Important Precautions for Application and Maintenance of H11 Hot Work Tool Steel

The performance of H11 steel is fully dependent on the heat treatment process, and must strictly follow the standardized procedure. For annealing, adopt spheroidizing annealing at 860-890°C, cool slowly after heat preservation, which will obtain uniform spherical carbides and improve subsequent processing performance. For quenching, keep the temperature at 1000-1030°C after insulation and quench with oil, avoid coarse grains caused by excessive temperature or insufficient quenching caused by low temperature. For tempering, perform multiple tempering at 530-560°C, and try to avoid the tempering range around 500°C, as tempering in this range will reduce impact toughness.

H11 steel is mostly used for high-precision molds such as die-casting molds and injection molding inserts, which requires high surface quality. It generally needs grinding and polishing to ensure finish and reduce friction and wear. If you need to further improve surface hardness, nitriding can be carried out at 500-600°C, and it must be ensured that the surface is thoroughly polished before treatment—nitriding effect can only be guaranteed when the roughness Ra ≤ 0.4μm. For aluminum alloy die-casting molds, it is recommended to maintain the hardness at 45~50 HRC: too high hardness is easy to cause thermal fatigue cracks, and stress relief tempering at 200~300°C is required after EDM processing. For high extrusion ratio or high-strength metal extrusion, the mold life may be shortened, so it is necessary to optimize the lubrication scheme to adapt to the working condition.

During use, the working temperature range must be strictly controlled. Although H11 steel has excellent heat resistance, it is recommended that the long-term working temperature should not exceed 600°C, excessive temperature will cause steel softening and deformation, and reduce the accuracy and stability of the mold. It should also avoid long-term use at too low temperature, low temperature may cause cold brittleness, reduce the toughness and impact resistance of the steel. It is necessary to reasonably control the temperature range according to the specific working condition to ensure the stability of the mold.

In daily use, it is necessary to regularly clean and lubricate the mold surface, check the mold for cracks, wear and other damages in time. Early treatment of small defects can effectively delay mold aging, reduce unexpected shutdowns during production, and extend the overall service life of the mold. The storage and transportation links also need to meet environmental requirements: H11 steel should be stored in a dry, ventilated environment free of corrosive gas, to avoid corrosion of the steel surface by moisture, acid and alkali media. Be careful to handle gently during loading and unloading, prevent collision damage to the finished surface, and maintain material integrity.