O7 tool steel
OTAI SPECIAL STEEL is O7 tool steel stockholders and suppliers from china. more 16 years experience in AISI O7 tool steel round bar, flat bar and plate supply.
AISI O7 Steel is a high quality Cold work tool steel. It belong to the high quality high carbon alloy tool steel. Oil Quenched & Tempered Hardenss is 28-34 HRC. AISI O7 steel Annealing delivery hardenss less than 250HB.
Related Specifications ASTM A681M DIN EN 10083/3 JIS G4053 GB GB/T1299
Form of Supply
AISI O7 tool steel, we can supply the round bar, steel flat bar, plate, hexagonal steel bar and steel square block. AISI O7 steel Round bar can be sawn to your required lengths as one offs or multiple cut pieces. O7 steel Rectangular pieces can be sawn from flat bar or plate to your specific sizes. Ground tool steel bar can be supplied, providing a quality precision finished bar to tight tolerances.
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- Round
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- sheet
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- Square
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- Plate
Chemical composition
| C(％) | 1.10～1.30 | Si(％) | 0.10～0.60 | Mn(％) | 0.20～1.00 | P，S(％) | ≤0.030 |
| W(％) | 1.00～2.00 | Cr(％) | 0.35～0.85 | Mo (％) | ≤0.30 | V(％) | 0.15～0.40 |
Heat treatment Related
- Annealing of O7 Tool steel
Slowly heated to 720-760 ℃（1328-1400℃） and allow enough times, let the steel to be thoroughly heated, Then cool slowly in the furnace. The O7 tool steel will get MAX 250 HB （Brinell hardness）.
- Hardening of tool steel O7
O7 steels should be heated uniformly to 790-820°C (1454-1508°F) until completely heated through. If needed, the steels can be preheated at 300-500°C (572-932°F). About 30 min/per 25 mm of ruling section is to be provided and then the steels should be immediately quenched in oil.
- Tempering of O7 Cold work tool steel
Tempering of O7 steels is performed at 100-400°C (212-752°F), Soak well at the selected temperature and soak for at least one hour per 25mm of total thickness. Get Rockwell C hardness of 50 to 64.
Temperature [℃] 100 150 200 250 300 400
Hardness [HRc] 64-63 63-62 62-61 60-59 56-55 50-49
Mechanical Properties
The mechanical properties of tool steels O7 are outlined in the following table.
| Poisson’s ratio | Elastic modulus | Thermal expansion | Yield (0.2%, hardened to 60 HRC) |
Yield (0.2%, hardened to 62 HRC) |
Yield (0.2%,hardened to 50 HRC) |
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| T (25°C) | T (25°C) | T (20-100°C) | Mpa | Mpa | MPa | |
| 0.27-0.30 | 27557-30458 ksi | 11.2 x 10-6/ºC | 2150 | 2200 | 1350 | |
Applications
O7 steels are mainly used for short run tooling for cold forming dies, blanking dies, and cutting tools operating at ambient temper.
O7 tool steel typical applications include medium run dies, intricate press tools, drawing punches, broaches, bushings, lathe centres, chuck jaws, master cavity sinking hobs, paper cutting machine knives, plug gauges, thread gauges and precision measuring tools. Also commonly used in applications such as cams, cloth cutting knives, cold taps, reamers, collets, cutting hobs, strip slitting cutters, trimmer dies, tube expander rolls, plastic moulds and woodworking knives ature.
Regular size and Tolerance
| 1) Hot Rolled round bar | |||
| Diameter (mm) |
Diameter Tolerance (mm) |
Diameter (mm) |
Diameter Tolerance (mm) |
| ≤12.70 | -0.13 ～0.30 | >50.80～63.5 | -0.25～0.76 |
| 12.7～25.40 | -0.13～0.41 | >63.50～76.20 | -0.25～1.02 |
| >25.4～38.10 | -0.15～0.51 | >76.20～101.60 | -0.30～+1.27 |
| >38.1～50.80 | -0.20～0.64 | >101.60～203.20 | -0.38～3.81 |
| 2) Hot Rolled steel plate | |||
| Thickness (mm) |
Thickness Tolerance (mm) |
Thickness (mm) |
Thickness Tolerance (mm) |
| ≤25.4 | -0.41～0.79 | >127～152 | -1.60～2.39 |
| >25.4～76 | -0.79～1.19 | >178～254 | -1.98～3.18 |
| >76～127 | -1.19～1.60 | >254～305 | -2.39～3.96 |
Others O7 have not specified size, pls contact our experienced sales team.
AISI O7 tool steel round bar and flat sections can be cut to your required sizes. O7 tool steel ground bar can also be supplied, providing a high quality tool steel precision ground tool steel bar to your required tolerances. AISI O7 steel is also available as Ground Flat Stock / Gauge Plate, in standard and nonstandard sizes.
Contact our experienced sales team to help you with your O7 tool steel questionsadn enquiry by Email or Telphone. The questions will be reply in 24 hours.