氮化工艺对球铁镀铁层组织结构及耐磨性影响的研究

A Study on the Effects of Nitriding Technological Specifications for the Iron Plating Layers of Spherodial Graphite Cast Iron on the Structure and Wear Resistance

研究了不同的氮化工艺参数对球墨铸铁镀铁层组织结构及耐磨性的影响．低温镀铁层特殊的组织结构，使得在很低的氮化温度下，镀层仍可完全氮化．镀层中网、条纹随氮化温度升高而粘连粗化．氮化工艺对耐磨性影响的显著性大小顺序为：氮化温度、ＮＨ_３流量、氮化时间．温度升高耐磨性下降；时间延长，耐磨性趋于一致．在试验条件下获得的最佳氮化工艺为：Ｔ＝４５０℃，ＮＨ_３流量为３０Ｎｌ／ｈ，τ＝１ｈ．经该工艺处理获得的镀铁氮化层的耐磨性较之未氮化镀层提高了１６０倍左右．

The effects of nitriding technological specifications for the iron plating layers of spherodial grophite cast iron on the structure and wear resistance have been investigated. The testing results show that iron plating layers can be nitrided completely even under the lower nitriding temperature, The nets and stripes in plating layers become coarsening gradually with the increase of nitriding temperature. The effects of nitriding technological specifications on wear resistance in sequence are: nitriding temperature, the flow of NH_3 and nitriding time.An increase of temperature results in the decrease of wear resistance, and wear resistance changes gradually to the same with the time increase. The optimum nitriding technological specifications obtained under the circumstances of testing are: temperature: 450 ℃, the flow of NH_3: 30 NL / h, time: 1 h. The wear resistance of the nitrided iron plating layer obtained at using the technique above in comparison to that of iron plating layer increases by about 160 times.