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14

In short the heat treatments in steel change the phase of iron between the following phases: Austenite Cementite Martensite Bainite Ferrite Perlite. (Actually quenching does not allow low temperature phase changes to occur, so effectively the phases are sort of "frozen" in their high temperature equivalents). Figure 1 : example of continuoous ...


9

The effects of heating-quenching a metal is explained below Transformation hardening is the heat-quench-tempering heat treatment cycle addressed earlier in this article. It's used to adjust strength and ductility to meet specific application requirements. There are three steps to transformation hardening: Cause the steel to become completely austenitic by ...


7

You could try a bath of concentrated acid. As long as you could maintain circulation so the concentration was fairly constant, a spring presents a very uniform cross-section and should be dissolved at a consistent rate. I would recommend keeping one of the springs as a reference so that you can measure the result after a short period and adjust your time ...


6

You are mixing apples and oranges. Many steels harden by rapid cooling, but very few other metals do that; specifically, only aluminum bronze and certain titanium alloys. Many metals will strengthen by age hardening; Rapid cool softens, and then time at a lower temperature strengthens them. There are a myriad of combinations, like HSS (high-speed steels). ...


4

By "strength" do you mean stiffness/modulus? The modulus does not change with tensile or yield strengths. Make it with wire of 1/2 the diameter for 1/2 the modulus. Acid will hydrogen stress crack hardened steel ( This condition has many other names like "embrittlement".). Make it out of aluminum and get 1/3 the modulus or titanium and get 2/3 the modulus ( ...


4

The other answers describe the "materials science" mechanisms of iron vs. temperature. I'm going to add this: Matter "tries" to reach a minimum energy state whenever possible. In general, then, if you cool something as slowly as possible, you'll come closest to a solid which is a perfect crystalline structure. See "annealing."...


3

Another hypothetical way to reduce the amount of material in the spring would be to fix it in a jig stretched to double its normal length. Then, heat it sufficiently to anneal it and remove the tension in it. Then, re-temper it and cut it in half, back to its original length. But just buying a new spring would be a much simpler method.


3

Probably just another hypotetical idea: If you squeeze the wire from circular into a square shape, it will have about 54% of the original rate. If you squeeze it slightly more into a rectangle, it will at some point become 50%. And 1/2 the diameter of the wire does not gie you 1/2 the rate. It would give you 1/16 of the rate. 85% of the diameter gives you ...


3

When searching for 1100 watt heating tape, a number of returns match almost exactly the image you've provided. A few of the manufacturers provide NEMA separable molded plugs and also offer bare leads. The bare leads would be useful in this case, as you can add your own 90° banana plugs. To locate the correct plug, I used "right angle enclosed banana plug" ...


3

In steel hardness is closely related to tensile strength so a hardened steel will have both high hardness and high tensile strength. Toughness is a bit more difficult to quantify than strength but in general is the ability to resist impact and resistance to brittle fractures. Ductility plays a part in toughness as it tends to help a material to resist ...


2

Shrink fitting depend on the fact that you have a shaft and collar which are sized to an interference fit when cold. One problem with aluminium is that you have a fairly narrow window for heating it before it first anneals and then melts. A rough calculation suggests that that change in diameter with heating to 200C is in the order of thousandths of an ...


2

It depends what you want to achieve and what you mean by 'strength'. . Heat treating can be used to increase the yield stress of a hardenable steel (to a greater or lesser extent depending on the alloy and process used). But what it won't do is to increase the stiffness of the part as hardening and tempering have no significant effect on the Young's ...


2

There are three dye-pene types. The cheapest one is likely good enough ;1- A dye is applied ( usually red), 2- allow to soak ,3 - clean off surface dye( May use a cleaner for this ), 4- spray on a white developer: Depending on experience ,very small cracks can be found in any material. The second type of dye-pene uses a fluorescent dye and UV light ; faster ...


2

Solar Mike is exactly right, the method he cites is called dye penetrant and it works for ferrous metals, aluminum alloys, and composites as well. all you need is a bottle of the fluorescent dye, the spray-on developer powder, and a UV light. This will cost less than $100.


2

I would consider perhaps the easiest way would be to change the leverage... Failing that, I would get a new spring made with the details necessary and spare one 10% above and below your "new" value.


