O7 Cold Work Tool Steel Bars and Plates
Oil-quenched steel, due to the formation of tungsten carbides, exhibits more excess carbides, higher hardness, better wear resistance, and superior initial toughness compared to 9SiCr steel after quenching and low-temperature tempering. However, this steel is highly sensitive to the formation of carbide networks; if such networked carbides are present, the cutting edges of tools and dies may be prone to chipping, thereby reducing their service life. Steel containing carbide networks must be subjected to forging or normalizing according to the severity of the carbide network.
Applications of O7
Primarily used in medium- and low-load cold-working applications that demand high wear resistance and dimensional stability. Typical applications include: small- and medium-sized blanking dies (such as punching dies for hardware components and precision dies for electrical contacts), light-load cold-extrusion dies (for forming thin-walled metal parts), measuring tools and cutting tools (such as calipers and plug gauges), and plastic molding dies (including inserts for conventional injection molds).
Equivalent Grades and Commonly Used Specifications of O7
| Steel Grade | Specification | Specification Name |
| CrWMn/ T21290 | GB/T 1299 | Tool and Mould Steels |
| O7/T31507 | ASTM A681 | Standard Specification for Tool Steels Alloy |
| SKS31 | JIS G 4404 | Alloy tool steels |
| ХВГ | GOST 5950 | Tool Alloy Steel Bars, Strips and Coils General Specifications |
| Produce as other form and size according to technical requirements are available. | ||
Typical Chemical Composition of O7
|
Elements |
C | Si | Mn | P | S | Cr | W |
|
% Mass Fraction |
0.90~1.05 |
≤0.40 | 0.80~1.10 | ≤0.030 | ≤0.030 | 0.90~1.20 |
1.20~1.60 |
| Produce as other form and size according to technical requirements are available. | |||||||
Typical Heat Treatment Condition and Mechanical Properties of O7
|
Delivery Condition |
Mechanical Properties and Hardness of Heat-Treated Specimens | ||||||
| Rp0.2/(N/mm2) | Rm/(N/mm2) | A/% | Zb/% | Aku2d/J | HBW |
HRC |
|
|
Annealed Condition |
/ | / | / | / | / | 207~255 | / |
| As-quenched Condition（800℃-830℃, oil） | / | / | / | / | / | / |
≥62 |
| Produce as other form and size according to technical requirements are available. | |||||||
Product Forms and Size Range of O7
|
Product forms |
Size range |
|
Bars |
Diameter or side length: 5.0mm~1000mm |
| Flats |
thickness: 4.0mm~1000mm width: 300mm~2200mm |
| Produce as other form and size according to technical requirements are available. | |
