Different types of steel are produced according to the mechanical and physical properties required for their application. Various grading systems are used to distinguish steels based on these properties, which include density, elasticity, melting point, thermal conductivity, strength, and hardness (among others). To make different steels, manufacturers vary the type and quantity of alloy metals, the production process, and the manner in which the steels are worked to produce particular products.
3 Types of Steel
According to the American Iron & Steel Institute (AISI), Steel can be categorized into four basic groups based on the chemical compositions:
- Carbon Steel
- Alloy Steel
- Stainless Steel
There are many different grades of steel that encompass varied properties. These properties can be physical, chemical and environmental.
All steel is composed of iron and carbon. It is the amount of carbon, and the additional alloys that determine the properties of each grade.
Classifications
Types of Steel can also be classified by a variety of different factors:
Types of Steel can also be classified by a variety of different factors:
- Composition: Carbon range, Alloy, Stainless.
- The production method: Continuous cast, Electric furnace, Etc.
- Finishing method used: Cold Rolled, Hot Rolled, Cold Drawn (Cold Finished), Etc.
- Form or shape: Bar, Rod, Tube, Pipe, Plate, Sheet, Structural, Etc.
- De-oxidation process (oxygen removed from steelmaking process): Killed & Semi-Killed Steel, Etc.
- Microstructure: Ferritic, Pearlitic, Martensitic, Etc.
- Physical Strength (Per ASTM Standards).
- Heat Treatment: Annealed, Quenched & Tempered, Etc.
- Quality Nomenclature: Commercial Quality, Drawing Quality, Pressure Vessel Quality, Etc.
Steel Numbering Systems
There are two major numbering systems used by the steel industry, the first developed by the American Iron & Steel Institute (AISI), and the second by the Society of Automotive Engineers (SAE). Both of these systems are based on four digit code numbers when identifying the base carbon and alloy steels. There are selections of alloys that have five digit codes instead.
There are two major numbering systems used by the steel industry, the first developed by the American Iron & Steel Institute (AISI), and the second by the Society of Automotive Engineers (SAE). Both of these systems are based on four digit code numbers when identifying the base carbon and alloy steels. There are selections of alloys that have five digit codes instead.
If the first digit is a one (1) in this designation it indicates a carbon steel. All carbon steels are in this group (1xxx) in both the SAE & AISI system. They are also subdivided into four categories due to particular underlying properties among them. See below:
- Plain Carbon Steel is encompassed within the 10xx series (containing 1.00% Mn maximum)
- Re-Sulfurized Carbon steel is encompassed within the 11xx series
- Re -Sulfurized and Re-Phosphorized Carbon Steel is encompassed within the 12xx series
- Non-Re-Sulfurized High-Manganese (up-to 1.65%) carbon steel is encompassed within the 15xx series.
The first digit on all other alloy steels (under the SAE-AISI system), are then classified as follows:
2 = Nickel steels.
3 = Nickel-chromium steels.
4 = Molybdenum steels.
5 = Chromium steels.
6 = Chromium-vanadium steels.
7 = Tungsten-chromium steels.
8 = Nickel-chromium-molybdenum steels
9 = Silicon-manganese steels and various other SAE grades
3 = Nickel-chromium steels.
4 = Molybdenum steels.
5 = Chromium steels.
6 = Chromium-vanadium steels.
7 = Tungsten-chromium steels.
8 = Nickel-chromium-molybdenum steels
9 = Silicon-manganese steels and various other SAE grades
The second digit of the series (sometimes but not always) indicates the concentration of the major element in percentiles (1 equals 1%).
The last two digits of the series indicate the carbon concentration to 0.01%.
For example: SAE 5130 is a chromium alloy steel containing about 1% of chromium and approximately 0.30% of carbon.
The last two digits of the series indicate the carbon concentration to 0.01%.
For example: SAE 5130 is a chromium alloy steel containing about 1% of chromium and approximately 0.30% of carbon.
Carbon Steel
Carbon Steel can be segregated into three main categories: Low carbon steel (sometimes known as mild steel); Medium carbon steel; and High carbon steel.
