As a contractor,civil engineer, architect, building technologist, etc who is knew into field work,you may be having issues with your confidence. Well, that was me some years back. After graduation, I got my first contract and I was supposed to be excited but funny enough, I wasn’t. I had doubts and fears about competence because the reality of getting your personal field contract was different from being a student or doing your industrial training under an a senior colleague. I asked myself questions like, as the main person responsible for this job, how do I deal with labourers bad attitude, how do I identify a fake building material,etc. In this article, I will only discuss few ways to identify a fake steel bar.
This method may be a little unnecessary for especially an African supervisor who is handling a small project. It’s only some companies that can go as far getting a muriatic acid to check the originality of a steel bar. Having pointed this out,here are the steps involved in the chemical method.
Cut out a part or a spot of the steel bar that you don’t mind destroying a little.
Get an eye dropper and fill the eye dropper with muriatic acid. Drop a small amount of the acid on the test spot. Wait for half an hour.
Wipe the acid off the part you dropped. Examine the test spot. If it is discolored, the piece is stainless steel.
It’s as simple as that.
The rest methods are simply physical test. And some of them can be done within a short time, without even allowing your supplier to notice what you are doing.
Physical method 1
1. Inspect the surface of the metal first to identify a code label on it. If the metal has a number code printed on it, that may mean it is steel. Sometimes, this code is also printed on the shipping container or on the material used to wrap or protect the steel bars during shipping.
About these codes. You will be expecting to see the code showing the size of the bar and the other showing the steel bar type.
2. Expect to buy a steel that has either colours, dark brown, shiny silver, or red with rust. Carbon steel, used in pipes and buildings, is a dark brown color. Stainless steel, used in kitchens, is silver and shiny. In addition, reddish rust spots are an indication that the metal is steel.
Metal that has a red or yellow tint is copper or brass, not steel. Copper may also turn green as it ages.
3.Chip the metal to look for a silver coloring inside. Before attempting a chip test, look for any fractures. These spots usually give you a view of the inside of the metal. Otherwise, use a hammer and chisel to break off a small piece. Steel’s inner portion is always bright gray.
Hold the metal in place with clamps or vice grips before attempting to chip it.
Physical method 2:
Testing Other Characteristics
Make sure the metal is magnetic. If you are still uncertain, press a small magnet against the metal. Steel is generally magnetic because it is made of iron. Most other common metals, including aluminum, aren’t magnetic. If the magnet sticks, the metal is most likely steel.
Other magnetic metals are either rare or not used in pure forms. Cobalt and nickel, for example, are often components in steel.
Some stainless steel is not magnetic. When nickel is added during manufacturing, the magnetism fades. Identify this metal by color, by weight, or by trying another test.
Look for a heavier metal rather than a lighter one. Aluminum and stainless steel are both shiny and silver-colored, so they look similar. Distinguish between them by handling the metal. Stainless steel feels much heavier than aluminum. Steel feels stronger, more solid, and less prone to breaking in your hands.
To get used to the differences between these metals, compare household objects. For example, an aluminum can feels much different than a steel cup or utensil.
Test the hardness by filing the metal. Use a metal file to perform a file test. Lay the metal on a flat surface and rub the file against 1 end. Steel is a relatively hard metal, so filing off fragments should take some work. Depending on the file’s hardness, you may not even be able to wear off any of the metal this way. Look up the Moh’s scale for metals to compare hardness ratings.
In contrast, lead, aluminum, silver, and many other metals are softer than steel. Wearing them down with the file is easier.
Hardened steel, which has a medium to high carbon content, is stronger than all but a few metals. Most metal files won’t affect it.
Physical method 3:
Performing a Spark Test
Wear goggles and other safety gear. Take safety precautions before using a grinding wheel. Polycarbonate safety goggles protect your eyes from stray sparks and metal fragments. Also put on ear muffs to block out the machine’s noise and a respirator to avoid breathing in dust.
Steel-toed boots are also a good idea. Wear these in case you drop a heavy piece of metal.
Turn on a bench grinder. To test the metal, you need some sort of spinning wheel. The faster it rotates, the more sparks it will produce. Get a bench grinder or handheld grinder with a 24-grit carborundum wheel and wait for it to spin up to speed.
Hold the metal flat when pressing it against the wheel. Hold the ends of the metal in your hands directly in front of you. Keep a firm grip on the metal as you lower it onto the wheel. The contact produces sparks, which you should be able to see without moving your head.
Adjust the metal’s position until you get a clear view of the spark pattern.
Note if the sparks branch out in a pattern. Maintain a light amount of pressure on the metal as you watch the sparks. Steel produces sparks that branch out into about 5 yellow streaks. All the streaks are different lengths. The ends of the sparks fan out into tiny branches or “leaves,” like on a tree. Search online for a visual aid by searching for the steel spark test.
Both wrought iron and stainless steel produce long, even yellow streaks. The leaves on the end are smaller in stainless steel sparks.
Steel made with less carbon produces yellow sparks with different lengths. The leaves on the end fan out more with a lot of extra little branches.
Steel with high amounts of carbon produce sparks that begin spreading out near the grinding wheel. The sparks are duller or even red and fan out less at the end.
Some metals, including nickel and aluminum, produce few or no sparks.
Research credit: hunker.com and wikihow.com
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