中国微合金化技术与含铌钢发展30周-of Evolution(17)

中国微合金化技术与含铌钢发展30周-of Evolution

High Strength Microalloyed Linepipe: Half a Century of Evolution 37

Examples of the chemical compositions of X-65 sour service linepipe produced with the new technology (circa 1995) are presented in Table 12.

Table 12: Chemical Composition of API Grade X-65 for Sour Service

Evolution of Linepipe Producers & Production

As stated earlier manufacturing technologies for all HSLA steels improved rapidly from 1970 onward often due to demands from the linepipe arena. The demands occurred regionally, first in Alaska and later in the North Sea, followed by the demand for massive volumes of 56” OD X-70 (K60) linepipe from the former Soviet Union from 1970 through 1992 at which point the market collapsed.

Middle East demands from Saudi Arabia, Oman, Iran etc were for sour service X-60 and X-65 grades. In North America Canadian gas transmission companies such as TCPL and West Coast Energy led the move to higher strength levels.

For example: X-70 Nb-Mo steel was adopted by TCPL in 1970 produced at that time by IPSCO from semi-killed ingot steel [59]. Nowadays the pipe is produced from fully-killed continuously cast very low carbon (0.035%) skelp [60].

In the 1990’s there was diversified demand on pipe makers in traditional steelmaking regions from projects offshore China and Brazil, from the Gulf of Mexico and the Middle East. Starting in 1999 Indian and Chinese pipe producers emerged mostly equipped with modern steelmaking and pipe making facilities. India became a major exporter of line pipe to North America, whereas Chinese demand was generated internally. Between 1999 and 2005 Chinese producers developed API Grade X-70 and utilized it for the First West East Pipeline Project [33] which extends 4500 km from the autonomous regions of Lunnan and Hao’er’guosi in the West to Shanghai in the East. After 2005 API X-80 was systematically developed and in a crowning achievement is being used for approximately half of the Second West East Pipeline Project (18.4 to 25.0 mm x 48” OD). A list of major large diameter pipe mills in China with details of their estimated production capacities and size ranges is presented in Table 13. A listing of Indian pipe mills is shown in Table 14.

Globalization of Procurement

In the early 1970’s pipe manufacturer were located close to traditional steelmaking factories in Germany, UK, USA, Canada and Japan and Italy. Later, pipe making became more Internationalized and increasingly non-integrated see Table 15 below and 16 for longitudinal seam and helical respectively. For example countries such as Turkey, Greece and India have built pipe manufacturing facilities based on imported coils or plate, meanwhile procurement