Lub Rockwell hardness tester yog nruab nrog lub vijtsam loj uas tau tsim tshiab, uas yog kev txhim khu kev qha, ua haujlwm tau zoo thiab pom tau yooj yim, thiab yog li cov khoom siv high-tech sib txuas cov tshuab thiab hluav taws xob.
