why does steel stay hot longer than aluminum?
599695
Aluminum is 2.9 times as dense as iron. On the other hand, iron has roughly half the specific heat as aluminum.\n\nSpecific heat is measured in terms of how many calories of energy it takes to raise the temperature of one gram one degree centigrade. \n\nGiven two equal masses of aluminum and iron, the aluminum with the higher specific heat will take more energy to heat and give of more energy cooling. As a result, it will take longer to heat and cool. \n\nHowever, given two equal volumes of aluminum and iron, the aluminum will have only 1/3 the mass and therefore will need throw off only 2/3s as much heat to cool as the iron.
131979
a soft iron core increases the strength of an electromagnet, because iron a good conductor of electricity, and unlike steel it can be turned on and off, whereas steel is a permanant electromagnet.
149897
Depends on the temperature. At a guess at melting point not that different from solid aluminum.
262490
Steel is made in a mill.  It is an alloy of iron and some other element (which element varies).
1050458
Metals have a much higher thermal conductivity than similar non-metals.  This is because, in addition to the transport of heat by atomic vibration, heat is also carried very efficiently by the mobile electrons.  The electrons in a metal create something called an electron gas, and this gas actually has a temperature.  The electrons in this gas are free to move around carrying heat with them, and the electron gas heats the bulk of the metal.\n\nNote that it is not the individual electrons which are "hot", it is the statistical properties of huge numbers of electrons all moving at once that leads to us calling the electron gas "hot".  In a hot electron gas, some electrons are in a higher energy state than they need to be because there are empty quantum states at lower energies that can accept them.  The electrons can drop into those states by giving up some kinetic energy to an atomic nucleus, effecitvely injecting heat into the system at that point.  When you heat up one part of the metal, that heat kicks electrons out of their lowest energy states, making a hole that another electron can drop into, and the effect is that heat is moved from one part of the metal to another.\n\nNon-metallic solids do not have this electron gas conduction mechanism, so thermal conductivity in those substances is generally much lower.
413110
because they are made of steel
1186584
The hotter the surface gets the more resistance. It is a solid state item.
223614
copper and aluminum are best electricity conductors. I would say lead, since it's one of the densiest material out there. Heat is caused by vibrating atoms, denser material means the atoms are closer, and it's melting point is low too. As soon as you touch it with a hot soldering iron, the heat transfers right away and melts it.
1090476
Iron (like steel and certain alloys) contains atomic magnets or dipoles which can line up their 'magnetic axes' in a preferred direction.  In the magnetized state, all the magnetic axes will point in one specific direction, by which the iron filling will show polarity and hence be a magnet itself.\nWhen you heat the iron fillings, the high temperature makes the atoms to vibrate with increasing energy and this disturbs the dipoles and so the resultant magnetic axes point in their 'preferred' random directions, which keep changing due to the extra energy. If the iron fillings were magnetized before heating, all the magnetism would be lost. Magnetizing them after heating will not align the vigorously vibrating atomic magnets and rapidly changing magnetic axes.
930462
Steel is a metal alloy whose major component is iron, with carbon content between 0.02% and 1.7% by weight. Carbon is the most cost effective alloying material for iron, but many other alloying elements are also used.[1] Carbon and other elements act as a hardening agent, preventing dislocations in the iron atom crystal lattice from sliding past one another. Varying the amount of alloying elements and their distribution in the steel controls qualities such as the hardness, elasticity, ductility, and tensile strength of the resulting steel. Steel with increased carbon content can be made harder and stronger than iron, but is also more brittle. The maximum solubility of carbon in iron is 1.7% by weight, occurring at 1130° Celsius; higher concentrations of carbon or lower temperatures will produce cementite which will reduce the material's strength. Alloys with higher carbon content than this are known as cast iron because of their lower melting point. Steel is also to be distinguished from wrought iron with little or no carbon, usually less than 0.035%. It is common today to talk about 'the iron and steel industry' as if it were a single thing; it is today, but historically they were separate products.\n\nSteel is often classified by its carbon content: a high-carbon steel is serviceable for dies and cutting tools because of its great hardness and brittleness.\n\nlow- or medium-carbon steel is used for sheeting and structural forms because of its amenability to welding and tooling. \n\nAlloy steels, now most widely used, contain one or more other elements to give them specific qualities. \nAluminum steel is smooth and has a high tensile strength. \n\nChromium steel finds wide use in automobile and airplane parts on account of its hardness, strength, and elasticity, as does the chromium-vanadium variety. \n\nNickel steel is the most widely used of the alloys; it is nonmagnetic and has the tensile properties of high-carbon steel without the brittleness. \n\nNickel-chromium steel possesses a shock resistant quality that makes it suitable for armor plate. \n\nWolfram (tungsten), molybdenum, and high-manganese steel are other alloys. \n\nStainless steel, which was developed in England, has a high tensile strength and resists abrasion and corrosion because of its high chromium content.
