Dab tsi yog SS490 h txheej txheem hlau nqaj?
SS490 h cis yog kub dov h-zoo li cov qauv steel hlau uas tau raws li JIS G3101 cov qauv siv hluav taws xob zoo li 4,6 Tsis zoo li nws SS400 counterpart, SS490 h zoo li cov qauv hlau ua kom muaj zog txhim kho kev ncaj ncees thiab kev ntxhov siab, nrog kev cuam tshuam zoo rau kev khoov thiab shear rog.