Repairing Surface Fatigue Damage of the Metal Material by Heat Treatment

2010 ◽  
Vol 154-155 ◽  
pp. 425-428
Author(s):  
Ting Liang Guo ◽  
Zhao Xing Han

In this paper, using experimental method studied to repair surface fatigue damage of the metal material by heat treatment. Analyzed the mechanism to repair surface fatigue damage of the metal material by heat treatment. From the test, it have been found that the Metal materials has temping threshold behavior in repairing it’s fatigue damage by heat treatment. For the same kind of material, there is a threshold characteristics in choosing tempering temperatures when repaired the fatigue damage of metal material surface through changed tempering temperatures. Experimental results shows that the temping temperature threshold to repair metal material fatigue damage is the first tempering temperature after materials was hardened before it was in fatigue damage.

2020 ◽  
Vol 14 (2) ◽  
pp. 6789-6800
Author(s):  
Vishal Jagota ◽  
Rajesh Kumar Sharma

Resistance to wear of hot die steel is dependent on its mechanical properties governed by the microstructure. The required properties for given application of hot die steel can be obtained with control the microstructure by heat treatment parameters. In the present paper impact of different heat treatment parameters like austenitizing temperature, tempering time, tempering temperature is studied using response surface methodology (RSM) and artificial neural network (ANN) to predict sliding wear of H13 hot die steel. After heat treating samples at austenitizing temperature of 1020°C, 1040°C and 1060°C; tempering temperature 540°C, 560°C and 580°C; tempering time 1hour, 2hours and 3hours, experimentation on pin-on-disc tribo-tester is done to measure the sliding wear of H13 die steel. Box-Behnken design is used to develop a regression model and analysis of variance technique is used to verify the adequacy of developed model in case of RSM. Whereas, multi-layer feed-forward backpropagation architecture with input layer, single hidden layer and an output layer is used in ANN. It was found that ANN proves to be a better tool to predict sliding wear with more accuracy. Correlation coefficient R2 of the artificial neural network model is 0.986 compared to R2 of 0.957 for RSM. However, impact of input parameter interactions can only be analysed using response surface method. In addition, sensitivity analysis is done to determine the heat treatment parameter exerting most influence on the wear resistance of H13 hot die steel and it showed that tempering time has maximum influence on wear volume, followed by tempering temperature and austenitizing temperature. The prediction models will help to estimate the variation in die lifetime by finding the amount of wear that will occur during use of hot die steel, if the heat treatment parameters are varied to achieve different properties.


2019 ◽  
Vol 4 (1) ◽  
pp. 286-294
Author(s):  
László Tóth ◽  
Réka Fábián

The X153CrMoV12 ledeburitic chromium steel characteristically has high abrasive wear resistance, due to their high carbon and high chromium contents with a large volume of carbides in the microstructure. This steel quality has high compression strength, excellent deep hardenability and toughness properties, dimensional stability during heat treatment, high resistance to softening at elevated temperatures. The higher hardness of cryogenic treated samples in comparison with conventional quenched samples mean lower quantity of retained austenite as at samples quenched to room temperature and tempered in similar condition. In the microstructure of samples were observed that the primary carbide did not dissolve at 1070°C and their net structure have not been changed during to heat treatment. During to tempering at high temperature the primary carbides have become more and more rounded. After low tempering temperature in martensite were observed some small rounded carbides also, increasing the tempering temperature the quantity of finely dispersed carbides increased, which result higher hardness. The important issues in heat treatment of this steels are the reduction or elimination of retained austenite due to cryogenic treatment.


2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Qiang Li ◽  
Yutao Wang

In the thermal processing of metal materials, the performance of thematerial is more stable, and the heat-treated materials are processed into parts to make the performance more excellent and more in line with the performance requirements of mechanical parts. However, in thermal processing, metal materials are prone to problems, such as deformation, deformation of the appearance of metal materials, and fatal effects on the processing of mechanical parts. Therefore, this paper focuses on solving the causes of deformation in the thermal processing of metal materials, as well as solutions to improve the problems in the processing of metal materials.


2018 ◽  
Vol 284 ◽  
pp. 351-356 ◽  
Author(s):  
Mikhail V. Maisuradze ◽  
Maksim A. Ryzhkov

The high strength aerospace steel alloyed with Cr, Mn, Si, Ni, W and Mo was studied. The austenite transformations under continuous cooling conditions were investigated using the dilatometer analysis at the cooling rates 0.1...30 °C/s. The mechanical properties of the studied steel were determined after the conventional quenching and tempering heat treatment. The dependences of the mechanical properties on the tempering temperature were obtained. The novel quenching and partitioning heat treatment was applied to the steel under consideration. The microstructure and the mechanical properties were studied after three different modes of the quenching and partitioning (QP) treatment: single-stage QP, two-stage QP and single-stage QP with subsequent tempering (QPT).


