A process of making a field joint comprising the following steps: (i) abrading or sand blasting of the bare metal surface of a steel pipe; (ii-1) applying an epoxy primer or epoxy phenol primer on the bare metal surface, then applying a linear low-density polyethylene (LLDPE) resin having a maleic anhydride linear chain grafting or polypropylene resin having a maleic anhydride linear chain grafting, said resins having a maleic anhydride grafting content of 0.2 to 10%, on said primer, as an adhesive layer, or (ii-2) applying a linear low-density polyethylene (LLDPE) resin having a maleic anhydride linear chain grafting or polypropylene resin having a maleic anhydride linear chain grafting, said resins having a maleic anhydride grafting content of above 4%, on the bare metal surface, as an adhesive layer; (iii) abrading and cleaning the thermoplastic end cuts of the parent coatings; (iv) putting in place a mould around the pipe in the field joint area to define a cavity between the internal surface of the mould and the field joint; (v) injecting a field joint coating material based on a fast curable olefin liquid formulation in the cavity; wherein the field joint coating material comprises, (a) one olefin monomer or one oligomer able to undergo polymerisation and optionally cross linking (b) one catalytic system able to activate polymerisation and optionally cross linking process of said monomer or oligomer, wherein the monomer is a norbornene-type cycloolefin monomer, and wherein the catalytic system is able to activate Ring Opening Metathesis Polymerisation of a norbornene-type cycloolefin monomer. (i) abrading or sand blasting of the bare metal surface of a steel pipe; (ii-1) applying an epoxy primer or epoxy phenol primer on the bare metal surface, then applying a linear low-density polyethylene (LLDPE) resin having a maleic anhydride linear chain grafting or polypropylene resin having a maleic anhydride linear chain grafting, said resins having a maleic anhydride grafting content of 0.2 to 10%, on said primer, as an adhesive layer, or (ii-2) applying a linear low-density polyethylene (LLDPE) resin having a maleic anhydride linear chain grafting or polypropylene resin having a maleic anhydride linear chain grafting, said resins having a maleic anhydride grafting content of above 4%, on the bare metal surface, as an adhesive layer; (iii) abrading and cleaning the thermoplastic end cuts of the parent coatings; (iv) putting in place a mould around the pipe in the field joint area to define a cavity between the internal surface of the mould and the field joint; (v) injecting a field joint coating material based on a fast curable olefin liquid formulation in the cavity; wherein the field joint coating material comprises, (a) one olefin monomer or one oligomer able to undergo polymerisation and optionally cross linking (b) one catalytic system able to activate polymerisation and optionally cross linking process of said monomer or oligomer, (a) one olefin monomer or one oligomer able to undergo polymerisation and optionally cross linking (b) one catalytic system able to activate polymerisation and optionally cross linking process of said monomer or oligomer, wherein the monomer is a norbornene-type cycloolefin monomer, and wherein the catalytic system is able to activate Ring Opening Metathesis Polymerisation of a norbornene-type cycloolefin monomer.