Steel FAQs
Below you will find a list of most frequently asked questions relating to steel, steel grades, alloy steel, and more.
What is a Steel Grade?
Steel is a uniquely versatile combination (alloy) of iron and carbon. The iron atoms can organize themselves in several different three-dimensional geometric arrangements (called lattice structures). The carbon atoms can occupy several different locations between the iron atoms. Different heating and cooling paths result in different arrangements of the iron and carbon atoms. Adding other chemical elements changes the mechanical properties of the steel and its response to heat treatment.
A “Steel Grade” is a defined chemistry that has been made and processed in a particular way. (A “Standard” specifies away of doing something. It might be a test method, a packaging method, or a delivery protocol.)
ASTM Grades meet the exacting standards for specific grades of steel developed by the American Society for Testing and Materials. The standards include mechanical properties and steel chemistries and specify the testing methods to be used. For some grades, additional steelmaking and thermal processing is also specified. You can be confident that these steel plates will meet your customer’s expectations.
Other organizations in other countries have specifications that use different letter and number combinations for the same or similar steel chemistries (SAE, EN, DIN, JIS, etc.).
Rely on Steel Warehouse to provide quality, steel grades & standards at competitive prices.
Figure from MICROALLOYED STEELS FOR THE AUTOMOTIVE INDUSTRY by Debanshu Bhattacharya
What do Steel Grade Numbers Mean?
For SAE/ASTM 10XX steels, the last two numbers are the approximate carbon content. For example, 1008 steel contains about 0.08% carbon and 1018 steel contains about 0.18% carbon.
What is Alloy Steel?
Alloy steels contain significant amounts of elements other than carbon. These alloying elements increase hardness, strength, or chemical resistance, while also saving weight. The elements most commonly added to make alloy steels are: silicon, copper, nickel, chromium, manganese, tungsten, molybdenum, and vanadium.
Effects of Alloying Elements
| Element | Positives | Negatives |
| Carbon (C) | Increases strength and hardness | Reduces ductility, toughness, and weldability |
| Manganese (Mn) | Increases strength and hardness. Mitigates Sulfur (S) | |
| Phosphorus (P) | Increases strength and hardness. Reduces corrosion | Decreases ductility and toughness. Segregates |
| Sulfur (S) | Improves machinability | Decreases ductility and toughness. Reduces weldability |
| Silicon (Si) | Added to "tie-up" Oxygen | |
| Aluminum (Al) | Added to "tie-up" Oxygen. Similar grain size to increase strength and toughness | |
| Vanadium (V) | Increases strength | |
| Niobium (Cb, Nb) | Increases strength | |
| Chromium (Cr) | Increases strength. Slows corrosion | |
| Copper (Cu) | Slows corrosion | |
| Nitrogen (N) | Increases strength and hardness | |
| Boron (B) | Increases hardenability | |
| Titanium (Ti) |
What Causes Steel Defects?
Steel is made by a series of processes. First, steel is melted. While the steel is molten, some elements like sulfur are removed and some elements like manganese, vanadium, and boron are added. Elements that are removed to make one grade of steel to make it more formable will be added to a different grade of steel to make it stronger. Next, elements like silicon and aluminum that combine with oxygen to make solid compounds that have high melting temperatures are added to keep the oxygen from forming compounds that might melt when the steel is heated for rolling. These compounds can remain as microscopic particles, called ‘inclusions’. Current steel making practices have greatly reduced the size and frequency of these inclusions.
The liquid steel is ‘cast’ – cooled, to freeze it. It is then either rolled immediately while the solidified steel is still hot, or completely cooled and reheated and rolled later. Surface defects introduced during casting and rolling that could cause surface cracking and tearing are removed. Both the internal inclusions and surface cracks can cause defects when you form the steel to make a final product. We will help you select a steel grade that economically meets the internal and surface requirements for your product. Contact Us Today!
How Do I Select the Most Appropriate Steel Grade?
Consider Strength, Formability, Corrosion Resistance, Weight, Chemistry, Cost, and Recommended uses.
To explore on your own, A36 steel is a good place to start. It is a low carbon steel with good strength coupled with formability. It is easy to machine and fabricate and can be securely welded. From there, you can see how improved properties – stronger, more bendable, more resistant to corrosion – will be an even better match for you.
Consider Strength, Formability, Corrosion Resistance, Weight, Chemistry, Cost, and Recommended uses.
Strength is measured as a force per unit area until the steel begins to stretch (Yield Strength) or break (Tensile Strength, in kilo(1000)-pounds per square inch (ksi), or Mega-Pascal (MPa).
1 ksi = 6.9 MPa (As a simple approximation, 100 ksi ~ 700 MPa)
Formability is how much you can stretch the surface before cracks appear, measured as the % Elongation of the original piece.
We will be glad to personally guide you through the selection process. Contact Us Today!
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