2015 ◽  
Vol 8 (8) ◽  
pp. 225-232 ◽  
Author(s):  
Jingwei Dong ◽  
Qijian Wu ◽  
Wenwen Jiang ◽  
Qi Xu

Author(s):  
Matthew C. Morrison ◽  
Kenneth J. Bateman

The transfer and storage of molten salts are being examined to support electrorefining operations at the Idaho National Laboratory. Two important factors that will need to be considered when removing molten salt from either of the two electrorefiners are (1) how to remove salt in a safe and timely manner and (2) how to store significant amounts of electrorefiner salt. A Vacuum Induced Salt Transfer and Storage (VISTAS) system is being evaluated to address these two important factors. This process draws a vacuum in a container through the use of a venturi vacuum pump. The end of a heated drawtube is inserted into the molten salt bath and the molten salt is pulled into the container. A redundant level switch triggered both by the thermal conductivity of the salt and a preset temperature threshold then activates a solenoid, which turns off the argon supply to the venturi vacuum pump, stopping the flow of molten salt. A cooling coil is incorporated into the salt transfer equipment design as a failsafe if the level switch was to fail. A full-scale version of the conceptual design (43 kg capacity) was fabricated to test the vacuum draw salt withdrawal method in an inert argon atmosphere glovebox. In addition, a custom molten salt furnace was designed and fabricated within the glovebox to represent the actual size of an electrorefiner port. Initial testing of the VISTAS system was very successful. The salt was transferred at a consistent rate and the level switch reliably stopped flow. Because the system has a failsafe cooling mechanism, it is considered to have low risk of a salt spill. The container was found to improve storage density, reduce the diffusion of moisture, and reduce material surface area when compared to current options. This system appears to be well suited for this application and further development is recommended.


2016 ◽  
Vol 851 ◽  
pp. 615-619 ◽  
Author(s):  
Zhi Ling Wang

With the development of social information in the background of big data, this paper gives the practical problems in the construction of network course of "metal materials and heat treatment". The aim of the study established on the basis of the Internet will provide us more comprehensive supports and services, and more friendly practical systems in teaching. Our research will build a public open platform for the cultivation of high-quality talents and the promotion of lifelong learning process. This paper has focused on the theoretical value of the network course construction, construction objectives, the content and advantages of the construction. The results of this paper are helpful to improve the teaching effects of the course of "metal materials and heat treatment" in vocational colleges.


Author(s):  
M. Ahmadi Najafabadi ◽  
J. Teymuri Shandi

Acoustic emission (AE) has been known as an excellent technique to monitor crack propagation and fracture mechanism. For more domination on AE behavior of materials, comprehensive knowledge on effective parameters is necessary. Heat treatment as one of the important factors on AE characteristics of a material must be considered. This investigation is primarily aimed at studying the effect of tempering heat treatment on characteristics of acoustic emission signals monitored during tension tests of a cold-work tool steel. Single edge notched samples of AISI D2 cold-work tool steel were prepared. Then, respectively annealing, austenitizing and tempering were performed. Tempering was carried out at 5 different temperatures from 0 to 575 C. Finally, samples were loaded at tension and AE signals recorded synergistically. Analyzing of the characteristics of AE signals showed that: (a) In all tempering conditions, the AECC increases slowly at the beginning and rapidly at the point of crack growth, although at higher tempering temperatures we have gradual rise in AECC plot; (b) Increasing tempering temperature, average value of AE count number, amplitude, energy and peak frequency decreases; (c) At 525 C, because of secondary hardening, average value of investigated AE parameters increase strongly and (d) analyzing the relation between fracture mode, AE characteristics and tempering temperature showed that special AE behavior of specimens tempered at 525 C is because of the transformation of retained austenite in ferritic matrix.


Author(s):  
Max Böhnke ◽  
Moritz Rossel ◽  
Christian R. Bielak ◽  
Mathias Bobbert ◽  
Gerson Meschut

AbstractIn order to reduce fuel consumption and thus pollutant emissions, the automotive industry is increasingly developing lightweight construction concepts that are accompanied by an increasing usage of aluminum materials. Due to poor weldability of aluminum in combination with other materials, mechanical joining methods such as clinching were developed and established in series production. In order to predict the relevant characteristics of clinched joints and to ensure the reliability of the process, it is simulated numerically during product development processes. In this regard, the predictive accuracy of the simulated process highly depends on the implemented friction model. In particular, the frictional behavior between the sheet metals as well as between the sheet metal and clinching tools has a significant impact on the geometrical formation of the clinched joint. No testing methods exist that can sufficiently investigate the frictional behavior in sheet materials, especially under high interface pressures, different relative velocities, and long friction paths, while allowing a decoupled consideration of the test parameters. This paper describes the development of further testing concepts based on a proven tribo-torsion test method for determining friction coefficients between sheet metal materials for the simulation of clinching processes. For this purpose, the correlation of interface pressure and the relative velocity between aluminum and steel sheet material in clinching processes is investigated using numerical simulation. Based on these findings, the developed concepts focus on determining friction coefficients at interface pressures of the above materials, yield stress, as well as the reproduction of the occurring friction conditions between sheet metal materials and tool surfaces in clinching processes using tool substitutes. Furthermore, wear investigations between sheet metal material and tool surface were carried out in the friction tests with subsequent EDX analyses of the frictioned tool surfaces. The developed method also allows an optical deformation measurement of the sheet metal material specimen by means of digital image correlation (DIC). Based on a methodological approach, the test setups and the test systems used are explained, and the functionality of the concepts is proven by experimental tests using different sheet metal materials.


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