what factors influence cracking of heat treated steel gears? how can we prevent cracks in heat treatment.\nhow can we predict cracks in heat treatment of steel components? how can we simulate heat treatment?
124163
Uneven heating and cooling causes internal stresses which lead to cracking. To prevent or reduce it the part could be designed so that heat would flow through it more evenly thus reducing the thermal stresses.
55591
What will work for you depends a lot on what the material to be coated is, on the application, time spent at temperature, heat cycling, peak temperatures, etc.\n\nHere's a non-ablative coating for metals that can withstand sustained temperatures of 850ºC (1560ºF) and thermal shocks from 1030ºC (1885ºF) immediately to a cold water bath:\n\nhttp://www.indestructible.co.uk/cat2/PL134-R1.html
237997
Friction, Heat generated to name 2 reasons.
48703
Most corrosion is on the outside so it really doesn't make a difference, hot or cold. What determines corrosion is the \nenvironment outside of the pipe.
457317
Usually mechanical joints cause localized stress risers. If the joints are not carefully engineered and fabricated, the stress risers will cause decreased fatigue resistance.\n\nIt's a rule of thumb, not a mathematical proof. A lightly-loaded structure with joints may be more fatigue-resistance than a heavily-loaded continuous structure. A well-designed joint with correct stress relief and correct fabrication is likely to be less of a problem than a sharp corner machined into a part, even if they both carry equal load.
471512
R&D Projects\nAdvanced Computations\n\n \n\nAlloy Selection System for Elevated Temperatures (ASSET)\n \nMany aspects of equipment design and operation as well as alloy selection and design are influenced by the expected lifetimes of equipment in high-temperature, corrosive gases.  Currently, many processes are limited by the inability to predict corrosion rates for equipment used in high-temperature processes. A new database is being developed to enhance the ability of the chemical industry to predict corrosion of commercial alloys.  Benefits in improving the ability to manage corrosion data for alloys in high temperature, corrosive gases will be far reaching in the chemical industry.   Better characterization of alloys under operating conditions will result in reduced energy use and maintenance, increased process safety, cost-effective use of expensive alloys in equipment designs, and improved productivity.   \n\nASSET will be an alloy selection and corrosion prediction system that includes a database linked to thermomechanical calculation programs.  The linked programs will use experimentally measured corrosion data obtained under well-controlled conditions to predict the corrosion rates for commercial alloys.   This project will include data on an extensive list of alloys exposed to a wide range of complex and corrosion gases for temperatures of 250 to 1,150oC.  The considerations being used to generate the corrosion data include oxidation, sulfidation, sulfidation/oxygenation and carburization.  The approach to this project includes improving and expanding the ASSET system and training participating companies in its use.
668484
You should know, AS A STRUCTURAL ENGINEER, that steel has a melting point at about 2750 degrees farenheit.\n\nYou should know, AS A STRUCTURAL ENGINEER, that steel loses half of its strength at about 1100 dg farenheit, and at 1800 dg F it loses about 90% of its strength.\n\nJet fuel does not burn hot enough (800-1500 dg F) to MELT the steel, and the towers did not come down because the jet fuel melted the steel.  The jet fuel burned off in a matter of minutes, but it was the ignition source for other combustible material, that heated the steel enough to weaken it and cause the structural failure.  Official investigation reports that pockets of the rubble were burning at about 1832 dg Farenheit.\n\nAS A STRUCTURAL ENGINEER, you should also know that a "pancaking" EFFECT is the result of structural failure of the floor support system, and can be caused by many forms of structural catastrophe, including weakened support by fire, physical damage, etc.  The CAUSE of those things can be planes slicing through steel, fires, and yes demolition teams destroy support systems to bring down buildings as well.\n\nJust because the effect is the same doesn't mean the cause is the same.  Of course, you already knew that because YOU'RE A STRUCTURAL ENGINEER, right?\n\nAS A STRUCTURAL ENGINEER, you should know how the towers were constructed and study the report before you make conclusions agreeing with a conspiracy theory.\n\nDo your homework with facts, not conspirasites.  It will serve your career better.
61241
From what I know about permanent magnets, the heat is the killer when you get near the transistion temperature of the material.  When you do this, the magnetic domains become randomly aligned again and the pole force gets reduced.  If you keep heating it, you can totally demagnatize the material.  In fact, during the manufacturing process, the material is heated very hot under a very strong magnetic field and cooled, allowing the aligned domains to be "frozen" making a high force pole.  \n\nSo in motor design, the aerodynamics of the rotor, the eddy currents generated while running, and the torque loads, will all contribute to heating the magnets.  If you can master the thermal design, you can make very powerful motors.
113423
when something gets too cold\nexample: at room temps, steel is tough, can be bent but not break, welded, and hammered. when you get it cold enough, and hit it with a hammer, it would shatter just like a glass window.