Low Carbon Steel (Mild Steel): Typically contain 0.04% to 0.30% carbon content. This is one of the largest groups of Carbon Steel. It covers a great diversity of shapes; from Flat Sheet to Structural Beam. Depending on the desired properties needed, other elements are added or increased. For example: Drawing Quality (DQ) – The carbon level is kept low and Aluminum is added, and for Structural Steel the carbon level is higher and the manganese content is increased.
Medium Carbon Steel: Typically has a carbon range of 0.31% to 0.60%, and a manganese content ranging from .060% to 1.65%. This product is stronger than low carbon steel, and it is more difficult to form, weld and cut. Medium carbon steels are quite often hardened and tempered using heat treatment.
High Carbon Steel: Commonly known as “carbon tool steel” it typically has a carbon range between 0.61% and 1.50%. High carbon steel is very difficult to cut, bend and weld. Once heat treated it becomes extremely hard and brittle.
Alloy Steels
Alloy steels are so named because they are made with a small percentage of one or more metals besides iron. The addition of alloys changes the properties of steels. For example, steel made from iron, chromium, and nickel produces stainless steel. The addition of aluminum can make steel more uniform in appearance. Steel with added manganese becomes exceptionally hard and strong.
Alloy steel is a steel that has had small amounts of one or more alloying elements (other than carbon) such as such as manganese, silicon, nickel, titanium, copper, chromium and aluminum added. This produces specific properties that are not found in regular carbon steel. Alloy steels are workhorses of industry because of their economical cost, wide availability, ease of processing, and good mechanical properties. Alloy steels are generally more responsive to heat and mechanical treatments than carbon steels.
The heat-treated type is available in both Annealed and Normalized. To learn more about Annealing and Normalizing, visit our Metal Glossary
Alloy Steel can be purchased online and at any Metal Supermarkets location. It can be cut to your exact specifications.
A333 PIPE SPECIFICATIONS
ASTM A333 covers nominal (average) wall seamless and welded carbon and alloy steel pipe intended for use at low temperatures. Several grades of ferritic steel are included. Some product sizes may not be available under this specification because heavier wall thicknesses have an adverse affect on low-temperature impact properties.
Chrome Moly Pipe
Chrome Moly Pipe has become a standard in the power generation industry and the petrochemical industry, not only because of its tensile strength, corrosion resistance and high-temperature strength, but also because of its cost-effectiveness. Grades P-11, P-22 – P-91 & P-92 are prevalent grades for the power industry, while P-5 & P-9 are the grades utilized in major refinery processing.
Common applications include food handling/processing, medical instruments, hardware, appliances, and structural/architectural uses.
Available standard and specification as below:
ASTM / ASME
American Society for Testing and Materials(ASTM), American Society of Mechanical Engineers (ASME)
| Product name | Executive standard | Dimension (mm) | Steel code/ Steel grade |
| Seamless Ferritic and Austentic Alloy Steel Boiler, Superheater and Heat-Exchanger Tubes | ASTM A213 | 10.3~426 x 1.0~36 | T5, T9, T11, T12, T22, T91 |
| Wwall seamless and welded carbon and alloy steel pipe intended for use at low temperatures | ASTM A333 | 1/4″~42″ x SCH20~XXS | Gr1, Gr3, Gr6 |
| Seamless Ferritic Alloy Steel Pipe for High-Temperature Service | ASTM A335 | 1/4″~4″ x SCH20~SCH80 | P5, P9, P11, P12, P22, P91, P92 |
| Seamless Carbon and Alloy Steel for Mechanical Tubing | ASTM A519 | 16″~42″ x 10~100mm | 4130, 4130X, 4140 |
EN
| Product name | Executive standard | Dimension (mm) | Steel code/ Steel grade |
| Seamless Ferritic Alloy Steel Pipes for High Temperature Use | EN 10216-2 | 8″~42″ x 15~100mm | 13CrMo4-5, 1-CrMo9-10, X10CrMoVNb9-1, 15NiCuMoNb5-6-4 |
In Length of : Standard length, Double length & In Cut length also.
Other Services : Draw & Expansion as per required Size & Length, Heat Treatment, Bending, Anneling, Machining Etc.
Specialize : Heat Exchanger & Condenser Tubes
Other Services : Draw & Expansion as per required Size & Length, Heat Treatment, Bending, Anneling, Machining Etc.
