What exactly is Mild Steel?

A. Hello David!

In the States, "mild steel" refers to low carbon steel; typically the AISI grades 1005 through 1025, which are usually used for structural applications. With too little carbon content to through harden, it is weldable, which expands the possible applications.

Yet according to my Materials Handbook ⇦[this on on Amazonaffil links] by Brady, "ingot iron", a grade of nearly chemically pure iron used for construction and magnetic purposes, is also called "mild steel" in the UK.

Hope this helps!

A. David,

You'd get a better answer if you approached one of the faculty at a local University!

Mild steel = steel = iron ... where iron ore is heated up along with a goodly measure of coke along with, I believe some gypsum or lime to a eutectic melting point of 1050 °C ... eutectic meaning that if the right amount of concentrated iron ore is mixed with these ingredients, then the min. melting temperature in the blast furnace will be as above, i.e., less BTU losses.

The resultant mix is iron ore or 'cast iron' but it is quite brittle. Ah, now to make it into steel, we have to reduce the phosphorus and sulfur content AND the carbon content... this is done by adding certain ingredients such as, I believe, aluminum to make the 'iron' more malleable somewhat, i.e., to make it into steel. This is done normally in separate furnaces, often called open hearth furnaces, too.

In some steel foundries (mainly abroad) they use a very high phosphorous iron ore. And it was a Englishman by the name of Henry BESSEMER who in effect invented the Bessemer furnace, a large, snorting and spark generating cupola type furnace where the phosphorus generated much of the heat due to a so-called exothermic reaction. Again, this 'iron' has to be treated to make it more workable and not brittle.

Now after this is done ... voilà, we have MILD STEEL !

For more boring info, go thou to any steel manufacturer!

I forgot! Usages! Every railway line is made of mild steel, your car or motor bike is made of mild steel, even some of your pots and pans are. The usages are legion! Ships, metal piping, bicycles, you name it!

I hope this helps the school project!

A. How wrong of Freeman Newton to state that "every railway line" is made of 'mild' steel. All 'curved' lines are made of Manganese Steel, mild steel would just not cope with side thrust of steering a train round a bend!

Thanks for the correction, John, but please try to avoid ad hominems like "How wrong of . . .". Freeman did a nice job of offering the student some examples, and actually some of the components of the other examples he offered like cars, motorbikes, ships, piping, and bicycles are also alloy steel rather than mild steel. Thanks again for the enlightenment about curved rails though! Ted Mooney, P.E. Striving to live Aloha finishing.com - Pine Beach, New Jersey April 4, 2011 Actually I think the thing John P. (Leics) could have made more of from Freeman's little blurb is the use of voilà anywhere in an article about steel... Surely it is the creeping end of one or the other of the languages in use... It's getting in everywhere - Macdonald's & Nescafe's advertisements if you please chuck in - and voilà arrrghhhh Bruce Trout - Cookham, Berkshire April 4, 2011  Hi, Bruce. Focus please! Voilàs & violins are made of wood, not steel. Regards, Ted Mooney, P.E. Striving to live Aloha finishing.com - Pine Beach, New Jersey Hey Ted, Viola=stringed instrument. Voila=there it is, which has nothing to do with a wood stringed instrument.) Mike Gee - Sayville, New York, USA September 27, 2015 Gee, Mike, I actually knew that. But thanks! Regards, Ted Mooney, P.E. Striving to live Aloha finishing.com - Pine Beach, New Jersey September 2015

A. Mild steel is a carbon steel typically with a maximum of 0.25% Carbon and 0.4%-0.7% manganese, 0.1%-0.5% Silicon and some + traces of other elements such as phosphorous,it may also contain lead (free cutting mild steel) or sulfur (again free cutting steel called re-sulfurised mild steel) The stuff is used everywhere, looking out of my office window I can see diesel pump injector parts, loudspeaker pole pieces, Automated packing machinery parts and I haven't even got my glasses on. How its made and more info, depending upon the age of your son it's probably an idea he spends a Saturday morning at the local library researching his homework. Whilst the internet's good you still can't beat browsing through books at the library for homework.

Regards,

A. Composition: Iron alloy with 0.3% carbon Properties: Malleable and ductile, and therefore bends fairly easily Uses: nuts, bolts, screws, tubes, girders

Methods of Identification:
Appearance: Bright drawn mild steel has a smooth, bright surface; black mild steel is covered with a blue-grey oxide
Dropping: Gives out a ringing note Grinding: Gives off a shower of long white sparks Effect of Heating: Slightly tougher but little change

Mild steel is the most common form of steel as its price is relatively low while it provides material properties that are acceptable for many applications. Mild steel has a low carbon content (up to 0.3%) and is therefore neither extremely brittle nor ductile. It becomes malleable when heated, and so can be forged. It is also often used where large amounts of steel need to be formed, for example as structural steel.

