Is stainless steel considered as alloy steel? 2

[Sam Low]

Hi Guys!

I would like to clarify if stainless steel material defined as alloy steel ?
As far as I concerned, technically all the steels are considered as alloy steel since they are content other elements besides carbon and ferrous (which is carbon steel).

For example;
Stainless steel - Iron alloy steel
Hastelloy - Nickel alloy steel


Please confirm if my concept is correct. Thanks!

 

[hydtools]

"Steel" is an iron carbon alloy. Add other ingredients and it is still alloy steel.

Ted

 

[Scuka]

Alloying element is one which is intentionally added to modify the properties of metal.
Does your stainless steel have that?

technically all the steels are considered as alloy steel

No they're not ALL alloy steels, because even though they have elements other than Fe and C in them, they're impurities, not something that has been added with the purpose of modifying the properties.

If you attach the term "alloy steel" to all steels, you basically destroy its meaning and defeat the point of having the term in the first place.

 

[Geoff13]

Some codes provide rules on this.

For instance ASME Section VIII Division 1 lists "carbon and low alloy" steels in Table UCS-23, "high alloy" steels in Table UHA-23, and "non-ferrous" steels in Table UNF-23.1 thru 23.5.

When I hear stainless steel I think of materials like SA-240 plate, and this is "high alloy" in ASME's classification system. Not sure what Hastelloy is and whether it fits in Table UHA-23 or Table UNF-23.3.

 

[EdStainless]

Stainless steel is only called steel because it is common name for iron based alloy, most are not steels at all since they so low in C. The stainless grades do not fit the 'alloy steel' nomenclature.
Nickle alloys are very much not steels, they are Ni based alloys period.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[drawoh]

Sam Low,

The term "alloy steel" generally is used to indicate high[‑]strength steel. Some stainless steel alloys actually are rather soft. "Alloy steel" is carbon steel which requires protection from rust. In the absence of a formal code defining terms, I would make the distinctions above.

--
JHG

 

[TheTick]

I'm curious as to why this is a question? Did some hack specify "alloy" steel on a drawing?

 

[Sam Low]

Hi Scuka/hydtools/EdStainless/drawoh,

I should say that carbon steel is the steel found in nature which born naturally and without any additive element in the material.
Alloy steel is a material formed by adding different elements into the carbon steel to make it having different properties, such as Chromium, Nickel, Manganese etc.

So stainless steel can be concluded as a high alloy steel with chromium additive which is also defined in ASME Section VIII Div 1 (since it is under section "UHA" = High alloy)

I totally agreed with Geoff13.
Thanks guys!

Hi Thetick,

Some of the project specification mention the requirements for carbon steel, low alloy steel and high alloy steel but they never mentioned SS.
That is the reason why I have to look into the definition of alloy steel since the material we used in the project is SS.

Please take a look in the attached photo ya.

 

[hydtools]

Iron is the natural element.
Add anything to it and you have ferrous alloy.

Ted

 

[drawoh]

Hi Scuka/hydtools/EdStainless/drawoh,

I should say that carbon steel is the steel found in nature...

The element is iron. Pure iron normally is not found in nature. It becomes steel when you add carbon to it. "Carbon steel" is a redundancy. We need agreed upon terms so that we can intelligently discuss stuff. "Alloy steel" normally means high[‑]carbon, high[‑]strength, probably heat[‑]treated steel. "Stainless steel" normally means an alloy of iron, nickel and chrome, which is corrosion resistant, and which may or may not be high strength.

If this matters, you need to clear about your requirements, and you need to call up your materials by alloy number.

--
JHG

 

[weldstan]

Very few metals like gold, silver, copper, tin etc., are found in nature on earth and steel (iron) isn't one of them.

