HTP工艺对X80级管线钢组织和性能的影响

Effect of the HTP on the Structure and Mechanical Properties of X80 Ferrite Steel

利用HTP工艺将X80级管线钢轧制成16 mm厚的板坯,对其组织和性能进行研究,结果表明:经高温轧制的X80级管线钢的屈服强度达到600 MPa以上,其屈强比为0.86,韧脆转变温度低于-60℃,且达到了很好的强韧性匹配;钢中低的硫、磷和高的锰含量及细小的组织能有效的降低韧脆转变温度;钢中存在两种典型的析出物,一类析出物是以TiN为主,在TiN周围有少量的(Nb、V)(C、N)的复合析出物,另一类析出物为大量的NbC和少量TiC、VC同时析出形成的复合析出物;这些很细小的析出物对钢的组织细化和强化起到了重要作用.

The structure and mechanical properties of X80 pipeline steel through HTP rolled into 16 mm thick slab were tested. The results show that the yield strength of tested has reached above 600 MPa, and the ratio of tensile strength to yield strength is 0.86, and ductile-brittle transition temperature is lower than -60 ℃, and good strength and toughness are obtained. Low contents of P, S, high content of Mn and fine microstructure have good effect on reducing the ductile-brittle transitiop temperature. Two different precipitations are observed in X80 pipeline steel： a class of TiN is the main precipitations with a small number of （Nb, V） （C, N） complex precipitations in the TiN around, and the other is the complex formed precipitations with large number of NbC precipitations and a small amount of TiC, VC. Remarkable strengthening and refinement can be caused by these precipitations.