Effects of rare-earth Y addition on microstructure and mechanical properties of lead-tin bronze

Piston pump rotor is one of the indispensable parts of hydraulic machinery,whose performance and quality determine the drive efficiency and service life of the piston pump.This paper mainly studies the effect of rare-earth yttrium(Y)on the microstructure and properties of the wear layer in piston pump rotor.The material of the wear layer is composed of lead-tin bronze.By adding different contents of rare earth Y,observe the change of microstructure and properties of lead-tin bronze.Through comparison,the addition of rare-earth Y can improve the tensile strength and elongation of lead-tin bronze,and the organization of lead particle morphology has become much smaller and uniformer than that without rare-earth.However,if the amount of rare-earth is too high,the tensile strength and elongation decrease,and the lead particles in the organization also have the tendency to grow up.Finally,it is concluded that when the amount of rare earth is 0.04%,the comprehensive performance is the best.

鴨峁溝坝系指出了坝地利用的正确途徑

鴨峁沟在綏德县城东辛店沟内的上游段,坝系流域面积1.16平方公里,沟长1980米,流域内有毛沟6条,沟壑密度每平方公里4.9公里。其土壤、地貭、地形、地貌,均代表典型的黄土丘陵沟壑区。一、坝系形成过程鸭峁沟坝系是由下游向上游、由支沟到毛沟,一座坝接一座坝陆續发展而成的。一九五三年修筑一号坝,一九五六年秋加高一次之后再没有加高过,現在坝高12.5米。一九五四年修筑二号坝。