High-quality steel is widely used in many industrial and commercial applications. It is strong, durable and can withstand very high temperatures. The type of steel used in a particular application depends upon the desired mechanical properties and expected service life of the end product. In general, higher quality steels are more expensive and can be harder to find. To ensure proper selection and availability in the marketplace, the following table provides a comparison of commonly used domestic steel numbers with their corresponding imported steel numbers.
Domestic Steel Number Imported Steel Number
A108 S235JR
A36 SS400
A36 Q235B
SAE 1020 S20C
SAE 1045 C45/C45E
SAE 1060 C60
SAE 4140 SCM440
SAE 5160 SUP9
SAE 8620 8620
HSLA A1008 SPFC490
HSLA A569 DD11
When selecting steel for a particular application, it is important to consider its chemical and mechanical properties as well as its cost. A fundamental understanding of each steels physical and chemical characteristics will allow the end user to make an informed decision. A number of factors which should be taken into consideration include: yield strength, tensile strength, ultimate strength, ductility, toughness and fatigue strength.
Yield strength is the pressure at which a material will begin to deform permanently. Tensile strength is the maximum pressure the material can withstand before it breaks. Ultimate strength is the maximum pressure the material can withstand before failure. Ductility is a measure of how much a material can be bent, stretched or compress without breaking. Toughness describes how a material will respond to impacts and sudden force. Finally, fatigue strength is the amount of stress that a material can withstand cyclically over a period of time.
Each steel number has a standard chemical composition which will determine its various mechanical properties. Carbon, sulfur and phosphorus are the main components in the chemical composition of steel. The amount of each is determined by its steel number. For example, A36 steel is typically composed of 0.26% carbon, 0.40% sulfur and 0.045% phosphorus. In comparison, SAE 4140 steel is composed of 0.38-0.43% carbon, 0.17-0.37% sulfur and 0.030% phosphorus.
In addition to the type of steel (domestic or imported), other important factors that should be taken into consideration when selecting steel for an application include the grade, or strength level of the steel, as well as its formability, weldability, and cost. Grade, formability and weldability can all be affected by the treatment of the steel such as hot or cold rolling and heat treating. The cost of the steel will be affected by its availability, quantity, and the particular alloy chosen.
Finally, the end user should consider corrosion resistance when selecting the appropriate steel. Many kinds of steel have increased corrosion resistance by adding certain elements to the alloy, such as chromium or nickel. This is especially important when selecting steel for outdoor or marine applications.
In summary, there are several important factors to consider when selecting the appropriate steel for an application. Comparing the appropriate domestic and imported steel numbers is an excellent starting point for selecting the right steel for the job. It is important to consider the chemical composition, mechanical properties, grade, formability, weldability, corrosion resistance and cost of the steel, as well as its availability and proper application. With the right knowledge and proper selection strategies, the end user can select the most appropriate steel for their particular application.
