Assab Steel Rod/Bars,QRO 90 SUPREME Hot Work Steel Rod/Bar

Assab Steel Rods QRO 90 SUPREME Hot Work Steel Rod Product Information -:- For detailed product information, please contact sales. -: Assab Steel Rods QRO 90 SUPREME Hot Work Steel Rod Synonyms -:- For detailed product information, please contact sales. -:

Assab Steels QRO 90 SUPREME Hot Work Steel Product Information -:- For detailed product information, please contact sales. -: ### **Assab Steels QRO 90 SUPREME: Premium High-Performance Hot Work Tool Steel for Extended Die Life** --- #### **1. Introduction** **Assab Steels QRO 90 SUPREME** is a high-performance, **premium martensitic chromium-molybdenum-vanadium (Cr-Mo-V) hot work tool steel** manufactured using the **Electro-Slag Remelting (ESR)** process. Unlike standard H13-type steels, QRO 90 is a **proprietary alloy** specifically engineered to deliver superior performance in the most demanding aluminum die-casting and other hot work applications. Its optimized chemistry and ESR structure are designed to provide outstanding **thermal fatigue resistance** (heat checking resistance), **excellent thermal conductivity**, and **high toughness at elevated temperatures**, resulting in significantly extended die life and reduced downtime. **Key Value Propositions:** * **Superior Thermal Fatigue Resistance:** Outstanding resistance to the formation and growth of heat-checking cracks, a primary failure mode in aluminum die casting. This is achieved through a balanced microstructure and high thermal conductivity. * **High Thermal Conductivity:** About 10-15% higher than standard H13, promoting faster heat dissipation from the die surface, reducing thermal gradients and stress. * **Excellent Toughness at Service Temperatures:** Maintains good ductility and impact resistance even at high operating temperatures, reducing the risk of catastrophic cracking. * **Enhanced High-Temperature Strength:** Superior resistance to heat softening (hot hardness) compared to standard H13. * **Excellent Isotropic Properties (ESR):** Uniform performance in all directions due to a clean, homogeneous microstructure, ensuring predictable behavior in complex dies. --- #### **2. International Standard Designations** * **Assab / Uddeholm:** QRO 90 SUPREME (ESR) * **AISI / ASTM A681:** H13 **Modified / Proprietary Grade** (It is a distinct alloy, not a direct H13 equivalent) * **European Norm (EN):** Proprietary (Closest matrix is a modified 1.2344) * **DIN:** Proprietary alloy (X35CrMoV5-1 modified) * **Common Industry Reference:** Premium High-Conductivity Die-Casting Steel * **Competitor Equivalents:** Similar proprietary high-performance grades include **Böhler W300 ISOBLOC** and **ThyssenKrupp TQ1**. --- #### **3. Chemical Composition (Typical Weight %)** | Element | Carbon (C) | Silicon (Si) | Chromium (Cr) | Molybdenum (Mo) | Vanadium (V) | | :--- | :---: | :---: | :---: | :---: | :---: | | **%** | 0.38 | 0.30 | 2.60 | 2.30 | 0.55 | *Key Difference vs. H13: **Lower Chromium (Cr) and Silicon (Si)**, **Higher Molybdenum (Mo)**. This unique composition is the foundation of its higher thermal conductivity and thermal shock resistance.* --- #### **4. Physical & Mechanical Properties** * **Density:** 7.80 g/cm³ * **Thermal Conductivity:** **~32.0 W/m·K** (at 20°C) – *Higher than H13 (~28 W/m·K)*. * **Coefficient of Thermal Expansion:** 12.5 x 10⁻⁶/K (20-200°C) * **Specific Heat Capacity:** ~460 J/kg·K * **Elastic Modulus:** ~205 GPa * **Typical Operational Hardness:** **44-48 HRC** (Commonly used at 44-46 HRC for optimal toughness/thermal fatigue balance in aluminum die casting). * **Hot Hardness:** Superior retention of hardness at temperatures above 500°C compared to standard H13. --- #### **5. Heat Treatment** * **Soft Annealed Hardness:** ~ 185 HB * **Stress Relieving (after rough machining):** 600-650°C * **Preheating:** Two-stage preheating at 650°C and 850°C is crucial. * **Austenitizing Temperature:** **1010-1030°C** (Lower than H13, important for optimal properties). * **Quenching:** High-pressure gas quenching (preferred) or oil. * **Tempering:** **Double tempering is mandatory.