Performance of TMCP steel with respect to mechanical properties after cold forming and post-forming heat treatment

David Porter (Corresponding Author), Anssi Laukkanen, Pekka Nevasmaa, Klaus Rahka, Kim Wallin

    Research output: Contribution to journalArticleScientificpeer-review

    19 Citations (Scopus)

    Abstract

    The paper describes the results of work done in the Finnish part of the ECOPRESS project on the mechanical properties of pressure vessels made from the TMCP steel grade P420ML2. Dished end (DE)-cylinder assemblies with diameters of 2500 mm and thicknesses of 15 and 30 mm have been examined using DE in both the cold-formed (CF) and CF and post-forming heat treated conditions. The blanks for the DEs contained welds to enable the effect of cold forming on weld metal to be evaluated.

    Cold forming increases both the transition temperature and the strength of the DEs. Nevertheless, toughness against brittle fracture in the CF state is good for all parts of the DEs and girth weld with T27J<−50 °C in the absence of blank welds and <−20 °C when blank welds are present. For PFHT DEs T27J<−50 °C even for the blank welds. T27J was found to correlate with the fracture toughness reference temperature T0 which can be used to determine the minimum operating temperature. The impact toughness of the CF DE can be determined by compressing plate specimens 15% and ageing 30 min at 250 °C. Such a procedure can form the basis for an additional requirement on PxxxM/ML grades when high cold forming strains are involved in vessel manufacture. Ductile fracture is not of concern, as upper shelf toughness remains high in all parts of the DE.

    The yield and tensile strengths of a CF DE are much greater than those of the cylinder, whereas the membrane stresses on the cylinder are greater than those on the DE. Consequently, design can be safely based on the properties of the nominally unformed cylinder. Furthermore, tensile instability will be first reached in the cylinder before it is reached in the DE, even though Y/T is at its lowest in the cylinder. Secondary bending stresses are greatest at the DE knuckle, but the CF DE has more than sufficient ductility in bending to accommodate the bending strain. The high Y/T of CF DE is combined with high material ductility and is therefore fully acceptable.

    Original languageEnglish
    Pages (from-to)867 - 877
    Number of pages11
    JournalInternational Journal of Pressure Vessels and Piping
    Volume81
    Issue number10-11
    DOIs
    Publication statusPublished - 2004
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Steel
    Welds
    Heat treatment
    Mechanical properties
    Toughness
    Ductility
    Fracture toughness
    Ductile fracture
    Brittle fracture
    Pressure vessels
    Superconducting transition temperature
    Yield stress
    Tensile strength
    Aging of materials
    Metals
    Membranes
    Temperature

    Keywords

    • dished ends
    • cold forming
    • heat treatment
    • ProperTune

    Cite this

    @article{46654c999c3f487d9554fa19e4331cca,
    title = "Performance of TMCP steel with respect to mechanical properties after cold forming and post-forming heat treatment",
    abstract = "The paper describes the results of work done in the Finnish part of the ECOPRESS project on the mechanical properties of pressure vessels made from the TMCP steel grade P420ML2. Dished end (DE)-cylinder assemblies with diameters of 2500 mm and thicknesses of 15 and 30 mm have been examined using DE in both the cold-formed (CF) and CF and post-forming heat treated conditions. The blanks for the DEs contained welds to enable the effect of cold forming on weld metal to be evaluated.Cold forming increases both the transition temperature and the strength of the DEs. Nevertheless, toughness against brittle fracture in the CF state is good for all parts of the DEs and girth weld with T27J<−50 °C in the absence of blank welds and <−20 °C when blank welds are present. For PFHT DEs T27J<−50 °C even for the blank welds. T27J was found to correlate with the fracture toughness reference temperature T0 which can be used to determine the minimum operating temperature. The impact toughness of the CF DE can be determined by compressing plate specimens 15{\%} and ageing 30 min at 250 °C. Such a procedure can form the basis for an additional requirement on PxxxM/ML grades when high cold forming strains are involved in vessel manufacture. Ductile fracture is not of concern, as upper shelf toughness remains high in all parts of the DE.The yield and tensile strengths of a CF DE are much greater than those of the cylinder, whereas the membrane stresses on the cylinder are greater than those on the DE. Consequently, design can be safely based on the properties of the nominally unformed cylinder. Furthermore, tensile instability will be first reached in the cylinder before it is reached in the DE, even though Y/T is at its lowest in the cylinder. Secondary bending stresses are greatest at the DE knuckle, but the CF DE has more than sufficient ductility in bending to accommodate the bending strain. The high Y/T of CF DE is combined with high material ductility and is therefore fully acceptable.",
    keywords = "dished ends, cold forming, heat treatment, ProperTune",
    author = "David Porter and Anssi Laukkanen and Pekka Nevasmaa and Klaus Rahka and Kim Wallin",
    year = "2004",
    doi = "10.1016/j.ijpvp.2004.07.006",
    language = "English",
    volume = "81",
    pages = "867 -- 877",
    journal = "International Journal of Pressure Vessels and Piping",
    issn = "0308-0161",
    publisher = "Elsevier",
    number = "10-11",

    }

    Performance of TMCP steel with respect to mechanical properties after cold forming and post-forming heat treatment. / Porter, David (Corresponding Author); Laukkanen, Anssi; Nevasmaa, Pekka; Rahka, Klaus; Wallin, Kim.

