Eric Larsen
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Sam is right, you are not!
Shoot well
Shoot well
Question(s) about "Stainless" Steel...
- Thread starter mikey357
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it's the chromium that make stainless steel more resistant to corrosion and staining , not the nickel which is added for malability , 12% chromium in a steel alloy makes it classified as stainless steel, yes all steels are magnetic but the alloying makes them more resistant to magenatism , and yes maybe I should go back to school , it's only been 20 years since I learned this stuff and actually applied it in my living .and this is the first time i've actually used some of it in 20 years . 
stellarpod
New member
It is my understanding that the "L" in 304L or 316L implied lower carbon and better weldability.
Some grades of stainless actually become more magnetic when machined.
A common misconception is that stainless is superior in strength to carbon steel. In most instances, with the stainless grades we commonly see, it is, in fact weaker in both tensile and yield strength. It's only real advantage over carbon steel is it's ability to resist corrosion. The 17-4 SS, Monels, Nitronics and Duplex SS' have been developed specifically in an attempt to achieve superior strength while still offering some level of corrosion resistance.
Although it is certainly true that stainless steel can and does oxidize, the appearance of "rusting" stainless steel, in many instances, is due to surface contamination with ferrite material. In this instance it is the particles of iron or carbon steel, imbedded at a microscopic level that cause the rust. The particles are imbedded in many ways including, but not limited to, sand- or shot-blasting with media that is contaminated, having been used on iron or carbon steel parts, and machining the SS with contaminated inserts or tooling that have previously been used to cut iron or carbon steel. A process called "pickling" and "passivation" is used to clean the ferrous material from the surface of the stainless. I think it uses an acid-bath method.
I believe all this to be accurate. However, there are obviously several of you who are much more qualified than I to answer these questions. If I've goofed somewhere feel free to correct me.
Some grades of stainless actually become more magnetic when machined.
A common misconception is that stainless is superior in strength to carbon steel. In most instances, with the stainless grades we commonly see, it is, in fact weaker in both tensile and yield strength. It's only real advantage over carbon steel is it's ability to resist corrosion. The 17-4 SS, Monels, Nitronics and Duplex SS' have been developed specifically in an attempt to achieve superior strength while still offering some level of corrosion resistance.
Although it is certainly true that stainless steel can and does oxidize, the appearance of "rusting" stainless steel, in many instances, is due to surface contamination with ferrite material. In this instance it is the particles of iron or carbon steel, imbedded at a microscopic level that cause the rust. The particles are imbedded in many ways including, but not limited to, sand- or shot-blasting with media that is contaminated, having been used on iron or carbon steel parts, and machining the SS with contaminated inserts or tooling that have previously been used to cut iron or carbon steel. A process called "pickling" and "passivation" is used to clean the ferrous material from the surface of the stainless. I think it uses an acid-bath method.
I believe all this to be accurate. However, there are obviously several of you who are much more qualified than I to answer these questions. If I've goofed somewhere feel free to correct me.
Stellarpod......I and my ASTM books agree with you.
Biggie with me is the lack of comparable yield strength of the 4XX series stainless compared to 4340 etc. 4XX being commonly used in civillian firearms.
Electropolishing will also insure that stainless does not show corrossion spots. Makes 3XX motorcycle spokes look like chrome and they stay that way.
Sam
Biggie with me is the lack of comparable yield strength of the 4XX series stainless compared to 4340 etc. 4XX being commonly used in civillian firearms.
Electropolishing will also insure that stainless does not show corrossion spots. Makes 3XX motorcycle spokes look like chrome and they stay that way.
Sam
Stellapod:
The manufacture's guide that I use to order steel has all of the chemical and mechanical properties for all of the steels that it sells. We use this guide quite a bit at work because for some things that we build or repair we have to know the exact chemical properties of what we use , to make sure that it is compatible with the system that it is goin into. In case you are wondering, I work at a Nuclear plant and they tend to be anal about certain things. The content of various stainless steels is one of them.
