test of mild steel

In the U.S. the ends are spray painted. the code is known to those in shipping and receiving.

Without the spray painting I think it would be difficult to tell. Perhaps by testing with a hardness tester but that would not be an easy, visual option.

No visual test...use a needle file?

Besides the file sound as Del says why not use a permeability meter.

I have one in my lab which is used by the MoD for checking types of steel.

John.

Scratch test and file tests will mark the sample. Grinding will show carbon content in the lenght, spread and color of sparks. These are economical and easy tests. There is a machine to measure the hardness of metals. It is called a rockwell tester.

07b mechanic

Bend and twist and turn --go on and on >>>.

The wire which will break first is hardened steel

The one which refuses to snap is lowest carbon steel.

<> I read your response to " Test of mild Steel " ... " excellent answer "

<> I am 66 years old and have worked as a machinist/Mold Maker for close to 50 yrs

<> Your answer telegraphed your age.

<> I agree with your answer .. I learned about it in trade school when I was 15.

<> I still work in the trade and don't know of any better way.

<> " Hi Five " for " The over the hill gang "

Actually this answer is misleading on several accounts.

First, the color of the spark stream will not change by carbon content, the number of bursts and carrier lines will. see number 4 below for further clarification on the color issue.

Second, Unhardened high carbon steel is indistinguishable from hardened high carbon steel by sparktesting, the spark bursts, carrier lines, swellings from alloying elements/deoxidizers and other visible characteristics of the spark stream are the product of chemistry, not microstructure ( microstructure is the reason it is "harder")

Third, It is not the "tail " that changes, but the number of bursts, or the fuzziness of the sparks near the end of the carrier lines. The "tail" which most sparktesters refer to as a spear head is not an indication of carbon content (or hardness Duhh uhh!) as much it is an indication of the presence of moly or phosphorous.

Fourth, I have found that the real high alloy tool steels, drill rods etc will haveboth a much busier spark stream and appear to be 'redder' than "regular carbon and alloy steels." But I have never, and have never seen any qualified sparktester do a commercial sort on the basis of color alone. As daylight, ambient conditions, background and type of shop lighting can all influence the perceived color.

Spark test will not sort hardened vs unhardened material, unless there is chemical difference, especially with respect to carbon content.

milo 'Sorted several rail cars of mixed grade line pipe with a portable generator and and a grinder, back in the day.'

In the past,men have used a diamond,with a normal sapphire cut, to scratch the steel in several directions. If it is mild steel, with too much carbon to be structural steel, then a part will stick to the diamond. If it is mild steel, but not adequately cold rolled, then it will scratch it, in two directions. When it is adequately rolled for all structural uses, within its structural category, then it will not be able to scratch the steel, in more than one direction.

Case hardened steel instead, has a whiter color, than cold rolled steel, or steel ingots, ready to be heated and rolled into shapes.

It can be tested, only by a needle of a harder steel, made with titanion or with rodion and if it is true, case hardened steel, then, it will only make a short scratch, along the direction of it longest dimension.

If you want to know more about steel types and their preparation then go to http://www.atomic-elements.info and then click on element #26 Iron & read everything that is written on that page, over several days, if necessary, so that you can comprehend, how steel was developed and what types of steel are used, for each of the many uses, that steel is used for today.

We wrote those pages and we can then answer more technical questions, to help you, to assist in your country's development. dr.manly@atomic-elements.info

No visual check is possible. But you can use Poldi Bar test to find out hardeness and then come to the conclusion.

ther are instrument

to give fast result with math calculation but they are too costly.

like

magnetic hysterisis loop tracer. constant magnetic field apply and remoove.

check its resudual field remain and make graph what are the impuarity in it.

The spark tests that others have suggested can be used to distinguish between high and low carbon steels; alloys to if you know how to read the spark stream for deoxidizers and alloy attributes.

The spark tests will do nothing for you regarding hardened/ unhardened material.

The best way for a shop hand to get quick hardness is to temper back a set of files to different hardness ranges. and mark them after confirming their hardness on a tockwell tester. if properly takne care of, these will give you a great is/is not indication of hardness for the balance of your career. When the file doesn't mark the material, the material is harder than the hardness marked on the file.

milo

I think mild carbon steel should oxidized much more easily, which should give a characteristic "colour". After hardenning, the piece would surely have a blackish aspect (because of highT oxidation), but if you polish it, and you also polish a mild steel, the steel piece should get much more easily oxidized, and should appear "darker" I would say...

How about a Texas Nuclear Analyzer? It will give the PMI (Positive Material Identification) leaving no doubt what you are testing.

Everybody gets so much information all day long that they lose their common sense. Gertrude Stein (1874 - 1946)

I have always found that the "ring" test for iron/steel is reliable- this is where the sample is tapped with a fingernail or a hammer etc- the hardened sample will ring higher- cast iron for instance will not ring- case hardened steel etc will- this can easily be proven by taking several samples of same length mild steel rod say- harden & temper using oxide colour- ring test- voila!.

If there is a seam or crack in the steel it will not ring.

We have used this auditory "drop test" or "slap test" to sort cracked stock.

milo

hi,hafeez-as far as my knowledge goes-the only way to identify hardened and soft steels is either by hardness test or by microexamination under metalurgical microscope. some guys test with file,hammer&punch-but not trust worthy.