ASME STP-NU-042:2013 pdf free download

ASME STP-NU-042:2013 pdf free download

The reduction in creep strength and other properties of Inconel 617 are discussed in Section 2 and compared with those of Hastelloy XR.
1.1.2 High Temperature Strength
The material to be selected will need to have the high temperature strength that satisfies the design requirements of the hot parts of the cooling system eomponents.
1.1.3 Low Temperature Strength and Other Properties
Significant stress and therefore creep damage arc typically expected when the temperature of metal parts is high. However. deformation.controlled stress is usually fully relaxed within several tens of minutes or less than one hour due to sery significant creep with hot parts, and therefore significant residual stress can be expected alter a plant has shut down. If the mechanical strength is as high at low temperature as expected there will be no critical issues relating to low temperature strength. And. as discussed in Section 2 thermal aging at the high temperatures of 850°C and above will cause a significant reduction in the fatigue strength and fracture toughness. including impact energy. at low temperatures in Hastelloy XR as well as in conventional nickel-base super alloys. This issue is not considered critical in selecting the candidate materials but should he kept in mind.
1.1.4 Workability and Weldability
If llastclloy XR or lnconcl 617 is used, fabrication and welding of the high temperature parts of a helical coil type IHX have been demonstrated to be feasible through the following construction experience, even in Japan.
• HTT’R for Hasielloy XR
• IHX of 1.5MW thermal output in ERANS project for Inconel 617
It should be noted here that several techniques need to he developed in order to construct the helical coil type IHX gis’en below:
• Welding techniques where the best welding conditions and appropriate welding materials can be selected in order to improve the ductility of welded joints and avoid any separation of the weld bonds of Hastelloy XR (and probably the other nickel-base super alloys). The separation cannot be detected through tensile testing but only through fatigue testing.
• ECT technique for use in welding the joints of the coils as ihe length of a coil will be 30m or more and tubes of around 5m in length will need to be joined together.