Low-alloy High-speed Steels Research Articles

Influence of Heat Treatment on Content of the Carbide Phases in the Microstructure of High-Speed Steel

Abstract This article presents the results of investigations of the effect of heat treatment temperature on the content of the carbide phase of HS3-1-2 and HS6-5-2 low-alloy high-speed steel. Analysis of the phase composition of carbides is carried out using the diffraction method. It is determined that with increasing austenitising temperature, the intensification of dissolution of M6C carbide increases. As a result, an increase in the grain size of the austenite and the amount of retained austenite causes a significant reduction in the hardness of hardened steel HS3-1-2 to be observed. The results of diffraction investigations showed that M7C3 carbides containing mainly Cr and Fe carbides and M6C carbides containing mainly Mo and W carbides are dissolved during austenitisation. During austenitisation of HS3-1-2 steel, the silicon is transferred from the matrix to carbides, thus replacing carbide-forming elements. An increase in a degree of tempering leads to intensification of carbide separation and this process reduce the grindability of tested steels.

Investigation of contact phenomena in turning using tools made of low-alloy high-speed steels

Investigation of contact phenomena in turning using tools made of low-alloy high-speed steels

Surface Layer Properties of Low-Alloy High-Speed Steel after Grinding

Abstract Investigations of the surface layer characteristics of selected kinds of low-alloy high-speed steel after grinding were carried out. They were carried out on the flat-surface grinder with a 95A24K grinding wheel without cooling. The influence of grinding parameters was defined especially for: the quantity of secondary austenite, surface roughness, microhardness and grinding efficiency with a large range of grinding parameters: grinding depth 0.005–0.035 mm, lengthwise feed 2–6 m/min, without a cross-feed on the whole width of the sample. It was found that improvement of grinding properties of low-alloy high-speed steels is possible by efficient selection of their chemical composition. The value of the grinding efficiency is conditioned by grinding forces, whose value has an impact on the grinding temperature. To ensure high quality of the tool surface layer (i.e. a smaller amount of secondary austenite, lack of wheel burn and micro-cracks) in the case of sharpening of tools made of low-alloy high-speed steel, the grinding temperature should be as low as possible.

Research on durability of turning tools made of low-alloy high-speed steels

Research on durability of turning tools made of low-alloy high-speed steels

Tempering behavior of a semi-high speed steel containing nitrogen

The decomposition behavior of martensite and precipitation characteristics of carbonitrides during the tempering process of a low-alloy high-speed steel (semi-HSS) containing nitrogen were investigated by means of transmission electron microscopy, scanning electron microscopy, energy dispersive spectrometry and electron energy loss spectroscopy. The results shown the secondary hardening effect is reinforced with addition of nitrogen and the secondary hardening temperature range has expanded. The stability of retained austenite is also studied. When tempered in the temperature range of 425–525 °C, large quantities of fine-scale V-rich nitride precipitations distribute in the matrix homogeneously. A complex carbonitride phase can form when tempered at 550 °C.

Plasma Surface Alloying W-Mo Low-Alloy HSS

The plasma surface alloying low-alloy high speed steel (HSS) is carried out in vacuum chamber where a source electrode (W-Mo) and a work piece are properly placed. By using the sputter of glow-discharge, under the common function of electric field and temperature field, the desired alloying elements (W- Mo) are sputtered from the source cathode, traveling toward the substrate. Subsequently the alloying elements deposit onto the surface of the substrate, forming alloy diffusion layer which the depth may vary from several micron to several hundreds micron. In the end a surface low-alloy HSS steel would be produced after ultra-saturation ion carbonization. The composition of the alloyed layer is equal or similar with it of low-alloy HSS. The carbonized layer, without coarse eutectic ledeburite structure, possesses high density of finely and dispersed alloy carbides with tungsten equivalent 10% above and a significant improvement in surface hardness and wear resistance. The principle of plasma surface alloying and its test results and commercial products application are introduced in this paper.

Use of hypereutectoid high-speed steel 11M5F for the production of cutting and cold-stamping tools in the Avtovaz Joint-Stock Company

The development of low-alloy high-speed steels that reduce the production cost of cutting tools and dies can present practical interest for plants and small enterprises manufacturing tools for their special purposes. The present paper gives the results of an investigation of hypereutectoid low-alloy high-speed steel 11M5F and a widely used steel of grade R6M5. The basic and technological properties of these steels are compared, and the results of industrial tests of cutting, thread-rolling, cold-stamping tools and tools for semihot deformation operating under various conditions are described.

