Flowserve G4 Marathon Sleeveline Plug Valves - Manual (Page 5)

TABLE 1
CAP SCREWS - STUDS
HHCS - Finished Heavy Hex Head Cap Screw Alloy identification stamp required on each piece.
HCS - Finished Hex Head Cap Screw Certification required.
STUD - Stud Alloy Specification (40 KSI Minimum Yield Strength, 12% Minimum Elongation)
Dimensions per ASME B18.2.1
B9 - Stainless Steel per ASTM A193, Class 2B, Grade B8 (AISI type 304)
B16 Stainless Steel per ASTM A193, 100% hardness tested
B7 - Chromium - Molybdenum Alloy Steel per ASTM A193, Grade B7
B7M - Chromium - Molybdenum Alloy Steel per ASTM A193, Grade B7M, 100% hardness tested
B7MT - Chromium - Molybdenum Alloy Steel per ASTM A193, Grade B7M, 100% hardness tested, Teflon ® coated, Dupont SP11C, Type B - Color blue or green
B8M - 316 Stainless Steel per ASTM A193, Grade B8M, Class 1, 40 KSI Min. Yield Strength, 12% Min. El.
B8C2 - 304 Stainless Steel per ASTM A193, Grade B8, Class 2
C20 -
Carpenter C20, CB-3 (UNS NO8020), ASTM B473, 40 KSI Min. Yield Strength, 12% Min. El.
HC - Hastelloy C276 (UNS N10276), ASTM B574
I625 - Inconel 625 (UNS N006625), ASTM B446
I825 Incoloy 825 (UNS N08825), ASTM B425, 40 KSI Min. Yield Strength, 12% Min. El.
IN - Inconel 600 (UNS N0660), ASTM B166, 40 KSI Min. Yield Strength, 12% Min. El.
M - Monel (UNS N04400), ASTM B164, Class A or B, 40 KSI Min. Yield Strength, 12% Min. El.
HB - Hastelloy B (UNS 10665), ASTM B335
I718 - Incoloy 718, AMS 5595B
MKH - Monel K-500, Cold drawn and aged hardened, QQN-286 and ASTM F468
L7 -
Chromium-Molybdenum Alloy Steel per ASTM A320, Grade L7
L7M - Chromium-Molybdenum Alloy Steel per ASTM A320, Grade L7M, 100% hardness tested
L7T - Chromium-Molybdenum Alloy Steel per ASTM A320, Grade L7, Teflon ® coated, Dupont SP11C, Type B - Color blue or green
L7MT - Chromium-Molybdenum Alloy Steel per ASTM A320, Grade L7M, 100% hardness tested, Teflon ® coated, Dupont SP11C, Type B - Color blue or green
N - Nickel per ASTM B160 (UNS N0220), 40 KSI Min. Yield Strength, 12% Min. El.
B7YC - Chromium-Molybdenum Alloy Steel per A193, Grade B7, Yellow Zinc Dichromate Plated
Material Selection
Selecting the proper fastener material is the ultimate responsi-
bility of the customer because the supplier does not typically
know in what service the valves will be used or what elements
may be present in the environment. Flowserve normally sup-
plies B7 (carbon steel) for ductile cast iron and carbon steel
valves. For stainless steel and high alloy valves, B8 (stainless
steel) fasteners are supplied as standard. All fasteners used
must have a minimum yield strength of 40,000 PSI, a mini-
mum elongation of 12% and be compatible with the process
fluid. Determining compatibility to the process fluid goes
beyond a material being resistant to general corrosion
because the more important consideration is a material’s
resistance to stress corrosion cracking. Depending on the
service, it may make sense to use B7 fasteners on high alloy
valves. One such service would be marine environments
because of stainless steel’s susceptibility to stress corrosion
cracking in chloride environments. Another key aspect of
fasteners is frequent visual inspection. Because of the com-
mon practice of using steel fasteners rather than stainless
steel to avoid chloride stress corrosion cracking, visual
inspection is recommended to monitor the general corrosion
of these fasteners. If jacketing or insulation is used on a valve,
SECTION IV
PRESSURE CONTAINING FASTENERS
it must be periodically removed for visual inspection of the
fasteners. If you wish assistance in determining the proper
fasteners to use, please refer to the attached chart.
Design & Type
Flowserve’s valve design standards adopt ASME B18.2.1
(1996) as the standard for fastener type and design. This
national standard requires that finished hex “head” cap
screws be used when the head of the fastener is turned. A
finished hex “head” cap screw and a heavy hex cap screw
have a bearing surface under the head to minimize frictional
resistance during tightening. They also comply to qualified
body diameters and fully formed head dimensions. Cookeville
Valve Division’s policy is to use finished hex “head” and heavy
hex “head” cap screws for all pressure retaining fasteners.
This includes top caps, packing adjusters, plug adjusters,
bottom caps, body halves or other pressure retaining compo-
nents. Compliance is made with ANSI B18.2.2 (1987), Square
and Hex Nuts, when studs and heavy hex nuts are required.
Additional information on these items may be obtained from
the Flowserve Corporation, Cookeville Valve Operation,
Cookeville, Tennessee.
5
Flow Control Division
Section 1.0