Thermal cycling treatment of low-carbon steels with hardening from the intercritical temperature range

Conclusions Thermal cycling treatment of 08Kh2G2F and 30KhGSN2A steels with intermediate hardening from intercritical range temperatures (Ac₁+20–40°C) provides an ultrafine austenitic grain size of 2.5–3.5 m. The obtaining of a finer and more uniform structure of these steels in comparison with thermal cycling treatment consisting of three hardenings from the area of the stable state of austenite provides a 1.2–1.4 times higher impact strength at low temperatures.Institute of the Physics of Solids, Academy of Sciences of the USSR. I. P. Bardin Central Scientific-Research Institute for Ferrous Metallurgy. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 47–49, August, 1988.     

Suppression of temper brittleness of steel upon quenching from the temperatures of intercritical range

The methods of decreasing temper brittleness of quenched steels are considered, which were proposed by Academican Sadovskii with his colleagues and were based on the study of the nature and specific features of temper embrittlement. Various methods of decreasing steel sensitivity to the development of brittleness are discussed, which are based on the use of new steelmaking technologies and specific features of realization of heat and thermomechanical treatments. The effect of steel quenching from the intercritical range on the development of temper brittleness has been studied in detail.     

Quenching steel 09G2S from the intercritical temperature range with the use of rapid austenitization

A promising method for improving the strength properties of low-carbon steels is quenching from the intercritical temperature range. This process is quite simply carried out in metallurgical production on the rolling mill stream, as well as in a heat treating shop using separate heating. In this article the specifics of quenching from the intercritical temperature range with the use of electrical heating are considered.Institute of Metal Physics, Academy of Sciences of the Ukraine, Kiev. UkrNIIKM Prometei, Mariupol'. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 15–17, August, 1994.     

Quenching tool steels in a fluidized bed

Metal Science and Heat Treatment -     

临界区退火对冷轧TRIP钢组织及力学性能的影响

利用扫描电子显微镜(SEM)、X射线衍射(XRD)以及室温单轴拉伸试验研究了临界区退火温度对低合金冷轧C-Mn-Al-Si系TRIP钢微观组织及力学行为的影响。结果显示,随着临界区退火温度的升高,TRIP钢组织中铁素体相和残留奥氏体相的含量降低,而贝氏体相的含量不断增加;试验钢的屈服强度和抗拉强度均提高,而塑性则不断下降。高临界区温度下形成了较多的贝氏体相,大量位于贝氏体板条间的片状残留奥氏体因变形过程中过于稳定而无法使TRIP效应得以充分的发挥,从而影响材料加工硬化能力的提高。     

Quenching of aerospace forgings from high temperatures using air-assisted, atomized water sprays

The nickel-based superalloy or titanium materials used in the aerospace industry are cooled from high temperatures during the heat treatment process to obtain appropriate strength properties. However, unacceptably high residual stresses can be developed in some situations if the rate of cooling is too high so that air-assisted, atomized water sprays have been suggested as an alternative to the widely used techniques of quenching in oil or water. Thus, this article examines two aspects of the use of air-water sprays for quenching aeroengine forgings. First, basic experimental heat transfer data are presented for a wide range of water flows and for surface temperatures up to approximately 850 °C, for both plane and recessed surfaces. Second, the heat transfer data are used in numerical simulations to study the influence of nonuniform spray distributions on the residual stress patterns in a typical forging. This paper was presented at the ASM Third International Conference on Quenching and Control of Distortion, 24–26 March 1999, in Prague, Czech Republic.     

Ductile-brittle transition in steels at near-solidus temperatures

A complex study of the nature of the little-investigated phenomenon of high-temperature brittleness of steels, i.e., the ductile-brittle transition observed in the temperature range t = (0.92–0.98)t _melt, is described. Regular features in the behavior of mechanical properties of low-alloy steels in this temperature range are considered. The effects of the chemical composition (carbon, impurities), preliminary plastic deformation, high-temperature annealing, and test medium on the mechanical properties are studied. Special features of the fracture mechanism at the studied temperatures are described. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 9–20, April, 2006.