Operating pressure limits for seamless stainless pipe and tube are detailed by Sandvik Steel in a new 40-page booklet. Tables list the highest permissible internal pressures for pipes according to US, German, and Swedish standards. Also listed are factors for a variety of stainless steel grades, allowing system designers to calculate the maximum allowable pressures from the reference grade data.
To perform these calculations, the maximum pressure for the reference grade is chosen in relation to the specified pipe size and operating temperature. The user then multiplies this figure by the given factor for the material grade required.
Grade pressures included are to ASME B31.3, German standard DIN 2413 (1994) and grade W.Nr. 1.4306 and Swedish standard RN78 for grade SS 2352. Pressure values are for pipe ODs from 6-219mm and wall thicknesses from 3-23mm. Values are given for eight different temperatures in the range 20-400!C.
Sandvik points out that the pressures quoted are intended as a guide. Dimensions of piping systems are dependent on external factors such as thermal stress and static weight. System designs may also be subject to approval by pressure vessel authorities.
Coiled tubing
An eight-page technical brochure has also been issued on Sandvik's range of coiled, seamless stainless steel tubes for the oil and gas industry. This covers the size range, manufacturing capabilities and forms of supply.
The chief benefit of coiled tubing to downhole and subsea equipment producers and operators is fewer welds and fittings. This simplifies installation, cuts time spent on the installation, and also provides higher system integrity.
Chemical and physical properties of the key steel grades are described in the new brochure, with special focus on super duplex stainless steel grade 2507. Examples are included of Sandvik's coiled tube experience on steel tube umbilicals and other subsea applications in the Gulf of Mexico and North West Europe.
