The only way to know is to look for or ask supplied what grade of hss they use, M1 M2 M50 etc.
Molybdenum High Speed Steels (HSS)Edit
Combining molybdenum, tungsten and chromium steel creates several alloys commonly called "HSS", measuring 63–65 Rockwell "C" hardness.
M1
M1 lacks some of the
red-hardness properties of M2, but is less susceptible to shock and will flex more.
M2
M2 is the "standard" and most widely used industrial HSS. It has small and evenly distributed carbides giving high wear resistance, though its decarburization sensitivity is a little bit high. After heat treatment, its hardness is the same as T1, but its bending strength can reach 4700 MPa, and its toughness and thermo-plasticity are higher than T1 by 50%. It is usually used to manufacture a variety of tools, such as drill bits, taps and reamers. 1.3343 is the equivalent numeric designation for M2 material identified in ISO 4957.M7M7 is used for making heavier construction drills where flexibility and extended drill life are equally important.
M50
M50 does not have the red-hardness of other grades of tungsten HSS, but is very good for drills where breakage is a problem due to flexing the drill. Generally favored for hardware stores and contractor use. It is also used in high-temperature
ball bearings. These steels are obtained by alloying tungsten, chromium, vanadium, cobalt and molybdenum with steel.
Cobalt High Speed Steels (HSS)
The addition of
cobalt increases heat resistance, and can give a Rockwell hardness up to 70 Min.
[12]
M35
M35 is similar to M2, but with 5% cobalt added. M35 is also known as Cobalt Steel, HSSE or HSS-E. It will cut faster and last longer than M2.
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M42
M42 is a molybdenum-series high-speed steel alloy with an additional 8% cobalt.
[12] It is widely used in metal manufacturing industries 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.
[13]
