A Review of the Boiling Curve with Reference to Steel Quenching

Abstract

This review presents an analysis and discussion about heat transfer phenomena during quenching solid steel from high temperatures. It is shown a description of the boiling curve and the most used methods to characterize heat transfer when using liquid quenchants. The present work points out and criticizes important aspects that are frequently poorly attended in the technical literature about determination and use of the boiling curve and/or the respective heat transfer coefficient for modeling solid phase transformations in metals. Points to review include: effect of initial workpiece temperature on the boiling curve, fluid velocity specification to correlate with heat flux, and the importance of coupling between heat conduction in the workpiece and convection boiling to determine the wall heat flux. Finally, research opportunities in this field are suggested to improve current knowledge and extend quenching modeling accuracy to complex workpieces.

Experimental study of the effect of the concentration of water/polyalkylene glycol solutions on heat transfer in steels subjected to quenching

“…Figure 5 shows the evolution of the detachment of the oxide layer formed during heating, which occurs during the first fractions of a second of the contact of the hot piece with the cooling medium, which, with the help of the impact of the jets of fluid on the surface, it quickly detaches, leaving an irregular surface, showing areas of little contact with the fluid and causing fluctuations in the curves during heat extraction. According to Barrena et al [17], the wall surface roughness affects single-phase convection since it improves the specific surface area, increasing the heat flux. No oxide layer remnants were found after the treatments.…”

“…Once a temperature close to the re-dissolution temperature of the polymer is reached, and when the liquid close to the piece is mixed with colder liquid, the characteristic explosion of polymer solutions occurs, giving way to the convective heat extraction mechanism, presenting an increase in heat flux. According to [17,18], the uniformity of the heat flow is critical to minimize thermal and phase transformation stresses, helping to reduce distortion and cracking problems. From the above, it can be mentioned that a more negligible difference between the maximum heat flux q1 max and q2 max reduces the risk of distortion and cracking of the material.…”

Numerical Simulation and Experimental Research on the Quenching Process of 1045 Steel Based on Thermo–Fluid–Solid Coupling Model

“…[3] Scholars mainly optimize the heat transfer coefficient from two aspects: measurement methods and measurement tools. [4,5] However, the heat transfer coefficient is influenced by many factors, such as the quenching medium type, [6] surface condition, [7] surface shape, [8] and stirring intensity. [9] Thus, the required heat transfer coefficient for different quenching process simulations is also different, which results in the need for an enormous database of heat transfer coefficients to accommodate different quenching processes.…”

Automatic Method for Vickers Hardness Estimation by Image Processing

“…Materials such as steel used in automotive axles, cutting tools, among other applications, are subjected to constant forces or loads, which can cause deformation or breakage of the material. The search for continuous improvement has led to the implementation of materials in the form of thin films, which consist of improving the surface properties of the substrate such as steel, providing high hardness, low coefficient of friction, and wear and corrosion resistance in chemically aggressive environments, allowing for increasing its useful life and covering a wide field of applications [ 8 , 9 , 10 , 11 , 12 ].…”

“…There are different methods to modify the hardness of the material, either by heat treatment such as quenching or tempering to modify the microstructure [ 11 , 12 ] or by depositing thin film coatings on the surface of the base material. Among the most commonly used coatings in the industry are Titanium Nitride (TiN) and Niobium Nitride (NbN).…”