S-Type Cultivator Tines Which Comply With ISO Standard: FEM Analysis of Stresses and Manufacturing Issues

ISO Standard is propagating in all aspects of industries worldwide. In order to keep competitiveness, companies are subjected to necessity for their production to be in accordance with ISO. S-type cultivator tines are used in agriculture for the soil preparation. Dimensions and the methods of testing S-tines are proposed by the standards ISO 5678-1993(E) and ISO 8947-1993(E), respectively. The fatigue test defined by ISO-8947(E) proved to be very rigorous. Stresses which develop in the S-type tine during the fatigue test were determined by the finite element method, using MSC Patran/MD Nastran software packages. Results show that tensile stresses during the test are as high as 1100 MPa (around 160 ksi). It is very strict requirement to have the yield strength higher than that value. This requirement is possible to achieve using thermomechanical treatment, a combination of metal working and heat treatment of mainly high-strength low-alloy (HSLA) steels.