ADI铁路机车制动器耐磨件的试制

An Experiment of Using ADI to Produce Wear-Resistant Parts of Locomotive Braking Device

用牌号为QTD1400—1的等淬球铁（ADI）试制了东风4B内燃机车制动装置用衬套等铸件，其球化率为2-3级、石墨球大小5～7级、珠光体体积分数大于80％，等淬热处理工艺为：880。920℃x1～2h＋240～280℃×1～2h，热处理后金相组织为针状铁素体＋富C奥氏体＋球状石墨，力学性能检测结果为：抗拉强度1460～1510MPa，伸长率1．6％。4％，硬度46．0～48．5HRC。通过30万km行车试验证明，ADI衬套等耐磨件可以满足内燃机车制动装置的服役使用要求，在相同工况条件下的磨耗是原来钢衬套的1／3～1／5。

An experiment of using QTD1400-1 grade ADI to produce several wear-resistant parts used for the braking device of Dongfeng 4B model internal combustion engine locomotive was conducted. For the production of ADI bush,one of these parts, the nodular iron with nodularity of 2-3 grade, graphite size of 5-7 grade and pearlite volumetric fraction more than 80% was used, and the following iso-quenching process was adopted：austenizing temperature and holding time of 880-920 ℃× 1-2 h,iso-quenching temperature and holding time of 240-280 ℃xl-2 h. The as-heat treated microstructure was acicular ferrite ＋ carbon-rich austenite ＋ nodular graphite. The mechanical properties test result was as： tensile strength of 1 460- 1 510 MPa,elongation of 1.6%-4% ,hardness of 46.0-48.5 HRC. It was proved by 300 000 km running test that the ADI bush and other wear-resistant parts met the working requirements of the locomotive braking device ;and under the same working conditions,the wear-off of the ADI bush was 1/3-1/5 of that of the steel bush.