In the guide it specifically states that the "L" designation means the addition of a small amount of lead to improve machinablity. In some cases, the addition of lead will improve machinablity up to 50 %, which makes quite a difference if one is turning it on a lathe. This "L" also applies to carbon steel, one of the carbon metals we use the most has the designation 12L14. It has exellent machinablity, it is rated near the top of the scale.
We have had several discussions over the years about the "L" designation with our metallurgist's and our mechanical and nuclear engineers about the potential effects of the lead additive on some of our systems, mainly our emergency cooling water and our primary water systems. With the high levels of radioactivity that we see with our primary water systems , it sometimes has an adverse effect on some steels, even stainless. The radioactivity tends to shorten the usable life of stainless by making it more brittle and prone to crack over a period of time. This can and does cost the nuclear industry major bucks and is a problem that they constantly struggle with.
I may have told you more than you care to know. Just to insure the accuracy of my info, I went back and checked the quide on propertys of stainless and the chemical designations of each, and no where did it mention that the "L" in it meant lower carbon. If you can show me some info on it or point me in the right direction, I'd sure like to see it.
"Some grades of stainless actually become more magnetic when machined"
That would be an effect that comes from "work hardening". It is very noticable when drilling a hole in stainless. If you happen to let the bit dwell in the hole you are drilling, you will notice that it becomes more difficult to drill the hole. Or if your bit is dull, it tends to work harden the piece even more.
Im still in the learnin mode and learn stuff here evertime I get on this forum. If Im wrong in any way, do me a favor and let me know. You might even save me from makin a fool of myself.
The manufacture's guide that I use to order steel has all of the chemical and mechanical properties for all of the steels that it sells. We use this guide quite a bit at work because for some things that we build or repair we have to know the exact chemical properties of what we use , to make sure that it is compatible with the system that it is goin into. In case you are wondering, I work at a Nuclear plant and they tend to be anal about certain things. The content of various stainless steels is one of them.
In the guide it specifically states that the "L" designation means the addition of a small amount of lead to improve machinablity. In some cases, the addition of lead will improve machinablity up to 50 %, which makes quite a difference if one is turning it on a lathe. This "L" also applies to carbon steel, one of the carbon metals we use the most has the designation 12L14. It has exellent machinablity, it is rated near the top of the scale.
We have had several discussions over the years about the "L" designation with our metallurgist's and our mechanical and nuclear engineers about the potential effects of the lead additive on some of our systems, mainly our emergency cooling water and our primary water systems. With the high levels of radioactivity that we see with our primary water systems , it sometimes has an adverse effect on some steels, even stainless. The radioactivity tends to shorten the usable life of stainless by making it more brittle and prone to crack over a period of time. This can and does cost the nuclear industry major bucks and is a problem that they constantly struggle with.
I may have told you more than you care to know. Just to insure the accuracy of my info, I went back and checked the quide on propertys of stainless and the chemical designations of each, and no where did it mention that the "L" in it meant lower carbon. If you can show me some info on it or point me in the right direction, I'd sure like to see it.
"Some grades of stainless actually become more magnetic when machined"
That would be an effect that comes from "work hardening". It is very noticable when drilling a hole in stainless. If you happen to let the bit dwell in the hole you are drilling, you will notice that it becomes more difficult to drill the hole. Or if your bit is dull, it tends to work harden the piece even more.
Im still in the learnin mode and learn stuff here evertime I get on this forum. If Im wrong in any way, do me a favor and let me know. You might even save me from makin a fool of myself.
stellarpod
New member
Watchman:
Thanks for the info. My background is in the pressure vessel manufacturing sector, specifically ball valves for the oil and gas business. Our guiding references are the ASTM Boiler Code specifications as well as several API (American Petroleum Institute) specs. If memory serves we choose 316L Stainless over standard 316 when producing components for butt-weld or socketweld applications - specifically because of it's superior weldability. I'll do some checking with my books in the next few days and report back.
Assuming this thread doesn't get slammed shut for being off-topic of course...
