ensures a homogeneous mixture of nanoparticles in the lubricant, preventing settling or uneven distribution. The rotation speed and strength of the magnetic field can often be controlled, providing flexibility in the mixing process.

The device has the feature of auto-calibration, variable speed using microprocessor control in the range of 200-2200 rpm with control accuracy of +/- 5 rpm.

Operation of Magnetic Stirrer:
a) Setup: The rod-shaped magnet (stir bar) is placed in a beaker containing the nano-lubricant.
b) Magnetic Field Generation: The magnetic stirrer has a magnetic field generator, usually located beneath the surface of the platform holding the beaker. This magnetic field is what drives the rotation of the stir bar.
c) Rotation Mechanism: The magnetic stir bar is rotated by the magnetic field. As the magnetic field changes, the stir bar follows, creating a stirring motion in the nano-lubricant.
d) Stirring Action: The rotation of the stir bar agitates the nano-lubricant, promoting the dispersion of nanoparticles. This stirring action is essential for breaking down agglomerates of nanoparticles and ensuring their even distribution throughout the lubricant.

II. Ultrasonic Probe Sonicator:
The Ultrasonic Probe Sonicator of Fig.3 is an advanced tool employed in the second phase of nano-lubrication preparation. This step focuses on the thorough mixing of nano-particles with the lubricant, and the sonicator achieves this by utilizing high-frequency sound waves.

Components:
a) Generator: The sonicator is equipped with a powerful generator boasting 900 watts of output, operating at a frequency of 20 kHz. This high power and frequency are essential for generating intense ultrasonic waves.
b) Converter Cable: Connecting the generator to the ultrasonic probe, the converter cable facilitates the transmission of electrical energy to the sonication system.
c) Probe (6mm): The heart of the sonication process, the 6mm probe is responsible for emitting ultrasonic waves into the nano-lubricant. This probe is meticulously designed to ensure effective disruption and homogenization of the nano-particles in the lubricant.
d) Microprocessor Controlled System: A sophisticated microprocessor-controlled system oversees the entire sonication process. It manages the parameters such as power intensity, duration, and frequency, ensuring precision and reproducibility in the nano-lubrication mixing.

Principle of Operation:
a) High-Frequency Sound Waves: The generator produces electrical energy at a frequency of 20 kHz. This energy is then converted into high-frequency sound waves by the ultrasonic probe.
b) Probe Design: The 6mm probe is strategically designed to focus and deliver these ultrasonic waves into the nano-lubricant. The high-frequency waves create alternating high-pressure and low-pressure cycles, inducing cavitation in the liquid.
c) Cavitation Effect: Cavitation involves the formation, growth, and implosion of microscopic bubbles in the liquid. The implosion generates localized shockwaves and microstreaming, disrupting agglomerates and promoting the homogenization of nano-particles in the lubricant.

Key Features:
a) Generator Power: The 900-watt generator provides substantial energy for effective nano-particle disruption.
b) Probe Size: The 6mm probe size balances precision with coverage, ensuring comprehensive mixing throughout the nano-lubricant.
c) Controlled by Microprocessor: The microprocessor-controlled system enables fine-tuning of parameters, allowing for precise control over the sonication process.

III. Ultrasonic Bath Sonicator
In the third procedural stage, ultrasonic bath sonicator has been used. This specialized device serves the dual purpose of redispersing nano-sized powders within liquid matrices and achieving homogeneity in dispersions of nanoparticles. Sonication, a technique involving the application of ultrasonic waves, is employed to effectively disrupt agglomerates present in the system without inducing alterations to the inherent physicochemical properties of the primary particles.

The ultrasonic bath sonicator of Fig.4 used in this case exhibits a considerable capacity, specifically accommodating up to 15 liters of the target liquid and nanopowder mixture. This device operates at an ultrasonic frequency of 60 kHz, signifying 60,000 cycles per second, thereby ensuring precision in the disruption of agglomerates. Furthermore, the efficient execution of this process requires a power input of 120 watts, facilitating the generation of the necessary ultrasonic waves for optimal dispersion and homogenization of the nanoparticle-laden liquid medium.

