AISI- High Speed steel
|Class||High Speed Steel|
|Category||Tungsten-Molybdenum Tool Steel|
|Grades||U.S ASTM A600, SAE J437, SAE J438, AISI M2. M42, M35
Germany DIN 1.3343, 1.3243, 1.3247
U.K B.S, BM2, BM42, BM34
It is a high performance steel with high hardness and good wear resistance properties.It is often used as a cutting tool as it can cut metal at very high rate than any other carbon tool steel due to presence of tungsten and cobalt that gives it much higher strength.
It is mainly used in manufacturing of cutting tools such as twist drills, reamers, machine bits, taps. dies, saw blades and other cutting tools etc.
HIGH SPEED STEEL CHEMICAL COMPOSITION:
High speed steel grades:
M2 is a high-speed steel in tungsten–molybdenum series. The carbides in it are small and evenly distributed. It has high wear resistance. After heat treatment, its hardness is the same as T1, but its bending strength can reach 4700 MPa, and its toughness and thermoplasticity are higher than T1 by 50%. It is usually used to manufacture a variety of tools, such as drill bits, taps and reamers. Its decarburization sensitivity is a little bit high.
M35 is similar to M2, but with 5% cobalt added. The addition of cobalt increases heat resistance. M35 is also known as HSSE or HSS-E.
M42 is a molybdenum-series high-speed steel alloy with an additional 8% cobolt. It is widely used in metal manufacturing because of its superior red-hardness as compared to more conventional high-speed steels, allowing for shorter cycle times in production environments due to higher cutting speeds or from the increase in time between tool changes.
To increase the life of high-speed steel, tools are sometimes coated. One such coating titanium nitride. Most coatings generally increase a tool’s hardness . The coating also helps to decrease the temperature associated with the cutting process and increase the life of the tool.
Impact of alloying elements on the HSS steel properties:
Carbon: Forms carbides, increases wear resistance, is responsible for the basic matrix hardness.
Tungsten and Molybdenum: Improves red hardnesss, retention of hardness and high temperature strength of the matrix, form special carbides of great hardness.
Vanadium: Forms special carbides of supreme hardness, increase high temperature wear resistance, retention of hardness and high temperature strength of the matrix.
Chromium: Promotes deep hardening, produces readily soluble carbides.
Cobalt: Improves red hardness and retention of hardness of the matrix.
Aluminium: Improves retention of hardness and red hardness.
Since it is possible to achieve specific properties by careful adjustment of these alloying elements, we are able to offer the most suitable high speed steel grade for virtually all kinds of application.