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Hot work tool steel bars are engineered to maintain mechanical strength, toughness, and dimensional stability under continuous high-temperature operating conditions. As a professional manufacturer of forged and hot rolled tool steel bars, we supply premium hot work steels designed for demanding applications such as die casting, hot forging, extrusion, and high-load industrial tooling.
Through controlled forging processes and precise heat treatment, our hot work tool steel bars exhibit uniform microstructure, enhanced thermal fatigue resistance, and reliable performance in severe thermal and mechanical environments.
Hot work tool steels are a class of alloy tool steels specifically developed to resist softening, cracking, and thermal fatigue during repeated exposure to elevated temperatures, typically above 500°C. These steels contain optimized combinations of chromium, molybdenum, and vanadium to achieve a balance of hot hardness, toughness, and wear resistance.
Common hot work tool steel grades include H11, H13, 1.2343, and 1.2344, which are widely used in forging dies, die casting molds, and extrusion tooling.
Our manufacturing capabilities support multiple product forms to meet different engineering and machining requirements:
Forged Hot Work Tool Steel Bars
Hot Rolled Tool Steel Bars
Peeled & Turned Bars
Rough Machined Bars
Custom Forged Tool Steel Components
Forged bars are recommended for large cross-sections or critical applications where superior internal soundness and grain flow orientation are required.
Hot work tool steels are alloy steels primarily composed of chromium (Cr), molybdenum (Mo), and tungsten (W), with controlled additions of vanadium and carbon. This alloying system is designed to provide an optimal balance of hot strength, toughness, wear resistance, and resistance to thermal fatigue.
Chromium (Cr): Improves hardenability, oxidation resistance, and high-temperature strength
Molybdenum (Mo): Enhances hot strength, toughness, and resistance to softening
Tungsten (W): Provides excellent red hardness and high-temperature wear resistance
The precise chemical composition is carefully controlled to ensure consistent performance in severe thermal and mechanical service conditions.
Chromium-based hot work tool steels are the most widely used group due to their excellent balance of strength, toughness, and thermal fatigue resistance.
Widely applied in die casting and hot forging
Good resistance to heat checking
Excellent toughness after heat treatment
H13 is the industry workhorse grade, extensively used for aluminum die casting molds and forging dies due to its versatility and long service life.
Molybdenum-containing grades offer enhanced hot strength and improved toughness, particularly under high thermal stress.
Improved resistance to softening at elevated temperatures
Better performance under heavy mechanical loads
Suitable for large-section tooling components
These grades are often selected where both thermal stability and mechanical strength are critical.
Tungsten-based hot work tool steels provide very high red hardness, making them suitable for extremely demanding applications.
Exceptional high-temperature hardness
Superior wear resistance
Performance characteristics similar to high-speed steels
These grades are typically used in applications requiring sustained hardness at very high operating temperatures.
We manufacture hot work tool steel bars in accordance with major international standards:
AISI / ASTM: H11, H13
DIN / EN: 1.2343, 1.2344
JIS: SKD6, SKD61
GB: 4Cr5MoSiV1
Custom chemical compositions available upon request
Each heat is strictly controlled to ensure chemical consistency and mechanical reliability.
| Tool Steel Group | AISI / ASTM | DIN / EN | JIS | GB / Others | Typical Applications |
|---|---|---|---|---|---|
| Hot Work Tool Steel | H11, H12, H13 | 1.2343, 1.2344 | SKD6, SKD61 | 4Cr5MoSiV1 | Die casting dies, forging dies, extrusion tooling |
| Cold Work Tool Steel | D2, D3 | 1.2379, 1.2080 | SKD11 | Cr12MoV | Blanking dies, cutting tools, wear parts |
| Plastic Mold Tool Steel | P20, P20+Ni | 1.2311, 1.2738 | — | 3Cr2Mo | Injection molds, plastic tooling |
| High Speed Tool Steel | M2, M42 | 1.3343 | SKH51 | W6Mo5Cr4V2 | Cutting tools, drills, milling tools |
| Shock Resisting Tool Steel | S7 | 1.2355 | — | — | Impact tools, punches, chisels |
| Water Hardening Tool Steel | W1 | 1.1545 | SKS | — | Simple tools, hand tools |
✅️ All grades can be supplied in forged or hot rolled bar form, with customized dimensions and heat treatment conditions available upon request.
| Item | Specification |
|---|---|
| Diameter / Section | 20 – 800 mm |
| Length | Up to 12,000 mm |
| Delivery Condition | Annealed / Soft Annealed / Q&T |
| Heat Treatment | Normalizing, Quenching & Tempering |
| Surface Condition | Black, Peeled, Machined |
| Testing | UT, Hardness, Chemical Analysis |
Excellent hot strength retention at elevated temperatures
Superior resistance to thermal fatigue and heat checking
Uniform grain structure achieved through controlled forging
High toughness to prevent premature cracking
Stable performance during cyclic heating and cooling
Our forged hot work tool steel bars are optimized for long service life in thermally aggressive environments.
Hot work tool steels are designed to be processed through controlled manufacturing steps to achieve optimal mechanical performance and service life. Proper processing is critical to ensure dimensional stability, machinability, and resistance to thermal fatigue.
Hot work tool steel bars are commonly produced through open-die forging or controlled hot forging, which refines the grain structure and improves internal soundness. Forging is particularly recommended for large cross-sections or critical tooling components where directional grain flow enhances fatigue resistance and toughness.
For certain sizes and applications, hot rolled tool steel bars provide a cost-effective solution with consistent mechanical properties. Hot rolling is suitable for standard dimensions where extreme internal integrity is not required.
Hot work tool steels offer good machinability in the annealed or soft-annealed condition. Proper tool selection, cutting parameters, and cooling methods are essential to minimize tool wear and maintain surface integrity.
