we produce harrow disc blades as follows · · minimum 12” dia. To maximum 30” dia. · · minimum 2.5mm thickness to maximum 10mm thickness. steel material – · · boron steel (30mnb5) , with hardness of 48 to 52 hrc. · · high carbon steel (sae 1080) , with hardness of 38 to 42 hrc. minimum order should be one 20 feet container mix of different size & types of disc. one size / type of disc moq is 100 pcs.