ThePipingMart Blog Grades S7 Tool Steel (UNS T41907) – Composition, Properties and Uses

S7 Tool Steel (UNS T41907) – Composition, Properties and Uses

Tool Steel S7

Tool steel S7 is a versatile and reliable tool steel that can be used for various purposes. UNS T41907 is renowned for its heat resistance, machinability, and corrosion resistance, making it a popular choice in many industries. Let’s take a closer look at tool steel S7 and how it works.

S7 Tool Steel Composition

Content (%)
Iron, Fe
Carbon, C
Manganese, Mn
Silicon, Si
Chromium, Cr
Molybdenum, Mo
Vanadium, V
Copper, Cu
Phosphorus, P
Sulfur, S

S7 Tool Steel Physical Properties

Properties Metric Imperial
Density 7.83 g/cc 0.283 lb/in3

S7 Tool Steel Mechanical Properties

Properties Metric Imperial
Hardness, Rockwell C (air cooled from 941°C, 649°C temper temperature) 41 41
Hardness, Rockwell C (air cooled from 941°C, 449°C temper temperature) 53 53
Hardness, Rockwell C (air cooled from 941°C, 149°C temper temperature) 57 57
Modulus of elasticity 207 GPa 30000 ksi
Charpy impact (V-notch; air cooled from 941°C; 425°C temper temperature) 13.6 J 10.0 ft-lb
Charpy impact (V-notch; air cooled from 941°C; 649°C temper temperature) 16.3 J 12.0 ft-lb
Charpy impact (V-notch; air cooled from 941°C; 200°C temper temperature) 16.9 J 12.5 ft-lb
Machinability (1% carbon steel) 70.0 – 75.0% 70.0 – 75.0%
Poisson’s ratio 0.27-0.30 0.27-0.30

S7 Tool Steel Thermal Properties

Properties Conditions
T (°C) Treatment
Thermal expansion 12.6 x 10-6/ºC 20-200

S7 Tool Steel Equivalents

  • ASTM A597
  • ASTM A681
  • UNS T41907

S7 Tool Steel Uses

Tool steel S7 is mainly used in applications that require shock resistance, vibration dampening, and extreme durability. This type of tool steel is commonly used for forging dies, punches, chisels, screws, hammers, shear blades and more. It can also be used in the production of plastic injection moulds as well as for cold-work operations such as blanking, or punching dies due to its excellent wear resistance.

Corrosion Resistance

Tool steel S7 is highly resistant to corrosion from most chemicals and water-based solutions. This makes it an ideal choice for use in environments where there is exposure to high levels of humidity or corrosive materials such as acids or alkalis. It also has excellent weldability and can be easily cut with any standard cutting process, such as plasma or laser cutting.

Heat Resistance

One of the main benefits of using tool steel S7 is its heat resistance. This tool steel has an extremely high melting point, allowing it to withstand temperatures up to 2200°F (1204°C) without any softening or loss of strength. Additionally, this type of material offers excellent thermal shock resistance, which means that it will not degrade quickly when exposed to sudden changes in temperature like some other metals can.

Heat Treatment

In order to maximize the properties of tool steel S7, it must be properly heat treated before being put into use. Heat treatment involves heating the material up to certain temperatures depending on what results are desired from the material before cooling it back down slowly over time. Heat treating this type of metal will increase its hardness while maintaining its toughness and wear resistance so that it can perform better during heavy-duty operations such as machining or drilling operations where speed and precision are essential factors for success.


The machinability rating for tool steel S7 is rated at 50%, meaning that this type of metal can be easily machined using standard cutting techniques with minimal effort required compared to other types of metals with lower machinability ratings, such as stainless steel or aluminium alloys, which may require specialized tools or equipment in order to achieve the desired results efficiently without causing any damage to the material itself or the machine being used during operation.


In conclusion, tool steel S7 is an ideal choice for applications that require high levels of durability and performance under extreme conditions such as high temperatures or heavily corrosive environments due to its superior heat and corrosion resistance qualities along with its easy machinability rating, making it easy for operators to work with this type of metal quickly and efficiently with minimal effort required compared to other types of metals available on the market today! With these advantages comes a higher cost than traditional metals, but if you’re looking for extra performance, then investing in Tool Steel S7 should definitely be considered!

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S7 Tool Steel (UNS T41907) – Composition, Properties and Uses

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