193387
I've broken several graphite shafts.  Steel shafts are better if you are younger, or stronger with a faster swing speed.  Steel provides a heavier club, and better feel for what the clubhead is doing, and what happens at contact.  Graphite tends to dampen vibrations from contact, break if abused, and be too light for me to have a consistent swing.
272569
1.  Steel weakens long before it melts.  Melting is the point of turning to liquid, just like we learned in science class.\n\nJet fuel burns at 800° to 1500°F, not hot enough to melt steel (2750°F). However, experts agree that for the towers to collapse, their steel frames didn't need to melt, they just had to lose some of their structural strength--and that required exposure to much less heat. "I have never seen melted steel in a building fire," says retired New York deputy fire chief Vincent Dunn, author of The Collapse Of Burning Buildings: A Guide To Fireground Safety. "But I've seen a lot of twisted, warped, bent and sagging steel. What happens is that the steel tries to expand at both ends, but when it can no longer expand, it sags and the surrounding concrete cracks."\n\n"Steel loses about 50 percent of its strength at 1100°F," notes senior engineer Farid Alfawak-hiri of the American Institute of Steel Construction. "And at 1800° it is probably at less than 10 percent." NIST also believes that a great deal of the spray-on fireproofing insulation was likely knocked off the steel beams that were in the path of the crashing jets, leaving the metal more vulnerable to the heat.\n\nBut jet fuel wasn't the only thing burning, notes Forman Williams, a professor of engineering at the University of California, San Diego, and one of seven structural engineers and fire experts that PM consulted. He says that while the jet fuel was the catalyst for the WTC fires, the resulting inferno was intensified by the combustible material inside the buildings, including rugs, curtains, furniture and paper. NIST reports that pockets of fire hit 1832°F.\n\n"The jet fuel was the ignition source," Williams tells PM. "It burned for maybe 10 minutes, and [the towers] were still standing in 10 minutes. It was the rest of the stuff burning afterward that was responsible for the heat transfer that eventually brought them down."\n\n2.  Towers & WTC came down like engineered demolition: Yes, it was LIKE a demolition, however just because the effect is the same does not mean the cause is the same. The pancaking effect is the result of structural failure of floor support system, and can be caused by numerous forms of structural catastrophe, including weakened support by fire.  \n\nJust because you don't like the magazine means that all of his sources were bogus and none of it makes sense right? I am an engineer, and I know that the simplest explanation is usually correct. Show me someone who knows what he/she is talking about, who knows about structural design, structural failure, fire-rated assemblies, and maybe they will have some credibility, unlike the "internet investigators" who read someone else's "explanation" and don't question it.\n\nThat's a contradiction in itself. They question the official 9/11 story, but don't question the conspiracy theories. Have a mind of your own, and do the research both ways.
531782
force required would be area under shear stress multiplied by the shear stress value(tau) of a particular material, in this case steel.\n\nthe first question is easy. the required area is the cross sectional area of that bolt. pi(r)². please substitute r in meters only.\n\nfor the second question, the shear area is not the area of the circle plate but the area of the ring around it. this area is effectively a rectangle, and can be calculated by multiplying the circle's circumference (2pi x r) by the thickness of the circle (0.0058m).
544079
there are various factors which affects rate of reaction. like temperature,pressure and concentration of the reactants involved. and they all have different effects
104285
The type of plastic selected has a great influence on the performance of the plated plastic part. ABS plastics are the base materials in most cases.\n\nCheck out the following:
443876
First, here is a back drop of info to help you determine wether brazing or soldering will be msot effective for you. \n\nBrazing use molten metal to join two pieces of metal, yes. However, the metal added during the process has a melting point lower than that of the workpiece, so only the added metal is melted, not the workpiece. \n\nSoldering uses metals with a melting point below 800 degrees Fahrenheit; brazing uses metals with a higher melting point. Because soldering and brazing do not melt the workpiece, these processes normally do not create the distortions or weaknesses in the workpiece that can occur with welding. \n\nSoldering commonly is used to join electrical, electronic, and other small metal parts. Brazing produces a stronger joint than does soldering, and often is used to join metals other than steel, such as brass. Brazing can also be used to apply coatings to parts to reduce wear and protect against corrosion.\n\nI recommend copper or aluminum for your small project.
595508
All of the above.\n\nActually even Magnetism is affected by heat.  Heat a magnet and it will lose its magnetism.\n\nChemical composition will also change.
598585
Good Morning!  Saw this one and had to try my hand.  If the "knob" is not screwing down all the way?  and there is thread damage to the parts?  That is called cross-threading.  Some also refer to this as "galling".  In some situations?  the thread "pitch" of one part could differ from the other causing the problem as well.  Hope this helps in some small way!  Hyway.