ASME HPS:2003 pdf free download

ASME HPS:2003 pdf free download.HIGH PRESSURE SYSTEMS.
2463 Liquid Metal Embrittlement Metals t’such as iinc or cadrniuin which are use-tI as protectise coatings and metal-based lubricants such as lcad may become molten when exposed to high temperatures (as in a lire They may cause cmhnttlemcnt of sonic alloy steels to which they come in contact while molten.
2464 Radiation Embrittlement. Radiation damage is the effect on the mechanical properties of a material by emission of light and heavy particles from tissionable materials. The light particles theta and gamma rays or cathode and s-rays) affect the properties of some non-metallic elements but have little effect on the pmpetlic-s of stnk-tunsl alloys.
Heavy particle effects (alpha. neutron, and lission (ragments on structural alloys are the result (toni collisions with atomic nuclei in polycrvstalline grain structures. Fast neutrons can penetrate to signiticant depths into the metals while fission-fragment damage (includes alpha particlest is shallow to the exposed surface. Loss of ductility and fracture toughness occurs. Very small areas ot high temperature which arc quickly quenched by heat conduction to surrounding material may also occur and cmhrittlc some alloys. (Ill
These effects shall be considered any time a fissionable material is located near a high pressure system. Shielding is a very practical method of pn4ccting pressure components from radiation, Direct hazards to personnel from all radiation shall be carefully and thoroughly presented by designs prepared by nuclear radiation experts.
2470 Fatigue
Fatigue failures are usually categorized as either:
(a) Low Cvt’k. Fewer than about lO cycles and a stress level considerably higher than the endurance limit; or
(bj flitI, Cvck. More than lO cycles and a stres.s level just abose the endur.uue limit.
Some of the common sources of fatigue arc fluid
pressure. bending, and thermal gradients. Metal fatigue
may be analyzed using the rules of the ASME Boiler
and Pressure Vcsscl Code, Section VIII. l)isision 2 or
3. See Appendix A. para. AIOO.
131 171 1151 1201 1221 1241
2471 Pressurized Fluid. Pressurized fluid fatigue is caused by fluctuating stress due to repeated pressure pulse-s and cracks usually originating at a stress concentrator in the inner bore. The failure plane is orientedLongitudinally, or parallel with the inner bore. Randomvibrational pressures can be gcncratcd by separatedflow of fluids over obstructions or other local velocitylpressure changes in flowing media.These excitationscan be of sufficient magnitude. under certain flow ratesand disturbances, that fatigue failures can result.[3] [14]