Erratum to: Effect of Tempering on the Structure and Coercive Force in the AISI D3 (217H12WF) Ledeburite Chromium Steel

The main purpose of the studies was to establish the effect of the tempering temperature on the changes of carbide and retained austenite contents. It has been found that the course of changes of the coercive force of hardened steel after austenitizing is qualitatively similar to the hardness changes. That means in practice it is possible to determine the 217H12WF steel hardness based on the measurement of the coercive force.     

Nondestructive testing of the heat-treatment quality of sintered 30NM steel

Conclusions To eliminate scrap for hardness of parts of sintered 30NM steel after hardening and low-temperature tempering of them with possible variations in carbon content of the material, the following conditions are necessary: nondestructive testing and inspection of parts after sintering for carbon content by the method of measurement of their coercive force. If necessary measurement of the density of the parts after sintering using the saturation magnetization is possible; nondestructive testing and inspection of the hardened parts based on hardness by measurement of their coercive force. In some cases prediction of the hardness after hardening and low-temperature tempering using the results of measurement of the coercive force of hardened parts is possible.Translated from Poroshkovaya Metallurgiya, No. 8 (272), pp. 75–80, August, 1985.     

Correlation of rail structure with the Rayleigh-wave velocity and the coercive force

The velocity of Rayleigh waves is correlated with the depth of the decarburized layer and the hardness of rail steel. With increase in the depth of the decarburized layer and decrease in the hardness, the velocity of Rayleigh waves increases. Conversely, in the same conditions, the coercive force of the rail steel declines. The thickness of the decarburized layer is determined by this method and confirmed by direct measurements.     

（W，Ti，Ta）C复式碳化物对WC-（6％-8％）Co超细硬质合金性能的影响

以WC-6％Co和WC-8％120为研究体系,在1390℃压力烧结下制备不同配比复式碳化物的超细硬质合金。分别采用洛氏硬度检测、抗弯强度检测、钴磁检测、矫顽磁力检测等方法,通过扫描电镜和电子衍射分析,研究了不同量的（W,Ti,Ta）C复式碳化物对超细硬质合金性能的影响。结果表明：WC-6％Co-2％（W,Ti,Ta）C超细硬质合金的矫顽磁力为45．39kA·m^-1,硬度为94．0HRA,抗弯强度为2280MPa;WC-8％Co-2％（w,Ti,Ta）C超细硬质合金的矫顽磁力为37．4kA·m^-1,硬度为93．4HRA,抗弯强度为2670MPa;WC-8％Co-2％（w,Ti,Ta）C-0．5％（Cr3C2/VC）的矫顽磁力为38．2kA·m^-1,硬度为93．6HRA,抗弯强度为2780MPa;它们具有较高的综合性能。     

Structure of IF steel in continuous annealing

The recovery and recrystallization kinetics of IF titanium steel is studied by investigating the microstructure, measuring the coercive force, and analyzing the residual stress. The results are familiar, except for the initial and final temperatures of these processes, which are specific to the steel employed. We assume that, on heating cold-rolled IF steel in the range 550?C650°C, the dislocation density is unchanged on account of retardation by small TiC particles. Formulas are derived for the coercive force as a function of the grain size and may be used for monitoring purposes.     

Effect of impurities in iron powders on the physical properties of sintered magnetically soft materials

The effect of impurities in the iron powder on the physical properties of sintered magnetically soft materials was studied. Although vanadium increased the coercive force, it improved properties such as the saturation magnetization, specific electrical resistance, and hardness. The coercive force and bend strength of the powder materials were linearly dependent on the amount of carbide-forming elements. Phosphorous decreased this undersirable effect. Increasing the fraction of carbide forming elements in the materials decreased their densities, and increased their specific electrical resistances, phosphorous being unable to change this dependence.     

Insight into the microstructural characterization of ferritic steels using micromagnetic parameters

The influence of tempering-induced microstructural changes on the micromagnetic parameters such as magnetic Barkhausen emission (MBE), coercive force (H _c), residual induction (B _r), and maximum induction (B _max) has been studied in 0.2 pct carbon steel, 2.25Cr-1Mo steel, and 9Cr-1Mo steel. It is observed that, after short tempering, the micromagnetic parameters show more or less linear correlation with hardness, which is attributed to the reduction in dislocation density, but long-term tempering produces nonlinear behavior. The variation in each of these parameters with tempering time has been explained based on the changes in the size and distribution of ferrite laths/grains and precipitates. It has been shown that the individual variation in the microstructural features such as size and distribution of laths/grains and precipitates during tempering can be clearly identified by the MBE parameters, which is not possible from the hysteresis loop parameters (H _c and B _r). It is also shown that the MBE parameters can not only be used to identify different stages of tempering but also to quantify the average size of laths/grains and second-phase precipitates.     