A. The simplest way of describing mild steel is a steel in everyday use which will rust (i.e., it is not stainless steel). Many people have made reference to the carbon content of mild steel and unless you know what this does then its pointless. Basically when manufacturing steel carbon is added in varying amounts to alter the properties of the steel.

A low carbon steel such as mild steel will be quite soft and malleable so can be bent and forged into different shapes with minimal heat treatment. Higher carbon steels (up to about 0.9%) can be hardened using a method of heating and quenching (fast cooling in oil or brine) to a point where they can be used for cutting other steels, you would know high carbon steel as a drill bit or lathe tool.

Hope this is helpful.

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April 29, 2008

Hi, Scott. Thanks for the input, but I can't quite fully agree with it. Mild steel is low carbon steel, steel that is not hard and brittle -- the stuff that plates and structural shapes are usually made of. A file will rust very quickly, but I would not consider a file to be made of mild steel -- but maybe when you said "everyday use" you were implying structural shapes as opposed to files and drills and similar tools.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Hi, folks. The Internet is a giant one-room schoolhouse, so unfortunately we have questions from graduate engineers and elementary students homogenized into a single thread :-)

Greg might best be served with a reference to the ASM Metals Handbook, but that 24-volume set might leave Todd with no starting point at all :-)

Todd, I think what you might consider is that steel can be relatively soft (even though a soft steel is harder than a hard wood or hard plastic) or steel can be extremely hard and brittle, or anywhere in between. What hardness you want depends on the application.

Consider a file. If it was softer than the metal you are filing, you'd just wear the teeth off and nothing more. A drill that is not harder than what you are drilling would just spin around until the point was gone. A soft hacksaw would be of no value either. But if you made buildings and bridges and cars of really hard steel, you wouldn't be able to file, drill, or saw the component parts. Further, if you do much metalwork, you'll find that files can shatter and drills can break because they are very brittle. You wouldn't want to build an apartment building where the I-beams were very hard steel and someone pounding on the ceiling with a broom handle because of a noisy upstairs neighbor would be at risk of shattering the beam and bringing the building down :-)

Regards,

A. Mild Carbon Steel, is a steel which contains iron plus small quantities of other elements i.e. 0.18-0.23% Carbon, 0.30-0.60% Manganese. 0.30% max. Silicon, 0.040% max. Phosphorous and 0.50% max. Sulfur.
Usually steel plates in tanks and structural steel in buildings and other steel structures like billboards and frames of column for electrical cables are made of mild carbon Steel.

A. Hello David
I'm here to solve your problem. Mild steel is low carbon steel with a variety of applications. The major disadvantage is the poor resistance to corrosion.

A. Mild steel is the most common form of steel. Mild steel means - steel with less than 0.15% carbon low-carbon steel, soft-cast steel. Neither brittle nor ductile. This form is use in many applications due to low price material.

A. Sadly there doesn't seem to be a good answer as to why Mild steel is called Mild, unless you take the mild to mean malleable or easily worked, which low-carbon steels certainly are. Wrought Iron preceded it and was very fibrous and got its structure from being repeatedly worked when hot.
Confusingly Cast Iron has even more carbon in it, (and even less iron as a result). It isn't easy to work, but is very easy to cast into a wide variety of shapes. The purest iron can often be found in "tin" cans, which actually have very little tin in or on them.

A. Hi, Shalander. Sorry, no, you can't make such a substitution. But please tell us about the components in question and a fuller answer may be possible.

Regards,

A. Hi, Mittal.

These terms are vague, context dependent, and just handy slang used to describe something when you don't have more exacting information. They are broad brush terms that you cannot really put a fine point onto, but I would say there is no difference between mild steel and mild carbon steel.

Here is some general stuff:
- Stainless steel or corrosion resisting steel has significant amounts of other metals in it. For example 3xx stainless steel usually has about 18 percent chromium and 8 percent nickel, and sometimes some additional metals like molybdenum. 4xx stainless steels usually have about 18 percent chromium.
- Mild steel usually means a soft, unhardened steel of low carbon content, like 0.2 percent. This is what I-beams and structural elements for buildings are made of.
- Carbon steel usually means steel with "carbon only", in other words a non stainless steel. It may be mild steel, but not necessarily. For example, a spring might be made of stainless steel or of carbon steel, but a spring is not made of mild steel. Good luck.

Regards,

A. Hi, Amy.

I don't think "corrosivity" is the word you are looking for. I believe that a strong acid would have "corrosivity", whereas a steel which is designed to resist corrosion would have good "corrosion resistance".

