8418 Hot Work Tool Steel Round Bar
Short Description:
8418 hot work tool steel round bar is a Cr-Mo-V high-temperature tool steel with high molybdenum content for die casting dies, extrusion tooling, hot punches and forging dies. Custom diameter, surface, cutting, UT, MTC and EN 10204 3.1 available.
8418 Hot Work Tool Steel Round Bar is a Cr-Mo-V hot work tool steel supplied for die casting dies, hot extrusion tooling, hot forging dies, hot punches, mandrels, inserts, cores, ejector pins and other high-temperature tooling components. Compared with conventional H13 type hot work steels, 8418 is often selected when higher hot strength, improved thermal fatigue resistance and better resistance to softening are required.
SAKY STEEL supplies 8418 hot work tool steel round bar and forged 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, ultrasonic testing when specified, MTC and EN 10204 3.1 documentation.
Product Parameters
| Item | Product Details |
|---|---|
| Product Name | 8418 Hot Work Tool Steel Round Bar |
| Grade | 8418 / High-Mo Hot Work Tool Steel |
| Material Family | Chromium-molybdenum-vanadium hot 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, machined |
| Delivery Condition | Annealed or heat treated when specified |
| Standard Reference | Supplier specification / ASTM A681 reference |
| Tolerance | Mill, h9, h11 or drawing-specific |
| Available Services | Cutting, peeling, turning, grinding, rough machining, UT when specified |
| Certificates | MTC, EN 10204 3.1, dimensional and inspection reports |
Chemical Composition
8418 is generally treated as a high-molybdenum Cr-Mo-V hot work tool steel. Its molybdenum content is typically higher than conventional H13 type grades, which helps improve hot strength, temper resistance and thermal fatigue performance. The table below provides typical reference chemistry for material selection discussion.
| Element | Typical Reference Content | Technical Function |
|---|---|---|
| Carbon | About 0.32–0.40% | Provides hardenability and working hardness |
| Chromium | About 4.75–5.20% | Improves hardenability and high-temperature behavior |
| Molybdenum | About 2.30–3.30% | Improves hot strength, temper resistance and thermal fatigue resistance |
| Vanadium | About 0.40–0.80% | Refines grain and improves wear resistance |
| Silicon | Controlled range | Supports oxidation behavior and matrix strength |
| Manganese | Controlled range | Supports melting control and hardenability |
| Phosphorus | Controlled maximum | Restricted to support toughness |
| Sulfur | Controlled maximum | Restricted to limit inclusions and improve die reliability |
| Iron | Balance | Base metal matrix |
Actual chemical composition shall be confirmed by the applicable product specification and MTC.
Mechanical and High-Temperature Properties
Mechanical and service properties of 8418 hot work tool steel round bar depend on diameter, melting quality, heat treatment, working hardness, test direction and service temperature. The values below are typical references and should not replace order-specific MTC or heat-treatment records.
| Property | Typical Reference | Condition | Engineering Meaning |
|---|---|---|---|
| Annealed Hardness | Usually below about 229–235 HB | Annealed bar | Supports machining before hardening |
| Working Hardness | About 44–52 HRC reference | Hardened and tempered | Selected according to die application |
| Thermal Fatigue Resistance | High for hot work tooling | Repeated heating and cooling | Helps resist heat checking in dies |
| Hot Strength | High with suitable heat treatment | Application dependent | Useful in die casting, hot forging and extrusion tooling |
| Resistance to Softening | Improved by high Mo content | Elevated temperature service | Helps maintain die hardness during service |
| Toughness | Good when properly treated | Proper heat treatment | Helps reduce cracking and chipping risk |
| Wear Resistance | Good at elevated temperature | Hardened and tempered | Supports die life in hot forming service |
| Density | About 7.8 g/cm³ reference | Room temperature | Used for bar weight calculation |
Common Size Table
| Diameter | Length | Surface | Processing | Typical Use |
|---|---|---|---|---|
| Ø10–30 mm | 1000–6000 mm | Peeled or ground | Cutting and grinding | Ejector pins, cores and small hot work tools |
| Ø35–80 mm | 2000–6000 mm | Peeled or turned | Machining allowance | Hot punches, inserts and tooling shafts |
| Ø85–160 mm | Custom cut length | Rough turned | Saw cut or machined | Die casting and extrusion components |
| Ø165–300 mm | Made to order | Forged and turned | UT when specified | Large hot work tooling |
| Above Ø300 mm | Project specific | Forged or machined | Technical review required | Heavy dies and tool blocks |
Different Specifications Comparison
Round Bar Surface and Production Comparison
| Condition | Main Feature | Recommended Use | Purchase Advice |
|---|---|---|---|
| Hot Rolled Bar | Economical mill surface | Rough machining | Specify machining allowance |
| Forged Bar | Suitable for large sections | Heavy hot work dies | UT and forging ratio may be specified |
| Premium Quality Bar | Improved consistency when specified | Critical die casting and extrusion dies | Confirm exact quality requirement in order |
| Peeled Bar | Scale-free surface | CNC machining | Reduces surface preparation |
| Ground Bar | Tight tolerance and smooth finish | Precision tooling components | State h9, h8 or drawing tolerance |
Comparison with Related Hot Work Tool Steels
| Grade | Main Strength | Relative Limitation | Typical Selection |
|---|---|---|---|
| H13 / 1.2344 | Balanced toughness, hot strength and heat checking resistance | Lower Mo content than many 8418 references | General die casting, extrusion and forging tools |
| 8407 | Premium H13 type performance | Quality level depends on order requirement | Critical die casting dies and high-service tooling |
| 8418 | Higher Mo design for hot strength and softening resistance | Exact equivalence must be confirmed by specification | Demanding hot work dies, extrusion and thermal fatigue service |
| H21 / 1.2581 | Tungsten hot strength and red hardness | Different toughness and machinability balance | Special hot punches and high-temperature tools |
Equivalent Standards and International Names
| System | Designation | Relationship |
|---|---|---|
| Commercial Grade | 8418 | High-Mo hot work tool steel reference |
| Material Family | Cr-Mo-V hot work tool steel | Used for hot work tooling applications |
| Related Grade | H13 / 1.2344 type comparison | Not automatic equivalence; compare by MTC |
| Product Standard Reference | ASTM A681 reference | Tool steel specification reference when applicable |
| Certificate | MTC / EN 10204 3.1 | Used to confirm actual composition and traceability |
Production Process Flow
Alloying materials are selected according to the required 8418 chemistry.
