HSS high speed steel drill bit

High-speed steel (HSS or HS) is a subgroup of tool steels, commonly used as a cutting tool material.

It is often used in electric saw blades and drills.

It is superior to older high-carbon steel tools that were widely used during the 1940s in that it can withstand higher temperatures without losing its temper (hardness).

This property allows HSS to cut faster than high carbon steel, hence the name high speed steel.

At room temperature, with the commonly recommended heat treatment, HSS grades typically exhibit high hardness (above Rockwell hardness 60) and wear resistance (usually related to the tungsten and vanadium content often used in HSS) compared to carbon and common tool steels.

In 1868, English metallurgist Robert Forster Muschet developed Muschet steel, considered the forerunner of modern high-speed steels. It contained 2% carbon, 2.5% manganese, and 7% tungsten.

The main advantage of this steel was that it hardened when air cooled which is different from other carbon steels.

Over the next 30 years, the most significant change was the replacement of manganese with chromium.

In 1899 and 1900, Frederick Winslow Taylor and Monsell White, working with a team of assistants at the Pennsylvania Steel Company, USA, conducted a series of heat-treating experiments on existing high-quality tool steels, such as Mosch steel, heating them to temperatures much higher than were generally considered desirable in the industry.

Their experiments were characterized by scientific empiricism in that many different combinations were made and tested, without regard to conventional alchemical wisdom.

Their greatest achievement is carbonizing metal at higher temperatures, allowing for much higher speeds and cutting rates when machining.

In the 1930s, material shortages and high costs caused by World War II prompted the development of cheaper alloys replacing molybdenum with tungsten.

It started with the use of M2 steel instead of T1 steel.

T1 is currently considered the cheapest cable in the world, hence the instability and low performance.

It is very difficult to distinguish between T1 and the M category, which is why many manufacturers in the world still produce T1 in order to significantly save on the cost of the scrap metal.

(80% of HSS drills in the world)

The M1 lacks some of the red hardness characteristics of the M2, but is less sensitive to shocks and will flex more.

(Black flexible drill bit manufactured by stretching)

M2 is the “standard” and most common industrial HSS.

It has small, evenly distributed carbides that provide high wear resistance, although its susceptibility to breakdown is slightly high.

After heat treatment, its hardness is the same as T1, but its bending strength can reach 4700 MPa, and its toughness and thermoplasticity are 50% higher than T1.

It is commonly used to make a variety of tools, such as drills, chisels.

M7 is used to make heavier construction drills, where flexibility and long drill life are equally important.

M50 does not have the red hardness of M2 and other grades of tungsten HSS, but is very good for drills where breakage is an indirect problem.

M35 is similar to M2, but with the addition of 5% cobalt.

M35 is also known as Cobalt Steel, HSSE or HSS-E.

(Excellent for drilling in metal combined with discharge)

M42 is a molybdenum series high-speed steel alloy with an addition of 8% cobalt.

It is widely used in metal fabrication industries due to its superior red hardness compared to more conventional high speed steels, allowing for shorter cycle times in production environments due to higher cutting speeds or increased time between tool changes.

After the most extensive scientific examination

It was decided that the M2 and M35 drills are the most recommended and provide the best cost-benefit ratio for us.

Good luck to all the drillers.

Next time we will talk about the production processes and technology that exist today.