Bellows 1-4 will operate with vacuum inside and one atmospheric pressure differential on the
outside. Bellows 1-4 is made of 316L/316LN stainless steel (SS) and welded together with
E310/ER/310 welding rods. The vendor is responsible to design and fabricate the bellows, to fabricate their flanges and
mechanisms for constraining the bellows, to weld the bellows and their flanges, to assemble the
bellows with flanges, and to meet the requirements of leak tests and vacuum tests. The vendor is responsible to conduct vacuum and leak tests before shipping to Jefferson Lab.
Jefferson Lab will perform vacuum and leak tests as part of the acceptance criteria for each
bellows assembly. Bellows 1 and bellows 2 are identical. Only one set of flanges item A09005-
15-01-0014 and 0016 are to be supplied to TJNAF by the vendor; the knife edges of the bellows
without the blind flange shall be properly protected to prevent damage during shipping and
handling. The vendor is responsible to develop the leak test fixtures for Bellows 3 and 4;
TJNAF will develop its own leak test fixtures for leak testing bellows 3 and bellows 4. The
bellows assemblies shall be sufficiently packed to protect their finish and mechanical integrity
and to protect against contamination from dirt, water, debris and other contamination during
shipping and handling. The vendor may choose either welded or formed bellows. If the bellows are formed, the vendor
shall follow the latest ASME Section VIII Division 1, Appendix 26 or EJMA standard to design
the bellows and to compute their spring rates and fatigue life. The vendor shall document the
computation and provide the calculation document to Jefferson Lab for review prior to
fabrication. All bellows that are formed from rolled and welded tubes shall have the tube seam
weld planished, if necessary, to assure that failures do not occur at the weld.
The MOLLER Experiment is sensitive to the chemical composition of 316L or 316LN. The
vendor shall provide material test reports that list the chemical composition. Typical material
specifications or certificates are not acceptable. No foreign material, including company name plates, of any type is allowed to be attached to the
bellows unless they are explicitly approved by TJNAF. The preferred method of cutting the bellows sheets is to use a saw or a mill (PMAG0000-0100-
R0029). If the vendor prepares and cuts the bellows sheet with a shear machine, a small amount
of material (>=0.005'') shall be filed away at the cutting edge to reduce magnetic permeability
(PMAG0000-0100-R0029). The cutting method of the bellows sheet and whether a small amount
of material is filed away shall be recorded in the report of quality inspection. E310/ER310 welding rods shall be used to weld the bellows; however, it is acceptable to weld
the longitudinal seams of the bellows without any filler metal. The required documents of
welding processes are Welding Procedure Specifications, Procedure Qualification Records, and
Welding Performance Qualifications of welders.
.webp)