Specialize : Heat Exchanger & Condenser Tubes
The Advantages Of Alloy Steel Pipe
The alloy steel pipe adopts high quality carbon steel, alloy structural steel and stainless & heat resisting steel as raw material through hot rolling or cold drawn to be made.
The main applications of alloy steel pipe is power station, nuclear power plant, high pressure boiler, high temperature superheater and re-heater coil etc. of high temperature pipeline and equipments.
The advantages of alloy steel pipe: 100% recycled, it is suitable for the national strategy of environmental protection, energy-saving and resource-saving. Therefore, the national policy encourages the expansion of the high pressure alloy steel pipe applications.
At present, the proportion of the total alloy steel tube is half of the developed countries. The applications of alloy steel pipe provide a broad space for the industry development. According to the research of the China association of special steel alloy pipe expert group, our country’s high pressure alloy steel pipe material demand grows by an average of up to 10-12%.
Stainless Steels
Stainless steel is a steel alloy with increased corrosion resistance compared to carbon/alloy steel. Common alloying ingredients include chromium (usually at least 11%), nickel, or molybdenum. Alloy content often is on the order of 15-30%.
- Austenitic steels, which are very high in chromium, also contain small amounts of nickel and carbon. These are very commonly used for food processing and piping. They are valued, in part, because they are non-magnetic.
- Ferritic steels contain about 15% chromium but only trace amounts of carbon and metal alloys such as molybdenum, aluminum, or titanium. These steels are magnetic, very hard and strong, and can be strengthened further by cold working.
- Martensitic steels contain moderate amounts of chromium, nickel, and carbon, They are magnetic and heat-treatable. Martensitic steels are often used for cutting tools such as knives and surgical equipment.
Stainless steel pipe Available Grades
Additionally, many austenitic stainless steels are weldable and formable. Two of the more commonly used grades of austenitic stainless steel are grades 304 and 316. To help you determine which grade is right for your project, this blog will examine the difference between 304 and 316 stainless steel.
Stainless Steel 304/304L
Excellent mechanical properties, resistance to many corrosive agents. Useful where sanitation and cleanliness are important. Non magnetic in the annealed condition. Hardness and tensile strength can be increased by cold working, but modified by lowered carbon content providing good resistance to corrosion in welded construction where subsequent heat treatment is not practical. Grade 304L (L= low carbon) is the same as the above except it has an extra-low-carbon analysis, the advantage of which is that it precludes any harmful precipitation in the 800º F to 1500º F range, such as might otherwise occur in welding heavier sections.
Typical Applications: Dairy, beverage and food product handling/processing equipment. Used for handling acetic, nitric, and citric acids; organic and inorganic chemicals, dye stuff, crude and refined oils; instruments; hospital equipment; applications requiring welding.
Available products: Round Bar, Rectangular Bar, Square Bar, Hexagonal Bar, Channel, Beam, Angle, Flat Sheet, Expanded Mesh,Perforated Sheet, Plate, Floor Plate, Pipe, Round Tube, Square Tube and Rectangular Tube
Typical Chemical Analysis: * C – .08 Max. *Mn – 2.00 Max. *P – .04 Max. *S – .03 Max. *Si – 1.0 Max. *Cr – 18.00/20.00 *Ni – 8.00/10.50 *Cu – .75 Max. *Mo – .75 Max.
Excellent mechanical properties, resistance to many corrosive agents. Useful where sanitation and cleanliness are important. Non magnetic in the annealed condition. Hardness and tensile strength can be increased by cold working, but modified by lowered carbon content providing good resistance to corrosion in welded construction where subsequent heat treatment is not practical. Grade 304L (L= low carbon) is the same as the above except it has an extra-low-carbon analysis, the advantage of which is that it precludes any harmful precipitation in the 800º F to 1500º F range, such as might otherwise occur in welding heavier sections.
Typical Applications: Dairy, beverage and food product handling/processing equipment. Used for handling acetic, nitric, and citric acids; organic and inorganic chemicals, dye stuff, crude and refined oils; instruments; hospital equipment; applications requiring welding.
