DIN 1.2510 O1 Cold Work Tool Steel Round Bar is an oil-hardening cold work tool steel supplied as round bar for punches, dies, gauges, cutting tools, blanking tools, reamers, broaches, knives and precision tooling components. It is commonly referenced as AISI O1, UNS T31501, DIN 1.2510, 100MnCrW4 and JIS SKS3, depending on the applicable standard and market.
SAKY STEEL supplies O1 / 1.2510 tool steel round bar in annealed, hot rolled, forged, peeled, turned or ground condition according to purchase requirements. Available services may include cutting, peeling, turning, grinding, rough machining, dimensional inspection, hardness testing, MTC and EN 10204 3.1 documentation when specified.
| Item | Product Details |
|---|---|
| Product Name | DIN 1.2510 O1 Cold Work Tool Steel Round Bar |
| Grade | O1 / 1.2510 / SKS3 |
| UNS / EN Designation | UNS T31501 / 100MnCrW4 |
| Material Family | Oil-hardening cold work tool steel |
| Product Shape | Round bar and forged round bar |
| Size Range | Regular and custom diameters by order |
| Length | 1000–6000 mm or cut to length |
| Surface Finish | Black, peeled, turned, ground |
| Delivery Condition | Annealed or heat treated when specified |
| Standard | ASTM A681 / DIN EN ISO 4957 |
| Tolerance | Mill, h9, h11 or drawing-specific |
| Available Services | Cutting, peeling, turning, grinding, machining |
| Certificates | MTC, EN 10204 3.1, dimensional report |
O1 / 1.2510 is a manganese-chromium-tungsten cold work tool steel. Its carbon content provides high hardness after heat treatment, while manganese, chromium and tungsten improve hardenability, wear resistance and dimensional stability during oil quenching.
| Element | Typical Reference Content | Technical Function |
|---|---|---|
| Carbon | About 0.85–1.05% | Provides high hardness and wear resistance |
| Manganese | About 1.00–1.40% | Improves hardenability and oil-quenching response |
| Chromium | About 0.40–0.70% | Improves hardenability and wear resistance |
| Tungsten | About 0.40–0.70% | Supports wear resistance and edge retention |
| Silicon | About 0.15–0.50% | Supports deoxidation and matrix strength |
| Vanadium | Controlled minor addition | May refine grain and support wear resistance |
| Phosphorus | Controlled maximum | Restricted to support toughness |
| Sulfur | Controlled maximum | Restricted to limit inclusions |
| Iron | Balance | Base metal matrix |
Actual chemical composition shall be confirmed by the applicable product specification and MTC.
Mechanical properties of O1 tool steel round bar depend on diameter, heat treatment, quenching medium, tempering temperature, working hardness and test condition. The following values are typical references and should not replace order-specific MTC or heat-treatment results.
| Property | Typical Reference | Condition | Engineering Meaning |
|---|---|---|---|
| Annealed Hardness | Usually below about 229 HB | Annealed bar | Improves machinability before hardening |
| Working Hardness | About 58–64 HRC reference | Hardened and tempered | Used for cutting, punching and gauge tools |
| Hardening Temperature | About 780–820°C reference | Subject to procedure | Oil quenching is typically used |
| Tempering Range | About 150–250°C for high hardness | After hardening | Adjusts hardness and toughness balance |
| Dimensional Stability | Good for oil-hardening grade | Proper heat treatment | Useful for precision tooling |
| Wear Resistance | Good for cold work tools | Hardened condition | Supports cutting edges and forming dies |
| Density | About 7.85 g/cm³ | Room temperature | Used for bar weight calculation |
| Service Condition | Cold work use | Ambient or moderate temperature | Not intended as hot work die steel |
| Diameter | Length | Surface | Processing | Typical Use |
|---|---|---|---|---|
| Ø6–25 mm | 1000–6000 mm | Ground or peeled | Cutting and grinding | Pins, small punches and tools |
| Ø26–80 mm | 2000–6000 mm | Peeled or turned | Machining allowance | Punches, dies and gauges |
| Ø85–160 mm | Custom cut length | Rough turned | Saw cut or machined | Larger die components |
| Ø165–250 mm | Made to order | Forged and turned | UT when specified | Tooling blanks and heavy parts |
| Above Ø250 mm | Project specific | Forged or machined | Technical review required | Special cold work tooling |
| Condition | Main Feature | Recommended Use | Purchase Advice |
|---|---|---|---|
| Hot Rolled Bar | Economical mill surface | Rough machining | Specify machining allowance |
| Forged Bar | Suitable for larger sections | Heavy tooling blanks | UT may be requested |
