Mechanical properties of steels with low hardenability after quenching and tempering at low temperatures

Conclusions We measured the static bending strength, the hardness, and the impact strength of steels with low hardenability after induction heating followed by quenching and low-temperature tempering. We have recommended optimum quenching temperatures, tempering temperatures (in the case of induction heating), and the hardenability of steels for machine parts of different sizes. We have shown that the static bending strength and the impact strength of samples of quenched carbon steels are as high as those of case-hardened alloy steels.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 35–42, June, 1963     

含硫高速钢的高温摩擦性能(英文)

引入适量的硫可以明显改善铁基材料的摩擦学性能。采用粉末冶金技术制备了含硫高速钢样品材料,采用销盘高温摩擦试验机研究了该样品材料与不同配副(自对偶和GT35钢结硬质合金)摩擦时的高温摩擦性能,通过SEM、EDS和XPS检测了摩擦面,并分析了其摩擦机理。结果表明:与自对偶盘和GT35盘这2种对偶材料摩擦时,摩擦因数的变化趋势是随着温度的升高而逐渐降低的,磨损率则是随着温度的升高而逐渐变大的;在400℃和700℃时的摩擦因数曲线比室温时更加平稳,与GT35摩擦时样品材料的综合高温摩擦性能最佳;在400℃以下时,由于样品材料中硫化物的软化会使得材料的摩擦因数随着温度的升高而降低,在400℃以上时样品材料摩擦因数的降低主要是由于摩擦面的氧化物作用而引起的。     

Properties and rational use of low-alloy high-speed steels

Conclusions Of the investigated low-alloy high-speed steels 11R3AM3F2 steel is closest to R6M5 steel in service characteristics and then R2M5 and 11M5F.However, 11R3AM3F2 steel has poorer grindability than R6M5 steel and therefore its use in place of more highly alloyed steels is technically and economically desirable only for tools of simple form not requiring large amounts of grinding (saws for metal, cutters, etc.).R2M5 steel may be a replacement for R6M5 steel for various tools in machining of comparatively easily machinable materials (low-alloy and carbon steels, gray iron, aluminum and copper base nonferrous metals, etc.).11M5F steel, with its basic properties at the level of R2M5 steel, is characterized by a high tendency toward decarburization, oxidation, and mixed grain size in heat treatment, which requires high-quality hot working and heat treatment of the billets and tools for rational use of it.ÉK41 and ÉK42 steels are significantly inferior to the above steels in all production characteristics and may not be considered as fully equivalent replacements for R6M5 steel. Narrow areas of use in which the reduction in life of the tool will not be significant may possibly be found for them. However, even such a use of these steels does not lead to economy in material and financial resources since it significantly complicates operation of the tool services.In contrast to ÉK41 and ÉK42 steels, 11M5FYuS steel is promising together with R2M5 steel.Ukrainian Scientific-Research Institute for Special Steel. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 51–55, May, 1988.     

Hemocompatibility evaluation of plasma-nitrided austenitic stainless steels at low temperature

In this study, plasma-nitrided austenitic stainless steel was prepared using a microwave system as a function of the nitriding duration. The nitride layers were characterized via scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy, atomic force microscopy and a Vickers micro-hardness tester. The effects of plasma nitriding on the compatibility of blood with the austenitic stainless steel were also investigated. Based on the XRD and TEM observations, it was inferred that only a single γ_N phase was detected in the whole process of experiments. The γ_N layer, which was formed on austenitic stainless steel, exhibited lower platelet adhesion and activation than the untreated specimens. The clotting time of the PN specimens was prolonged and increased with the treatment time. This work suggested that the blood-compatible manner of plasma nitriding by controlling surface characteristic on austenitic stainless steel improved the anticoagulant properties, and made austenitic stainless steel suitable candidates in the field of surgical and medical instruments.