scholarly journals Features of heat treatment quality testing of U8A steel articles during pulsed bipolar asymmetric magnetization

2020 ◽  
Vol 64 (4) ◽  
pp. 398-405
Author(s):  
Z. M. Korotkevich ◽  
V. A. Burak
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Coercive Force ◽  
Magnetic Induction ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Treatment Temperature ◽  
Treatment Quality ◽  
Magnetic Parameters ◽  
Quality Testing

To detect deviations of required heat treatment temperature of tool carbon steel U8A is one of the important tasks of manufactured products quality assurance. By analyzing researchings, held earlier, it was found that most of instrumental carbon steels standard magnetic characteristics have ambiguous dependence from the heat treatment temperature and cannot be used for purposes of nondestructive testing. Results of researching magnetic parameters of high-quality tool carbon steel U8A, which are good for heat treatment quality testing, are considered. The parameters were defined on steel cylindrical samples by the instrument IMI–I, suited for measuring the ferromagnetic rods magnetic induction during pulsed magnetization in open magnetic circuit. Applicability of the difference δBmp–Br between the magnetic induction of maximum demagnetizing pulse amplitude and the residual magnetic induction for tool carbon steel U8A hardening temperature testing is determined. The coercive force Hс and the coercive force taking on asymmetric magnetic hysteresis loop Hса of the steel can be used to determine underheating and overheating during hardening but these magnetic parameters are inapplicable for hardening temperature testing. It is given that the magnetic induction taking on asymmetric magnetic hysteresis loop Brа and the magnetic induction ВδmH of the magnetic field strength of maximum difference δmH along the axis Н can give measurement sensitivity more than 40 % per 100 °C in low temperature (under 350 °C) tempering testing.

Physical methods of research and monitoring

2019 ◽  
Vol 85 (1(I)) ◽  
pp. 35-44
Author(s):  
S. G. Sandomirski
Keyword(s):  
Heat Treatment ◽  
Coercive Force ◽  
Remanent Magnetization ◽  
Structural Changes ◽  
Mechanical Load ◽  
Magnetic Hysteresis ◽  
Steel Structures ◽  
Magnetic Characteristics ◽  
Magnetic Parameters ◽  
Saturation Intensity

The main magnetic parameters sensitive to the structure of steels are the parameters of their saturation loop of magnetic hysteresis: the coercive force Hcs and remanent magnetization Mrs. The saturation magnetization or saturation intensity Mr is most sensitive to the phase composition of steels. The variety of steel grades and modes of technological treatment (e.g., heat treatment, mechanical load) determined the use of magnetic structurescopy and magnetic characteristics — the coercive force Hc, remanent magnetization Mr , and specific hysteresis losses Wh on the subloops of the magnetic hysteresis of steels — as control parameters in diagnostics of the stressed and structural states of steel structures and pipelines. It has been shown that changes in Hc, Mr , and Wh are more sensitive to structural stresses and structures of steels than the parameters of the saturation hysteresis loop of magnetic hysteresis (Hcs, Mrs, and Mrs). The formulas for calculating Hc, Mr and Wh are presented to be used for estimation of changes in the parameters upon heat treatment of steels. Features of the structural sensitivity of the subloop characteristics and expediency of their use for magnetic structural and phase analyzes are determined. Thus, the range of changes in Ìr attributed to the structural changes in steels upon gradual Hm decrease is many times wider compared to the range of possible changes in Mrs under the same conditions. Conditions (relations between the magnetic parameters) and recommendations regarding the choice of the field strength Hm are given which provide the justified use of Hc, Mr and Wh parameters in magnetic structurescopy

Tempering temperature control of medium carbon steel according to the parameters of the saturation magnetic hysteresis loop

2019 ◽  
Vol 85 (12) ◽  
pp. 38-42
Author(s):  
S. G. Sandomirski
Keyword(s):  
Coercive Force ◽  
Structural Changes ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Medium Carbon Steel ◽  
Carbon Steels ◽  
Tempering Temperature ◽  
Medium Carbon ◽  
Magnetic Parameters ◽  
Medium Carbon Steels

The main magnetic parameter sensitive to the structure of steel is the coercive force (Hc). However, the coercive force of steels with a carbon content more than 0.3% appeared unsuited for control of the tempering temperature (Tt), hardness (HRC), and mechanical properties of hardened products made of such steels due to non-monotonous character of Hc dependence on the tempering temperature after their quenching The goal of the study is to develop a method for control of the structural changes of medium-carbon steels that occur upon heat treatment proceeding from the information parameters generated using the coercive force Hc and the ratio KS of their residual magnetization (Mr) to the magnetization of technical saturation (Ms) in a practically important temperature range. The advantage of the developed approach compared to those based on measuring the relaxation magnetic parameters of steels is that the parameters Hc and KS can be measured using standard methods with the minimal relative errors of measurement (2 and 1%, respectively). We consider three different combinations of the parameters Hc and KS – H0, Hc1, and Hc2 — and analyzed their dependence on the tempering temperature and hardness of medium carbon steels C30 and C45. The parameters H0, Hc1, and Hc2 monotonously change as the hardness of medium-carbon steels decreases. The correlation coefficient between the values of H0, Hc1 and Hc2 and HRC £hardness of steel 30 in the range of 32  HRC  41 is 0.959, 0.965 and 0.978, respectively. The results obtained makes it possible to abandon the complex and inaccurate measurements of the relaxation magnetic parameters of steels when developing the methods and devices for magnetic structuroscopy, and focus on enhancing of the accuracy of measuring£ Hc and Mr/Ms ratio of the material.

