scholarly journals Development of a Technology of Isothermal Annealing With the Use of the Forging Heat for Chromium-Molybdenum Steel

2020 ◽  
Author(s):  
Artur Barełkowski ◽  
Roman Kuziak
Keyword(s):  
Heat Treatment ◽  
Isothermal Annealing ◽  
Test Results ◽  
Repeated Heating ◽  
Industrial Practice ◽  
Forging Process ◽  
Molybdenum Steel ◽  
Processing Line ◽  
Heat Released ◽  
Grade Steel

The article discusses the results of investigations performed during a thermo-mechanical treatment of forgings made of chromium-molybdenum 42CrMo4 grade steel. The treatment was realized during a regular series production. The forging process was combined with a heat treatment carried out directly after forging on a specially adapted station. Such a production technology will make it possible to eliminate the step of repeated heating of the forgings. On the example of an element of a steering gear, it was demonstrated how it is possible to perform an isothermal annealing process starting from the temperature at which the trimming of the forgings ends. During the cooling of the forgings, it is enough to maintain the temperature at the proper level in order for the exothermal phase transformation of austenite into pearlite to take place. With an appropriate design of the processing line, the heat released during the transformation could be used to maintain the applied temperature, thus limiting the consumption of energy needed to power the devices. The test results show that, with the properly selected temperature of isothermal annealing, it is possible to obtain an equilibrial ferritic-pearlitic structure in the required hardness scope. Introducing such a solution into the industrial practice would allow significant savings of the energy used for the heat treatment.

Mechanical Properties and Microstructure of Aluminum Alloy Al-6061 Obtained by the Liquid Forging Process

2010 ◽  
Vol 654-656 ◽  
pp. 1420-1423 ◽  
Author(s):  
Chun Wei Su ◽  
Peng Hooi Oon ◽  
Y.H. Bai ◽  
Anders W.E. Jarfors
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aluminum Alloy ◽  
Treatment Process ◽  
Forging Process ◽  
Al 6061 ◽  
Casting Alloys ◽  
Suitable Heat Treatment ◽  
Structural Applications ◽  
Wrought Aluminum

The liquid forging process has the flexibilities of casting in forming intricate profiles and features while imparting the liquid forged components with superior mechanical strength compared to similar components obtained via casting. Additionally, liquid forging requires significantly lower machine loads compared to solid forming processes. Currently, components that are formed by liquid forging are usually casting alloys of aluminum. This paper investigates the suitability of liquid forging a wrought aluminum alloy Al-6061 and the mechanical properties after forming. The proper handling of the Al-6061 alloy in its molten state is important in minimizing oxidation of its alloying elements. By maintaining the correct alloying composition of Al-6061 after liquid forging, these Al-6061 samples can subsequently undergo a suitable heat treatment process to significantly improve their yield strengths. Results show that the yield strengths of these liquid forged Al-6061 samples can be increased from about 90MPa, when they are in the as-liquid forged state, to about 275MPa after heat treatment. This improved yield strength is comparable to that of Al-6061 samples obtained by solid forming processes. As such, the liquid forging process here has been shown to be capable of forming wrought aluminum alloy components that has the potential for structural applications.

Comparison between Charpy Transition Temperature TCVN and Reference Temperature T° for 10Ni3CrMoV Steel

2007 ◽  
Vol 539-543 ◽  
pp. 4488-4493
Author(s):  
Yi Fei Gao ◽  
Jun Chang Shen ◽  
Bo Qun Wu
Keyword(s):  
Heat Treatment ◽  
Transition Temperature ◽  
Material Design ◽  
Reference Temperature ◽  
Test Results ◽  
Test Technique ◽  
Fracture Appearance Transition Temperature ◽  
Qt Steels ◽  
Fracture Appearance ◽  
Lower Tolerance

Charpy transition temperature TCVN and reference temperature To for 10Ni3CrMoV steel were determined using two different experimental techniques such as Charpy V-notch impact test technique and reference temperature To test technique. It was found that two methods provided different test results. The median master curve with upper and lower tolerance bounds was got from the test. The upper tolerance bound is often used for material design and application. At the same time the TCVN and To results were discussed for two kinds of heat treatment which are QT(Quenching and Temper) and QLT(Quenching, anneal and temper). JC (med ) K values calculated were 101 and 105MPam1/2 for the QT and QLT steels, respectively. These indicated that the QLT steels have the higher JC (med ) K , the lower reference temperature and lower energy (or fracture appearance) transition temperature(ETT50 or FATT50) than the QT steels. This was mainly related with the different microstructures of two kinds of heat treatment.

