What Is S2 Steel? Common Uses And How It Is Made?

S2 Steel

S2 steel is a type of shock-resisting alloy steel. As a class of tool steels, they are specifically designed to resist damages caused by heavy impacts, such as from the likes of an earthquake or explosion. It is manufactured by melting iron, carbon, silicon, and other materials together.

Such shock-resistant steels are called “Group S” steels, and they can be categorized in 7 types by the AISI (American Iron and Steel Institute) classification system. They are S1, S2, S3, S4, S5, S6, and S7. 

By tweaking their chemical composition, you can control the toughness of Group S steels. The common element in the composition of these steels is silicon because it enhances the steels’ strength and creates a tempering-resistant micro-structure. 

Now that you have an idea of the different types of Group S steels, let’s take a closer look at the features, applications, and properties of S2 steels. 

S2 Steels Features

The following features distinguish S2 alloy steel from the rest.

  • Can be welded using standard methods
  • While in the annealed condition, S2 steel can be coldworked
  • Conventionally machinable and formable

Common Uses Of S2 Steels

Because of its resistance to high-impact shocks, S2 steels are used for manufacturing tools, such as hammers and chisels, that have repetitive, hard-impact applications. It is also widely used for manufacturing ball bearings, especially in the mining industry. Some screwdrivers and bits are made with S2 steel as well.

S2 Steel

How Are S2 Sheets Of Steel Made?

S2 steels are made by mixing alloying elements, such as silicon, carbon, iron, manganese, and so on, at extremely high temperatures. Below, you will find an overview of the chemical composition of S2 steel.

Chemical Composition of S2 Steels

Iron (Fe)97.0%
Silicon (Si)1.05%
Carbon (C)0.4-0.55%
Molybdenum (Mo)0.4%
Manganese (Mn)0.4%
Vanadium (V)≤0.5
Phosphorus (P)≤0.03
Sulfur (S)≤0.03

Physical Properties

The following table summarizes the physical properties of S2 sheet steels.

Physical Properties of S2 Steel

Density7.79 g/cc0.281 lb/in3
Melting Point1421°C2590°F

Mechanical And Thermal Properties

The mechanical and thermal properties of S2 alloy steel are listed below.

Mechanical and Thermal Properties of S2 Steel

S2 Steel

Smelting Options

The smelting options for S2 sheet steels are as follows.

Smelting Options for S2 Steel

EAFElectric Arc Furnace
EAF+ESREAF and Electro Slag Remelting
VIM+PESRVacuum Indication Melting and Pressure Electro Slag Remelting 
EAF+LF+VDEAF, VD, and Ladle Refining

Other Designations

The following designations are considered equivalent to S2 sheet steels. These specifications or standards cover S2 steels.

  • ASTM A681

ASTM A681 specification measures the mechanical, chemical, and physical requirements of alloy tool steels.

  • SAE J437

SAE J437 standard involves the chemical composition, classification, and identification of tool and dies steels.

  • FED QQ-T-570

FED QQ-T-570 specification covers alloy steels for manufacturing as they are covered by ASTM A681 specifications. 

  • UNS T41902

A production-grade that indicates high-quality steel products.

Heat Treatment and Fabrication

The following characteristics of S2 sheet steels are needed to be considered while applying proper heat treatment and fabrication procedures.


S2 steel can be formed using conventional procedures, such as hot forging and hot rolling. High-speed hydraulic, precision forging, electro-hydraulic, and oil-hydraulic methods can be employed for hot forging.


The forging of S2 steel requires a minimum temperature of 871ºC or 1600ºF. The recommended temperature range is 899ºC to 1093ºC or 1650ºF to 2000ºF.

Heat Treatment

Initially, S2 sheet steel is preheated to 649ºC or 1200ºF. The preheating needs to be conducted very slowly. Next, direct heat is applied until the steel reaches a temperature of 871ºC or 1600ºF. Finally, the steel is cooled down by holding it for 10-20 minutes and quenching it with water or brine. 

The heat-treatment options include the following.

  • +N: Normalized
  • +A: Annealed
  • +QT: Quenched and tempered in water or oil
  • +NT: Normalized and tempered


S2 sheet steels have a machinability rating of 85% of that of the W group steels.


Standard procedures can be used to weld S2 steels.

Cold Working

When under annealed conditions, S2 sheet steels can be cold-worked.


A temperature range of 177ºC to 427ºC or 350ºF to 800ºF needs to be used to temper S2 steel and reach a hardness value of C on the Rockwell scale.


To perform annealing on S2 steels, it needs to be performed at a temperature of 788ºC or 1450ºF. Next, cool it down in the furnace at a maximum rate of 4ºC per hour.

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