Research And Development On LW135 Track Shoe

Track shoe is mainly used to make crawler running parts of excavators and bulldozers.LW135 track shoe is used to make crawler of mini excavators.In the recent years,the acceleration of urbanization has increased the need of mini excavators rapidly and the need of LW135 track shoe shot up.A kind of hot rolled LW135 track shoe was researched and developed successfully which has an important significance in the serialization of track shoe in LaiWu Steel.The main contents and results in this paper are shown as following:(1)The effects of various factors on hardenability were studied,especially the effects of different contents of titanium(Ti),chromium(Cr)and boron(B)on hardenability.Combining with the properties of target steel and the capacity of production line,the main chemical element content was made for LW135 track shoe with steel grade 25MnB.(2)The pass sequence of track shoe was designed according to the practical situation of production line as well as the shape dimension of target section steel.The layout of mill:RI rough mill was equipped with 7 passes and series passes of S1-S2-S3 for finish rolling and used 150*150 mm square billet.(3)The rolling process of track shoe in the pass sequence was elastic-plastic FEM simulated to verify the rationality and feasibility of groove design by using ANSYS software,a numerical simulation method for 3D model,the law of metal flow,stress distribution,strain distribution and deformation process of typical passes during rolling process were analyzed in detail.The reliability and accuracy of the FEM simulation analysis are verified by drawing sample of the middle pass.(4)The key points of steelmaking and rolling process in the industrial test were made,and qualified LW135 track shoe products with grade 25MnB were produced in the industrial test.The end quenching hardenability test results show that the hardness at J1.5,J9,J15 reached to 46?50 HRC,42?46 HRC and 20?24 HRC respectively.The hardness value of each position had less fluctuation,controlled in 3?5HRC,which realized narrow hardenability band control.The grain size was Level 7?8,decarburized layer was less than 0.3 mm,and the rating level of inclusions in class A,class B and class C were less than 1.0.The properties met the technical requirement,and the track shoe can be mass produced.