2

Temperature resistance is especially useful for machine tools eg drills, lathe tools ect etc. Mechanised cutting generates a lot of heat and equally cutting tools need to be tempered fairly hard for obvious reasons and it is very easy for something like a drill to get well into the normal tempering range of carbon steel, thus losing its original temper. ...


2

This answer is from the riding/cycling side, not an engineering view. If you think of the forces involved on a head tube, then the "static" force ( while it is standing still) is upward through the head tube. The top tube is under compression and the downtube is under tension. When riding, its roughly the same, but there are sideways forces from steering ...


2

While I think the concentrated acid solution is brilliant, I'd like to suggest a refinement. Rather than use just any old acid, you should specifically use a chemical etchant. Typically, a chemical etchant's nucleophile strength does not come from Hydrogen, so it should have the benefit of much lower -if not entirely eliminated- hydrogen enbrittlement. (...


2

At that high temperature , there are some things like carbides and intermetallics going into solid solution. Also some chemical homogenization ( which is similar to the solution). To a small degree the temperature is becoming more uniform ; although the surface has reached temperature the core of a thick component takes longer to reach temperature ; Usually ...


2

You are asking how to quench and temper 1095, aka; carbon steel, to make it "file hard" ( the hardness described in the question). File hard depends a little on the file and the person but Rockwell C 60 is a good level and can be made with your relatively thin 1095. A concentrated solution of boric acid may reduce decarburization , dip parts and ...


1

Does it have to be vinyl? Model airplanes use this process to apply skins to wood framed wings. It's called "covering film", like Monokote. Just any sheet of shrink wrap with a pre-applied adhesive really.


1

Another way to decrese the stiffness without making the spring longer: Making it longer would obviously decrese the stiffness. And adding other springs in series would do also. You could add springs in series and put them one in another. The inner springs should be shorted and connected end-to-end. You could have three springs in total. The second ...


1

With 13" diameter and 6" thickness they are VERY "stocky" to flame harden. It would require very high heat flux to heat the surface before the whole wheel is hot. Like 20 oxy-acetylene tips on a 6" wide burner. The goal is to heat the surface to 1600F while the bulk is no hotter than 500F so that you get a conduction quench. Induction heating would work - ...


1

I don't know about a computer game, but in the real world max C in the skin is more like 1.5 % with time like 24 hours. Carbide formers like Cr, Mo , will increase that slightly.Also there are trade secrets in the "pack" , alkali metals and earths can facilitate carburization and affect C content. High surface C has few applications so most commercial ...


1

Because of the total mutual solubility , Ni -Fe alloys are more ductile than about any other ferrous combination. Like any metal , if heavily cold worked ,ductility is reduced. If carbon is added, ductility can be drastically reduced . Generally Ni-Fe alloys are used for unique magnetic properties. Not much else can be said without more information.


1

Eddy current analysis, we paid $17k per unit, but they're for manufacturing lines. I'm not sure how much a smaller hand-held unit with a stylus-type probe is. We buy our equipment from Magnetic Analysis Corp. but I don't know if they have the smaller equipment.


1

It will reduce the weld HAZ some , but not much. It depends on the dimensions and the heat input of the weld, the alloy , the original hardness , and the original heat treatment. The primary cooling is by conduction which is affected by the temperature difference. So the temperature difference will be 75 F / 2800 F , or 32 F /2800 F , not much of a ...


1

This is a layman's view, but based on some engineering principles of which I am aware. The tool steel as you describe would become a direct short. As such, the resistance isn't necessarily going to be high enough to make it red hot. There may be other components in the circuit (clamps, cable connections, cables, etc.) that would have higher resistance than ...


1

Additionally, switch rooms and IT rooms tend to just recirculate the room volume with some small DX cooling. It is not viewed as an occupied space, hence no need for extract for heat rejection, you would need some provision for smoke extract though. Also another design consideration, exposing an IT space to external environment is not a good idea if you are ...


1

The required strain is: (0.125 - 0.115)/0.115 = 0.087 the thermal expansion coefficient of aluminum is ~ 22 10^-6/C, so to expand that much you need to heat to 0.087/(22 10^-6) or ~4000C ie You will melt the aluminum long before it expands that much. Note the drawing tolerance is -0/+0.01, so maybe buy a bunch and you will get lucky :-) Hunt around ...


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