Common Challenges in Working with M35 Tool Steel and How to Overcome Them

M35 Tool Steel

M35 tool steel is an alloy steel. This means that it is made out of iron combined with other metals that give it properties that are uniquely its own. Among the metals combined with iron are molybdenum and cobalt, to name a few.


However, the very unique properties that make M35 tool steel special are also what make it challenging to work with. There are distinct challenges during processing that encompasses machining, heat treatment, and finishing. In order to overcome those challenges, M35’s properties need to be understood and effective strategies need to be used.


Challenge 1 -- Machinability


Any of the numerous high speed steel suppliers will tell you that M35’s basic strength and complex composition does present challenges during the process of machining. Being hard, it is difficult to cut which leads to tools wearing out quicker, slower processing times, and increased forces when cutting. This can have a negative impact on the workpiece’s surface finish and shorten the life of tools which lead to higher costs of production.




  • Use of sharp and top quality tools – Making use of tools made from materials like carbide will help to break off pieces much more smoothly and will last longer.
  • Slow and steady – Though it may seem unusual, cutting slower and using less force helps to control the M35 tool steel pieces and helps make the tools last longer.
  • Special lubricants – These are types of oils that greatly help to reduce friction and heat which prolongs the life of tools and gives a smooth finish to the final product.


Challenge 2 -- Heat Treatment


Heating up M35 tool steel just right is tricky. If you do not follow the proper procedures and timing, things can go wrong like the metal bending out of shape, cracking, or not being strong enough to wear well.




  • Maintain control of temperature – Using precise temperature monitoring systems and calibrated furnaces will result in the workpiece getting uniform and consistent heating.
  • Making use of controlled atmospheres – The use of inert gases like nitrogen or no gases (a vacuum) can prevent unwanted rust, and loss of carbon from the steel during heating which preserves the steel’s properties as most high speed steel suppliers can attest to.
  • Finding the ideal cooling strategy – It is important to carefully choose which cooling medium (like oil, air, or water) and the speed of cooling (rate of quenching) to achieve the needed microstructure and specific hardness for the application. It may be best to consult M35 tool steel heat treatment specialists for best results.


Challenge 4 -- Grinding and Finishing


High speed steel suppliers will tell you that M35’s high hardness can make grinding and polishing a very demanding job that requires special abrasives and techniques to achieve the finish required.




  • Employing CBN or diamond grinding wheels (CBN being a superhard material second only to diamonds) – These are wheels that have extremely high wear resistance and cutting ability for faster and efficient grinding.
  • Consider electrolytic grinding -- This technique makes use of an electrically charged wheel and electrolyte solution.
  • Polish with appropriate compounds -- Diamond or CBN pastes or slurries ensure a smooth and polished finish minimizing surface damage.


Understanding the unique challenges that M35 tool steel presents and making use of the right solutions, machining, heat treatment, and finishing can be optimized. This helps to extend tool lifespans and ensures the finished products meets the requirements of the application.