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Properties and Applications of Molybdenum
Published in C. K. Gupta, Extractive Metallurgy of Molybdenum, 2017
The high-speed steel family is characterized by a variety of combinations of properties such as varying degrees of resistance to wear, strength, toughness, and an ability to be shaped prior to hardening. The major alloying elements, in addition to carbon, in high speed steel are tungsten, molybdenum, vanadium, chromium, and cobalt. These steels are generally divided into two classes: the tungsten types and the molybdenum types.
Cutting Oils
Published in W. S. Robertson, Lubrication in Practice, 2019
A. R. Lindsay, J. C. D. Russell
There are five main types of tool material: Carbon steel and medium alloy steels are relatively uncommon because they have been superseded by materials of superior hot hardness and wear resistance. However they can be easily shaped and their principal use is in small form tools operating at low speeds. Watermix fluids are used to keep these tools as cool as possible.High-speed steel (h.s.s.) tools are still widely used, although they have been superseded by carbides and ceramics for very high cutting speeds. High-speed steel combines good hot hardness and high-wear resistance and is extremely tough. Either neat oils or watermix fluids can be used with h.s.s. tools depending on the requirements of the operation.Cast alloy tools have a greater hot hardness than h.s.s. tools but less toughness. Typical uses are drills, single point tools and parting off tools. Neat oils are used where possible to protect the tools from heavy shock loading.The earliest forms of carbide tool were much harder but less tough than h.s.s. Composite carbides of tungsten, titanium, tantalum or niobium improved all-round performance. The most recent significant development is the coated carbide. A tough grade of tungsten carbide is coated with a thin layer of hard, wear-resistant titanium carbide. With such improvements the eventual replacement of h.s.s. in most applications is likely. Carbide tools require the minimum of lubrication and so watermix fluids are generally applied.Ceramic tools have even greater hardness but less toughness than carbides. These are used for very high-speed turning and watermix fluids are used to cool chips and minimise workpiece distortion.
An environment-friendly and sustainable machining method: near-dry EDM
Published in Materials and Manufacturing Processes, 2019
Krishnakant Dhakar, Kuldeep Chaudhary, Akshay Dvivedi, Omkar Bembalge
The machining parameters used in the experiments were selected through a literature survey. Also, the subsequent pilot experimentations were carried out in the selection of the machining parameters. The parameters like current, pulse-on-time, and pulse-off-time were chosen to examine their effects on GEC and MRR. The machining parameters level is given in Table 2. Taguchi L9 orthogonal array was utilized to plan the experimentations. This L9 array was utilized to evaluate the correlation between machining parameters and responses in wet EDM and near-dry EDM. The design and experimental results obtained using the L9 array are given in Table 3. The experiments were performed on HSS work material. High-speed steel has high hardness even at high temperature, high wear resistance along with good toughness properties. Due to these properties, it is generally used for making dies and mounds and many machine tools.
Studies on the surface of high-performance alloys machined by micro-EDM
Published in Materials and Manufacturing Processes, 2018
Wujun Feng, Xuyang Chu, Yongqiang Hong, Li Zhang
Titanium alloys, stainless steels, and high-speed steels are three types of high-performance alloys that are widely used in the aerospace industry. Titanium alloys are characterized by low density, high-temperature strength, and endurance strength; therefore, they have been used to replace aluminum alloys in fabricating the shells of aircraft engines. Stainless steel is another type of material applied extensively to space launch vehicles and exhaust passages around rocket engines because it possesses good plasticity and toughness. High-speed steel is mainly used in high-speed cutting of aircraft parts because it has high hardness and good wear resistance. In aerospace materials, surface accuracy is extremely important; low-quality surfaces can have serious consequences in many cases. Because the abovementioned three types of materials are difficult to machine, the selection of suitable machining methods for these types of intractable materials must be considered carefully.
In-situ VN reinforced powder metallurgy M30 steels prepared from water atomized powers via pressureless sintering
Published in Powder Metallurgy, 2020
Haixia Sun, Fang Yang, Qian Qin, Biao Zhang, Alex A. Volinsky, Zhimeng Guo
Owing to their excellent strength, toughness and hardness, tool steels are widely used in cutting tools and wear parts. Among tool steels, high-speed steel (HSS) is one of the most common kinds with special microstructure and excellent properties. In terms of the microstructure, fine carbides are uniformly distributed in the steel matrix. Thereinto, the carbides characteristics, such as particle size, distribution, structure and interface with the matrix play an important role in determining the microstructure and mechanical properties of the HSS.