采用OM、SEM、EDS、冲击和拉伸试验机等对不同大规格的H13钢锻件进行了组织和性能方面的研究。结果表明：由于尺寸效应，大规格H13钢锻件存在严重的碳化物偏析现象，甚至出现了大块白色铁素体块状区域；液析碳化物主要为富V的MC型碳化物，且液析碳化物尺寸在锻件1/2半径处最大，这可能与大规格电渣锭母材的凝固特性有关；锻件心部冲击韧性偏低，断口为撕裂岭和准解理断裂面，属于脆性断裂断口形貌；塑性从心部到边部逐渐增大，在1/2半径处由于大尺寸液析碳化物的存在，塑性存在波谷值。

By using OM、SEM、EDS、impact and tensile testing machine, microstructure and mechanical properties of large size of H13 steel forging piece were studied. The results were that because of "size effect",H13 steel of large size had severer carbon segregation,even with massive white ferrite massive region existed;eutectic carbide was V-riched MC type carbide,and at 1/2R position,the size of eutectic carbide was largest,which was likely related with solidification characteristics of large size electroslag ingot;impact toughness at center area was low and the fracture surfaces were tear ridge and quasi cleavage fracture surface,belonging to brittle fracture,plasticity increased from center to edge area and at 1/2R area,because of large size of eutectic carbide,plasticity had trough value.