Estimation and control of the properties of the polymer quenching medium UZSP-1 for quality heat treatment of steels

The international standard ISO 9950: 1995 (E) has been put into action for oils, and an analogous document is being worked on for synthetic quenching media. In this connection, it is important to determine the requirements to be imposed on these media for evaluating and controlling their parameters in order to provide the requisite quality of heat treatment. The present paper describes the results of a study of the properties of the polymer quenching medium UZSP-1 conducted with the aim of developing specifications for the medium. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 17–20, July, 1997.     

Effect of thermal conductivity and viscosity on cooling performance of liquid quench media

Abstract

In this present work, the effect of the thermophysical properties of quenchants on its cooling performance was investigated. Water, brine solutions, polymer solutions and mineral oils were chosen to have quench media with varying thermophysical properties. Cooling curve analyses were carried out by using standard ISO/DIS 9950 quench probe. Grossmann H quench severity of the quench media was determined from the relation of H and cooling rate. Cooling curve analysis results showed that the change in thermophysical properties of the quench media had significant effect on the cooling history of the quench probe. The viscosity of the quenchant used for immersion quenching is the most important factor that controls the cooling performance of the quenchant compared to thermal conductivity of the quench medium.     

用不同方法测定的淬火油冷却性能的数字化

建立了淬火油冷却性能的数字化模型.通过试验确定,符合国际标准ISO 9950:1995的国标GB/T 30823-2014/ISO 9950:1995《测定工业淬火油冷却性能的镍合金探头试验方法》(热电偶在探头心部)可以被采用.按中国石化行业标准SH/T 0220-92(热电偶在银探头心部)和日本标准JIS K2242...     

Effect of composition on oil quenchant performance

Abstract

Quenching is the most common method of hardening metals and involves continuous cooling from a given austenitising temperature to achieve full transformation into a martensitic structure. The cooling rate depends mainly on the thermal characteristics of the metal, the section thickness of the workpieces and the heat removal properties of the quenching medium. Oils, when used as quenching media contain a base oil and different types of additives according to the application requirements. As the base oil, it is possible to use mineral, synthetic and natural oils, either separately or in combination. Mineral base oils are widely used because of their advantages in stability in comparison with natural oils, or lower price in comparison with synthetic oils. There are numerous additives available for use but, besides functional properties, the environmental and safety requirements have to be considered in their selection, e.g. barium additives must be replaced with less harmful compounds. Additionally, petroleum derivatives should be replaced by renewable base stocks that are biodegradable, which is a general trend in lubricant development. By changing the composition of the base oils and additives, heat transfer characteristics are also changed. This study presents the results of the analysis of physical and chemical properties, as well as of cooling characteristics of new quenching oils with different compositions. Cooling curves have been evaluated according to ISO 9950 standard.     

Cooling Characteristic of Polymeric Quenchant: Calculation of HTC and Prediction of Microstructure and Hardness

The present paper discusses the influence of experimental conditions on the quenching performance of poly(2-ethyl-2-oxazoline) (PEOX) aqueous solutions used as cooling medium, using a standard ISO Inconel alloy probe for measurements of cooling rate. The evaluation procedure is demonstrated on characterization of cooling power of water-based polymer (PEOX) solutions by using different concentration, temperatures, and agitation conditions of the cooling media. The results show that the different experimental conditions have a significant effect on the cooling performance. The polymer quenching mechanism and the comparative cooling characteristics of water, and water-based PEOX polymer solution with concentrations from 2.5 to 15 wt.% were discussed. The study involved the assessment of the quenching severity by calculating the hardening power (HP) via empirical equations. Calculation of heat transfer coefficients as well as prediction of microstructural constituents and the hardness profile in a cross-section of steel sample were carried out on the basis of inverse calculation from the recorded cooling curve.     

热电偶在探头中位置变化对冷却曲线的影响

为了加深对冷却曲线的了解，采用ISO9950标准探头和平板探头(热电偶安置在三个不同位置)对N32油、PAG类水溶性介质和水的冷却曲线进行了测量。结果表明，由于探头形状的不同使表面的传热能力存在较大的差异，导致表面湿润条件也不相同，其结果使两种形状探头测量的冷却曲线产生差异，其中平板探头可以反映出更多的冷却机理方面信息。     

