Development and plant verification of tube quenching unit

conference paper

en

Tube manufacturing industry is focusing on the improvement of the mechanical properties of tubes by heat treatment. The proper way of the heat treatment leads to improved mechanical properties with saving of cost of alloys. This paper describes the stages of applied research and development leading to a functional prototype of a quenching unit for seamless steel tubes in steelmaking company Trinecke Zelezarny. The development started by the mapping of the current state and critical assessment of the technical and technological level of the existing equipment in the tube mill. The next step, laboratory quenching tests showed the quenching limits of rolled tube materials (micro alloyed and low-alloy steels applied in the OCTG industry, power engineering and mechanical engineering). Heat transfer coefficients of several nozzles configurations were measured on the laboratory stand and with these boundary conditions numerical simulations of the tube quenching process were performed. The final construction design was realized based on results of quenching tests, numerical simulations and plant limits. Verification plant measurements were performed with tubes instrumented by thermocouples. Tubes were heated in a furnace and after that tubes passed through the quenching prototype unit. The measured temperatures and obtained heat transfer coefficients from plant measurement showed good agreement with laboratory data. This confirms that the laboratory measurements leads to optimization of the design process.

Tube manufacturing industry is focusing on the improvement of the mechanical properties of tubes by heat treatment. The proper way of the heat treatment leads to improved mechanical properties with saving of cost of alloys. This paper describes the stages of applied research and development leading to a functional prototype of a quenching unit for seamless steel tubes in steelmaking company Trinecke Zelezarny. The development started by the mapping of the current state and critical assessment of the technical and technological level of the existing equipment in the tube mill. The next step, laboratory quenching tests showed the quenching limits of rolled tube materials (micro alloyed and low-alloy steels applied in the OCTG industry, power engineering and mechanical engineering). Heat transfer coefficients of several nozzles configurations were measured on the laboratory stand and with these boundary conditions numerical simulations of the tube quenching process were performed. The final construction design was realized based on results of quenching tests, numerical simulations and plant limits. Verification plant measurements were performed with tubes instrumented by thermocouples. Tubes were heated in a furnace and after that tubes passed through the quenching prototype unit. The measured temperatures and obtained heat transfer coefficients from plant measurement showed good agreement with laboratory data. This confirms that the laboratory measurements leads to optimization of the design process.

QUENCHING – HEAT TREATMENT – TUBE – HEAT TRANSFER – SPRAY COOLING – HEAT TRANSFER COEFFICIENT – PLANT MEASUREMENT

13.06.2018

Associazione Italiana di metallurgia

Milano

978-88-98990-14-6

The 7th International Congress on Science and Technology of Steelmaking

1–8

8