正火温度对建筑耐火钢的组织与性能的影响

Effect of Normalizing Temperature on Microstructure and Properties of Fire-resistant Steel for Building

研究了正火温度对耐火钢组织与力学性能的影响。结果表明,当正火温度为700℃和750℃时,组织由针状或者条状铁素体和少量马氏体组成;升高正火温度至800℃,耐火钢基体组织中条状铁素体含量有所减少,而块状铁素体含量有所增多;继续升高正火温度至850℃,基体组织中主要为块状铁素体;当正火温度为700℃和750℃时,虽然耐火钢的强度较高,但是塑性较差,且屈强比高于0.8,无法满足耐火钢的使用要求;正火温度为800℃时,耐火钢的抗拉强度、屈服强度和断后伸长率分别为595 MPa、465 MPa和22%。

The effect of normalizing temperature on the microstructure and mechanical properties of refractory steel is studied.The results show that when the normalizing temperature are 700 ℃ and 750 ℃,the microstructure consists of needle-like or striped ferrites and a small number of martensites; when the normalizing temperature increases to 800 ℃,the content of striped ferrite in the matrix microstructure of refractory steel decreases,but the content of bulk ferrite increases; when the normalizing temperature continues to increase to 850 ℃,the matrix micro structure consists of mainly ferrite; when the normalizing temperature are 700 ℃ and 750 ℃,although the strength of the refractory steel is high,the plasticity is poor,and the yield ratio is higher than 0. 8,which can＇t meet the requirements for the use of refractory steel（ 0. 8）. The tensile strength,yield strength and elongation at break are 595 MPa,465 MPa and 22% when the normalizing temperature is 800 ℃.