The effect of TiO2 nanoparticles on fluid quenching characteristics

Abstract

Nanofluids are colloidal suspensions of nanoparticles in base fluids. Some of the particles used in recent research are metal oxide and carbide particles, such as SiC, CuO, Al₂O₃ and TiO₂, graphite and carbon nanotubes and particles. Quenching in such colloids results in better cooling abilities, higher impact toughness and smaller dimension changes of steels, compared with pure quenching media. In this investigation, nanofluids with TiO₂ powders of 50 nm average particle size were investigated. Base fluids of primary interest were deionised (DI) water, some commercial quenching oils and polyalkylene glycol water solution of various polymer concentrations, 5–30 vol.-%. The investigated fluids were prepared with the addition of the same TiO₂ powder with different concentrations, from extremely low, 10 mg nanopowder per litre to 1 g L^?1. The cooling characteristics of these colloids were compared with the results of base fluids, but also with the results of previous measurements carried out on the fluids with addition of Al₂O₃ micrometre and submicrometre size particles. All of the cooling curves were measured and recorded by the IVF Smart Quench system using a stainless steel probe of 12·5 mm diameter in accordance with ISO 9950 standard. The cooling rate (CR) versus temperature and time was compared for all of the investigated media. The preparation of fluids was conducted with great care, with respect to mechanical stirring and sonification times. The average particle size was measured for each case. In order to better understand the phenomena that occur during the quenching process, a high speed camera was used for recording the experiments. Titanium oxide nanoparticles show the most significant effects on the cooling properties of the water based polymer solution. The maximum cooling rate increases with higher particle concentration. When comparing the results of experiments with alumina particles, smaller and thermally less conductive TiO₂ particles show greater effects on nanofluid properties.     

Cooling Capacity Optimization: Calculation of Hardening Power of Aqueous Solution Based on Poly(N-Vinyl-2-Pyrrolidone)

Polymer quenchants are becoming increasingly popular as substitutes for traditional quenching media in hardening metallic alloys. Water-soluble organic polymer offers a number of environmental, economic, and technical advantages, as well as eliminating the quench-oil fire hazard. The close control of polymer quenchant solutions is essential for their successful applications, in order to avoid the defects of structure of steels, such as shrinkage cracks and deformations. The aim of the present paper is to evaluate and optimize the experimental parameters of polymer quenching bath which gives the best behavior quenching process and homogeneous microstructure of the final work-piece. This study has been carried out on water-soluble polymer based on poly(N-vinyl-2-pyrrolidone) PVP K30, which does not exhibit inverse solubility phenomena in water. The studied parameters include polymer concentration, bath temperature, and agitation speed. Evaluation of cooling power and hardening performance has been measured with IVF SmartQuench apparatus, using standard ISO Inconel-600 alloy. The original numerical evaluation method has been introduced in the computation software called SQ Integra. The heat transfer coefficients were used as input data for calculation of microstructural constituents and the hardness profile of cylindrical sample.     

Zak-PG polymer quenching medium

The present work is devoted to the properties of new fireproof polymer quenching medium ZAK-PG with reversible solubility based on PG-40 polymer. The developed medium makes it possible to use various cooling regimes with various contents of the polymer in the solution. A composition in which the polymer content remains unchanged during use is suggested. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 7–8, February, 1999.     

Effect of the viscosity of the UZSP-1 polymeric quenching medium on its hardening capacity

The UZSP-1 polymer quenching medium is a very efficient domestic substitute for quenching oils. The stability of the properties of water-based polymer quenching media depends largely on the molecular weight characteristics of the polymer component. The molecular weight of the polymer affects the viscosity of the polymer concentrate used for preparing the quenching medium. The present work is devoted to investigation of the effect of the viscosity of the initial UZSP-1 concentrate on the quenching capacity of aqueous solutions with different polymer contents.Translated from Metallovedenie i Termischeskaya Obrabotka Metallov, No. 3, pp. 28–31, March, 1995.     

淬火介质的冷却特性曲线究竟说明了什么

在用标准测试仪检测淬火介质冷却特性的同时,用摄像机摄录了探棒周围的状况.对比发现,按测得的冷却特性曲线的形状划分的冷却阶段,与探棒表面实际发生的冷却情况大不相同.说明了产生这种差异的原因.通过分析和推理,得出了结论:不能从淬火介质的冷却特性曲线去划分探棒所处的冷却阶段;凭测出的冷却特性曲线不可能准确推算实际工件可能获得的冷却情况;淬火介质的冷却特性曲线只宜用在介质冷却特性的相互对比中.     

