OHNS

Punches and Dies – Used in sheet metal forming and blanking operations due to excellent wear resistance. Forming Tools – Ideal for tools that require dimensional stability and hardness after heat treatment. Broaches – Suitable for making internal or external broaching tools that demand high precision. Chisels and Engraving Tools – Common in hand tools where sharpness and edge retention are critical. Shear Blades – Used in cutting tools for paper, metal, and plastic industries. Knurling Tools – Maintains detail and wear resistance during repetitive use. Taps and Reamers – Used in machining threads and holes, requiring high accuracy and surface finish. Woodworking Tools – Effective in applications like carving tools, knives, and cutters due to good edge holding capacity. Jigs and Fixtures – Maintains shape under stress and repeated use in tool holding and assembly tasks. Cold Work Tooling – Applied in press tools, trimming dies, and forming dies where cold working is involved.

We are a trusted dealer, stockist, and supplier of OHNS alloy steel, catering to a wide range of industrial clients across India. With a strong distribution network and quality assurance, we offer OHNS steel in various forms—including round bars, flats, squares, and tool blanks—in both annealed and hardened conditions.

Annealed Condition: – Typically around 180–220 Brinell Hardness (HB) – Soft enough for machining and shaping After Hardening: – Can reach 58–62 HRC (Rockwell Hardness C) – Achieved by oil quenching and tempering – Offers excellent wear resistance and edge retention Tempered Condition: – Hardness can be adjusted depending on tempering temperature – Balances toughness and durability for tooling applications

Annealing: Heat to 800–850°C Hold uniformly, then slow cool in a furnace Purpose: To soften the material for machining and relieve internal stresses Hardening: Heat to 780–820°C Ensure uniform temperature throughout the section Quench in oil to achieve high hardness and wear resistance Tempering: Reheat to 150–300°C, depending on required hardness and toughness Hold for 1–2 hours, then air cool Purpose: To reduce brittleness and increase toughness after hardening

Preheat: Slowly preheat the steel to 600–650°C to minimize thermal shock. Austenitizing (Hardening Heat): Raise the temperature to 780–820°C uniformly. Hold until the steel is thoroughly heated throughout the section. Quenching: Quench immediately in oil to achieve full hardness. Oil quenching minimizes distortion and cracking compared to water quenching. Resulting Hardness: After proper oil quenching, OHNS can reach 58–62 HRC, depending on section size and quenching method. Tempering (Recommended Post-Hardening Step): Temper to reduce brittleness and improve toughness, especially for tools and dies.

Weldability: – Poor weldability due to high carbon content (~0.9–1.0%). – Prone to cracking and distortion if not properly preheated and post-heated. Precautions Required: Preheat to around 250–350°C before welding to reduce thermal shock. Post-weld heat treatment (tempering or annealing) is essential to relieve stresses and restore ductility. Use low hydrogen electrodes or matching filler rods for best results.

Annealed Condition (Best for Machining): – OHNS steel is easily machinable in its annealed state, with a typical hardness of 180–220 HB. – It can be turned, milled, drilled, and ground with standard cutting tools. – Produces clean surface finishes and precise dimensions. After Hardening: – Once hardened (58–62 HRC), OHNS becomes very difficult to machine. – Only suitable for grinding or EDM (Electrical Discharge Machining) after hardening. Tooling Recommendations: – Use high-speed steel (HSS) or carbide-tipped tools for best results. – Adequate coolant and low feed rates help reduce tool wear. Applications in Machining: – Ideal for making precision dies, punches, and cutting tools that require tight tolerances and surface finish.