Today let's understand the types of steels available.
There are four main steel that we can categorized. The best way to remember this is to remember by CAST.
C arbon Steel
A lloy Steel
S tainless Steel
T ool Steel
Let's look at each steel and it's use.
Carbon Steel
It is made from mixing steel and carbon. And with depending on how much carbon is added the strength of the steel will change and it will categorized by three category. Low, Medium and High. The higher the carbon content, it will be harder to weld and bend which makes it harder to work with.
Low Carbon Steel (0.04~0.30% Carbon) : Most common steel in the market. Used in basic structural beams, bars, tubes, sheets, screws, gates, fences.
Medium Carbon Steel (0.31~0.60% Carbon) : Used in structurally in buildings and bridges, axles, gears, shafts, rails, pipelines and couplings, cars, fridges
High Carbon Steel (0.61~1.00% Carbon) : Used in making cutting tools, blades, punches, dies, springs and high-strength wire.
Ultra High Carbon Steel (1.01~2.00%) : Used in making extremely hard components like blades, cutting tools and large machine parts, hot water radiators, industrial castings and it’s also called ‘cast iron’ (ie. Cast Iron Pan)
Alloy Steel
It is made from mixing steel with one or more other elements such as titanium, nickel and etc... By combining different type of elements will gives the steel a different specs.
Aluminium – Removes oxygen, sulfur, and phosphorus from steel.
Chromium – Adds hardness. Increased toughness and wear resistance.
Cobalt – Used in making cutting tools; improved Hot Hardness (or Red Hardness).
Copper – Improves hardening and corrosion resistance.
Manganese – Increases surface hardness. Improves resistance to strain, hammering & shocks.
Molybdenum – Increases strength. Improves resistance to shock and heat.
Nickel – Increases strength & toughness. Improves corrosion resistance.
Tungsten – Adds hardness and improves grain structure. Provides improved heat resistance.
Titanium – improves hardness and strength.
Vanadium – Increases strength, toughness and shock resistance. Improved corrosion resistance.
Stainless Steel
Stainless Steel as everybody might have heard is what the name says, it has a strong resistant to rusts and stains.
A lot of people might be mistaken or think that Stainless Steel is a family under Alloy Steel. Well you are not wrong, however stainless steel uses one concentrated element which is chromium contains at lease 10~20% to achieve its performance to become stainless steel. It is 100% recyclable when it reaches it's end of it's
Stainless Steel has it's many uses. In this modern architectural era, most external steel cladding uses stainless steel. For example the famous Walt Disney Concert Hall designed by Frank Gehry's external finishes are all made from stainless steel.
Also having a project that is related to medical facilities highly relies on stainless steel for hygienic purpose.
There is 5 types of Stainless Steel
Austenitic Stainless Steel - Contains 7~9% Nickel
It makes it non magnetic, more ductile and more reactive to temperature. Great use for cooking utensils
Ferritic Stainless Steel - Contains standard chromium with less than 0.1% Carbon
It has a great ductility and formability. However overheating the materials can have a brittle result. It is commonly use for auoomotive applications, kitchenwares and industrial equipments.
Martensitic Stainless Steel - Contains standard chromium with carbon ranging between 0.1 ~ 1.5%
It is similar to Ferritic Stainless Steel, however with more carbon content it can he heated to higher temperatures to increase the hardness to lower its brittleness. Mainly used in cutlery and multipurpose tools.
Duplex Stainless Steel - It's a combination of 50% Austenitic and 50% Ferritic Stainless Steel
Duplex is twice as strong as regular austenitic and ferritic stainless steel, however due to it's strength it is not as easily formed. It is becoming more common due to its lover prices and it is highly used in chemical plants and piping.
Precipitation Hardening Stainless Steel
This type of still is different because of its heat treatment process to achieve very high strength and corrosion resistance. Also the hardening is achieved by containing more elements with such aluminium, titanium, copper and etc... Most commonly used in Gears, Valves, High strength Shafts, Turbine Blades and etc...
Tool Steel
Tool steel refers to a variety of carbon and alloy steels (ie. tungsten, molybdenum, cobalt and vanadium) is mixed together to increase durability and heat resistance of the metal for well-suited to be made into tools. There are 6 types of Hardening process which are; Water Hardening, Air Hardening, D Type, Oil Hardening, Shock Resisting Types and Hot-Working.
Unfortunately I do not have the confidence to share this knowledge. The worst thing I can do is to give you a false information and I suggest you to call up the experts and potentially share this knowledge with me. LOL
Hope this will help. We as architects use and work a lot with steels. I believe it is crucial to understand the basic of steel so that when you specify steel for your design, you know exactly which steels you are working with. Next let's look at some coatings for steel
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TK