Jul 10 2012
Topics Covered
IntroductionClassificationPropertiesApplications
Introduction
Tool steels are high-quality, carbon and alloy steels that are commonly used to make cutters, reamers, bits etc used for machining metals, plastics, and wood. They are usually melted in furnaces and processed to give them properties required for shaping other metals into useful components. They are ingot-cast wrought products capable of withstanding high temperatures and heavy loads. Tool steels normally contain carbide formers like chromium, vanadium, molybdenum and tungsten in different combinations and cobalt or nickel for enhancing performance at high temperatures.
Tool steels are provided in the soft or annealed condition, so that they can be machined into tooling components. These steels can be heat-treated to improve the hardness after being fabricated into a tool.
Classification
Tool steels are classified based on their properties and composition as follows:
- High-speed steels
- Molybdenum high-speed steels
- Tungsten high-speed steels
- Intermediate high-speed steels
- Hot-work steels
- Chromium hot-work steels
- Tungsten hot-work steels
- Molybdenum hot-work steels
- Cold-work steels
- Air-hardening, medium-alloy, cold-work steels
- High-carbon, high-chromium, cold-work steels
- Oil-hardening cold-work steels
- Water-hardening tool steels
- Shock-resisting steels
- Low-alloy special-purpose tool steels
- Low-carbon mold steels
Properties
The primary properties of tool steels are listed below:
- Toughness
- Wear resistance
- Hardness
- Heat resistance
Applications
The major applications of tool steels are in the following processes:
- Forming, stamping, cutting and shearing of plastics and metals
- Extrusion of plastic sections e.g vinyl window frames and pipes
- Stamping of computer parts from metal sheets
- Slitting of steel coils into strips
- Dies for compacting of powder metal into forms such as gears.