CC BY
15
Setion 3. Mechanical engineering
Mustafayev Amir Gochu, Azerbaijan State Oil and Industry University
Aliyeva Irada Karim, Agarzayev Bahruz Karimbala, Abdullayeva AynurRamiz, Azerbaijan State Marine Academy E-mail: [email protected]
HEAT PROCESSES ON THE CONTACT AREA OF THE DOWN-HOLE MILLING TOOLS
Abstract: Influence of the convection heat exchange in the contact area of down- hole milling tool on the cutting ability has been investigated.
Keywords: Cutting edges of the mills, milling tool, heat exchange.
Introduction: It is known that high temperature occurring on the cutting surface accelerates the wearing process of the tool and reduces work efficiency [1].
Set up task: Study of the heat conductivity distribution on the surface of down-hole milling tool.
Task solution: Theoretical researches of the milling conditions on the community basis of heat conductivity laws. Heat distribution formed on the surface of mill-metal is described by two equations of heat balance and heat conductivity. For milling equation of heat balance is presented in the form:
qo = qd + qr + qo.c + qcut + qwei = qi + q2+qh + qe (1)
Where Q0 istotalheat. Qc - is equivalent heat spent on metal cutting
QT - is equivalent heat corresponding to the friction on the contact surface of the tool;
Qd - is equivalent heat, corresponding to deformation of the cutting layer;
Qs.c. - is equivalent heat corresponding to the burnishing of chips;
Qimll - is equivalent heat of the well total heat Q0 in any way transfers to the mill (1) Q^ then to the processed metal (2) Q2, chip Qch and environment Qe (fig.1).
Heat separated from the active area is equiva-lently spent on milling and determined due to the formula:
SFv
Qo =
427S
(2)
Where Fz - is tangential main force of milling v - is rotation frequency of the mill a - is a coefficient considering uneven distribution of specific force on the contact area S - is total contact area of mill with milling material.
For simplifying the task with the known approximation let's consider the heat exchange in the objects of mill (1) and metal (2). That's why interacting objects- mill and processed metal are presented in the form of cylinder. Consequently these two factors are thermally connected in the direction of Z axis with columns of drilling and break-down pipes having relatively unlimited dimensions on the contact surface (in the horizontal direction it has restriction). In these conditions due to V. V. Tompson, influence of heat exchange of external surfaces of the mill and processed material can be disregarded. Mathematical description of temperature field of the considered conditions of the milling of metallic objects can be presented on the basis of general laws of heat conductively. To determine the reliability of theoretical data, ex-
HEAT PROCESSES ON THE CONTACT AREA OF THE DOWN-HOLE MILLING TOOLS
periments were carried out. Samples of the circular have been described in [2]. The processed sample 2 mill used as a composition material and processed made from steel 40XH has been equipped with the
material have been prepared. Experimental instal- heads of thermocouples in various radii and dis-
lation and model samples used for research process tances from axis Z and X correspondingly (fig.1).
Figure 1. Calculated heat scheme of milling (chromium-nickel alloy)
Artificial thermocouple chromel - copper has been used in the milling process to measure the temperature. While processing the sample milling plane was approaching the junction and thermocouples recorded the temperature. The research results have been presented in the graphics (fig. 2). Milling regime has been corresponded to the model conditions of the milling process: specific loading on the mill is 20kH, rotation frequency of the mill is 185 rot/min. Location of thermocouples in the sample allowed quanti-tively to valuate temperatures change depending on the radius. This change is not significant (total 11%)
[3]. The obtained regime data allow scientifically to justify the construction of the cooling system of down - hole mills. Divergence between theoretical and experimental data (no more 11%) testified accuracy of theoretical decisions mentioned above.
Conclusion
1. Carried out researches on the milling process allow to evaluate heat processes taking place on contact surfaces of mill-metal.
2. The obtained experimental data allow scientifically justifying the construction of the cooling system of down-hole mills.
References:
1. Hasanov A. P. "Break-down-restore works in oil and gas wells". - M., Nedra - 1987.- 180 p.
2. Mustafayev A. G. and et. all "Heat regime of the work of milling installations and increase of their efficiency in well repairing". - Baku.- 1997.- 123 p.
3. Mustafayev A. G., Hasanov R. A. Study of the temperature processes in milling of metallic objects. Tyumen, Russia SOU,- 2011.- P. 67-82.
