Topics CoveredIntroductionChemical CompositionPhysical PropertiesMechanical PropertiesOther DesignationsFabrication and Heat Treatment Tempering Annealing Cold Working Welding Forging Forming Machinability Heat TreatmentApplications
Air-hardening, medium alloy, cold work steels or group A steels include the A2, A3, A4, A6, A7, A8, A9, and A10 steels. Sufficient amounts of manganese, molybdenum and chromium present in group A steels provide full hardness in sections comprising thickness of at least 100 mm (4 in.) in diameter when air cooled.
Carbon content of group A steels range from 0.5 to 2%. These steels are provided with air hardening characteristics that allow minimum cracking and distortion on quenching.
A10 air-hardening, medium-alloy, cold-work steels contain manganese, molybdenum, chromium and vanadium to perform the deep hardening process without being quenched, thus reducing the deformation level to a minimum extent during hardening of A10 steels. A10 steels have medium toughness and high wear resistance.
The sections below will provide an overview on A10 tool steels.
The chemical composition of A10 tool steels is outlined in the following table.
The following table shows the physical properties of A10 tool steels.
The mechanical properties of A10 tool steels are displayed in the following table.
|Hardness, Rockwell C
|Bulk modulus (typical for steels)
|Machinability (based on carbon tool steel)
|Shear modulus (typical for steels)
Equivalent materials to A10 tool steels are:
- ASTM A681
- FED QQ-T-570
- UNS T30110
Fabrication and Heat Treatment
A10 tool steels are tempered at 204 to 427°C (400 to 800°F), thus forming a hardness of about Rockwell C 62 for low temperature to Rockwell C 55 for the 427°C (800 F) temper.
A10 tool steels are annealed at 774°C (1425°F) and cooled in a furnace in a very slow manner at a temperature of -3.9°C (25°F) per hour or less.
Conventional methods are used for cold working of A10 tool steels in the annealed condition.
A10 tool steels can be welded as they are alloy steels.
A10 tool steels are forged at 1024°C (1875°F) down to 899°C (1650°F) and forging below 871°C (1600°F) is not recommended for these steels.
Forming of A10 tools steels is performed through the hot forging and machining processes.
A10 tool steels have medium machinability which has a rating of about 85%.
A10 tool steels are preheated at 649°C (1200°F) in a slow manner following an increase in temperature to 802°C (1475°F). They are then held for 45 to 60 minutes, removed and finally cooled in air. This same heat treatment is also used to harden the A10 tool steels.
A10 tool steels are used for a variety of complex die shapes and for thread rolling dies.