SWRCH45K冷镦钢盘条显微组织均匀性研究

Research on microstructure uniformity of SWRCH45K cold heading wire rod

Φ6.5 mm SWRCH45K盘条经球化退火,在冷镦过程中开裂。对盘条进行金相检验,钢中夹杂物总级别为2级,未发现大型夹杂物,盘条显微组织出现局部偏析和魏氏组织。采用热模拟试验,将6.5 mm SWRCH45K盘条分别加热到860,900℃,并分别进行炉冷、空冷、吹风冷却,对SWRCH45K盘条的显微组织和晶粒度进行分析。结果表明:采用860℃加热并炉冷后,其显微组织为铁素体与珠光体,基本上未形成魏氏组织,晶粒度较均匀。提出适当调整精轧、终轧与吐丝温度,降低斯太尔摩线的辊道速度,可消除魏氏组织,改善偏析与晶粒不均匀现象。

Diameter 6.5 mm SWRCH45K wire rod cracked during cold heading after spheroidizing annealing. The wire rod was microstructure examined, the general grade of inclusions in steel was grade 2, there was no large inclusion, the partial segregation and Widmanstatten structure existed in wire rod microstructure. Thermal simulation was adopted to heat diame ter 6.5 mm SWRCH45K wire rod to 860, 900 ℃ separately, and cooled with furnace, air and blowing wind three different cooling speed, the microstructure and grain size of SWRCH45K wire rod were analyzed. Results show that the microstruc ture is ferrite and pearlite, there is no Widmanstatten structure in wire rod, grain size is relative uniformity, when it is heated to 860 ℃ and furnace cooling. It is proposed that properly adjusting finish rolling, final rolling and wire laying tempera ture, slowing Stelmor line roller speed, eliminating Widmanstatten structure,improving segregation and mixed grain.