正火处理对建筑结构用超厚规格H型钢抗层状撕裂性能的影响

对建筑结构用超厚规格热轧H型钢进行了920℃正火处理，利用光学显微镜和扫描电镜对热轧态和正火态型钢的显微组织进行观察，对比分析了抗层状撕裂性能(Z向性能)差异及其与显微组织的对应关系。结果表明，热轧态型钢在正火处理后获得细铁素体+超细珠光体组织，组织均匀性得到显著提升，晶粒细化明显。两种试验钢Z向性能均达到Z35要求，与热轧态相比，正火态型钢的抗拉强度升高约12 MPa,断面收缩率提高约13%。正火处理后的基体组织细化及夹杂物球化等对H型钢Z向力学性能的提高较大。

Influence of normalizing treatment on lamellar tearing resistance of super thick H-section steel for building structure

Ultra-thick hot-rolled H-section steel for building structure was normalized at 920 ℃, the microstructure of hot-rolled and normalized H-section steel was observed by using optical microscope and scanning electron microscope, and the difference of lamellar tearing resistance (Z-direction performance) and its relationship with microstructure were compared and analyzed.The results show that after normalizing,fine ferrite+ultrafine pearlite structure is obtained,the microstructure uniformity is significantly improved, and the grain refinement is obviously. Comparing with the hot-rolled steel, the tensile strength of the normalized steel increases by about 12 MPa, and the percentage reduction of area increases by about 13%. The refinement of matrix structure and spheroidization of inclusions after normalizing have a greater improvement on Z-direction mechanical property of the H-section steel.