** Temper in the range of **540-620°C**. For aluminum die casting, tempering at 580-600°C to achieve 44-46 HRC is typical. The hardness curve is flatter than H13, offering more flexibility. --- #### **6. Product Applications** QRO 90 SUPREME is engineered for applications where thermal fatigue and heat checking are the primary limits on tool life. 1. **High-Pressure Aluminum Die Casting (Primary Application):** * Core and cavity inserts for large, complex components (e.g., engine blocks, transmission housings, structural parts). * Units with high thermal load and severe cooling conditions. * "High-heat-checking-risk" areas like sharp corners and thin ribs. 2. **Copper and Brass Die Casting / Hot Forging:** * Dies and inserts where service temperatures are extremely high. 3. **Hot Work Tools Requiring Fast Heat Removal:** * Tools for which internal water cooling is critical to performance. 4. **Plastic Molds for High-Temperature Polymers:** * Molds for engineering plastics processed at very high temperatures (e.g., PEEK, PPS). --- #### **7. Quality & Supply Forms** * **Quality:** Electro-Slag Remelted (ESR) for utmost cleanliness and homogeneity. Subject to strict ultrasonic inspection. * **Available Forms:** * ESR blocks and billets. * Precision ground flat stock. * Black or peeled round and flat bars. * Custom pre-machined tool components. --- #### **8. Comparison: QRO 90 SUPREME vs. Standard H13 (e.g., 8407)** | **Property** | **QRO 90 SUPREME** | **Standard H13 (8407)** | | :--- | :--- | :--- | | **Thermal Conductivity** | **Higher (~32 W/m·K)** | Standard (~28 W/m·K) | | **Thermal Fatigue Resistance** | **Superior** (Best-in-class) | Very Good | | **Hot Hardness** | **Better retention at high temp** | Good | | **Optimal Hardness Range** | Slightly lower (44-48 HRC) | Slightly higher (46-52 HRC) | | **Typical Tempering Temperature** | Slightly higher (for same hardness) | Standard | | **Alloy Design** | Proprietary (Lower Cr/Si, Higher Mo) | Standard (5% Cr) | | **Primary Advantage** | **Extended die life in thermal fatigue applications** | Excellent all-around balance | --- #### **9. Conclusion** **Assab Steels QRO 90 SUPREME** is a purpose-built, premium solution for the most challenging hot work environments, particularly aluminum die casting. Its patented alloy design, focused on maximizing thermal conductivity and thermal fatigue resistance, directly addresses the core mechanisms that limit the life of standard H13 dies. For high-production, high-value die-casting operations where unplanned downtime and die repair costs are critical metrics, the investment in QRO 90 SUPREME translates into a demonstrable return on investment through dramatically increased shot counts, improved part quality consistency, and reduced maintenance. It is the definitive choice when pushing the performance limits of hot work tooling. -:- For detailed product information, please contact sales. -: Assab Steels QRO 90 SUPREME Hot Work Steel Specification Dimensions Size： Diameter 20-1000 mm Length <7243 mm Size:We can customized as required Standard： Per your request or drawing We can customized as required Properties（Theoretical） Chemical Composition -:- For detailed product information, please contact sales. -: Assab Steels QRO 90 SUPREME Hot Work Steel Properties -:- For detailed product information, please contact sales. -:

Applications of Assab Steel Rods QRO 90 SUPREME Hot Work Steel Rod -:- For detailed product information, please contact sales. -: Chemical Identifiers Assab Steel Rods QRO 90 SUPREME Hot Work Steel Rod -:- For detailed product information, please contact sales. -:

Packing of Assab Steel Rods QRO 90 SUPREME Hot Work Steel Rod -:- For detailed product information, please contact sales. -: Standard Packing: -:- For detailed product information, please contact sales. -: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and Steel Rod drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 3714 gallon liquid totes Special package is available on request. E FORUs’ is carefully handled to minimize damage during storage and transportation and to preserve the quality of our products in their original condition