Comparative Measurement and Evaluation of the Quenching Intensity of Palm Oil, Canola Oil and a Conventional Petroleum Oil Quenchant Based on Temperature Gradient Measurements

In contrast with small laboratory probes developed to evaluate the cooling properties of relatively small samples of a quenchant, the new Liscic/Petrofer probe is designed to measure and record the quenching intensity under real industrial conditions. The Liscic/Petrofer probe is a cylindrical Inconel 600 probe with a 50-mm diameter and a 200-mm length and is instrumented with three thermocouples on the same radius of the cross-section at the middle point of its length. The outer thermocouple measures the temperature 1 mm below the surface, the second one 4.5 mm below the surface, and the third one at the center of the probe. The working principle of the probe is the measurement of the dynamic of heat extraction, which is best represented by the change of temperature gradients. Comparative testing was recently performed with the Liscic/Petrofer probe in two different vegetable oils (canola oil and palm oil) and a commercially available conventional petroleum oil quenchant. The work was performed at the Quenching Research Centre (QRC) of the Faculty for Mechanical Engineering, University of Zagreb, Croatia. The results of this work showed distinctive differences in the quenching behavior of these three quenchant media. The results of this comparative study are reported herein

Uphill Quenching of Aluminum Alloys

Uphill quenching is often not well understood and there are relatively few publications on the topic. Uphill quenching was originally developed by Alcoa approximately 50 years ago for aluminum alloys. It has also been referred to as “deep freezing” or “tri-cycle stress relieving.” Uphill quenching has been reported to provide residual stress reduction that may exceed 80 %. Therefore, uphill quenching is typically used to achieve dimensional stability in several critical types of aluminum parts. Uphill quenching is typically applied after quenching and before aging. The uphill quenching process consists of the immersion of the part into a cryogenic environment and after cooling is immediately followed by transferring to a hot-steam fixture to obtain a temperature gradient that maintains the mechanical properties gained with the heat treatment. When performed properly, uphill quenching results in low residual stresses and improved dimensional stability. This paper provides an overview of the uphill quenching process and its application in the heat treatment of critical aluminum alloy components such as large aerospace components

Uphill Quenching of Aluminum Alloys

This article describes the concept of uphill quenching process applied in the heat treatment of aluminum alloys. Uphill quenching is interesting since residual stress reductions of up to 80% has been reported. In addition, substantial improvements in dimensional stability have been achieved for several types of aluminum parts. Often, uphill quenching is applied after quenching and before aging during the heat treatment of aluminum alloys. The uphill quenching process consists of the immersion of the part in a cryogenic environment, and after homogenization of the temperature, the part is transferred to the hot steam chamber to obtain a temperature gradient that will maintain the mechanical properties gained with this process. The results obtained are lower residual stress and better dimensional stability. The aim of this article is to provide a review of this process and to compare it with conventional heat treatment

Bioquenchants Formulated from Epoxidized Soybean Oil: Evaluation of Metal Quenching and Heat Transfer Performance

Vegetable and animal oils as a class of fluids have been used for hundreds of years, if not longer, as quenchants for hardening steel. However, when petroleum oils became available in the late 1800s and early 1900s, the use of these fluids as quenchants in addition to their use in other industrial oil applications quickly diminished. This was primarily, but not exclusively, due to their generally very poor thermal-oxidative instability and the difficulty for formulating fluid analogs with varying viscosity properties. Interest in the use of renewable fluids, such as vegetable oils, has increased dramatically in recent years as alternatives to the use of relatively non-biodegradable and toxic petroleum oils. However, the relatively poor thermal-oxidative stability has continued to be a significant reason for their general non-acceptance in the marketplace. Soybean oil is one of the most highly produced vegetable oils in Brazil. Currently, there are commercially produced epoxidized versions of soybean oil which are available. The objective of this paper is to discuss recently obtained results showing the potential use of bioquenchants formulated from epoxidized soybean oil and heat transfer properties as viable alternatives to petroleum oils for hardening steel

Vegetable Oils as Metal Quenchants: A Comprehensive Review

There is an ongoing interest in the development and use of renewable base stocks to formulate quenchants. The most common criterion of vegetable oils as renewable base stocks is their biodegradability and that they be non-toxic. A comprehensive overview of all aspects of vegetable oils that impacts their potential for commercial use is provided. Topics discussed include: vegetable oil structure, processing, physical properties, classification, biodegradation and toxicity; oxidation and inhibition; wetting and wetting kinematics; and applications. As a class, vegetable oil-based quenchant formulations reported in the literature to date exhibit a number of disadvantages, the most notable being their relatively poor thermal-oxidative stability in comparison with petroleum oil-based quenchants in use. Potential pathways to vegetable oil-based fluid compositions that may rival the thermal-oxidative stability of many petroleum oil-based quenchants were introduced

Uphill Quenching of Aluminum Alloys: A Progress Report

This paper describes the uphill quenching process which is applied in the heat treatment of aluminum alloys. This lesser known process was developed by Alcoa and first applied more than 50 years ago for aluminum alloys of several thicknesses. Uphill quenching has been reported to reduce residual stresses by \u3e 80%. Typically, uphill quenching is applied after quenching and before aging of aluminum alloys. Uphill quenching consists of the immersion of the part in a cryogenic environment and after equilibration, the part is transferred immediately to a fixture in a superheated steam chamber to obtain a temperature gradient sufficient to maintain the improved mechanical properties gained with heat treatment that result in low residual stresses and superior dimensional stability. Assuming that most of the stresses that appear in aluminum alloys during heat treatment are due to the quenching process, then this intermediate treatment becomes a potentially effective tool for the heat treatment of aluminum alloys. The aim of this paper is present an overview of recent work showing tensile test results obtained with uphill quenching relative to conventional quenching processes

Quenchant Cooling Curves, Rewetting, and Surface Heat Flux Properties of Vegetable Oils

Vegetable oils are currently used for biodegradable and renewable base stocks for quenchant formulation. However, there are relatively few references relating to their true equivalency, or lack thereof, comparative to the quenching performance of petroleum oil-based quenchant formulations. To obtain an overview of the variability vegetable oil quenching performance, the cooling curves and rewetting properties were determined, and the surface heat flux properties were calculated. The vegetable oils that were studied included canola, coconut, corn, cottonseed, palm, peanut, soybean, and sunflower oils. Cooling curves were obtained using the Tensi multiple-surface thermocouple 15 mm diameter by 45 mm cylindrical Inconel 600 probe (Note: Themultiple thermocouple probe was custommanufactured to conform to a drawing provided by: Heattec located at Seglaregatan 1C, 302 90 Halmstad, Sweden). For comparison, similar data was obtained with Houghto-Quench H100, a conventional (slow) petroleum quenchant oil, and Houghto-Quench HKM, an accelerated (fast) petroleum oil quenchant (Houghton International Inc., Valley Forge, PA). The results of this work will be discussed here