Weldability and Post Weld Heat Treatment of T23 Boiler Grade Steel

2017 ◽  
Vol 4 (2) ◽  
pp. 168-171
Author(s):  
M.Mohandas Pravin kumar ◽  
M.Deepak Kumar ◽  
V. Karthik
Keyword(s):  
Heat Treatment ◽  
Post Weld Heat Treatment ◽  
Grade Steel ◽  
Weld Heat

scholarly journals Heat treatment effect on metal matrix composite with brass matrix and fly ash

2018 ◽  
Vol 204 ◽  
pp. 05020
Author(s):  
Aminnudin Aminnudin ◽  
Moch. Agus Choiron
Keyword(s):  
Heat Treatment ◽  
Fly Ash ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Coal Combustion ◽  
Metal Matrix ◽  
Treatment Process ◽  
Impact Test ◽  
Test Results ◽  
The Matrix

Metal matrix composite (MMC) is a combination of two or more materials using metal as a matrix. In this paper we used brass as the matrix and fly ash as for the particle. The fly ash used is fly ash which is produced from coal combustion in the Paiton power plant. Fly ash composition in the MMC are 5% and 10%. The MMC was produced with gas furnace. Heat tratment to MMC was done at 350 and 400 °C.Hard testing process, tensile test and impack test are carried out at MMC before heat treatment and after heat treatment. From the test results showed an increase in hardness, tensile strength and impact test showed the heat treatment process at a temperature of 350 °C. Heat treatment at a temperature of 400 °C does not improve the mechanical properties of MMC

scholarly journals Two-Phase Numerical Modeling of Grade Intermixing in a Steelmaking Tundish

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 40 ◽  
Author(s):  
Md Irfanul Haque Siddiqui ◽  
Man-Hoe Kim
Keyword(s):  
Numerical Simulation ◽  
Three Dimensional ◽  
Interface Tracking ◽  
Residual Volume ◽  
Two Phase ◽  
Throughput Rate ◽  
Industrial Practice ◽  
Outflow Rate ◽  
Major Trend ◽  
Grade Steel

The sequential casting of slabs is a major trend in the steel industry where steel quality is the most important factor. The operating parameters have the most influence on mixing phenomenon apart from the design and shapes of the tundish and its furniture. Moreover, in industrial practice, the bath height in tundish varied with time when the ladle is changed. In the present work, the numerical simulation has been carried out to study the effect of residual volume and outflow (throughput) rate on the mixing phenomenon inside the tundish. A transient, three-dimensional two-phase model using the Volume of Fluid (VOF) method and Level Set interface tracking method has been used to investigate the intermixed grade steel formation. A comparison of the two interface tracking schemes, i.e., Geo-reconstruct and Modified HRIC (High-Resolution Interface Capturing Scheme) has also been presented. The results obtained through numerical simulation has been compared with experimental results. In a later section, the results showed that residual volume has a significant effect on the grade mixing. The mixing phenomenon in tundish is considerably influenced by the advance-pouring box (APB). Further, the outflow rate of tundish has little impact on the grade intermixing phenomenon.

Research into the Flow Stress of Al-Mg-Si Alloy (AD-35) during the Abrupt Change of the Strain Rate at Elevated Temperatures

2013 ◽  
Vol 554-557 ◽  
pp. 1099-1104 ◽  
Author(s):  
Pavel A. Petrov ◽  
Viktor Voronkov ◽  
Konstantin Potapenko ◽  
Mikhail Petrov ◽  
Olga Gamzina
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Elevated Temperatures ◽  
Abrupt Change ◽  
Hot Forging ◽  
Experimental Investigations ◽  
Engineering Strain ◽  
Industrial Practice ◽  
Transient Change ◽  
Forging Process

In industrial practice of rolling and hot forging, i.e. extrusion-type forging, abruptchanges in strain rate during the deformation of the material occur. For accurate numericalsimulation of a forging process, the experimental investigation of the effect of the transient changein strain rate on plastic flow behaviour is necessary. The present paper deals with the investigationof this effect on the flow stress of an AD-35 aluminium alloy during its deformation within thetemperature range of 350-450 °C. During continuous uniaxial compression loading of a cylindricalspecimen, the strain rate was either constant or abruptly increased or decreased from its initial valueat engineering strain of app. 26 %. The following strain-rate histories were applied: 1) constantstrain rate of 0.1, 1.0 and 10 s-1; 2) abrupt strain-rate increasing from 1.0 to 10.0 s-1; 3) abrupt strainratedecreasing from 10.0 to 1.0 s-1. The results of the experimental investigations corresponded tothe transient change in strain rate histories were used to verify the model of softening as well as themodel of hardening of the AD-35 alloy during the abrupt change of the strain rate. It allows todefine these models explicitly.