Thanks for the info. My background is in the pressure vessel manufacturing sector, specifically ball valves for the oil and gas business. Our guiding references are the ASTM Boiler Code specifications as well as several API (American Petroleum Institute) specs. If memory serves we choose 316L Stainless over standard 316 when producing components for butt-weld or socketweld applications - specifically because of it's superior weldability. I'll do some checking with my books in the next few days and report back.
Assuming this thread doesn't get slammed shut for being off-topic of course...
Technically, you are right. ALL steel does indeed contain iron. By definition, steel is a malleable alloy containing both iron and carbon.
When you get past technical and down to practical....she has much better ground to stand on. There are guns which are advertised as being "Stainless Steel" which, in reality, aren't steel at all. The guns she speaks of do indeed contain no iron, but they also are not truly made of steel.
I hope, from that, you can determine who wins. I'm still leaning towards you being right, given the description of the argument in your original post.
When you get past technical and down to practical....she has much better ground to stand on. There are guns which are advertised as being "Stainless Steel" which, in reality, aren't steel at all. The guns she speaks of do indeed contain no iron, but they also are not truly made of steel.
I hope, from that, you can determine who wins. I'm still leaning towards you being right, given the description of the argument in your original post.
I missed something here. Which guns are advertised as "stainless steel" and have no iron in them? Anything that is steel is iron. Even the non-magnetic stuff you would find in the kitchen.
I'll second the vote for stainless not being the absolute best steel. I have Cold Steel Carbon V knife which holds an edge under any abuse. It's incredible compared to every other knife I've had.
I'll second the vote for stainless not being the absolute best steel. I have Cold Steel Carbon V knife which holds an edge under any abuse. It's incredible compared to every other knife I've had.
Interesting.....
suffix L in many steels denotes free machining due to addition of lead.
Suffix L as applied to 3XX stainless indicates extra low carbon content. To preclude any harmful precipitations in the 800°-1,500° range , such as might otherwise occur in welding heavier sections.
Sam
suffix L in many steels denotes free machining due to addition of lead.
Suffix L as applied to 3XX stainless indicates extra low carbon content. To preclude any harmful precipitations in the 800°-1,500° range , such as might otherwise occur in welding heavier sections.
Sam
OH no!!! here we go again !(loud" thud" from head hitting table !! ) BTW when I went to school 20 years ago it was to be a NDT Tech but do to funds I never received my card , as for the gentleman that works in a Nuke plant , yes they think the radiation has something to do with causing a premature aging on the materials ,A power utility did a mega million dollar research project on it with IIT .the answer was still unknown of when I left school .and apartently still being researched .
) BTW when I went to school 20 years ago it was to be a NDT Tech but do to funds I never received my card , as for the gentleman that works in a Nuke plant , yes they think the radiation has something to do with causing a premature aging on the materials ,A power utility did a mega million dollar research project on it with IIT .the answer was still unknown of when I left school .and apartently still being researched .John Forsyth
New member
First, just because you see an "L" in it, do not assume it means the same thing for different alloys. For 300 series SS, it means low carbon for better weldability. Watchman, you are correct for SAE numbered low carbon steels, in your example the "L" does mean the addition of lead to improve machining.
There are four major types of stainless steels, austinitic, ferritic, martensitic, and precipatation hardened. All are magnetic except for austinitic, i.e., the 300 series. The 300 series are also referred to generally as 18-8.
All stainlesses are heat treatable except for the 300 series.
There are four major types of stainless steels, austinitic, ferritic, martensitic, and precipatation hardened. All are magnetic except for austinitic, i.e., the 300 series. The 300 series are also referred to generally as 18-8.
All stainlesses are heat treatable except for the 300 series.
The Terminator
New member
DAVID NANCARROW
Senior Member
Posts: 563
Sure would like to hear her explain this, at least metallurically. Stainless steel is generally nothing more than an alloyed ferrous metal with a few percentage points more chrome, sometimes combined with other alloying elements IIRC.
