Steel plate

Abbreviation	Full description
ASTM International	American Society for Testing and Materials
ANSI	American National Standards Institute
AISC	American Institute of Steel Construction
AISI	American Iron & Steel Institute
ASCE	American Society of Civil Engineers
ASME	American Society of Mechanical Engineers
AWS	American Welding Society

Iron and carbon are the most abundant materials present in steel. Pure iron is not particularly strong or hard on its own, so it is the addition of carbon that helps give steel its great strength.

The crude iron used to produce steel has a relatively high amount of carbon. Its carbon composition can be as high as 2.1%, which is the greatest amount of carbon a material can contain and still be considered steel.

However, iron can be processed further to reduce carbon. This manipulation of carbon alters several material properties, including:

Strength: The load a material can bear, measured by yield point and tensile strength. Yield point is the point at which a material deforms, but does not break, and tensile strength is the amount of stress needed to actually break a material.

Ductility: The amount a material can be stretched without becoming brittle. Ductility is measured by elongation, which is the percent the length of a material increases before it breaks.

Hardness: The wear resistance of material and machinability of material. This is usually measured on the Rockwell hardness scale or Brinell Hardness scale.

The carbon present in steel is typically reduced so that it fits into three main categories of carbon steel: low (or mild), medium and high carbon steel. Each of these categories contain different levels of carbon, show in the chart below.

Type of carbon steel	Carbon composition
Low carbon/mild	0.05-0.25%
Medium carbon	0.26-0.60%
High carbon	0.61-1.50%

Carbon steel plate almost include all the common standards of steel plate/sheet.

1. ASTM A36 plates – The most common standards of carbon steel plate
2. ASTM A283 Grade A, B, C – Also most common material in carbon structural.
3. ASTM A516 – For boiler, vessel steel plate.
4. ASTM A537 – For heat treated carbon steel plate in fusion welded pressure vessels and structural steel plates.
5. ASTM A573 – A kind of structural steel plate with carbon-manganese-silicon.
6. ASTM A572 – ASTM A572 plate mechanical strength is higher than A36. Where with lower weight.
7. ASTM A737 – For boiler, pressure vessels steel plate of low alloy steel. and etc..

So carbon steel plates have a widely coverage for different types of steel plates in different industries.

Also known as mild steel, low carbon steel has low strength relative to steel with higher carbon levels. Low carbon steel is the most ductile – or machinable – type of carbon steel as well.

Chemical alloys can also be added to low carbon steel to enhance desired properties without increasing the material’s weight. For example, if low carbon steel requires greater hardness for its desired application, manganese can be added to increase hardness without adding weight. Low carbon steel that contains additional alloys is typically referred to as high strength, low alloy (HSLA) steel.

Some of the most common low carbon steel plate grades, all stocked by us, include ASTM A36, A572 Grades 42 & 50 and A830-1020. Each of these grades have moderate strength, high ductility and lighter weight due to the low carbon content and addition of other alloys. These properties make low carbon steel ideal for use in structural applications like building construction, bridges and transmission towers, where materials must be able to withstand high stress while also being easy to form into structural shapes.

Medium carbon steel provides a balance between low and high carbon steel, offering greater strength and hardness than low carbon steel while still remaining more ductile than high carbon steel. Medium carbon steel also typically contains other alloys, such as manganese, that also contribute to its properties.

In applications where greater toughness and hardness are required, medium carbon steel plate can receive heat treatments – such as quenching and tempering – that enhance these properties without compromising its machinability.

Quenching and tempering is a two-step heat treatment process. In the quenching step of this process, steel is heated to a temperature between 1,500-and 1,650-degrees Fahrenheit, then rapidly cooled with water. In the tempering step, the steel is then re-heated to a below-critical temperature – between 300 and 700 degrees – and air-cooled. This process alters the crystal grain structure of steel to enhance hardness and other mechanical properties.

Two common medium carbon steel plate grades that stocks are ASTM A516 Grade 70 and A830-1045. The moderate carbon composition and additional alloys give these grades – and other medium carbon grades – a balance of strength, hardness, ductility and wear resistance. These properties make medium carbon steel ideal for use in applications where materials must withstand strong forces without breaking or wearing out, such as machine parts – including gears, axles and bolts – pressure vessel tanks and automotive parts and components.