Failure analysis of heat treated HSLA wheel bolt steels

2010 ◽  
Vol 6 (3) ◽  
pp. 373-382
Author(s):  
Ali Nazari ◽  
Shadi Riahi
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Failure Analysis ◽  
Heat Treating ◽  
Boron Steel ◽  
Content Type ◽  
Heat Treated ◽  
Before And After ◽  
Molybdenum Steel ◽  
Optimum Heat

PurposeThe aims of this study is to analyze failure of two types of high‐strength low‐alloy (HSLA) steels which are used in wheel bolts 10.9 grade, boron steel and chromium‐molybdenum steel, before and after heat treatment.Design/methodology/approachThe optimum heat treatment to obtain the best tensile behavior was determined and Charpy impact and Rockwell hardness tests were performed on the two steel types before and after the optimum heat treating.FindingsFractographic studies show a ductile fracture for heat‐treated boron steel while indicate a semi‐brittle fracture for heat‐treated chromium‐molybdenum steel. Formation of a small boron carbide amount during heat treating of boron steel results in increment the bolt's tensile strength while the ductility did not changed significantly. In the other hand, formation of chromium and molybdenum carbides during heat treating of chromium‐molybdenum steel increased the bolt's tensile strength with a considerable reduction in the final ductility.Originality/valueThis paper evaluates failure analysis of HSLA wheel bolt steels and compares their microstructure before and after the loading regime.

scholarly journals False positive antigen test for Dirofilaria immitis after heat treatment of the blood sample in a microfilaremic dog infected with Acanthocheilonema dracunculoides

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Viktor Szatmári ◽  
Martin Willem van Leeuwen ◽  
Christine Jantine Piek ◽  
Luigi Venco
Keyword(s):  
Heat Treatment ◽  
Blood Sample ◽  
Real Time ◽  
Real Time Pcr ◽  
False Positive ◽  
Dirofilaria Immitis ◽  
False Negative ◽  
Correct Identification ◽  
Test Results ◽  
Antigen Test

Abstract Background Dirofilaria immitis is responsible for heartworm disease in dogs in endemic areas worldwide. Screening for this infection is done by blood tests. Antigen testing is the most sensitive method to detect an infection with adult (female) worms. Microscopic examination of a blood smear or Knott’s test can be used to detect circulating microfilariae, the infective larvae. To increase the sensitivity of the antigen test by decreasing the false negative test results, heating of the blood sample has been recommended in recent guidelines. Heating is believed to remove blocking immune-complexes. Circulating microfilariae are not specific findings for heartworm infection, as other nematodes (among others, Acanthocheilonema dracunculoides) can also result in microfilaremia. Although the type of microfilariae cannot be determined by microscopy alone, real-time PCR can reliably identify the infecting nematode species. Correct identification of the parasite is of major importance, as an infection with D. immitis requires antiparasitic therapy, whereas A. dracunculoides is thought to be a clinically irrelevant coincidental finding. The present case report describes a microfilaremic dog where the initial antigen test for D. immitis turned positive after heat treatment, whereas real-time PCR revealed that the microfilariae were A. dracunculoides (syn. Dipetalonema dracunculoides). Results A circa 5-year old, asymptomatic Spanish mastiff dog was referred for heartworm therapy because microfilariae were found via a screening blood test. The dog was recently imported to the Netherlands from Spain, where it had been a stray dog. Antigen tests on a plasma sample for D. immitis were performed with three different test kits, which all turned out to be negative. However, heat treatment of two of these samples were carried out and both of them led to a positive antigen test result. Real-time PCR showed that the circulating microfilariae belonged to A. dracunculoides species. Three administrations of moxidectin spot-on at monthly intervals resulted in a negative antigen and a negative Knott’s tests one month after the last treatment. Conclusions We conclude that heat treatment of initially negative blood samples for D. immitis could lead to false positive antigen test results if the dog is infected with A. dracunculoides.

Incidence and Recovery of Salmonellae and Other Bacteria from Commercially Processed Poultry Carcasses at Selected Pre- and Post-Evisceration Steps

1989 ◽  
Vol 52 (2) ◽  
pp. 88-91 ◽  
Author(s):  
H. S. LILLARD
Keyword(s):  
False Negative ◽  
Aerobic Bacteria ◽  
Processing Plant ◽  
Test Results ◽  
Negative Test ◽  
Commercial Plant ◽  
Sampling Points ◽  
Processing Line ◽  
False Negative Test ◽  
Progressive Sampling

This study was undertaken to determine whether bacteria are already attached to poultry skin when birds arrive at the processing plant. Multiple rinses were performed on breast skin and whole carcasses taken from five processing points in a commercial plant: Before scalding, after scalding, after picking, after the final washer, and from the exit end of the chiller. Aerobic bacteria and Enterobacteriaceae were recovered from carcasses in up to 40 consecutive whole carcass rinses with a difference of only about one log for Enterobacteriaceae, and 1 to 2 logs for aerobes from the first to the last rinse of carcasses taken from the beginning and the end of the processing line. Data from rinses prior to scalding indicated that bacteria were firmly attached to poultry carcasses when they first arrived in the plant. Not all bacteria were removed during processing; however, there were fewer aerobes and Enterobacteriaceae at progressive sampling points. Attached salmonellae were not always recovered in the first whole carcass rinse, but were sometimes recovered in 3rd, 5th, and 10th rinses. These data show that a single whole carcass rinse can result in false negative test results for salmonellae. Because of the small number of positive samples in this study, the probability of recovering salmonellae with a single whole carcass rinse could not be estimated accurately.

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