Chemistry, cleanliness and residual elements are controlled during steelmaking.
Premium quality or remelting requirements can be discussed when specified.
The material is processed into round bar or forged bar form.
Annealing improves machinability before final die manufacturing.
Bars may be peeled, turned, ground, machined or cut to size.
Dimensions, surface, hardness and traceability are checked.
Heat-number marking and export packing are prepared.
Product Inspection
| Inspection | Method | Purpose |
|---|---|---|
| Chemical Analysis | Laboratory analysis or MTC review | Confirm 8418 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 |
| Microstructure Review | Available when specified | Supports premium quality verification |
| Traceability Review | Heat number and label verification | Link product to MTC and EN 10204 3.1 |
Product Packaging
Bars can be protected with anti-rust oil, VCI paper, film or waterproof wrapping.
Steel straps, separators and padding reduce movement and scratching.
Ground or machined bars can receive end caps or padded protection.
Export packing is selected according to bar diameter, length and weight.
Grade, size, heat number and customer shipping marks can be retained.
Applications, Core Performance and Fabrication
Primary Applications
- Aluminum die casting dies and inserts
- Hot extrusion dies, mandrels and liners
- Hot forging dies and die inserts
- Hot punches, hot shear blades and trimming tools
- Cores, ejector pins, nozzles and die casting components
- Hot work components requiring resistance to softening
Core Performance
8418 is valued for hot strength, thermal fatigue resistance, temper resistance, toughness and resistance to softening at elevated temperature. These properties help extend tool service life in die casting, extrusion and hot forging applications when heat treatment and die design are properly controlled.
Machinability
Machinability is generally best in the annealed condition. Major turning, milling, drilling and rough machining are usually completed before hardening and tempering. Peeled, turned or ground bars help reduce preparation time before CNC machining.
Heat Treatment
8418 is normally supplied annealed before machining and then hardened and tempered according to the final tool requirement. Heat treatment should be selected according to section size, die geometry, target hardness, working temperature and impact load.
Nitriding and Surface Treatment
Nitriding may be used to improve surface hardness and wear resistance for selected die casting and extrusion tools. Surface treatment should be selected after considering base hardness, die design, service temperature and required case depth.
Why Choose SAKY STEEL?
Diameter, length, surface finish and machining allowance can be supplied according to drawings.
Material identification can be maintained from documentation to final packing.
MTC (Mill Test Certificate / 质保书) can be provided according to the purchase order.
EN 10204 3.1 documentation is available when specified by the order.
Hardness, dimensional, PMI, UT and microstructure review can be arranged when specified.
Bundles, wooden cases, pallets and customer shipping marks can be arranged.
FAQ
What is 8418 hot work tool steel?
8418 is a high-molybdenum Cr-Mo-V hot work tool steel used for die casting dies, extrusion tooling, hot forging dies, hot punches, inserts and other high-temperature tooling components.
Is 8418 the same as H13 or 8407?
No exact equivalence should be assumed. 8418 is often compared with H13 / 8407 type hot work steels, but it normally has a different alloy balance, especially higher molybdenum content. Final equivalence should be confirmed by MTC and customer specification.
What applications use 8418 round bar?
8418 round bar is used for die casting dies, extrusion dies, hot forging dies, hot punches, mandrels, cores, ejector pins and hot work components requiring thermal fatigue resistance and resistance to softening.
Can 8418 bar be supplied ground or peeled?
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.
What hardness is used for 8418 tool steel?
8418 is usually supplied annealed for machining. After hardening and tempering, the working hardness is selected according to die type, service temperature, impact load and required tool life.
Is ultrasonic testing available for 8418 bars?
UT can be arranged for suitable bar diameters and forged bars when specified. The order should define the test method, acceptance level and reporting requirement.
Can MTC and EN 10204 3.1 be provided?
SAKY STEEL can provide MTC and EN 10204 3.1 documentation according to the purchase order. Hardness, dimensional, PMI, UT or microstructure reports may also be arranged when specified.
