灰铸铁件裂隙状氮气孔缺陷分析和解决措施

Case Study of Fissure Type Nitrogen Blow Hole on Grey Iron Casting

灰铸铁件裂隙状氮气孔往往形成于初生奥氏体枝晶间,导致形状成为裂隙状,从形状和产生的位置上容易误判为铸件的缩孔、缩松。灰铸铁件裂隙状氮气孔产生的原因是由于炉料中含有过高的氮导致铁液中的含氮量超标,解决灰铸铁件裂隙状氮气孔的根本措施是合理配料、使用含氮量低的炉料来降低铁液中的含氮量,其次是使用钛铁和含锆的孕育剂使铁液中的氮转化为氮化物,从而降低铁液中的[N]含量,使其在合理的范围之内。

Fissure type of nitrogen blow hole on grey iron casting is usually formed in between the austenite dendrite and it appears in fissure which is easily mistaken as porosity and shrinkage from shape and section.The fissure type nitrogen blow hole on grey iron casting is caused by high Nitrogen content in the molten metal,reasonable charging ratio and low Nitrogen content charging which reduces the Nitrogen content in the molten metal is the root measurement to prevent fissure type of nitrogen blow hole,using Ferrotitanium and Zirconium based Inoculant to turn Nitrogen into nitride to reduce the nitrogen content in the molten metal to proper addition is the second option.