国产精品成人久久久久_制服丝袜影音先锋_最近免费看av_五月天综合网_99热免费观看_久99久精品视频免费观看_国产日韩在线一区二区三区

     For geological prospecting, coal mining, tipping of electric and air drilk; for coal bed and other homogeneous rocks such as non-silicified shale, skyline and rock salt, etc.; and for medium hard sandstone limestone and interspersed soft and hard rocks.

     For coring crowns, electric coal drill bits, coal cutting picks. oil cone bits and scraping knife bits used in geological prospecting, coal mining and oil well boring.

     For coring crowns, electrical coal drill bits, coal cutting picks, cone drill bits and scraping knife bits, used in geological prospecting coal mining and oil well boring.

     For rotary rock drill bits for medium hard and hard rock; and for coal cutting picks and oil drill bits for cutting of honse-stone containing formations.

     For tipping of bits for heavy rock drills and rotary hammer rock drills cutting hard rock formations . e. g. , latent hole drills and deep-hole drills, rock drills, etc.

     For oil cone drills, for hard and medium hard rock and for tipping bit of rotary hammer rock drills and heavy rock drills.

     Top strength and less wear resistance, for bits of rotary hammer rock drills and heavy rock drills , for hard and very hard rocks .

     For oil cone drill bits for medium soft and medium hard rocks.