Influence of Combined Mechanical Processes on Tribological Properties of Tool Steels Vanadis 8 and Vancron 40 With a Similar Hardness

Surface integrity is important factor for components exposed to wear, like cold working tools, which need to possess high hardness combined with high wear resistance. Surface treatments such as grinding, hard turning, and hard turning with slide burnishing have been developed for its improvement. Vancron 40 and Vanadis 8 tool steels, of different chemical composition and different types and amounts of carbides, were now investigated. Heat treatment was carried out in vacuum furnaces with gas quenching to hardness of Vancron 64 ± 1 HRC and of Vanadis 65 ± 1 HRC. 3D topography, optical and scanning electron microscopy, X-ray diffraction and ball-on-disc tribological tests against Al2O3 and 100Cr6 balls as counterparts were used to examine wear and friction. For both steels, the lowest values of dynamic frictions and wear rates against Al2O3 counterbodies were achieved after sequential process of hard turning with slide burnishing with a burnishing force of 180 N. For alumina balls, the increase of wear resistance, achieved after hard turning plus burnishing in comparison to grinding exceeds 50 and 60%, respectively for Vanadis 8 and Vancron 40 steels.

A Comparison of Modern Heating Methods to Reduce a Heat Treaters CO2 Carbon Footprint

Several governments across the world have recently stepped up their action to fight climate change. Initiatives include from clean energy production to efficient buildings and reduced emissions from industry. The manufacturing industry will need to examine methods to reduce its carbon footprint, especially across energy-intensive sectors such as heat treatment. This paper explains and explores the latest developments in energy management in heat treatment with a specific focus on electrical heating and associated digital tools. In this paper, developments in IGBT (insulated-gate bipolar transistor) and SCR (silicon-controlled rectifier) technology will be compared as energy-efficient alternatives to variable reactance transformers (VRT’s) for electric vacuum furnaces.

Vacuum Carburizing in a Pit Furnace: A 21st Century Solution to Large Component Case Hardening

Low pressure carburizing (LPC) is a proven, robust case hardening process whose potential is only limited by the style and size of vacuum furnace. Today, LPC is typically used in horizontal vacuum furnaces where the opportunity to carburize large parts is limited. In this paper we present a new adaptation of the technology in large pit type vacuum furnaces, capable of opening to air at elevated temperature. This underscores the potential of LPC to carburize larger, more massive parts in a clean, effective and efficient process. The result is quality casehardened parts without the undesirable side effects of atmosphere gas carburizing such as the use of a flammable atmosphere, reduced CO and NOx emissions, no intergranular oxidation, and limited retort life. Another significant advantage is decreased process time. The case study presented here shows that eliminating furnace conditioning and increasing process temperature can significantly reduce cycle durations by nearly three times and cut utility costs in half. Under these conditions, a return on investment (ROI) is in the neighborhood of 1 – 2 years is possible, making LPC in a pit style furnace a cost-effective solution than traditional atmosphere gas carburizing technologies.

Development of a method for siliconizing high-density graphite of the MPG grade

Рассмотрен способ силицирования высокоплотного графита марки МПГ; показано, что процесс силицирования протекает на всю глубину заготовки и кремний равномерно распределяется по объему поры, при этом карбид кремния распределяется по поверхности, в то время как кремний остается в остальном объеме поры; исследованы физико-механические характеристики и фазовый состав графита после силицирования; показано, что такой силицированный графит возможно использовать в качестве нагревателей вакуумных печей, а также в химических источников тока. A method of siliconizing high-density graphite of the MPG grade is considered; it is shown that the siliconizing process proceeds to the entire depth of the workpiece and silicon is evenly distributed over the pore volume, while silicon carbide is distributed over the surface, while silicon remains in the rest of the pore volume; investigated the physical and mechanical characteristics and phase composition of graphite after siliconizing; it is shown that such siliconized graphite can be used as heaters for vacuum furnaces, as well as in chemical current sources.

Effects of zirconium addition on electrochemical and mechanical properties of Mg-3Zn-1Ca-1RE alloy

Purpose The effect of zirconium, zinc, calcium and rare earth group as the alloying elements on mechanical properties and corrosion behavior of magnesium alloys was investigated in the simulated body fluid. Design/methodology/approach Pure magnesium and the alloying elements were melted and zirconium was finally added to obtain different alloys. The castings were annealed and some samples were aged heat treated. X-ray fluorescence was used for the elemental analysis and LSV was used for electrochemical corrosion evaluations. Findings Results showed that corrosion resistance decreases with increasing zirconium content. The lowest corrosion rate was obtained for the samples containing 0.3% and 0.45% of Zr from annealed and aging heat-treated samples, respectively. Yield stress enhances with increasing the zirconium content and degrades by the aging heat treatment. Originality/value These alloys were studied for the first time. Effect of casting without using protective flux and vacuum furnaces. Effect of annealing at 440°C for 2 h and artificial aging at 200°C for 16 h. Alloy’s electrochemical behavior on the body’s simulation environment has been investigated. Improvement of mechanical properties after annealing heat treatment by high zirconium percentage.

