Usually referred to as the peen, this exact sample of circular dimples is machined in to the cast-steel mildew where the pipe is created and serves because the system to the initial Develop of the iron pipe wall over the centrifugal casting method. On greater diameter pipe (pipe 24-inches and https://www.facebook.com/permalink.php?story_fbid=pfbid02tJPWHHg1rTdFG2QGPy9uotjaFV1em5Rre2kwfW5n4uXnSrNrQqQvzimuKd9fbU1Zl&id=61560512640678&__cft__[0]=AZU6NrURjse9LQKravz1mBHbZQ-hGh6s9SRvhuo9Dhe6Ot9FX008g28v7YbZu6trT0xb9GRDZP7yc856m2SjzNNqYSnwxuMvol7bYkFQaDK_F1SJoWrhnQB2Rb-W_YEbMaFwS-uNp43z858-QLd5VUapXSQE7TOYb1JmvEDSii2UAu-JZUwbVGi0_IbDGQhjHb7myu_nbu3RUILxflsE4pmK&__tn__=%2CO%2CP-R