基于团簇式的304不锈钢成分新标准

New composition standard of 304 stainless steel based on cluster formula

由于钢铁行业标准规定的成分区间较宽,企业均规定了各自的经验性成分标准,导致最终产品的品质不稳定。以最常用304不锈钢为典例,利用团簇式方法,试图解析国标成分并提出更严谨的成分标准。由于主要合金化元素Si、Cr、Mn和Ni的原子尺寸相近,在合金化元素归类为奥氏体稳定型(Ni,Mn)和铁素体稳定型(Cr,Si)后,确定出合金成分的最小结构载体满足16个原子的团簇式(C、P、S不进入团簇式)。利用该式分析了国标和24种文献报道的合金成分,发现实际成分位于(Cr,Si)_(3~3.5)-(Ni,Mn)_(1.5±0.25)限定区间,远小于标准范围。进而在现有国标框架内,结合Cr和Ni当量,确定出新形式的成分协同变化关系(mass%):1)在18.0≤Cr+1.7Si≤19.0范围内,0.6(Cr+1.7Si)-2.3≤Ni+1.06Mn≤2.5(Cr+1.7Si)-35.9;2)在19.0≤Cr+1.7Si≤20.6范围内,0.56(Cr+1.7Si)-1.59≤Ni+1.06Mn≤11.6;3)8.5≤Ni+30C+0.5Mn≤13.3;4)0.5(Cr+1.5Si)-(30C+0.52)≤Ni+0.5Mn≤2(Cr+1.5Si)-(30C+27.0)。该新成分标准为304不锈钢工业生产提供了成分控制依据,并为分析钢牌号成分提供了范例。

Due to the wide composition range stipulated in the steel industry standards,enterprises have stipulated their own empirical composition standards,resulting in the instability of the quality of final products.Taking the most commonly used 304 stainless steel as an example,the cluster formula method was used to analyze the composition of the national standard and put forward a more rigorous composition standard.Since the atomic sizes of the main alloying elements Si,Cr,Mn and Ni are similar,after the alloying elements are classified into austenite stable type(Ni,Mn)and ferrite stable type(Cr,SI),it is determined that the minimum structural unit of the alloy composition meets the cluster formula of 16 atoms(C,P and S do not enter the cluster formula).Using this formula,the alloy compositions reported in the GB standards and 24 literatures are analyzed.It is found that the actual composition lies in the limited range of(Cr,Si)_(3-3.5)-(Ni,Mn)_(1.5±0.25),which is far less than the standard range.Then,within the framework of the existing GB standards,combined with Cr and Ni equivalent,a new form of composition standard is proposed,which reflects the coordinated variations of the elemental ranges(mass%):1)in the range of 18.0≤Cr+1.7Si≤19.0,0.6(Cr+1.7Si)-2.3≤Ni+1.06Mn≤2.5(Cr+1.7Si)-35.9;2)in the range of 19.0≤Cr+1.7Si≤20.6,0.56(Cr+1.7Si)-1.59≤Ni+1.06Mn≤11.6;3)8.5≤Ni+30C+0.5Mn≤13.3;4)0.5(Cr+1.5Si)-(30C+0.52)≤Ni+0.5Mn≤2(Cr+1.5Si)-(30C+27.0).The new composition standard provides a composition control basis for the industrial production of 304 stainless steel and an example for the analysis of the composition of steel grades.