Page 248 - The Tribology Handbook

Piston rings B17

Table 17.8 Suggested sizes of rings

Piston ring GTOOVE side
Units Cylinder diameter (b) clearance
Axial width Radial thickness ( C)
Millimetres 2575 3-5 3-6 C = 0.025 X axial width
76150 5-10 5-10
15 1-230 6-12 G12 (N.B.-Groove
tolerance H7)
230-400 10-19 10-19
~~ ~~
- 400-800 12-25 12-25
Inches 1-3 0.125-0.187 0.125-0.218
3-6 0.187-0.375 0.1874.437
~ ___~
6-9 0.250-0.500 0.250-0.500
9-16 0.375-0.750 0.3 75-0.750
16-30 0.500-1.000 0.500-1.000

Table 17.9 Types of joints
Butt Scarf Lap or step

Suitable for all pressures Suitable for all pressures Not recommended where pressure
differential exceeds 10 atmospheres
Circumferential clearance (S) S = T X D X aP x T
where D = cylinder diameter,
ap = Coeff. of expansion of piston ring
material,
T = Operating temperature

Cylinder materials and finishes

Table 17.10 Typical cylinder materials
~ ~ ~~ __________
Material ryPe Remarks
Cast iron IS0 R185 220 grade Suitable only for continuous operation
Ni-Resist IS0 2892 AUS101. ASTM A436/1 Preferred to cast iron-less danger of corrosion
Stainless steel IS0 683/1 316816. AIS1 316 Used for machines where long shutdowns occur
Meehanite cast iron CR or CRS Similar to Ni-Resist

A suitable surfface finish for these cylinder liners is 0.4 to 0.6 pm R, or 2.4 to 3.6 prn

B 17.7