In ChinaIn the 7Os, China further improved and simplyfiedthe Japanese method and promoted it.Practice has proved that the orthogonal test designis one of the most popular method with the science andtechnology personnel of several methodsUsing it to arrange all kinds of scientificexperiments,indeed, is simple to learn, and the effect istemarkable2007.416
16 2007.4 In China In the 70s, China further improved and simplyfied the Japanese method and promoted it. Practice has proved that the orthogonal test design is one of the most popular method with the science and technology personnel of several methods . Using it to arrange all kinds of scientific experiments,indeed, is simple to learn, and the effect is remarkable
Example1:Howto improvethehardnessindexThe basic production process of improving thesteel workpiece hardness is :Quenching:Putting the 840℃C workpiece into akind of liguid medium , to improve its hardnessTempering: Heating the workpiece to 430℃ aftercooling, and keep one hour, and then cooling, torelease its internal stressHow to change the process parameters, in order to2007.4Improve the hardness index ?17
17 2007.4 Example 1：How to improve the hardness index The basic production process of improving the steel workpiece hardness is： Quenching:Putting the 840℃ workpiece into a kind of liquid medium , to improve its hardness. Tempering: Heating the workpiece to 430℃ after cooling, and keep one hour, and then cooling, to release its internal stress . How to change the process parameters, in order to improve the hardness index ？