Equipment for thermal process

The demand for efficient and qualitative thermal treatment makes certain requirements to the thermal equipment. The thermal equipment, that ideally corresponds to the assigned task of modern production facilities, is vacuum furnaces. The modern production requirements are the boundary conditions for the equipment manufacturers, focusing them on the need for all in one equipment capable of efficient wide production maneuvering, to ensure the possibility of developing and producing new products at minimal cost. As a result of practical research and development, focusing on the world experience and the real need for operation, the Sistem Teknik's article presents vacuum thermal equipment for multiple use – All in one. The equipment is controlled automatically, all parameters are regulated by the process master controller in compliance with the programmed cycle.

Development of Flux for Protection of the Surface of Liquid-Metallic Low-Melting-Point Fusible Melt

The results of the development of the flux CaO-Li2CO3-B2O3, operating in the oxidizing environment of the furnace, are shown. Flux is used to protect the melt from oxidation and removal of oxides from the coated sample surface. The use of this flux in open furnaces made it possible to apply high-quality nickel coatings with a thickness of 18 μm, which is comparable to the thickness of coatings obtained in vacuum furnaces in argon atmosphere. The negative effect of flux components on the sample surface was noted during prolonged contact under the conditions of the oxidizing environment of the furnace. Practical application of the research results will provide high-quality diffusion coatings on metal products. In addition, economic efficiency is maintained through accessibility of the equipment and flux components.

Qualification of brazing procedure for furnace brazing of austenitic steel according to requirements of the ASME BPVC section IX

The article presents the procedure for qualifying brazing technology in a vacuum furnace on the example of stainless steel elements joined with copper filler material from the F-No group. 105, in accordance with the ASME Sec. IX, part QB (ASME Boiler and Pressure Vessel Code. Qualification Standard for Welding, Brazing and Fusing; Procedures; Welders; Brazers; and Welding, Brazing and Fusing Operators). The essential variables of the furnace brazing process are discussed in relation to the requirements of the protocol of qualified PQR (Procedure Qualification Record) and BPS (Brazing Procedure Specification) in accordance with the ASME Sec. IX. The requirements for joints by the calculation code ASME Sec. VIII div.1 (Rules of Construction of Pressure Vessels), related to the working temperature of the designed device have also been taken into account. The paper presents examples of brazed joints made and their properties (strength, fill level of the clearance) obtained on the basis of the carried out tests. Attention was paid to the technological aspects during the performance of brazed joints using vacuum furnaces.

Impact of Mechanical Processes as a Pre-Sulphonitriding Treatment on Tribology Properties of Selected P/M Tool Steels

We have evaluated phase composition changes in the surface layer (SL) and wear resistance of steels investigated after various mechanical processes such as a pre-sulphonitriding treatments. Two various paths of surface modification were employed: Grinding–sulphonitriding (G-SN) and hard turning–slide burnishing–sulphonitriding (T-B-SN). Studies were carried out on Vanadis 8 and Vancron 40 tool steels, which are classified as advanced powder metallurgy (P/M) high-alloyed steels with different types and amounts of carbides. Heat treatment to the final hardness of 64 ± 1 HRC (Vanadis 8) and 62 ± 1 HRC (Vancron 40) was performed in vacuum furnaces with gas quenching. Precipitation of different types such as sulfides, nitrides, and carbides was observed using X-ray diffraction analysis. Tribological properties of SL were evaluated by pin-on-disc experiments. Pins of Al2O3 and 19MnB4 steel were used as counterbodies materials. 3D surface geometrical structure measurements were also performed. Wear tracks and cross-sections of SL were observed using optical and scanning electron microscopy. The three-stage process increases the wear resistance about 37% and 30%, respectively for Vanadis 8 and Vancron 40 (in case of alumina pins), whereas values of wear rates after tests performed against steel pins were very similar for two compared processes for both steels.

Selected properties of Vanadis 8 tool steel after grinding and hard turning

Two mechanical processes of surface layer (SL) modification were performed on Vanadis 8 tool steel: grinding (G) and hard turning (HT). This steel is classified as powder metallurgy (P/M) high-alloyed tool steel. Heat treatment was carried out in vacuum furnaces with gas quenching until hardness of 64 ±1 HRC was achieved. Surface geometrical structures (SGS), microstructures, residual stress levels and wear resistance of SL resulting in these processes were compared.