Power harrow is one of the rotary tillage machines that are regarded in recent years. This implement used for secondary soil manipulation and seed bed preparation. Blades of power harrow are working in soil to the depth of 250-280 mm, improvement soil drainage. The blades of power harrow are subjected to wear and failure,so those must be have impact and wear resistance properties that these properties are inverse. In Iran, blades of power harrow import from factories as Kuhn,in France or Maschio-Gaspardo,in Italy, and so far not successful production or economical. The quality and durability of the blade is depends on the suitable material and its heat treatment. Analysis of blade material imported by Maschio-Gaspardo and for producehigh-alloy steels in Iran as well as reasonable prices, smanth steel 16MnCr5 with the standard number of DIN1/7131, as steel basis were selected to conduct operations at different heat treatment. Five heat treatments consist of gas carburizing, carburizing-austempering, quenched, and tempering 150°C, quenched and tempering 300°C, and austempering was applied on 16MnCr5. An apparatus test abrasive wear was built (according to the standards ASTM G105-89) and wear resistance of treated steel were investigated exposed to wet sand (Quartz) and rubber wheel. The properties of impact resistance and hardness of steel was measured, using Charpy and Vickers test method,respectively. The microstructure of the steel was determinate by using optical microscope. ANOVA showed the three heat treatments, gas carburizing, austempering, and carburizing-austempering with microstructures martensitic, lower bainite, and upper bainite had higher hardness, impact resistance, and wear resistance, respectively. Tempering temperature increases from 150 to 300°C reduces the impact resistance due to temper embrittlement. The relationbetween hardness and impact energy is linear with negative slope, and the R 2 =0.815. The hardness of rubbery wheel and its mass of wear showed in all steel samples subjected heat treatment with increasinghardness rubbery wheel mass of wear increased. This reason was reduced in rubbery resilient properties and lower penetrates particle abrasive in rubber. According to coefficient of variation, the effect ofheat treatment on failure energy of samples was more than hardness and resistances wear. Upper bainite microstructure in gas carburizing treatment found the best structure to compare others microstructures to achieve best properties, hardness, wear resistance, and impact resistance in steel 16MnCr5 to be close to the Maschio-Gaspardo blade made in Italy.
