Papers by Keyword: 16Mn

Abstract: Coal-winning machine is to break coal with rotating mechanism. Owing to the harsh working environment and large stress, the top-disc plate, helical blade and tooth holder in cylinder often lose their wear resistance, hence causing overhauling of the machine and influencing the production of coal. With the modernization of the production technology and mining equipment of coal, the mining intensity of coal constantly increases, which calls for higher wear resistance of the top-disc plate, helical blade and tooth holder in cylinder. Currently, many studies have been performed on the wear resistance of the tooth holder in cylinder, but rare on the wear-resistant technology and wear resistance of the top-disc plate and helical blade in cylinder. In this paper, 16Mn steel which is used in the top-disc plate and helical blade in the cylinder of coal-winning machine was welded based on surfacing technology using EDTCrMnSi special wire to obtain composite wear-resistant steel plates. Then wear tester was employed to compare the wear of 16Mn steel and composite wear-resistant steel plate. Meanwhile, metallographic microscope and x-ray fluorescence spectrometer (XRF) were used to observe the microstructure of the materials and analyze the types and contents of elements in the surfacing layers of the composite wear-resistant steel plate. Furthermore, the influence of surfacing technology on the wear resistance of the material was analyzed. The results showed that there existed high contents of Cr, Si and Mn in the surfacing layers of the top-disc plate and helical blade in cylinder of the coal-winning machine after welded based on surfacing technology. Moreover, the wear resistance and service life of matrix were largely improved.

Abstract: In order to study the corrosion characteristics of 16Mn and X42 steel in natural seawater, the indoor contrast corrosion experiments are carried out in seawater by electrochemical method. Tafel polarization curves and electrochemical impedance spectroscopy (EIS) techniques are employed to investigate the corrosion electrochemical behavior of 16Mn and X42 steel, which are acquired by electrochemical workstation. The results of polarization curves and EIS reveal the respective corrosion rules of 16Mn and X42 steel in natural seawater. At last, the different influence of corrosion scale on the corrosion process of 16Mn and X42 steel is analyzed contrastively.

Abstract: Based on a system of macro & micro fracture appearance observation, energy spectrum analysis, metallurgical structure inspection and hardness test, the fracture mechanism and cause of specimen of 16Mn steel were obtained. The results showed that the large load was the main reason for the 16Mn steel specimen fracture, the fracture surfaces were different dimensional equiaxed dimples and some spherical particles which contain higher Mn, Si and O. The spherical particles may be an oxide which may be caused by the manufacturing process.

Abstract: In this article, the technology of ultrasound impacting is mentioned. The toe of 16Mn welded joints are treated by the ultrasound impacting, and the fatigue, hardness and residual compressive stress of the 16Mn welded joints are compared after treated by ultrasound impacting. The results shows that, the ultrasound impacting bring high residual compressive stress on the surface of the 16Mn welded joints, besides, the treatment of ultrasound impacting can improve the fatigue and hardness of the 16Mn welded joints, and when the impacting electric current is 1.5A, and the impacting time is 10 min, the fatigue and hardness of the sample is the best.

Abstract: In order to study the corrosion characteristics of 16Mn and Q235B steel in natural seawater, the indoor contrast corrosion experiments are carried out in seawater by electrochemical method. Tafel polarization curves and electrochemical impedance spectroscopy (EIS) techniques are employed to investigate the corrosion electrochemical behavior of 16Mn and Q235B steel, which are acquired by electrochemical workstation. The results of polarization curves and EIS reveal the respective corrosion rules of 16Mn and Q235B steel in natural seawater. At last, the different influence of rust layer on the corrosion process of 16Mn and Q235B steel is analyzed contrastively.

Abstract: In order to understand the influence of Heat-Affected Zone (HAZ) on fatigue properties of 16Mn steel, a series of cyclic torsional tests were conducted on 16Mn weld metal, the base metal, and the HAZ metal. The specimens of 2mm diameter were uniformly-spaced taken from a bulk 16Mn plate, which included a V-style welded joint in the center, and the space for each specimen was 4mm. From cyclic fatigue tests performed on specimens at different positions, one can observe that the fatigue damage evolution in the HAZ is faster than those in the weld and the base metal, i.e., HAZ has a significant effect on fatigue life of 16Mn. In addition, the peak stress decline curves of HAZ specimens in different rows are considerably diversified, but the damage evolution and fatigue properties of HAZ metal are similar in spite of their locations.

Abstract: The paper deals mainly with the corrosion of 16Mn steel under the condition of three different high temperatures and in NACE solution saturated with H2S at 1MPa partial pressure of CO2, by means of autoclave, SEM, XRD, weight loss method and electron-probe micro-analysis. The result showed: under the experimental conditions, the serious CO2/H2S corrosion happened to 16Mn steel ,so that the main corrosion films, ferrous sulfide, could be clearly found on both sides of the samples; at 60°C, characteristics of pitting corrosion manifested centered chiefly around CO2 corrosion ; at 90°Cand 120°C, around H2S ones . It was the cooperating effects of both the hydrogen damage and pitting corrosion caused by CO2/H2S corrosion that formed the special corrosion features on the surface of steel to a certain degree. It was indicated that the corrosion of CO2/H2S was the result of interaction of multi-factors.