Numerical Simulation Research On Surface Wear Behavior Of H13Steel And Prediction Of The Mould Life

With the rapid development of automobile industry, the requirement of automobilewith lightweight and safety is higher and higher, high strength steel has been used moreand more widely in industrial production, especially in automobile industry because of itscharacteristics of lightweight, high strength and the quality hot forming performance.Because high strength steel hot forming mould has characteristics of complex structure,high costs of materials, high accuracy, so high strength steel hot forming mouldmanufacturing cost a larger proportion in the product costs. It becomes the research focusthat reduces the mould costs by extending the mould life, it is the premise that predicts themould life accurately. The study found that70%failure of the moulds caused by mouldwear, therefore, reducing the wear is the key to improve the mould life, and the length ofthe mould life can be determined by mould wear.This article regards H13steel as the research object, making an intensive numericalanalysis and experimental study on the surface wear behavior, explores the effectivemethods to improve wear resistance of mould surface, and then predicts the mould life, allthese have higher theoretical and practical significance on perfecting the study ofimproving the wear resistance of the mould and reduce the mould costs.Firstly, this article finds the friction coefficient of H13steel smooth surfaces andGCr15under50,100,130and150N load, and those smooth surfaces and the non-smoothsurfaces(dot, stripe, grid) of H13steel under the same load through the pin-disc slidingwear test, then calculates the surface wear depth of H13steel. Through scanning electronmicroscope to observe the wear surface morphology of H13steel surface under differentload and surface morphology to get the related parameters of factors of the wear and therelated parameters of the numerical simulation needed.(1)The hardness of the dot, stripe and grid non-smooth unit cells increases throughlaser processing, as well with better wear resistance than the matrix material; Under the same load, the wear volume, wear rate and friction coefficient of the processed dot, stripeand grid non-smooth surfaces of H13steel processed by laser bionic are smaller than thesmooth surfaces, and those of the dot non-smooth surface of H13steel is the biggest, thegrid non-smooth surface is the smallest, the strip non-smooth surface is in the middle,(2)Non-smooth surface morphology can reduce the amount of wear and tear onmaterial, increase its wear resistance; the wear resistance is also different with thedifferent non-smooth surface.(3) Analysis and research on surface wear of SEM photos of H13steel shows: alongthe direction of wear and tear, the grinding crack and the density of furrows of the back ofthe non-smooth unit cell are less than the front of the non-smooth unit cell.Then, it establishes finite element three-dimensional model of the pin-disc slidingwear for numerical simulation on surface wear of H13steel. With adaptive grid techniqueof ABAQUS, combined UMESHMOTION wear subroutine, it gets the surface wear depthof H13steel and compared with experimental results, the error is5.01%.It verifies thevalidity and practicability of the numerical simulation within allowable error. Moreover, itgoes on with the two-dimensional and the three-dimensional temperature field simulationfor the H13steel pin sample in the process of pin-disc sliding wear, and the result isconsistent with a large number of research results.Finally, taking an example of punching bending model, with DP590high strengthsteel for sheet metal and H13mould steel for the material of die for the numericalsimulation analysis of die wear, combining ABAQUS,UMESHMOTION wear subroutineand C++,it extracts automatically contact stress of nodes on the contact slave surface inthe process of sliding wear, and obtains the contact stress of selected nodes on the contactmaster surface by interpolation method, then gets the single wear quantity of specificnumber of deformation by Archard formulas, and the cumulative wear quantity of wear bycalculating. At last, it arranges linear fitting for cumulative wear quantity and deformationtimes, combined with the allowed wear of die to get the service life of mould.We have mastered the wear law of H13steel by the study on its surface wear behavior, and proposed the method of non-smooth surface to improve wear resistance;analyzed the changes of surface stress, temperature and so on during the pin-disc wearprocess of H13steel by the means of numerical simulation, proposed an effective methodto predict the service life of mould, laid the foundation for the study on wear performanceof hot forming mould and increasing the mould life.