Dave,
You are quite wrong on this, sir! Stainless is a combination of Nickel, Chromium, and high carbon steel. Most of it is totally non-ferrous. The low grades of stainless, from #304 or lower contain a small amount of ferrous iron. The higher grades of 308, 316, et al, including 440, do not contain any traces of ferrous iron. I am in the profession of dealing with most metals that are produced, and I had to go to school for 5 miserable, long, years on this subject in order to graduate and make the small bucks. I will look around and see if I can find one of my many charts that list the properties and costs of the different members of the steel family. Around here, stainless steel is known as "white gold". Best and good luck -
Senior Member
Posts: 563
Sure would like to hear her explain this, at least metallurically. Stainless steel is generally nothing more than an alloyed ferrous metal with a few percentage points more chrome, sometimes combined with other alloying elements IIRC.
Dave,
You are quite wrong on this, sir!
Stainless is a combination of Nickel, Chromium, and high carbon steel. Most of it is totally non-ferrous. The low grades of stainless, from #304 or lower contain a small amount of ferrous iron. The higher grades of 308, 316, et al, including 440, do not contain any traces of ferrous iron. I am in the profession of dealing with most metals that are produced, and I had to go to school for 5 miserable, long, years on this subject in order to graduate and make the small bucks. I will look around and see if I can find one of my many charts that list the properties and costs of the different members of the steel family. Around here, stainless steel is known as "white gold". Best and good luck -The Terminator
New member
Say whaaat ?
Sam,
Ferric oxide is the chemical reaction between iron and oxygen. Stainless does not contain iron, it will form an oxide with the air, but it will not be rust, nor will it have any appearance of rust it will be clear, and it will protect the metal below the surface it is on. Stainless contains high grade steel, which is created when oxygen is forced over iron in the manufacturing process. All metals form oxides when in contact with air, or, oxygen. A small amount of iron present in low grade stainless will cause "rust" or ferric oxide to appear on the surface. Stainless steel does form an oxide when in contact with air, but it is a totally non-ferrous oxide and it protects the finish of the metal. Ditto for aluminum, aluminum-oxide is harder than the aluminum underneath it, and it has a hotter melting temperature, around 4300F vs around 1230 melting point for aluminum. If you guys are really interested, I will scan a few pages from my books. They are in storage, so it will take me a day or two to dig them out.
Sam,
Ferric oxide is the chemical reaction between iron and oxygen. Stainless does not contain iron, it will form an oxide with the air, but it will not be rust, nor will it have any appearance of rust it will be clear, and it will protect the metal below the surface it is on. Stainless contains high grade steel, which is created when oxygen is forced over iron in the manufacturing process. All metals form oxides when in contact with air, or, oxygen. A small amount of iron present in low grade stainless will cause "rust" or ferric oxide to appear on the surface. Stainless steel does form an oxide when in contact with air, but it is a totally non-ferrous oxide and it protects the finish of the metal. Ditto for aluminum, aluminum-oxide is harder than the aluminum underneath it, and it has a hotter melting temperature, around 4300F vs around 1230 melting point for aluminum. If you guys are really interested, I will scan a few pages from my books. They are in storage, so it will take me a day or two to dig them out.
The Terminator
New member
Geez, what a bunch of smart fellers! I need to start reading the full thread before submitting an answer to the original post! I see terms and words used that I haven't seen in years, like austinitic, ferritic, martensitic, and precipatation hardened. I see "L" and non "L" types. Now, I am going to have to get a magnet and put it on my Kimber 45, and my Browning A bolt 375. Usually when I get involved in this subject matter, I am the only "expert" on the subject, but I ain't gonna dig no books out for you scholarly types around here. I can see that in this thread, I am no more knowledgeable than many that are involved. Yes, the Xerox phenomena it is. Best -
Usually when I get involved in this subject matter, I am the only "expert" on the subject, but I ain't gonna dig no books out for you scholarly types around here. I can see that in this thread, I am no more knowledgeable than many that are involved. Yes, the Xerox phenomena it is. Best -