???? ????? ??????? ??????? ?? ????? ????? F91 ???????? ????? ??????

?????? ?????? ??????? ?? ????? ????? F91 ?????? ?? ???? Shijiazhuang Deye Piping Idndustrys Co.,Ltd. ?? ???? ????? ???? ?????? ????? ?????? ?????????. ????? ?? ????? ??????? F91 ????????? ??? ?? ????? ??? ?????? ????? ???? ????? ????? ??????? ???????? ??? ????? ??????? ????????? ?? ??????? ?????? ??? ????? ?????? ?????? ????? ?????? ?????? ???????? ??????????? ?????? ??? ?????? ?????? ????? ??? ? ????? ????? ????? ???? ????? ?????. ??? ???? ?????? ???? ??????? ???????? ????? ??? ???? ??????? ??????? ?????? ??? ??????? ?????? ?????? ?????? F91 Alloy Steel ?????? ?????? ??????? ??? ???????? ????????? ???????? ????????. ??? ?? ?????? ????? ?????? ???????? ??????? ?????? ????????? ??? ???? ???? ????? ????????? ???? ????? ?????? ?????? ??????? ?? ????????? ??????? ???????? ??? ?????? ?????? F91 Alloy Steel ?? ???? Shijiazhuang Deye Piping Idndustrys Co.,Ltd . ?? ?????? ?????? ????????? ???????? ??????