Estimation of the Ultimate Tensile Strength of Steel from Its <Emphasis Type="Italic">HB</Emphasis> and <Emphasis Type="Italic">HV</Emphasis> Hardness Numbers and Coercive Force

A formula is derived to accurately describe the tabulated relation between the Brinell (HB) and Vickers (HV) hardnesses of steel over the entire range of their possible variation. This formula and the formulas describing the relation between the HB hardness of chromium–molybdenum and chromium–nickel steels and their ultimate tensile strength σ_u are used to analyze the change in σ_u of 38KhNM steel upon quenching and tempering. The data that reveal a relation between σ_u of 38KhNM steel and its coercive force are obtained.     

Effect of plastic deformation on the physicomechanical properties of tungsten carbide-cobalt hard alloys

Summary A study was made of the effect of prior plastic deformation on the hardness, strength, coercive force, and electrical resistivity of tungsten carbide-cobalt hard alloys containing 10–25% cobalt. Plastic deformation decreases the hardness of the alloys. Up to a deformation of about 5–6%, all the alloys investigated showed a marked drop in hardness. Further deformation did not decrease the hardness of alloy VK25; for the alloys with lower cobalt contents, the hardness decrease was less pronounced.     

Coercive force, texture, and fracture in a low-carbon steel tube

The coercive force and crystallographic texture in a tube made from ferrite low-carbon steel are studied after fatigue and tensile tests during fracture after cyclic loading by hydraulic pressure. The texture was studied using synchrotron radiation (transmission geometry) by constructing three-dimensional distribution function of orientations. The typical texture of rolling of the ferrite steel is maximal in the median cross section of the tube wall, and the highest texture intensity is due to deformation preceding fracture. The coercive force is found to increase in portions neighboring to the fracture zone.     

Correlation between magnetic properties and the hardness of powder steels

Density and carbon content are studied for their effect on strength (hardness) and magnetic (coercive force, saturation magnetization) properties of powder steels ZhGr1 and ZhGr1D3. It is shown that the hardness of articles made of these steels may be determined indirectly by measuring two magnetic characteristics.Physicotechnical Institute, Russian Academy of Sciences, Izhevsk. Translated from Poroshkovaya Metallurgiya, Nos. 1–2, pp. 67–69, January–February, 1994.     

Monitoring the Physicomechanical Properties of 40X Steel on the Basis of the Limiting Magnetic Hysteresis Loop

The mechanical properties (strength σ_u, yield point σ_0.2, relative elongation ψ; and hardness HB and HRC) of 40X steel depend monotonically on the tempering temperature T_te after quenching and are closely correlated. Their relationships are described by linear regression equations. The corresponding correlation coefficients and computational errors are determined. The coercive force H_c of 40X steel is not clearly related to its physicomechanical properties over the whole range of T_te. However, magnetic analysis of the structure of 40X steel may be based on an algorithm that employs Hc and the ratio of the residual magnetization to the saturation magnetization. The results given by this algorithm depend uniquely on T_te over its practical range and are highly sensitive to change in the physicomechanical properties of 40X steel.     

WC-Co硬质合金矫顽磁力与最高烧结温度关系的研究

从理论上分析了硬质合金矫顽磁力的影响因素,指出在高温工况和实际生产工况中,炉控片的矫顽磁力主要与最高烧结温度有关。用炉控片对PVA压力烧结炉的高温温度场进行了实验研究,并通过对实验数据的分析和处理,获得矫顽磁力与最高烧结温度的定量关系式。     

Assessing the initial magnetic permeability of steel on the basis of the coercive force and the residual magnetization

A formula developed by statistical analysis permits the calculation of the initial magnetic permeability of structural steels, with acceptable accuracy for practical purposes, from measurements of their coercive force and residual magnetization. This formula yields new information regarding steel properties. Recommendations for nondestructive monitoring are developed.     