A study of TiN coatings on a low alloy high speed steel

Abstract This paper deals with the TiN coating of a new low alloy high speed steel W3Mo2Cr4VSi. According to transmission electron microscopy and X-ray diffraction investigations, the TiN coating can be divided into two layers: the main-body layer and the transition layer. The main-body layer consists of columnar TiN which is vertical to the substrate surface, with fine-grained TiN and small amounts of ϵ-Ti 2 N between some columns. The transition layer is composed of equiaxed grains of TiN, ϵ-Ti 2 N and α-Fe. The orientation relationship between the columnar TiN and the ϵ-Ti 2 N grains in the main-body layer was found to be (101) Ti 2 N ∥ (200) TiN and [111] Ti 2 N ∥ [011] TiN . It was shown that the amount of α-Fe in the transition layer decr eased with increasing silicon content in this steel. A compressive residual stress between 180 and 200 N mm −2 exists in the coating.

Thermophysical properties of low-alloy high-speed steels

To a significant degree the life of a cutting tool is determined by the temperature condition of its cutting edge since this characterizes the intensity of wear of the working surfaces. Under otherwise equal conditions the temperature condition of the edge will depend upon the thermophysical properties of the tool material [I]. Therefore for an objective comparative evaluation of new high-speed steels it is desirable to know their thermophysical properties. In addition the values of the thermophysical characteristics are necessary for calculation of the temperature fields in a cutting tool.

Optimization of the compositions of low-alloy high-speed steels

Optimization of the compositions of low-alloy high-speed steels

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

Of the investigated low-alloy high-speed steels 11R3AM3F2 steel is closest to R6M5 steel in service characteristics and then R2M5 and 11M5F.

Low-alloy tungsten-free high-speed steels 11M5F and 11M5FYu and their heat treatment

The development and heat treatment of two tungsten-free low-alloy high-speed steels 11M5F and 11M5FYu are discussed. The steels are characterized by the absence of eutectic molybdenum carbide, a heating temperature for hardening about 60/degree/: No. 11, (Nov 1987)C lower than for steel R6M5, and a low vanadium concentration. The steels contain about 1% C, 5% Mo, 4% Cr, and 1.5 % UV-14-1-2678-79. Tests were conducted to ascertain pertinent tool steel properties such as grindability, impact strength, and wear. Numerous industrial tests of cutting tools made of steel 11M5F have shown that their resistance is not lower, and those made of steel 11M5FYuS are markedly higher, than tools made of steel R6M5.

From steel R18 to tungstenless low-alloy high-speed steels

From steel R18 to tungstenless low-alloy high-speed steels

Hypereutectoid high-speed steels

Half of the tungsten and molybdenum contained in R6M5 and R18 steels is concentrated in the undissolved eutectic carbides hindering austenitic grain gowth in hardening and providing the necessary strength and impact strength. This article describes the tungsten-free low-alloy high-speed steel 11M5F with a chemical composition of 1.03-1.10% C, 5.2-5.7% Mo, 3.8-4.2% Cr, 1.3-1.7% V, 0.3-0.6% Si, and 0.3% Ce. The properties of 11M5F and R6M5 steels are examined and compared. The results of production and laboratory tests of the cutting properties of tools of the steels developed showed their high effectiveness, especially of 11M5F steel with 1% A1. The life of tools of the tungsten-free steels is two or three times greater than the life of tools of R6M5 steel.

VASCO M-50

Abstract VASCO M-50 is a hardenable (martensitic), low-alloy high-speed steel developed primarily for high-strength, high-load components (such as bearings and gears) designed for elevated-temperature service. It may be used at temperatures up to 600 F; this is in contrast to AISI 52100 steel which may be used up to only 350 F. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: TS-278. Producer or source: Teledyne Vasco.

Low-alloy high-speed steels for drill bits produced from cast blanks

The steels investigated have satisfactory cutting and technological properties and can be recommended for manufacturing drill bits from cast blanks for more complete utilization of high-speed steel scrap.