Comparison of Industrial Quenching Oils

This article is a response to the state of the art in monitoring the cooling capacity of quenching oils in industrial practice. Very often, a hardening shop requires a report with data on the cooling process for a particular quenching oil. However, the interpretation of the data can be rather difficult. The main goal of our work was to compare various criteria used for evaluating quenching oils. Those of which prove essential for operation in tempering plants would then be introduced into practice. Furthermore, the article describes monitoring the changes in the properties of a quenching oil used in a hardening shop, the effects of quenching oil temperature on its cooling capacity and the impact of the water content on certain cooling parameters of selected oils. Cooling curves were measured (including cooling rates and the time to reach relevant temperatures) according to ISO 9950. The hardening power of the oil and the area below the cooling rate curve as a function of temperature (amount of heat removed in the nose region of the Continuous cooling transformation - CCT curve) were calculated. V-values based on the work of Tamura, reflecting the steel type and its CCT curve, were calculated as well. All the data were compared against the hardness and microstructure on a section through a cylinder made of EN C35 steel cooled in the particular oil. Based on the results, criteria are recommended for assessing the suitability of a quenching oil for a specific steel grade and product size. The quenching oils used in the experiment were Houghto Quench C120, Paramo TK 22, Paramo TK 46, CS Noro MO 46 and Durixol W72.

Investigation of Quenchants Based on Sodium Aqueous Ionic Solutions

The mechanical properties of steel components are influenced by the microstructure, which is determined by the heat treatment cycle. In the quenching of the steel: water, oil, aqueous polymer solutions and aqueous salt solutions (brine) can be used as quenchants, which exhibit different characteristic cooling mechanisms. For example, when water is used as the cooling media, a stable vapor film is formed around the hot component resulting in nonuniformity of surface heat transfer during the cooling process, which is often responsible for distortion, and cracking. Using salt based on sodium (Na) as an additive forming a solution with distilled water was able to reduce or eliminate the vapor film, enhance the cooling rate and keep the heat flux in high values during the most part of the drop of the temperature that is better for a more homogeneous cooling. This work investigated the cooling performance of different salt solutions and quenching bath parameters (temperature and agitation). These analyses were made using cooling curves and heat flux to quantify the behavior and hardening power capacity of these salt solutions.

An Investigation of Nanomechanical Properties of Materials using Nanoindentation and Artificial Neural Network

Mechanical properties of materials can be derived from the force-displacement relationship through instrumented indentation tests. Complications arise when establishing the full elastic-plastic stress-strain relationship as the accuracy depends on how the material’s and indenter’s parameters are incorporated. For instance, the effect of the material work-hardening phenomenon such as the pile-up and sink-in effect cannot be accounted for with simplified analytical indentation solutions. Due to this limitation, this paper proposes a new inverse analysis approach based on dimensional functions analysis and artificial neural networks (ANNs). A database of the dimensional functions relating stress and strain parameters of materials has been developed. The database covers a wide range of engineering materials that have the yield strength-to-modulus ratio (σy/E) between 0.001 to 0.5, the work-hardening power (n) between 0–0.5, Poisson’s ratio (v) between 0.15–0.45, and the indentation angle (θ) between 65–80 degrees. The proposed algorithm enables determining the nanomechanical stress-strain parameters using the indentation force-displacement relationship, and is applicable to any materials that the properties are within the database range. The obtained results are validated with the conventional test results of steel and aluminum samples. To further demonstrate the application of the proposed algorithm, the nanomechanical stress-strain parameters of ordinary Portland cement phases were determined.

Evaluation of Quenchant’s Cooling and Hardening Performance

One of the most critical parts of the heat treatment process, and usually the least controllable one, is the quenching operation. Improper selection or application of a quenching medium, or a drift in its cooling characteristics during its lifetime, may result in products that do not meet specifications and therefore give rise to large additional costs to cover e.g. straightening, rework, rejection, delayed deliveries and, sometimes, lost goodwill for the heat treater. In the case of the use of aqueous polymer solutions, the thermo-kinetic parameters characterizing the heat removal capabilities of a quenchant, are variable, in a specific interval with a complex combination of temperatures (T), concentrations (C) and agitation rates (AR). When the direction and degree of change is known, the characteristics of heat removal can be efficiently modified and predicted within given limits. The aim of the work described in this paper is to investigate how the hardening power of Houghton AquaQuench BW-T depends on the complex influence and interaction of T, C and AR.

The Influence of GGG70L Laser Surface Hardening Power on Quenched Layer Performance

GGG70L die material laser phase change hardening aims to discover the Quenched Layer performance of the GGG70L die material hardened by the laser of different power. Making comparison and analysis in the experiment and considering the actual production factors such as cost, working efficiency and product quality standard, it is concluded that laser power being 1900 w, laser scanning speed 6mm/s, spot size 3×15 mm2, focal length being 305mm, the surface of the material quality can meet the requirements of industrial production, laser surface quenched layer becomes harder, good abrasion resistance on the surface of the material is obtained.

The Possibility of Correlation of Hardening Power for Oils and Polymers of Quenching Mediums

There are many literature references comparing the use of aqueous polymer quenching solutions with petroleum oil quenchants for a wide range of steels of varying hardenability and the relating parameters of describing properties of the quenching mediums. There are relatively little similar relating correlations between parameters of describing properties of the different quenching mediums. The quenchants used included: conventional quenching oil, martempering oil, and 5% and 25% aqueous polymer quenchant solutions (APQSs) of a polymer quenchant. These quenching media were selected to represent a broad range of quench severities as quantified by cooling curve analysis (ASTM D 6482) using a standard Inconel 600 probe and the Tensi Agitation Device. The test of correlation conducted between the Hardening Power parameters according to examples of oils and polymers. The enable work results in applying the Hardening Power independently from equation calculated for different quenching mediums and their work parameters.