 

[gtaw]

I guess it depends on what text you read. In my mind I simplify things as much as I can. I use the following:

Steel - ferrous alloys, i.e., iron based.
Carbon steels - low carbon steel, medium carbon steel, high carbon steel
Microalloyed steel - similar to low alloy
Low alloy steels - carbon, manganese, chrome, nickel, vanadium, etc. added to the iron
High alloy steels - depending on the particular alloy, higher percentage of manganese, chrome, etc.
Stainless steels - martensitic, ferritic, austenitic, duplex, P&H
Advanced high strength steel - heat treated to obtain the desired mechanical properties
Quenched and tempered steels - heat treated to obtain the desired mechanical properties
Thermo-mechanically enhanced steels - often microalloyed and rolled at lower temperatures than hot rolled steels
Bidirectional rolled steels - rolled in two directions perpendicular to previous direction of rolling to reduce anisotropic properties
I'm sure there are other families that I missed, but it gives an idea of the variants all belonging to the grand family of "steel".


Best regards - Al

 

[EdStainless]

Except for the few odd metals that Stan mentioned all others are found as dirt, oxides or sulfides usually.
They must then be smelted and refined to obtain metals.
There are some odd high Fe ores found in nature from which it is fairly easy to make a usable metal. We would only call these steels because they are Fe based, they do not resemble modern steels.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[harrislee12345]

hi, yes, i think it is. Steel is made of iron and carbon, and this is the same across stainless and carbon steel. What makes stainless steel different is the presence of chromium. To be stainless, the steel must contain at least 10.5% chromium. This is compared to carbon steel, which is made of iron and carbon with very few other materials present in the alloy. For this reason, carbon steel is sometimes referred to as a low-alloy steel. More about Stainless steel, alloy steel, tool steel, high speed steel, mould steel, spring steel, nickel alloy www.fushunspecialsteel.com

 

[TheTick]

Make an engineering decision and specify one or more specific grades of steel. Terms like "low alloy" and "high alloy" are for conference room chatter with muggles.

 

[abdulbadii]

Out of question, it, of course, is

Simply there's no steel element on earth, so the name is a telltale to us it is an alloy
There're matter elements such Fe, C, Ni, Cr, Co, Ti, V etc, but no e.g. St to mean 'steel' element

 

[CIVIL EXPERIENCES]

Hello friends. Today’s article is it is kind of a general lecture on alloy steel designation and some processing methods which we use for making or for processing bulk materials and that we will discuss today in the Civil Experience blog article

Here, you will learn about:

[ul]
[li]Types of alloy steel[/li]
[li]Properties of alloy steel[/li]
[li]Production and processing of alloy steel[/li]
[li]Applications and application areas of alloy steel[/li]
[/ul]

Alloy designation first, an alloy which is most important and widely used is steel and in steel, there are different alloy steel grade is available

These are given by designation provided by these 2 agencies AISI is the American Iron and Steel Institute and SAE is the Society of Automotive Engineers. Because these 2 agencies are responsible for making the grades or making the designation for the grades for different materials

Types of Alloy Steel
There are various subcategories of alloy steel which include:

[ol 1]
[li]Low-alloy steel[/li]
[li]High-strength low alloy (HSLA) steel[/li]
[li]High-alloy steel[/li]
[li]Stainless steel[/li]
[li]Microalloyed steel[/li]
[li]Advanced high-strength steel (AHSS)[/li]
[li]Maraging steel[/li]
[li]Tool steel[/li]
[/ol]

Generally, low alloy steels contain less than 8 wt.% non-iron elements, whereas high-alloy steels contain more than 8 wt.% non-iron elements. Both have typically superior mechanical alloy steel properties in comparison to carbon steels.

Read full more than 5000+ word article from the source link

https://www.civilexperiences.com/20...nation-properties-processing-application.html

Civil Experience Blog

 

[drawoh]

CIVIL EXPERIENCES,

If it does not matter, I will specify steel. If it matters, I will specify STEEL 4130, plus a heat treat. I don't think there is a practical grey area between those two.

--
JHG

 

[SSCon]

You should probably clarify why you're asking the question, these terms can have different practical meanings across different industries/ standards. E.G. CRA (Corrosion Resistant Alloy) could in general terms include stainless steels but in some standards almost no stainless steels would meet the criteria.

Regarding Hastelloy, it is not a steel but simply a Nickel alloy.

 

[Rex Hang]

Stainless steel is a corrosion-resistant alloy of iron, chromium and, in some cases​, nickel and other metals. Alloy steels are made by combining carbon steel with one or several alloying elements.