... part 4.alloy steel part 5.China 1.precision casting2.sewing machine parts3.mechanical part4.alloy steel part5.China1.precision casting2 ... machine, linear cutting machine, NC milling machine, polishing machine.Heat treatmentannealing, termpering, quenching, normalizing, solid solution.Testing facilityspectrometer, tensile test machine, hardness test machine, mircoscope. China sewing machine ...