公司四方钻杆和六方钻杆是使用AISI4145H或4145HM合金钢制造，严格按照API SPEC 7-1进行加工和检验。全长热处理，全长度和全截面经过超声波检测和漏磁检测。
        PDM makes square or hexagonal kellies with the materials of AISI 4145H or AISI 4145HM alloy steel according to API Spec 7-1. Full-length heat treating, full-length and full-section ultrasonic testing and magnetic leaking detection assure the quality reliability of kellies.