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normspanners
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So to take things literally as stated earlier the name alloy wheels cover both steel and aluminium because they are both alloys of some sort but ally wheel is closer to the aluminium mark than alloy
BUT according to the collins dictionary ;-
Definitions
plural noun
BUT according to the collins dictionary ;-
Definitions
plural noun
- wheels made from an steel alloy, usually of aluminium or magnesium, for improved properties such as reduced weight, better heat conductance and a shiny appearance
normspanners
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But by the seem of it, none of them can clearly explain or correctly rite fings down like what I do.
which seems incredible considering their purpose is to educate us
which seems incredible considering their purpose is to educate us
Wedg1e
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... he also told us stainless was non-ferrous because ithe piece he had was not magnetic
Don't get me started. We supply reference pieces to the NDT industry and even though we request chemical analysis certificates from our suppliers we still point a PMI gun at the pieces... and some 316 is magnetically attracted, some of it isn't, despite the PMI giving exactly the same composition each time.
Ref. alloy wheels: I used to go to an alloy wheel factory in Cardiff and seem to recall asking about the particular alloy; the guy told me it was 'straight' aluminium fresh from the smelting plant. Whether that means the plant made a particular mix just for them, or just for wheels, or just for a laugh we'll probably never know
However I do have a 1990s as-cast Rover (I think) wheel (that has had no machining or painting), I guess I could PMI it and see just what's in it...
I dont recall anything but an alloy being a mixture of 2 or more metals. The "substance" bit doesnt seem right to me. The only doubt is that some gases are actually metals eg Hydrogen. I wouldnt call a mixture of say Iron and Hydrogen an Alloy but it is 2 metals
There must be a better definition.
There must be a better definition.
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Doesn't working stainless make it magnetic as it changes from martenistic to austenistic (or something along those lines)?Don't get me started. We supply reference pieces to the NDT industry and even though we request chemical analysis certificates from our suppliers we still point a PMI gun at the pieces... and some 316 is magnetically attracted, some of it isn't, despite the PMI giving exactly the same composition each time.
Ref. alloy wheels: I used to go to an alloy wheel factory in Cardiff and seem to recall asking about the particular alloy; the guy told me it was 'straight' aluminium fresh from the smelting plant. Whether that means the plant made a particular mix just for them, or just for wheels, or just for a laugh we'll probably never know
However I do have a 1990s as-cast Rover (I think) wheel (that has had no machining or painting), I guess I could PMI it and see just what's in it...
What's a PMI gun?
I think it would be wrong to say hydrogen is actually metal, it has metallic properties but it also has non metallic properties. FWIW, did I read somewhere that, at some ridiculous temperature and pressure, oxygen has a metallic state?
There is a chemical definition of a metal..........the modern wording is " Elements that form cations when compounds of it are in solution and oxides of the elements form hydroxides rather than acids in water."
It used to be worded differently but I think it was the same chemically.
There are very few elements that are none metals.......they are the top right corner of the Periodic Table......The inert gases, halogens and then nonmetallics Carbon Silicon etc etc
normspanners
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That's why most of the "metals" we use are not actually metals at all but alloys: metals combined with other substances to make them stronger, harder, lighter, or better in some other way. Alloys are everywhere around us—from the fillings in our teeth and the alloy wheels on our cars to the space satellites whizzing over our heads. Let's take a closer look at what they are and why they're so useful!
What is an alloy?
You might see the word alloy described as a "mixture of metals", but that's a little bit misleading because some alloys contain only one metal and it's mixed in with other substances that are nonmetals (cast iron, for example, is an alloy made of just one metal, iron, mixed with one nonmetal, carbon). The best way to think of an alloy is as a material that's made up of at least two different chemical elements, one of which is a metal. The most important metallic component of an alloy (often representing 90 percent or more of the material) is called the main metal, the parent metal, or the base metal. The other components of an alloy (which are called alloying agents) can be either metals or nonmetals and they're present in much smaller quantities (sometimes less than 1 percent of the total). Although an alloy can sometimes be a compound (the elements it's made from are chemically bonded together), it's usually a solid solution (atoms of the elements are simply intermixed, like salt mixed with water).
The structure of alloys
If you look at a metal through a powerful electron microscope, you can see the atoms inside arranged in a regular structure called a crystalline lattice. Imagine a small cardboard box full of marbles and that's pretty much what you'd see. In an alloy, apart from the atoms of the main metal, there are also atoms of the alloying agents dotted throughout the structure. (Imagine dropping a few plasticballs into the cardboard box so they arrange themselves randomly among the marbles.)
Substitution alloys
If the atoms of the alloying agent replace atoms of the main metal, we get what's called a substitution alloy. An alloy like this will form only if the atoms of the base metal and those of the alloying agent are of roughly similar size. In most substitution alloys, the constituent elements are quite near one another in the periodic table. Brass, for example, is a substitution alloy based on copper in which atoms of zincreplace 10–35 percent of the atoms that would normally be in copper. Brass works as an alloy because copper and zinc are close to one another in the periodic table and have atoms of roughly similar size.
Interstitial alloys
Alloys can also form if the alloying agent or agents have atoms that are very much smaller than those of the main metal. In that case, the agent atoms slip in between the main metal atoms (in the gaps or "interstices"), giving what's called an interstitial alloy. Steel is an example of an interstitial alloy in which a relatively small number of carbon atoms slip in the gaps between the huge atoms in a crystalline lattice of iron.
How do alloys behave?
