Cooling process optimization during hardening steel in water polyalkylene glycol solutions

Objects of investigations are water solutions of polyalkylene glycol (PAG) which are used as the quenchants in the heat-treating industry. They are tested by standard cylindrical probe made of Inconel 600 material. The main and not solved yet is the problem of transition from data achieved for standard probe to data suitable for any form and size of real steel part. It opens possibility to make predictable calculations. Taken this into account, it has been investigated water solutions of PAG of different concentration. It is underlined that cooling intensity of quenchant can be evaluated by Kondratiev number Kn. The mentioned number Kn varies within 0≤Kn≤1 when generalized Biot Biv number varies within 0≤Biv≤∞. As a main achievement of investigation is established correlation between standard Kn number and Kn number of real steel part. In many cases, when film boiling is absent, the established correlation is a linear function. It allows optimizing quenching processes: obtain high surface compressive residual stresses, save alloy elements and improve environment condition. All of this is achieved by tolerating chemical composition of steel with size and form of quenched object as it is proposed by UA Patent No. 114174. Also, the number Kn allows interruption of quench process when surface compressive residual stresses are at their maximum value that essentially improves the quality of steel components. Moreover, interrupted cooling prevents quench crack formation, decreases distortion of quenched steel parts. The results of investigations can be used by engineers in the heat-treating industry and scientists for further research.

Analysis of Transient Boiling Processes during Steel Quenching in Water PAG Solutions to Decrease Distortion

The paper discusses results of testing standard cylindrical probe 12.5 mm diameter in water polymer solutions which was additionally instrumented with a surface thermocouple. It is shown that central thermocouple cannot depict many physical phenomena taking place during quenching in polymer solutions such as shoulder formation, self- regulated thermal process establishing, surface temperature transient from film boiling to nucleate boiling process. Moreover, it is shown that experimental data depicted by central thermocouple cannot be used for solving inverse problem to analyze quenching process in liquid media. Along with analyzing film and nucleate boiling processes during quenching, the paper discusses the possibility of quality quench process control via using sonar system. It is established an equation for evaluating duration of transient nucleate boiling process. As an example, the cooling characteristics of fresh and old polyalkylene glycol (PAG) polymer solutions are analyzed. It is shown that with passing time the critical heat flux density of polymer decreases and inverse solubility effect disappears. That is while the method and apparatus were developed to control in industrial condition the quality of quenched steel parts during hardening in liquid media.

Effects of Alkylamines-Based and Polyalkylene Glycol-Based Bonding Enhancers on the Performance of Asphalt Binders

The premature deterioration of asphalt pavements usually occurs due to different moisture damage mechanisms resulting in stripping, ravelling, potholes, and disintegration without proper treatment. Numerous efforts have been taken into consideration to improve the bonding between materials, hence prolonging the pavement life. This study evaluates the performance of asphalt binders incorporating Alkylamines-based (ALM) and Polyalkylene Glycol-based (PLG) bonding enhancers. Each bonding enhancer at 0.5% and 1.0% based on the weight of asphalt binder was separately blended with the conventional asphalt binder 60/70 penetration grade using a high shear mixer at 1000 rpm for 30 minutes at 160°C. The physical and rheological properties of modified binders were evaluated through penetration value, softening point, ductility, elastic recovery, rotational viscosity (RV), and dynamic shear rheometer (DSR) tests. Overall, additions of ALM and PLG show identical penetration grade compared to the control sample. Both ALM and PLG showcase a higher ductility and elastic recovery than the neat binder. The DSR test indicates the incorporation of bonding enhancers improves the modified binders’ rutting performance. While the application of ALM at 0.5% dosage increased the binder failure temperature out of all the tested samples, where the failure temperature is at 70°C, compared to others at 64°C. Studies at mastics and mixture levels should be conducted to appropriately understand the effect of bonding enhancer on the bituminous materials.

Residual stresses in the aluminium alloy 2014A subject to PAG quenching and vibratory stress relief

Generic hollow pump bodies made from aluminium alloy 2014A forgings have been solution heat treated and quenched into either cold water or polyalkylene glycol (PAG) solutions. An industry standard PAG type synthetic quenchant was evaluated, and the influence of two concentrations of the PAG solution on residual stress in the pump bodies was characterised, using neutron and X-ray diffraction. These residual stresses were then compared to those resulting after a pump in the as quenched condition was subject to a widely known but controversial commercial vibratory stress relieving procedure. The use of neutron diffraction allowed the through thickness residual stresses to be evaluated in the pumps. Results demonstrate that PAG quenching is highly effective at significantly reducing residual stress when compared to cold water quenching, but the impact is non uniform and cannot be simply quantified. In this investigation, we prove the effect of vibratory stress relief is negligible, and much less than that achieved by PAG quenching.

Development prospects for the production of Russian biodegradable lubricants based on group V base oils

Currently, requirements for the environmental safety of lubricants are being tightened. The production of biodegradable lubricants is growing in European countries. The analysis of the production of biodegradable lubricants in the Russian Federation is carried out. Currently, the range of biodegradable lubricants in Russia is limited due to the lack of capacity for the production of polyalkylene glycol oils and esters. However, increasing environmental requirements in the oil, metallurgical, machine-building, construction industries, energy, agriculture, forestry, and water resources require more and more production of lubricants with high environmental performance. To assess the Biodegradability of Russian lubricants, it is necessary to use GOST 32433-2013 identical to the international standard OECD 301B. It is shown that in European countries, polyalkylene glycols and synthetic esters (diesters and esters) are widely used for the production of biodegradable motor, transmission, hydraulic, and turbine oils. To expand the production of modern biodegradable lubricants in the Russian Federation, it is necessary to develop industrial production of API group V oils. The use of biodegradable greases, coolant and separation lubricants based on vegetable oils is promising.