Available products: Round Bar, Rectangular Bar, Square Bar, Hexagonal Bar, Channel, Beam, Angle, Flat Sheet, Expanded Mesh,Perforated Sheet, Plate, Floor Plate, Pipe, Round Tube, Square Tube and Rectangular Tube
Typical Chemical Analysis: * C – .08 Max. *Mn – 2.00 Max. *P – .04 Max. *S – .03 Max. *Si – 1.0 Max. *Cr – 18.00/20.00 *Ni – 8.00/10.50 *Cu – .75 Max. *Mo – .75 Max.
Stainless Steel 316/316L
Pump shafts and parts in machinery used to process paper, textiles, chemicals and pharmaceuticals. In aircraft applications, used for parts requiring low magnetic permeability and good corrosion resistance.
Grade 316 is a standard molybdenum-bearing grade, the second most commonly sought after grade next to grade 304 amongst the austenitic stainless steels. The molybdenum gives 316 better overall corrosion resistant properties than Grade 304, particularly higher resistance in chloride environments. Grade 316L (L= low carbon) ) is the same as the above except it has an extra-low-carbon analysis, the advantage of which is that it precludes any harmful precipitation in the 800º F to 1500º F range that might result from welding heavier sections. Therefore 316L is extensively used in heavy gauge welded components. Typically there is no price difference between 316 and 316L stainless steel.
Pump shafts and parts in machinery used to process paper, textiles, chemicals and pharmaceuticals. In aircraft applications, used for parts requiring low magnetic permeability and good corrosion resistance.
Grade 316 is a standard molybdenum-bearing grade, the second most commonly sought after grade next to grade 304 amongst the austenitic stainless steels. The molybdenum gives 316 better overall corrosion resistant properties than Grade 304, particularly higher resistance in chloride environments. Grade 316L (L= low carbon) ) is the same as the above except it has an extra-low-carbon analysis, the advantage of which is that it precludes any harmful precipitation in the 800º F to 1500º F range that might result from welding heavier sections. Therefore 316L is extensively used in heavy gauge welded components. Typically there is no price difference between 316 and 316L stainless steel.
Typical Chemical Analysis:
- * C – .08 Max. *Mn – 2.00 Max. *P – .04 Max. *S – .03 Max. *Si – 1.0 Max.
- *Cr – 16.00/18.00 *Ni – 10.00 – 14.00 *Cu – .75 Max. *Mo – 2.00/3.00 Max. *N – .10 Max.
Typical Mechanical Properties**:
| Data | Cold Finish (under 1⁄2” dia) | Cold Finish (over 1⁄2” dia) | Hot Rolled |
|---|---|---|---|
| Tensile Strength (PSI) | 90-125,000 | 75,000 Min. | 75-115,000 |
| Yield Point (PSI) | 45,000 Min. | 30,000 Min. | 30,000 Min. |
| Elongation | 35 Min. | 35 Min. | 40 Min. |
Chemical Analysis will vary on each heat number
All values are minimum values and are representative.
All values are minimum values and are representative.
Types of Stainless Steel
The three main types of stainless steels are austenitic, ferritic, and martensitic. These three types of steels are identified by their microstructure or predominant crystal phase.
- Austenitic: Austenitic steels have austenite as their primary phase (face-centered cubic crystal). These are alloys containing chromium and nickel (sometimes manganese and nitrogen), structured around the Type 302 composition of iron, 18% chromium, and 8% nickel. Austenitic steels are not hardenable by heat treatment. The most familiar stainless steel is probably Type 304, sometimes called T304 or simply 304. Type 304 surgical stainless steel is an austenitic steel containing 18-20% chromium and 8-10% nickel.
- Ferritic: Ferritic steels have ferrite (body centered cubic crystal) as their main phase. These steels contain iron and chromium, based on the Type 430 composition of 17% chromium. Ferritic steel is less ductile than austenitic steel and is not hardenable by heat treatment.
- Martensitic: The characteristic orthorhombic martensite microstructure was first observed by German microscopist Adolf Martens around 1890. Martensitic steels are low carbon steels built around the Type 410 composition of iron, 12% chromium, and 0.12% carbon. They may be tempered and hardened. Martensite gives steel great hardness, but it also reduces its toughness and makes it brittle, so few steels are fully hardened.
There are also other grades of stainless steels, such as precipitation-hardened, duplex, and cast stainless steels. Stainless steel can be produced in a variety of finishes and textures and can be tinted over a broad spectrum of colors.