Machining is typically performed prior to final heat treatment to reduce distortion and improve dimensional accuracy.
Heat treatment is a critical step in achieving the desired hardness and toughness. Typical processes include austenitizing, quenching, and tempering, carefully controlled to optimize high-temperature strength and resistance to heat checking.
Multiple tempering cycles are often applied to improve thermal stability and service performance.
Depending on application requirements, hot work tool steel bars can be supplied in black, peeled, turned, or rough-machined conditions. Surface conditioning improves dimensional accuracy and prepares the material for further processing.
Tool steels generally fall into six major groups, each designed for specific operating conditions:
Water Hardening Tool Steels
Cold Work Tool Steels
Shock Resisting Tool Steels
High Speed Tool Steels
Hot Work Tool Steels
Special Purpose Tool Steels (Plastic Mold Steels)
Selecting the appropriate tool steel group depends on key factors such as working temperature, required hardness, strength, shock resistance, toughness, machinability, and cost considerations.
Hot work tool steel bars are extensively used for aluminum die casting molds, die casting inserts, and high-pressure die casting tooling, where resistance to thermal fatigue, heat checking, and molten metal erosion is critical.
Grades such as H13 hot work tool steel bars are commonly selected for aluminum and magnesium die casting dies due to their excellent hot strength and long tool life.
Forged hot work tool steel bars are ideal for hot forging dies, press forging tools, and hammer forging components that operate under extreme mechanical loads and elevated temperatures. The forged structure improves internal soundness and grain flow, reducing the risk of premature cracking.
These steels are widely used in automotive forging dies, heavy machinery forging tools, and industrial forging applications.
Hot work tool steels are commonly applied in aluminum extrusion dies, copper extrusion tooling, and high-temperature extrusion components. Their ability to retain hardness and resist softening at elevated temperatures ensures dimensional stability and extended die life.
Grades with chromium-molybdenum alloy systems are especially suitable for high-load extrusion tooling.
Hot work tool steel bars are also used in high-temperature industrial tools, thermal forming components, and heat-resistant tooling parts subjected to repeated heating and cooling cycles. Typical applications include structural tooling components, industrial mandrels, and thermal load-bearing parts.
While plastic mold steels are typically used for injection molding, hot work tool steel bars are often selected for plastic mold components exposed to high processing temperatures, such as core inserts, hot runner-related tooling, and reinforced mold sections requiring superior thermal stability.
Selecting the appropriate tool steel requires evaluating the operating environment and performance requirements:
Operating temperature: Hot work vs cold work conditions
Required hardness and wear resistance
Thermal fatigue and heat checking resistance
Shock loading and toughness requirements
Tool life expectations and cost efficiency
Our engineering team provides technical support to assist customers in selecting the optimal tool steel grade and delivery condition for their specific application.
From raw material selection to final inspection, every production step is tightly monitored:
Electric arc furnace & secondary refining
Precision forging with controlled deformation ratios
Homogeneous heat treatment cycles
Ultrasonic testing (EN / ASTM standards)
Mechanical and metallurgical verification
This ensures consistent internal quality and repeatable performance across batches.
Extensive experience in forged tool steel production
In-house forging and heat treatment capabilities
Custom dimensions and grades supported
Stable supply for both prototype and series production
Engineering support for material selection and processing
Hot work tool steel is primarily used for tooling and components exposed to high temperatures, such as die casting molds, forging dies, and extrusion tools.
Hot work tool steels are designed to withstand elevated temperatures and thermal cycling, while cold work tool steels are optimized for wear resistance at room temperature.
Yes. Hot work tool steels are commonly forged to improve internal soundness, grain flow, and mechanical performance.
Chemical composition, dimensions, and heat treatment conditions can be customized to meet specific engineering requirements.
Hot work tool steel is a category of alloy tool steel specifically designed to operate at elevated temperatures, typically above 500°C. It maintains strength, hardness, and toughness under thermal cycling and resists softening, heat checking, and thermal fatigue.
Hot work tool steels are commonly alloyed with chromium, molybdenum, and tungsten, and are widely used for die casting, hot forging, and extrusion tooling.
Yes. Tool steels are specifically designed to be heat treated. Heat treatment processes such as austenitizing, quenching, and tempering are used to achieve the desired combination of hardness, toughness, and wear resistance.
For hot work tool steels, controlled heat treatment is critical to ensure thermal stability and resistance to cracking in high-temperature service.
Tool steels are generally classified into six main groups based on application and alloy content:
Water hardening tool steels
Cold work tool steels
Shock resisting tool steels
High speed tool steels
Hot work tool steels
Special purpose tool steels (plastic mold steels)
Each group is designed to meet specific requirements such as operating temperature, hardness, toughness, and cost efficiency.
Steels with sufficient carbon content and appropriate alloying elements can be heat treated. This includes most tool steels, alloy steels, and carbon steels.
Low-carbon steels such as mild steel generally cannot be significantly hardened by heat treatment alone, while alloyed tool steels respond well to controlled heat treatment processes.
Tool steel hardening temperatures vary depending on the grade, but typically range between 800°C and 1,100°C during the austenitizing stage.
Hot work tool steels such as H11 and H13 are hardened at higher temperatures to ensure adequate dissolution of alloy carbides and optimal high-temperature performance.
Oil-hardening tool steels such as O1 are considered among the easiest tool steels to harden due to their forgiving heat treatment requirements.
However, hot work tool steels are optimized not for ease of hardening, but for stable performance under thermal stress, which requires precise heat treatment control.
If you require forged or hot rolled hot work tool steel bars for high-temperature applications, please contact our engineering team to discuss specifications, grades, and delivery options.