B. Roll Bite Lubrication Application System for Nano-lubrication at ERM:

The skid-mounted Roll Bite Lubrication (RBL) system, as depicted in Fig. 5, has been specifically engineered and installed within the context of the ERM (Experimental Rolling Mill) to conduct a thorough examination of the influence of oil-in-water-based lubricants containing nano-particles on the performance of hot rolling processes. This intricate system is purposefully designed to generate a well-dispersed mixture of oil-in-water-based lubricants, infused with nano-particles, and subsequently administer it as a spray onto both the top and bottom rolls of the ERM. The resultant lubricating film, adhering to the rolls, functions to diminish friction and wear at the points of contact between the rolls and the steel strip being processed.

The comprehensive structure of the RBL system comprises several key components, including an oil storage unit, an oil flow circuit, a water flow circuit, an oil-water mixer, and a dispersion spray system. This design allows for meticulous control over various parameters, notably the oil flow rate and dispersion pressure, essential for tailoring the lubrication process to specific operational requirements. Schematic of the designed system is shown in Fig. 6.

To regulate the oil flow rate, a reciprocating duplex proportioning/metering pump, equipped with a Variable Frequency Drive (VFD), is deployed. This pump provides a dynamic range of flow rates, spanning from 1.5 to 12.4 liters per hour, thereby enabling precise adjustment based on operational demands. The oil-water mixer is ingeniously designed with a tube-type configuration featuring an internal spiral construction, facilitating the thorough blending of oil and water to create the desired dispersion before being sprayed onto the work rolls.

For calibration purposes, the system incorporates dedicated cylinders with capacities of 500 ml and 2500 ml to accurately calibrate the flow rates of both oil and water. In the case of a 400 mm wide mill, the RBL system is outfitted with two spray headers (as illustrated in Fig.7), strategically covering the roll barrel with a width of 350 mm. These headers, constructed with a three-piece dove-tail design, are equipped with flat jet nozzles fabricated from SS316 material. The spray angle is precisely set at 90°, resulting in a spray width of 180 mm at a height of 180 mm. Notably, the nozzles are configured with a pitch of approximately 185 mm and a nozzle offset of 5°, ensuring optimal and uniform dispersion across the rolling surfaces.

Technical details of main components of the RBL system are given below:

(a) Oil pump -electrical motor with suitable coupling
i) Pump: Reciprocating type, duplex proportioning/metering pump; 2 cylinders; 1.5 to 12.4 lph flow rate, pressure 48 bar; material of construction 316 SS; flow rate automatically controllable by varying stroke speed using variable speed drive.
ii) Motor: 0.37KW, 1415 RPM, 3 phase, 415VAC, 50 Hz.
iii) Control Panel with Variable Frequency Drive (VFD):
• Control panel with MCB, Starter, ON/OFF switches, safety device
• Suitable VFD for above mentioned pump-motor set to precisely control the flow rate of pump in the range of 1.5 to 12.4 lph. The VFD is suitable for operating at the above mentioned voltage and frequency. VFD has necessary protections for overload, instantaneous overcurrent, short-circuit, etc.

(b) Oil-water mixer: Tube type, diameter of 0.5 inch & 1 inch, internal spiral construction for shearing action, material SS 316/ SS 304.

(c) Spray header with nozzles
i. Spray header for 400 mm wide mill: Two number of spray headers, Single zone type, total 2 nozzles per headers for roll barrel coverage of 350 mm.
ii. Nozzle: The above headers is fitted with flat jet type nozzles in three-piece dove tail construction, flow rate:4 lpm (2 nos) and 2 lpm @ 5 bar (2 nos) pressure, angle 90+10o, spray width of 180 mm at a height of 180 mm, material SS316. Pitch of nozzle ~ 185 mm and nozzle off-set 5o.