Structure-Property Relationship of Cu-Al-Ni-Fe Shape Memory Alloys in Different Quenching Media

This paper presents the effects of heat treatments using various quenching media on the phase transformation parameters and microstructure parameters. The effects of different quenching methods, step-quenched and up-quenched, in various media were evaluated by using differential scanning calorimetry, field emission electron microscopy, energy-dispersive spectrometry, atomic force microscopy, x-ray diffraction, and Vicker’s hardness. The variations of the structure and properties of Cu-Al-Ni-Fe shape memory alloys were linked to the variations of morphology, type, and stabilization of the obtained phase. From the DSC results, the use of ice water as a quenching medium produced the highest transformation temperatures, while a brine solution-quenching medium resulted in the highest change of the entropy and enthalpy. Additionally, it was found that the best grain refinement was observed through the use of an oil-quenching medium, due to its high cooling rate.     

淬火冷却技术的研究进展

本文综述了国内外冷却技术发展概况。分为六个部分：水溶性聚合物类淬火介质的工业应用、淬火介质性能测试技术及其评价方法、冷却过程模拟技术、控制冷却技术及特殊冷却方法、冷却技术及设备在我国的推广应用、发展趋势。     

Modeling of oil quenching by a water-air stream controlled by a microcomputer

Conclusions By adjusting the cooling ability of a water-air stream we can obtain cooling rates of parts characteristic of oils and aqueous polymer solutions. With the use of a system of controlled cooling, this will make it possible to replace quenching in environmentpolluting media by ecologically clean water-air cooling without impairing the properties of the hardened steel.Institute of Heat and Mass Exchange, Academy of Sciences of the Belorussian SSR. Institute of Technical Thermophysics, Academy of Sciences of the Ukrainian SSR. All-Union Research Institute for the Planning and Construction of Petrochemical Equipment. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 36–37, April, 1991     

Development and application of alternate timed quenching by water and air

Abstract

Water and air are commonly used quench media with very different quenching powers; further, they are environmentally friendly and of very low cost. Theoretically, alternate quenching by water and air can produce any desired cooling rate between those of each medium alone. While this technology has not been practicable due to the difficulties in process design and control, the recent development of numerical simulation and processing control techniques has established a solid base for its industrial application. A new technology, alternate timed quenching by water and air (AT-quenching), is proposed. The technology has been applied to a medium carbon low alloy steel, the mechanical properties of which do not meet specification after oil quenching, but which suffers cracking after water quenching. The key points are to design the process by computer simulation and to realise it with digitally controlled quenching equipment. The technology has been successfully employed in production of large forged blocks of die steel for plastics moulding, long shaft forgings and forgings for marine crankshaft, effectively solving the difficulties that traditional processes and quenchants encounter.     

浆状冷却介质的特性和用途

研究了以水和微细粘土粉末等混合而成的浆状介质的稳定性、冷却特性其影响因素。比较发现，浆状介质具有高于风冷而低于普通机油的冷却速度，可用于一些高合金钢的淬火冷却、铝合金固溶处理，也可用于结构钢工件做等温正火冷却。提出了两种新的淬火冷却方法：（1）先水或水溶液而后浆状介质的双介质淬火方法；（2）工件在浆状介质中先做摆动以加快冷却，而后再停止摆动以防止淬火方法。浆状介质完全不污染环境，使用浆状介质成本极低，值得推广应用。     

由“冷却模型”到“冷却工程”的演进

冷却方式决定热处理工艺的类型。淬火是金属热处理中具有标志性的核心技术,其中最关键的操作环节是冷却。通过冷却曲线分析提出了钢探头在有物态变化介质中冷却时的主、辅界面模型。分析了钢在奥氏体化后冷却转变的物理冶金学现象与工程实际所能提供的冷却环境之间的联系。概述了淬火介质与冷却技术的研究现状与发展动态,特别指出了新的冷却技术及其装备开发的重要性。总之,从单纯的冷却模型研究到冷却工程的实现将是一大跨越。     

水溶性淬火介质在现代热处理中的应用

用水溶性淬火介质代替传统淬火介质进行热处理可增加效益，提高工件质量，改善工作环境；生产实践证明，水溶性淬火介质有效地解决了油淬不硬、水淬易裂的难题，避免了淬裂和软点的形成；具有良好的淬透性和理想的冷却速度。     

A study of the cooling kinetics of bearing steel in UZSP-1 polymer quenching medium

The problem of replacing quenching oils by relatively inexpensive and fireproof media based on water is very important for machine-building plants. The present paper is a study of the possibility of using a UZSP-1 polymer quenching medium for quenching parts of roll bearings from steels of the ShKh15 type. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 14–17, July, 1997.