Experimental study of the mechanical and corrosion properties of ethyl silicate resin applied on low carbon steel

2021 ◽  
Vol 2 (108) ◽  
pp. 68-74
Author(s):  
M. Ali ◽  
J.H. Mohmmed ◽  
A.A. Zainulabdeen
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Open Circuit Potential ◽  
Low Carbon Steel ◽  
Open Circuit ◽  
Treatment Temperature ◽  
Ethyl Silicate ◽  
Low Carbon ◽  
Corrosion Properties ◽  
Mixture Ratio

Purpose: This work aimed at evaluating the properties of the ethyl silicate-based coating that can be applied on low carbon steel. Design/methodology/approach: Two mixture ratio types (2:1, and 3:2) of resin and hardener respectively were used to prepared two specimen models (A and B). Findings: It found that some mechanical properties (tensile, hardness, and impact strength) of ethyl silicate resin were evaluated according to standard criteria. Research limitations/implications: The effect of heat treatments at various temperatures (100, 150, and 200°C) and holding at different times (10, 20 & 30) min on hardness was investigated. Practical implications: Moreover, an open circuit potential corrosion test with a solution of 3.5% Sodium Chloride at room temperature and 60°C was used to determine the corrosion resistance of low carbon steel specimens coated with the two mixture types. Originality/value: The effects of mixture ratios (for resin and hardener) and heat treatment conditions on properties of ethyl silicate-based coating were studied. From obtained results, acceptable values of tensile, hardness, and toughness were recorded. Increasing heat treatment temperature and holding time leads to enhance hardness for both model types. An open circuit potential (OCP) tests show that there is an enhancement of protective properties of ethyl silicate coatings with mixture type B in comparison with type A was achieved. Generally, the results indicate that specimen model B has higher properties as compared with specimen model A.

Effect of Post Weld Heat Treatment on Carbon Steel AISI 1050 in Heat Effected Zone

2013 ◽  
Vol 650 ◽  
pp. 612-615
Author(s):  
Prachya Peasura ◽  
Lersak Sumarn
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Treatment Time ◽  
Treatment Temperature ◽  
Post Weld Heat Treatment ◽  
Heat Treatment Time ◽  
P Value ◽  
Fine Grain ◽  
Steel Aisi ◽  
Weld Heat

The research was study the effect of post weld heat treatment parameters on microstructure and hardness in heat affected zone. The specimen was carbon steel AISI 1050 which thickness of 6 mm. The experiments with full factorial design. The factors used in this study were post weld heat treatment(PWHT) temperature of 500, 550, 600, 650 and post weld heat treatment time of 10 and 15 hour. The welded specimens were tested by tensile strength testing and hardness testing according to ASTM code. The result showed that both of post welds heat treatment temperature and post weld heat treatment time had interaction on hardness at 95% confidential (P value < 0.05). A factor affecting the hardness was the most PWHT temperature 550 ๐C and PWHT time 10 hr. of 279 HV. Microstructure can be concluded that low PWHT temperature and time effect on temper martensite with a coarse grain and martensite scattered throughout. Martensite was a smaller and greater fine grain, the ferrite and the volume decrease due to a higher temperature.This research can be used as data in the following appropriate PWHT parameters to carbon steel weld.

scholarly journals Studying the influence of synthesis parameters on the magnetic properties of CoNe ferrites

2020 ◽  
Vol 3 (2) ◽  
pp. 33-38
Author(s):  
L. A. Frolova ◽  
◽  
T. Ye. Butyrina ◽  
Keyword(s):  
Magnetic Properties ◽  
Coercive Force ◽  
Magnetic Hysteresis ◽  
Reaction Medium ◽  
Nonequilibrium Plasma ◽  
Treatment Temperature ◽  
Synthesis Conditions ◽  
Synthesis Parameters ◽  
Initial Ph ◽  
Mathematical Equations

The influence of synthesis conditions on saturation magnetization and coercive force of NiCo ferrites, which were obtained under the action of low-temperature contact nonequilibrium plasma (PNP), is investigated. The main influencing factors were the initial pH of the solution, the treatment temperature and the duration of plasma treatment. Mathematical equations adequately describe the obtained dependences. The results showed that the pH of the reaction medium is the parameter that most affects the magnetic hysteresis for samples obtained by processing KNP. Increasing the initial pH leads to an increase in coercive force.

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