There are countless ways to improve corrosion resistance, from applying coatings like paint, galvanizing, and chrome plating, to slightly modifying the composition to make Cor-ten (a steel which builds a more robust rust layer, deterring further corrosion), to major modification of the ingredients like adding nickel and chromium to make the steel corrosion resistant -- but in that case you have "stainless steel" and the term "mild steel" doesn't really apply anymore :-)

Again, an issue with the question is that "mild steel" is simply slang, and its meaning somewhat context-dependent. One of the implications of "mild steel" is that it is not corrosion resistant; so as you change its composition to make it more corrosion resistant, the semantic question immediately arises of whether it is valid to continue to call it mild steel :-)

Regards,

A. Yes, Tom, it is.

Regards,

A. Hi, Nad. I am not a metallurgist, so my answer is not conclusive, but I have never heard of it and think it's not possible because it has insufficient carbon to be hardened through heat treatment. Of course there are surface treatments that you can do to impart a hard surface. Good luck.

Regards,

A. David,

I encourage you and mostly your son to do some research by himself, because some of the information on the top as I see are false, that's why I decided to post this for you.

Hopefully it helps ...
Erfan

Mild steel (low carbon steel)

1. The commonly used alloy for structural steel members

2. Not more than 0.3% carbon

3. Small amounts of other alloys (such as nickel, chromium, molybdenum, manganese, vanadium, and silicon) improve strength, toughness, and other qualities

4. Reasonably strong, highly ductile, and easily welded

5. Equally strong in tension and compression

A. Hi Erfan.

Thanks for the informative answer. However, if you feel that "some of the information on the top as I see are false", it would be best to challenge the specific statements that you question rather than to use a brush so broad as to call into question every contribution from a dozen responders over a period of many years :-)

Thanks again.

Regards,

A. Hi Azman. No, it can't; the carbon level is too low for hardening. But "mild" is not a detailed specification, so the question and answer are not as exacting as they could be.

Regards,

A. Hi Vipin. Questions are usually answered better when you explain your situation and tell the readers why you want to know. Bicycles can be built from plain minimum quality mild steel such as ASTM A36 (36,000 psi yield point), but most consumers, even cheap ones, are concerned with the weight of a bicycle, so stronger low-alloy high-tensile steels like are common even on moderately priced bicycles, and very high tensile strength steels are sometimes used on custom bicycles.

Regards,

Q. Sir
I want to know that what is the grade of mild steel which is used to make bike frames of Honda Shine such as rear, front, bottom and swing arm? Sir I am collecting this information because I have to give an interview in Honda's vendor company in a quality department. They ask this question mostly; I searched on the net but I found nothing.

A. Well, no harm in asking, but I think the only answers you will get will involve the word "probably" and speak only of the "general types" of alloys "often used" for such purposes. Nearly every manufacturing detail at every manufacturer is considered proprietary. Unless there is some sales advantage for Honda in telling consumers what kind of steel they use, it's probably proprietary knowledge.

You are speaking of a motorcycle, rather than a bicycle, so economy may trump strength-to-weight ratio, and I would guess that they are built of cold finished drawn-over-mandrel tubing. Best of luck with the interview.

Regards,

Hi Sachin. Disadvantages compared to what alternative and for what application? Compared to medium or high carbon steel or alloy steel, it's weak. And compared to stainless steel and most other metals, mild steel corrodes fairly readily.

As for the accurate chemical composition and mechanical properties, you need to specify a particular grade, because "mild steel" is a term with fuzzy borders. It's like asking exactly how tall and many how pounds a medium-height pleasantly plump person is. In a steel book, find a grade that contains .15 to .2% Carbon, verify that the grade is considered a mild steel, and copy the chemical composition and mechanical properties from there. Good luck!

Regards,

A. Hi Steve. "Heavy" steel is pretty much meaningless. It just means thick in gauge as opposed to thin in gauge -- but compared to what? Steel is not resistant to rust; the paint or powder coating and its pretreatment system is what deters rust. Good luck.

On my last trip through Johnson City (and I mean final, not most recent) I got a robo ticket mailed to me from Las Vegas; you're not very welcoming down there :-)

Regards,

A. Hi Noor. I don't see any reason you can't do so if you find that the advantages of steel outweigh the disadvantages. I think it's just that when machine body members are very heavy and loaded in compression, just casting them with the necessary fillets, holes, radii, etc., ends up being more practical than fabricating, welding, and stress relieving steel.

Regards,

Hi Mr Noor,

It's so refreshing to see someone want to make a better product.
I'm seeing the automotive world moving the other way to save substantial costs.

Probably true, but in which aisle can we find that special sauce?

Regards,

A. Hi Tina. Mild steel is the most common construction metal because it's strong and inexpensive, so that's probably what it is. Steel is ferrous and magnetic.

Regards,

Hi again. No, the opposite; my guess (based on nothing but probability) is that the bed legs are ferrous.

Regards,