Steel pipes; steel tubes; pipes of metal; metal joint connectors for pipes; metal clamps for fastening pipes; fittings of metal for pipes; fastening collars of metal for pipes and tubes; drill pipes of metal; couplings of metal for pipes; couplings of metal for piping; couplings of metal for tubing; pipe couplings of metal; articles of metal for use in the drilling of gas wells; articles of metal for use in the drilling of oil wells