Coercive force and microstructure in a Zr-permalloy

An alloy containing 80.0 pct Ni, 12.65 pct Fe, 6.74 pct Mo, 0.36 pct Zr, and 0.25 pct Mn by weight was cast, homogenized, and successively cold rolled into thin strips with area reductions of 0, 50, 75, and 90 pct. Annealed samples were studied by optical and electron microscopy, electron diffraction, and magnetic testing to determine the effects of cold work and annealing upon the microstructure and magnetic properties of the alloy. Cold work produced a high initial hardness together with high coercive force. Recrystallization of the cold worked structures occurred upon annealing at 600°C (873 K) and above and caused significant and parallel decreases in hardness and coercive force. The activation energy for recrystallization was found to be 80.5 kcal/g mole (337.0 kJ/g mole) for the 50, 75, and 90 pct cold worked specimens. After annealing at 600°C (873 K), a small number of spherical Ni₄Mo particles were observed, but the particles produced little change in magnetic properties apparently because of their relatively coarse size and large spacing. Beginning at 700°C (973 K) ribbon-shaped particles of a Ni₅Zr intermetallic compound also precipitated out of solid solution. Both the Ni₄Mo and Ni₅Zr precipitates were the result of a homogeneous continuous precipitation reaction within the grains. A peak in coercive force at 800°C (1073 K) is attributed to domain wall pinning associated with the fine distribution of rodlike Ni₅Zr particles. Cold working 90 pct and aging at 800°C (1073 K) was found to increase coercive force by almost 60 pct from the minimum produced by complete recrystallization. Annealing, however, decreased hysteresis and improved squareness.     

Maximum magnetic permeability of magnetically hard steel and the limiting hysteresis loop

The proposed formula relates the maximum magnetic permeability μ _m of magnetically hard steel to its coercive force and residual magnetization. The calculation results may be used in nondestructive quality assessment of heat treatment and in magnetic structural analysis of steel, instead of the measurement of μ _m , which is laborious and less precise.     

Properties of Fe-Co alloy nanopowders formed under various conditions

The effect of the composition and formation conditions of Fe-Co alloy nanopowders on their particle size and magnetic properties is studied. A decrease in the hydrogen-reduction temperature from 450 to 350°C is found to lead to a decrease in the particle size of the powders and an approximately fivefold increase in their coercive force. The coercive force of the powders is shown to be two orders of magnitude higher than that of a compacted Fe-Co alloy. As the cobalt content increases, the coercive force is found to exhibit non-monotonic variations; the maximum coercive force is observed in an alloy containing 50–70% Co.     

0.08mm厚中频用取向硅钢极薄带制作工艺研究

文章介绍了利用我厂生产的0.27 mm厚普通取向硅钢(CGO)作为原料制作0.08 mm厚中频用取向硅钢极薄带的工艺研究过程,着重研究了不同退火温度与机组运行速度(即保温时间)的热处理工艺对取向硅钢磁性能的影响,确定了以900℃×10 m/min为最佳的热处理工艺,获得了取向硅钢极薄带的磁感应强度B 8=1.846 T,铁损P 1.5/400=11.15 W/kg,矫顽力H c=53.57 A/m的良好中高频电磁性能的制作工艺。     

Finite-Element Simulation of Conventional and High-Speed Peripheral Milling of Hardened Mold Steel

A finite-element model (FEM) with the flow stress and typical fracture is used to simulate a hard machining process, which before this work could not adequately represent the constitutive behavior of workpiece material that is usually heat treated to hardness levels above 50 Rockwell C hardness (HRC). Thus, a flow stress equation with a variation in hardness is used in the computer simulation of hard machining. In this article, the influence of the milling speed on the cutting force, chip morphology, effective stress, and cutting temperature in the deformation zones of both conventional and high-speed peripheral milling hardened mold steel is systematically studied by finite-element analysis (FEA). By taking into consideration the importance of material characteristics during the milling process, the similar Johnson–Cook’s constitutive equation with hardened mold steel is introduced to the FEM to investigate the peripheral milling of hardened mold steel. In comparison with the experimental data of the cutting force at various cutting speeds, the simulation result is identical with the measured data. The results indicate that the model can be used to accurately predict the behavior of hardened mold steel in both conventional and high-speed milling.     

Effects of alloy steel shot on matrix hardness of impregnated diamond bit based on WC

In order to study the hardness of WC- based matrix used for impregnating diamond bits, matrix samples were prepared by hot pressing with different volume fractions of alloy steel shot. The main performance parameters of matrix (hardness, abrasion resistance and bending strength) were tested, and the surface morphology was observed using SEM. The results show that the matrix becomes harder with the increasing of sintering temperature, but adding alloy steel shot will reduce the hardness of the matrix and the higher the content of alloy steel shot, the lower the hardness of the matrix. In the process of sintering, due to the non- uniform diffusion and enrichment of some elements in the matrix, a fragile bonding interface is formed inside the sample. Under the external force conditions, the brittle interface is prone to slip and damage, ultimately affects the hardness of the matrix.