| Peeled Bar | Scale-free surface | CNC machining | Reduces surface preparation |
| Turned Bar | Controlled diameter allowance | Tooling blanks | Confirm final machining size |
| Ground Bar | Tight tolerance and smooth finish | Precision tools and gauges | State h9, h8 or drawing tolerance |
| Grade | Main Strength | Relative Limitation | Typical Selection |
|---|---|---|---|
| O1 / 1.2510 | Good machinability and oil-hardening stability | Lower wear resistance than high-carbon high-chromium grades | Punches, gauges, cutting tools and dies |
| O2 / 1.2842 | Simple oil-hardening cold work grade | Different alloy balance and wear resistance | General cold work tools |
| D2 / 1.2379 | High wear resistance | Lower machinability and toughness than O1 | Long-run blanking and wear tools |
| A2 / 1.2363 | Air-hardening with good stability | Different hardening process and cost | Precision tools needing air-hardening response |
| System | Designation | Relationship |
|---|---|---|
| AISI / ASTM | O1 | Oil-hardening cold work tool steel grade |
| UNS | T31501 | UNS designation for O1 type steel |
| DIN / W.Nr. | 1.2510 | German material number reference |
| EN Name | 100MnCrW4 | European chemical designation |
| JIS | SKS3 | Japanese cross-reference |
| Chinese Reference | 9CrWMn | Common Chinese cold work tool steel reference |
| Product Standard | ASTM A681 / DIN EN ISO 4957 | Tool steel specification references |
| Inspection | Method | Purpose |
|---|---|---|
| Chemical Analysis | Laboratory analysis or MTC review | Confirm O1 / 1.2510 chemistry |
| PMI | Positive material identification | Available when specified; not a substitute for full chemistry |
| Hardness Test | HB or HRC test as applicable | Confirm annealed or heat-treated condition |
| Dimensional Inspection | Caliper, micrometer and length check | Verify diameter, length and tolerance |
| Surface Inspection | Visual and finish inspection | Check cracks, scale, laps or handling damage |
| Ultrasonic Testing | UT when specified | Evaluate internal soundness in suitable sizes |
| Traceability Review | Heat number and label verification | Link product to MTC and EN 10204 3.1 |
O1 is valued for good machinability in the annealed condition, good hardening response in oil quenching and useful wear resistance after hardening and tempering. It is often selected for short to medium production runs and precision tools where dimensional stability is important.
Machinability is generally good before hardening. Major turning, milling, drilling, grinding and shaping are usually completed in the annealed condition. Final grinding may be required after heat treatment when tight tolerance or sharp edges are needed.
O1 is normally annealed before machining and then hardened by oil quenching, followed by tempering to the required working hardness. Heating rate, soaking time, quenching temperature, oil temperature and tempering practice should be selected according to tool size and geometry.
Welding is not the preferred repair method for hardened O1 tooling because cracking and hardness variation may occur. If welding is necessary, a qualified repair procedure, preheating and post-weld heat treatment should be evaluated carefully.
DIN 1.2510 O1 is an oil-hardening cold work tool steel. It is used for punches, dies, gauges, cutting tools and precision tooling components requiring good wear resistance and dimensional stability.
O1, DIN 1.2510 and JIS SKS3 are commonly used cross-references for oil-hardening cold work tool steel. Final equivalence should be confirmed by chemical composition, heat treatment, hardness and inspection requirements.
ASTM A681 is commonly referenced for AISI O1 tool steel, while DIN EN ISO 4957 may be used for DIN 1.2510 / 100MnCrW4. The purchase order should specify the required standard and revision.
O1 is usually supplied annealed for machining. After proper hardening and tempering, working hardness is often selected in the high hardness range for punches, dies and cutting tools, subject to tool design and heat-treatment practice.
Yes. Black, peeled, turned and ground surfaces can be discussed according to diameter, tolerance and final machining requirement. Ground bars are suitable where tighter diameter control or improved surface finish is required.
O1 is mainly a cold work tool steel and is not the first choice for hot work dies. For hot forging, die casting or extrusion dies, H13, H11, H21 or other hot work tool steels are usually considered instead.
SAKY STEEL can provide MTC and EN 10204 3.1 documentation according to the purchase order. Hardness, dimensional, PMI or UT reports may also be arranged when specified.