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石油化工工业使用大量耐热钢管作蒸汽热转换管。目前普遍应用的是离心铸造奥氏体不锈钢管。这类钢管最常用的钢号是HK40镍铬不锈钢(Cr25-Ni20-0.4C)。HK40钢管的组织特点是其层片状共晶碳化物网络和数量极大的二次析出碳化物。这种特点赋于HK40钢管以相当好的蠕变断裂强度。正在发展中的新材料是在这一钢号的基础上添加碳化物形成元素Nb、Ti、Zr等,其组织特征是二次析出碳化物更弥散、更稳定,从而得到更高的蠕变断裂强度。
The petrochemical industry uses a large number of heat-resistant steel tubes for steam heat transfer tubes. Currently widely used in centrifugal casting austenitic stainless steel tube. The most commonly used steel for this type of pipe is HK40 nickel-chromium stainless steel (Cr25-Ni20-0.4C). HK40 steel is characterized by its lamellar eutectic carbide network and the amount of secondary precipitated carbide. This feature gives HK40 steel pipe with a fairly good creep rupture strength. The new material being developed is based on the steel added carbide forming elements Nb, Ti, Zr, etc., its organization is characterized by secondary precipitation carbide more diffuse, more stable, resulting in higher creep rupture strength.