Determination of the optimum preheat temperature in hardfacing hypereutectoid steels

2018 ◽  
Vol 32 (12) ◽  
pp. 748-749
Author(s):  
A. N. Belyaev
Keyword(s):  
Preheat Temperature ◽  
Hypereutectoid Steels

Weldability Investigation of Temper-Grade Steels

2008 ◽  
Vol 589 ◽  
pp. 31-35
Author(s):  
Gábor Lengyel ◽  
Béla Palotás
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Heat Conduction ◽  
Heat Affected Zone ◽  
Three Dimensional ◽  
Cold Cracking ◽  
Crucial Importance ◽  
Preheat Temperature ◽  
Wide Range

The mechanical properties of temper-grade steels can be modified in a wide range by heat treatment. The principle of heat treatment lies in the good hardenability, so when such steels are welded it is very likely that the heat affected zone is hardened. Considering the fact that in the case of design simplifications it may be needed to weld temper-grade steels, as well therefore it is of crucial importance to eliminate cold cracking. There are many methods available to determine preheat temperature. The applicability of methods for determination of preheat temperature was checked by experimental welding for both two and three dimensional heat conduction. According to our experience the different methods cannot be applied in general namely they are valid only under certain conditions.

Combustion Research Related to Utilization of Coal as a Gas Turbine Fuel

1984 ◽  
Vol 106 (4) ◽  
pp. 801-805
Author(s):  
D. M. Davis-Waltermire ◽  
R. J. Anderson
Keyword(s):  
Flue Gas ◽  
Atmospheric Pressure ◽  
Gas Turbines ◽  
Combustion Efficiency ◽  
Air Distribution ◽  
Preheat Temperature ◽  
Dependent Variables ◽  
Slurry Viscosity

A nominal 293 kw (1 MBtu/hr) atmospheric pressure, refractory-lined combustor has been used to investigate the effects of a number of combustor and fuel dependent variables on combustion efficiency and flue gas characteristics for minimally cleaned, coal-derived gas (MCG) and coal water mixtures. The variables which have been evaluted include: percent excess air, air distribution, combustion air preheat temperature, swirl number, fuel feedrate, coal particle size, coal loading in slurry, and slurry viscosity. Characterization of the flue gas included major/minor gas species, alkali levels, and particulate loading, size, and composition. These atmospheric pressure combustion studies accompanied by data from planned pressurized studies on coal-water slurries and hot, minimally cleaned, coal-derived gas will aid in the determination of the potential of these fuels for use in gas turbines.

scholarly journals Response Surface Methodology Approach to Recycling Aluminium Chips AA6061 by Optimum Hot Extrusion Parameter

2020 ◽  
Vol 4 (1) ◽  
pp. 1-6
Author(s):  
Syaiful Nizam Ab Rahim ◽  
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Prediction Interval ◽  
Hot Extrusion ◽  
Extrusion Process ◽  
Operating Conditions ◽  
Preheat Temperature ◽  
Rsm Model ◽  
Tensile Strenght

A method for recycling aluminium alloy chips by hot extrusion was studied as well as the possibility of using to recycle aluminium chips. As a result, according to an ANOVA analysis, preheat temperature is the most significant factor influencing the response variables investigated. Preheat temperature and the quadratic effect of factor preheat temperature provided a primary contribution to the responses investigated. Additionally, factor preheat time did not provide a significant contributing factor to the Ultimate Tensile Strenght. This developed the Response Surface Methodology (RSM) model for ER12, which can now be used for analysis and predicting the Ultimate Tensile Strenght for recycling aluminium chip using the hot extrusion process. The Miscellaneous Design and Response Surface Methodology enabled the determination of optimal operating conditions for obtaining hot extrusion production. The optimization of the analyzed responses demonstrated that the best results for hot extrusion process parameter. It reveals the empirical models developed were reasonably accurate, particularly for UTS at 550°C temperature and 3 hours preheating time. All the actual values for the confirmation run are within the 95% prediction interval.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

Distance to SN 1987A and the LMC

1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia
Keyword(s):  
Angular Size ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Distance Modulus ◽  
Absolute Size ◽  
Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

International determination of the total motion of the pole

1961 ◽  
Vol 13 ◽  
pp. 29-41
Author(s):  
Wm. Markowitz
Keyword(s):  
Secular Motion ◽  
The Future

A symposium on the future of the International Latitude Service (I. L. S.) is to be held in Helsinki in July 1960. My report for the symposium consists of two parts. Part I, denoded (Mk I) was published [1] earlier in 1960 under the title “Latitude and Longitude, and the Secular Motion of the Pole”. Part II is the present paper, denoded (Mk II).

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

Large-scale Motion of Solar Filaments

2000 ◽  
Vol 179 ◽  
pp. 205-208
Author(s):  
Pavel Ambrož ◽  
Alfred Schroll
Keyword(s):  
Magnetic Flux ◽  
Proper Motion ◽  
Time Scale ◽  
Large Scale ◽  
Accuracy Of Measurements ◽  
Solar Filaments ◽  
General Movement ◽  
Scale Motion ◽  
Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

Practical Realization of a Reference System for Earth Dynamics by Satellite Methods

1975 ◽  
Vol 26 ◽  
pp. 341-380 ◽  
Author(s):  
R. J. Anderle ◽  
M. C. Tanenbaum
Keyword(s):  
Reference Frame ◽  
Polar Motion ◽  
Pole Position ◽  
Control Points ◽  
Significant Information ◽  
Crustal Motion ◽  
Average Reference ◽  
Future Data ◽  
Existing Data

AbstractObservations of artificial earth satellites provide a means of establishing an.origin, orientation, scale and control points for a coordinate system. Neither existing data nor future data are likely to provide significant information on the .001 angle between the axis of angular momentum and axis of rotation. Existing data have provided data to about .01 accuracy on the pole position and to possibly a meter on the origin of the system and for control points. The longitude origin is essentially arbitrary. While these accuracies permit acquisition of useful data on tides and polar motion through dynamio analyses, they are inadequate for determination of crustal motion or significant improvement in polar motion. The limitations arise from gravity, drag and radiation forces on the satellites as well as from instrument errors. Improvements in laser equipment and the launch of the dense LAGEOS satellite in an orbit high enough to suppress significant gravity and drag errors will permit determination of crustal motion and more accurate, higher frequency, polar motion. However, the reference frame for the results is likely to be an average reference frame defined by the observing stations, resulting in significant corrections to be determined for effects of changes in station configuration and data losses.

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