You are being redirected because this document is part of your ASTM Compass® subscription.
    This document is part of your ASTM Compass® subscription.

    If you are an ASTM Compass Subscriber and this document is part of your subscription, you can access it for free at ASTM Compass

    The Effect of Phosphorus on the Mechanical Properties of X-70 Line Pipe Steel

    Published: 01 January 1989

      Format Pages Price  
    PDF (420K) 16 $25   ADD TO CART
    Complete Source PDF (6.4M) 302 $70   ADD TO CART

    Cite this document

    X Add email address send
      .RIS For RefWorks, EndNote, ProCite, Reference Manager, Zoteo, and many others.   .DOCX For Microsoft Word


    The effect of phosphorus content on the base plate properties and coarse-grained heat affected zone (HAZ) toughness of X-70 Cb-V line pipe steel has been studied. Three laboratory heats were melted with phosphorus contents of 0.001, 0.009, and 0.027%. The ingot sections were control rolled to 13-mm (0.512-in.) thick plates employing a single delay 4T rolling practice. The HAZ toughness was evaluated on specimens subjected to a weld simulation thermal cycle corresponding to 1315°C (2400°F) peak temperature in the HAZ of a submerged arc weld deposited with a heat input of 3 kJ/mm (76 kJ/in.).

    The as-rolled plates showed no significant effect of phosphorus variation on their microstructure, strength, or impact properties over the range investigated. The steels exhibited similar coarse-grained HAZ microstructures and hardnesses. Although the transition temperatures of the steels were significantly raised in the simulated HAZ condition, as expected, the variation in phosphorus content appeared to have little or no significant effect on toughness. Fractographic examination of the simulated HAZ impact specimens showed similar fracture appearances with no evidence of intergranular fracture.

    The conclusion is that a specification limit of 0.010% maximum on the phosphorus content in Arctic grade line pipe steels may be unduly restrictive for ensuring superior base plate and HAZ toughness properties, as well as adequate resistance to hydrogen induced cracking (HIC).


    line pipe steels, microalloyed steels, phosphorus in steel, control rolled, strength, impact toughness, submerged arc weld, heat affected zone (HAZ)

    Author Information:

    Kapadia, BM
    Research consultant, USX Corporation, Monroeville, PA

    Committee/Subcommittee: A01.13

    DOI: 10.1520/STP24587S