    In: International Journal of Pressure Vessels and Piping, Vol. 81, No. 10-11, 2004, p. 867 - 877.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Performance of TMCP steel with respect to mechanical properties after cold forming and post-forming heat treatment

    AU - Porter, David

    AU - Laukkanen, Anssi

    AU - Nevasmaa, Pekka

    AU - Rahka, Klaus

    AU - Wallin, Kim

    PY - 2004

    Y1 - 2004

    N2 - The paper describes the results of work done in the Finnish part of the ECOPRESS project on the mechanical properties of pressure vessels made from the TMCP steel grade P420ML2. Dished end (DE)-cylinder assemblies with diameters of 2500 mm and thicknesses of 15 and 30 mm have been examined using DE in both the cold-formed (CF) and CF and post-forming heat treated conditions. The blanks for the DEs contained welds to enable the effect of cold forming on weld metal to be evaluated.Cold forming increases both the transition temperature and the strength of the DEs. Nevertheless, toughness against brittle fracture in the CF state is good for all parts of the DEs and girth weld with T27J<−50 °C in the absence of blank welds and <−20 °C when blank welds are present. For PFHT DEs T27J<−50 °C even for the blank welds. T27J was found to correlate with the fracture toughness reference temperature T0 which can be used to determine the minimum operating temperature. The impact toughness of the CF DE can be determined by compressing plate specimens 15% and ageing 30 min at 250 °C. Such a procedure can form the basis for an additional requirement on PxxxM/ML grades when high cold forming strains are involved in vessel manufacture. Ductile fracture is not of concern, as upper shelf toughness remains high in all parts of the DE.The yield and tensile strengths of a CF DE are much greater than those of the cylinder, whereas the membrane stresses on the cylinder are greater than those on the DE. Consequently, design can be safely based on the properties of the nominally unformed cylinder. Furthermore, tensile instability will be first reached in the cylinder before it is reached in the DE, even though Y/T is at its lowest in the cylinder. Secondary bending stresses are greatest at the DE knuckle, but the CF DE has more than sufficient ductility in bending to accommodate the bending strain. The high Y/T of CF DE is combined with high material ductility and is therefore fully acceptable.

    AB - The paper describes the results of work done in the Finnish part of the ECOPRESS project on the mechanical properties of pressure vessels made from the TMCP steel grade P420ML2. Dished end (DE)-cylinder assemblies with diameters of 2500 mm and thicknesses of 15 and 30 mm have been examined using DE in both the cold-formed (CF) and CF and post-forming heat treated conditions. The blanks for the DEs contained welds to enable the effect of cold forming on weld metal to be evaluated.Cold forming increases both the transition temperature and the strength of the DEs. Nevertheless, toughness against brittle fracture in the CF state is good for all parts of the DEs and girth weld with T27J<−50 °C in the absence of blank welds and <−20 °C when blank welds are present. For PFHT DEs T27J<−50 °C even for the blank welds. T27J was found to correlate with the fracture toughness reference temperature T0 which can be used to determine the minimum operating temperature. The impact toughness of the CF DE can be determined by compressing plate specimens 15% and ageing 30 min at 250 °C. Such a procedure can form the basis for an additional requirement on PxxxM/ML grades when high cold forming strains are involved in vessel manufacture. Ductile fracture is not of concern, as upper shelf toughness remains high in all parts of the DE.The yield and tensile strengths of a CF DE are much greater than those of the cylinder, whereas the membrane stresses on the cylinder are greater than those on the DE. Consequently, design can be safely based on the properties of the nominally unformed cylinder. Furthermore, tensile instability will be first reached in the cylinder before it is reached in the DE, even though Y/T is at its lowest in the cylinder. Secondary bending stresses are greatest at the DE knuckle, but the CF DE has more than sufficient ductility in bending to accommodate the bending strain. The high Y/T of CF DE is combined with high material ductility and is therefore fully acceptable.

    KW - dished ends

    KW - cold forming

    KW - heat treatment

    KW - ProperTune

    U2 - 10.1016/j.ijpvp.2004.07.006

    DO - 10.1016/j.ijpvp.2004.07.006

    M3 - Article

    VL - 81

    SP - 867

    EP - 877

    JO - International Journal of Pressure Vessels and Piping

    JF - International Journal of Pressure Vessels and Piping

    SN - 0308-0161

    IS - 10-11

    ER -