812339
Chrome-moly steel has a density of 7.9g/cc, with an ultimate strength of 520MPa, and a modulus of 200GPa. \n\nTitanium (Ti3Al2.5v) has a density of 4.48g/cc, ultimate strength of 620Mpa, and modulus of 100GPa. \n\nThis means that the titanium is a lot lighter (over 40%), a little stronger (20%), but less stiff (by 50%). A titanium frame will flex a bit more than a steel frame, but that acts as a shock dampener and makes the ride a lot more comfortable. \n\nAluminum (assuming generic) has a density of about 2.8g/cc, ultimate strength of 425MPa, and a modulus of 73GPa. \n\nSo aluminum is actually a lot lighter than titanium, but it is weaker and less stiff (more flexible). \n\nHowever, these numbers are bulk properties, and do not take into account design differences with bike frames. A titanium bike frame will usually be lighter than an aluminum bike frame because you don't have to use as much metal to get the same strength and stiffness with titanium as you would have to do with aluminum and steel. \n\nIt's a LOT more expensive, so unless this is for a racing bicycle, a titanium frame will not be worth the expense.
1134140
Depends on the thermoconductive properties of a certain material. Copper for example will heat up or cool down very fast.
126297
You haven't provided us with enough information. This is a steel beam, not an iron beam. Steel can be an infinite number of different compositions and even different alloys. Each will respond differently to chnegs in temperature.
686314
"Hot" is a very subjective word.  How "hot" is "hot"? 100 degrees C? 500 degrees C?\n\nWhen an object absorbs heat energy its temperature rises, there is no way around it.  But for a given quanity of heat energy (Q) absorbed, some materials will increase in temperature (delta T) more than others.\n\nThe term "Specific Heat" (c) releates the amount of energy needed to raise 1 gram of a substance 1 degree C.\n\nQ = m*c*(delta T)\nHeat enegry = mass of the object * the specific heat * change in temperature\n\nA higher specific heat means that the material will experience a relatively smaller change in temperature for a given amount of heat as compared to another material with a higher specific heat.\n\nUsually, metals tend to have somewhat low specific heats but there are some metals which are higher than others.\nFor instance,...\n-Iron has a specific heat of .444 J/g degree C\n-Copper has a specific heat of .385 J/g degree C\n-Lithium metal (not that this is a practical building material) has a specific heat of 3.582 J/g degree C\n-liquid water's c = 4.184 J/g degree C\n\nmore complete tables of specific heat can heasily be found on the internet.
83439
Because water has a high SPECIFIC HEAT VALUE (C=J/gC) which just means that it can absorb a realitivy high ammount of heat (J=jouls) and keep its overall mass (g=grams) about the same temperature (C=celsius)\n\nits like 4.186 J/gC or somin i think, which is very high, while steel is only .113 J/gC
959853
The atoms of iron begin to move at a more rapid pace, causing the material to expand.  Once it expands enough there is so much energy that it can turn into liquid form, allowing it to flow freely so long as another force isn't standing in it's way.  The same thing happens to all matter when heated up.  You may even notice that the metal will begin to glow.  This is because of radiation in the form of photon particles.  It will also become highly ductile and maliable, which are two characteristics that iron have.  Heck, if iron were to be heated up far enough it could even become a gas.  However, I doubt you would ever be able to do it without both heat and compression with current technology.  You might even cause the gasses in the atmosphere around it to gain enough energy to start a fusion reaction, which could cause one yucky mess out of our atmosphere if they don't cool down.
607505
Aluminum DOES rust; it just isn't like iron rust. Aluminum oxide (chemical formula Al2O3) forms a thin film on the outside of the aluminum. \n\nSome people say, figuratively, that we have never really seen aluminum, because the oxide coating forms so quickly; (I have to disagree with what someone else wrote above) you can't scratch aluminum and then see the true color before the oxide covers it.\n\nAl2O3 is chemically the same as sapphire, it is very hard and strong. Once the coating has formed on the surface, it protects the rest of the aluminum in the bulk of the piece, so it doesnt corrode away. The coating is very thin, though-- only one molecule thick-- so we don't notice it and it doesn't really add any structural strength to the aluminum. \n\nBy contrast, iron rust is very weak. It crumbles and falls apart very easily; it can't even support its own weight. So it breaks off the surface of the iron and leaves fresh iron exposed to rust. That is why bridges and girders fall alart if they are not painted or protected from the elements. But aluminum protects itself.