C. Trial with the Developed System:
The rolling process was performed for different lubrication types. The types of lubricants include dry, water, emulsion, and optimised 0.1wt% TiO2 concentration in the emulsion. The lubrication was sprayed for every single pass and roll force was measured along with. Among various response parameters, the current investigation mainly focuses on roll force analysis. The roll force is one important factor to understand material processing. The roll force as a function of flow stress, stress, strain, boundary conditions, etc. enables material behaviour on deformation.

The roll force was obtained for various lubrication conditions for a single pass and was depicted in Fig.8. From the graph, it can be seen that there is significant reduction in roll force in first pass where reduction is the highest. With use of nano-lubrication, roll force reduced by 15-23% compared to other rolling conditions (with oil, with water and dry rolling).

According to the above-analysed results, nano-emulsion incorporated in the rolling process generated roll force variations. The variability in rolling force is dictated by the deviation in friction coefficient (COF) under varying lubrication. The TiO2 nano-lubrication lowers the COF and consequently the rolling force. The probable cause of reducing the roll force is reducing friction by incorporating the rolling effect of particles instead of sliding. Earlier sections also proved a slight increment in viscosity which bears the load, which also helps in reducing roll force.

The conceptual framework of this system can be effectively applied to the development of nano-lubrication in industrial hot rolling applications.

Those skilled in the art will recognize other use cases, improvements, and modification to the embodiments of the present disclosure. All such improvements and other use-cases are considered within the scope of the concepts disclosed herein.
, Claims:
1. A nano-lubrication system for Pilot Hot Rolling Mill, wherein the nano-lubrication system is a combination of a nano-lubrication dispersion system and a nano-lubrication application system, the said nano-lubrication dispersion system comprising:
magnetic stirrers for homogenous mixing of nanoparticles in the lubricant;
ultrasonic probe sonicator for thorough mixing of nano-particles with the lubricant by utilizing high-frequency sound waves; and
ultrasonic bath sonicator for redispersing nano-sized powders within liquid matrices.

2. The system as claimed in claim 1, wherein magnetic stirrers comprising a magnetic field generator and a stir bar.

3. The system as claimed in claim 1, wherein the stir bar is a rod-shaped magnet.

4. The system as claimed in claim 1, wherein the ultrasonic probe sonicator is equipped with a powerful generator boasting 900 watts of output, operating at a frequency of 20 kHz.

5. The system as claimed in claim 1, wherein the generator is connected to the ultrasonic probe using a converter cable.

6. The system as claimed in claim 1, wherein a probe is adapted to focus and deliver ultrasonic waves into the nano-lubricant.

7. The system as claimed in claim 6, wherein the probe having length of about 6mm.

8. The system as claimed in claim 6, wherein the probe having size so as to balance precision with coverage, ensuring comprehensive mixing throughout the nano-lubricant.

9. The system as claimed in claim 1, wherein the ultrasonic bath sonicator is used for achieving homogeneity in dispersions of nanoparticles.

10. A nano- lubrication System for Pilot Hot Rolling Mill as claimed in claim 1, wherein the nano-lubrication system is a combination of nano-lubrication dispersion system and nano-lubrication application system, the said nano-lubrication application system comprising:
a skid mounted Roll Bite Lubrication (RBL) system; and
one or more spray headers.

11. The system as claimed in claim 1, wherein the RBL system conducts a thorough examination of the influence of oil-in-water-based lubricants containing nano-particles on the performance of hot rolling processes.

12. The system as claimed in claim 1, wherein the RBL system is outfitted with two spray headers, strategically covering the roll barrel with a width of 350 mm.

13. The system as claimed in claim 1, wherein the headers are constructed with a three-piece dove-tail design.

14. The system as claimed in claim 1, wherein the headers are equipped with flat jet nozzles fabricated from SS316 material.

15. A method for application of nano-fluids in hot rolling lubrication, said method comprising:
stirring, for breaking down agglomerates of nanoparticles and ensuring their even distribution throughout the lubricant;
mixing of nano-particles with the lubricant by utilizing high-frequency sound waves;
generating a well-dispersed mixture of oil-in-water-based lubricants, infused with nano-particles, and subsequently administering it as a spray onto both the top and bottom rolls of an Experimental Rolling Mill.