EN31

Bearing Components – Used in the manufacturing of ball and roller bearings due to its high hardness and wear resistance. Gears and Shafts – Ideal for components that require strength, hardness, and fatigue resistance. Dies and Punches – Suitable for press tools and dies that undergo repeated impact and wear. Rollers and Sleeves – Used in rolling mills and industrial machinery for high-load conditions. High-Stress Machine Parts – Excellent for parts that need to withstand heavy loads without deformation. Knives and Cutting Tools – Ideal for blades and tools that demand a sharp, durable edge. Spindles and Arbors – Commonly used in precision engineering and machine tools. Automotive Parts – Used in components such as axle shafts, connecting rods, and crankshafts. Measuring Instruments – Suitable for high-precision tools and gauges due to dimensional stability. Wear-Resistant Bushings – Perfect for sliding and rotating applications where surface durability is key.

We are a trusted dealer, supplier, stockist, and distributor of EN31 alloy steel, offering high-quality materials to meet industrial and engineering demands. Our EN31 stock is available in a range of sizes and forms, including round bars, flats, squares, and forgings, supplied in annealed, hardened, or tempered conditions based on customer requirements. Serving industries across automotive, tool & die, manufacturing, and engineering sectors, we ensure: Prompt delivery across major cities in India. Competitive pricing and reliable inventory. Customized cut-to-size services. Technical assistance and test certifications.

EN31 is known for its exceptionally high hardness, especially after heat treatment. Its hardness values vary depending on the condition of the material. Annealed Condition: Hardness: Approximately 200–230 HB (Brinell Hardness) Suitable for machining and forming operations. Hardened Condition (after quenching and tempering): Hardness: Up to 60–63 HRC (Rockwell Hardness C) Ideal for applications requiring extreme wear resistance and durability. Case-Hardened or Induction-Hardened Surface: Surface hardness can reach 63–66 HRC, while the core remains tough and ductile.

EN31 responds well to various heat treatment processes, which significantly improve its mechanical properties, especially hardness and wear resistance. Annealing: Purpose: To soften the material for machining. Process: Heat to 780–800°C, then slowly furnace cool. Result: Improves machinability and relieves internal stresses. Hardening (Quenching): Purpose: To increase hardness and strength. Process: Heat to 820–840°C, hold until uniform temperature, then quench in oil. Result: High hardness (~60–63 HRC) suitable for wear-resistant applications. Tempering: Purpose: To reduce brittleness after hardening and improve toughness. Process: Reheat to 150–200°C, then air cool. Result: Balanced hardness and ductility. Sub-zero Treatment : Purpose: For dimensional stability and maximum hardness. Process: Cool to -80°C or lower after quenching, then temper.

Hardening is a critical heat treatment process for EN31 to achieve its notable wear resistance and high surface hardness. Heating: Heat the steel uniformly to a temperature of 820°C to 840°C. Hold at this temperature until the material is fully austenitized (even temperature throughout the cross-section). Quenching: Immediately quench in oil to rapidly cool the material. This transforms the structure to martensite, increasing hardness significantly. Tempering (Post-Hardening Step): Reheat to 150°C to 200°C, depending on the desired balance between hardness and toughness. This reduces internal stresses and brittleness caused by quenching. Resulting Hardness: After hardening and tempering, EN31 achieves 60–63 HRC (Rockwell Hardness C).

Welding EN31 can be challenging due to its high carbon content, which makes it prone to cracking, hardness in the heat-affected zone (HAZ), and reduced weld integrity. Preheating: Preheat to 250–350°C before welding. This reduces thermal shock and the risk of cracking. Welding Process: Use low-hydrogen electrodes (e.g., E7018) or TIG/MIG with proper filler material. Perform short, controlled weld passes to limit heat input. Post-Weld Heat Treatment (PWHT): Slow cooling after welding followed by tempering is recommended to relieve stresses and soften the HAZ. PWHT temperature: around 150–200°C, depending on application. Avoidance (When Possible): Welding is not generally recommended for critical applications due to risk of cracking. If welding is essential, expert supervision and strict thermal control are advised.

EN31 alloy steel offers moderate to low machinability, primarily due to its high carbon and chromium content which makes it extremely hard after heat treatment. Annealed Condition (Before Hardening): Machinability is significantly better when EN31 is in the annealed state (approx. 200–230 HB). Suitable for turning, milling, drilling, and grinding. Hardened Condition: After hardening (~60–63 HRC), machining becomes very difficult and typically limited to grinding operations. Requires special carbide or ceramic tools and slower cutting speeds. Coolant Use: Generous use of cutting fluids is essential to reduce heat buildup and tool wear. Tooling Advice: Use carbide-tipped tools for longer tool life. Low feed rates and moderate speeds help achieve better surface finishes and dimensional accuracy.