Page 25 - Valve Selection Handbook

12 Valve Selection Handbook

Table 2-1
Erosion Penetration
(Courtesy Crane Co.)

Resulting from the impingement of a 1.59 mm (V\f> inch) diameter jet of saturated
steam of 2.41 MPa (350 psi) pressure for 100 hours on to a specimen 0.13 mm
(0.005 inch) away from the orifice:

Class 1—less than 0.0127 mm (0.0005 inch) penetration
Stainless steel AISI tp 410 (13Cr) bar forged and heat treated
Delhi hard (17Cr)
Stainless steel AISI tp 304 (18Cr, lONi) cast
Stellite No. 6

Class 2—0.0127 mm (0.0005 inch) to 0.0254 mm (0.001 inch) penetration
Stainless steel AISI tp 304 (18Cr, lONi) wrought
Stainless steel AISI tp 316 (18Cr, 12Ni, 2.5Mo) arc deposit
Stellite No. 6 torch deposit
Class 3—0.0254 mm (0.001 inch) to 0.0508 mm (0.002 inch) penetration
Stainless steel AISI tp 410 (13Cr) forged, hardened 444 Bhn
Nickel—base copper—tin alloy
Chromium plate on No. 4 brass (0.0254 mm = 0.001 inch)
Class 4—0.0508 mm (0.002 inch) to 0.1016 mm (0.004 inch) penetration
Brass stem stock
1
2
Nitralloy A Ni
Nitralloy high carbon and chrome
Nitralloy Cr—V sorbite—fertile lake structure, annealed after nitriding 950 Bhn
Nitralloy Cr—V Bhn 770 sorbitic structure
Nitralloy Cr—Al Bhn 758 ferritic structure
Monel modifications
Class 5—0.1016 mm (0.004 inch) to 0.2032 mm (0.008 inch) penetration
Brass No. 4, No. 5, No. 22, No. 24
Nitralloy Cr—Al Bhn 1155 sorbitic structure
Nitralloy Cr—V Bhn 739 ferrite lake structure
Monel metal, cast
Class 6—0.2032 mm (0.008 inch) to 0.4064 mm (0.016 inch) penetration
Low alloy steel C 0.16, Mo 0.27, Si 0.19, Mn 0.96
Low alloy steel Cu 0.64, Si 1.37, Mn 1.42
Ferro steel

Class 7—0.4064 mm (0.016 inch) to 0.8128 mm (0.032 inch) penetration
Rolled red brass
Grey cast iron
Malleable iron
Carbon steel 0.40 C