People make and use alloys because metals don't have exactly the right properties for a particular job. Iron is a great building material but steel (an alloy made by adding small amounts of nonmetallic carbon to iron) is stronger, harder, and rustproof. Aluminum is a very light metal but it's also very soft in its pure form. Add small amounts of the metals magnesium, manganese, and copper and you make a superb aluminum alloy called duralumin, which is strong enough to make airplanes. Alloys always show improvements over the main metal in one or more of their important physical properties (things like strength, durability, ability to conduct electricity, ability to withstand heat, and so on). Generally, alloys are stronger and harder than their main metals, less malleable (harder to work) and less ductile (harder to pull into wires).
What is an alloy?
You might see the word alloy described as a "mixture of metals", but that's a little bit misleading because some alloys contain only one metal and it's mixed in with other substances that are nonmetals (cast iron, for example, is an alloy made of just one metal, iron, mixed with one nonmetal, carbon). The best way to think of an alloy is as a material that's made up of at least two different chemical elements, one of which is a metal. The most important metallic component of an alloy (often representing 90 percent or more of the material) is called the main metal, the parent metal, or the base metal. The other components of an alloy (which are called alloying agents) can be either metals or nonmetals and they're present in much smaller quantities (sometimes less than 1 percent of the total). Although an alloy can sometimes be a compound (the elements it's made from are chemically bonded together), it's usually a solid solution (atoms of the elements are simply intermixed, like salt mixed with water).
The structure of alloys
If you look at a metal through a powerful electron microscope, you can see the atoms inside arranged in a regular structure called a crystalline lattice. Imagine a small cardboard box full of marbles and that's pretty much what you'd see. In an alloy, apart from the atoms of the main metal, there are also atoms of the alloying agents dotted throughout the structure. (Imagine dropping a few plasticballs into the cardboard box so they arrange themselves randomly among the marbles.)
Substitution alloys
If the atoms of the alloying agent replace atoms of the main metal, we get what's called a substitution alloy. An alloy like this will form only if the atoms of the base metal and those of the alloying agent are of roughly similar size. In most substitution alloys, the constituent elements are quite near one another in the periodic table. Brass, for example, is a substitution alloy based on copper in which atoms of zincreplace 10–35 percent of the atoms that would normally be in copper. Brass works as an alloy because copper and zinc are close to one another in the periodic table and have atoms of roughly similar size.
Interstitial alloys
Alloys can also form if the alloying agent or agents have atoms that are very much smaller than those of the main metal. In that case, the agent atoms slip in between the main metal atoms (in the gaps or "interstices"), giving what's called an interstitial alloy. Steel is an example of an interstitial alloy in which a relatively small number of carbon atoms slip in the gaps between the huge atoms in a crystalline lattice of iron.
How do alloys behave?
People make and use alloys because metals don't have exactly the right properties for a particular job. Iron is a great building material but steel (an alloy made by adding small amounts of nonmetallic carbon to iron) is stronger, harder, and rustproof. Aluminum is a very light metal but it's also very soft in its pure form. Add small amounts of the metals magnesium, manganese, and copper and you make a superb aluminum alloy called duralumin, which is strong enough to make airplanes. Alloys always show improvements over the main metal in one or more of their important physical properties (things like strength, durability, ability to conduct electricity, ability to withstand heat, and so on). Generally, alloys are stronger and harder than their main metals, less malleable (harder to work) and less ductile (harder to pull into wires).
normspanners
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(PMI) Positive Material Identification gun we used a Optical Emission Spark Spectrometers which created a spark and could read the makeup of the material tested
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Wedg1e
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Metascop?
I rescued one of those from the bin a few years ago, spent bl**dy hours trying to repair it but discovered it had been dropped and the prism had cracked, so no light passed through it. Took me ages to figure out what was going on, I assumed it was just a misalignment of the various mirrors and lenses.
Bit of a learning curve to be able to read and interpret the viewed spectrum, mind you...
The current one we have uses x-ray fluoroscopy (I think!) - fires an x-ray beam at the part and then reads the emissions given off by the molecular stimulation.
Well it sounds plausible to me anyway
bill_gj
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Yes, sorry -- the point of my answer was that "Most 'pure' metals are usually useless in the context of engineering materials". And I am ignoring the electrical conductivity issues, primarily just looking at mechanical uses.
By the way, according to Britannica online (http://www.britannica.com/technology/duralumin)
"The original composition has been varied for particular applications; it may contain about 4 percent copper, 0.5–1 percent manganese, 0.5–1.5 percent magnesium, and, in some formulations, some silicon. After heat treatment and aging, these alloys are comparable to soft steel in strength."
Not being picky, of course.
I guess common usage tends to override anyone attempts at precise definitions. But I'd always taken the view that metal alloys were mixtures of more than one metallic element. On that basis Iron and carbon make steel (not an alloy), but add chromium (for example) and then you have alloy steel. I'd expect steel alloy spanners to be something better than carbon steel spanners (but I might be disappointed).
But I'm fully aware that common usage and other definitions exist.
But I'm fully aware that common usage and other definitions exist.
normspanners
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Its is still classed as an alloy, read post 29
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If someone specifies "alloy steel" then it will have more in it than just carbon.
What are the properties of the various alloying elements used in steel?
AFAIK, chromium is used for corrosion resistance and manganese and vanadium are for wear resistance but what about other elements?
What are the properties of the various alloying elements used in steel?
AFAIK, chromium is used for corrosion resistance and manganese and vanadium are for wear resistance but what about other elements?
normspanners
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It all depends on what purpose the steel is needed for, for instance a fork lift mast will have totally diff spec to the actual forks which will have a spring steel type composition, but having them too much like spring steel and they could snap, You want them to just bend so that you know they have been overloaded, they cant just spec 'alloy steel' coz that is open ended, IMO.
