Average pore size: 7 or 20 microns
Porosity: 25% air by volume
Linear Expansion: (@20 - 150°C) 6.67 - 6.94 in./in F

Heat transfer co-efficient
(at room temperature): 16.93 - 19.35 BTU/ft. hr. F
Tensile strength: 64,000 - 71,000 lbs./in.2Hardness: HMV 350 - 400
HSS Machinability: Good

Machining and Polishing

Porcerax II can be machined by conventional methods using cutoff saws, end mills, grinders, EDM methods, stoning, etc. It is important to remember that this material is honeycombed with thousands of microscopic holes which are affected by metal removal. Oil coolant is recommended. 

Grinding and milling closes the pores of this porous steel. Stoning, using a back and forth/side to side method, will re-establish permeability by removing the metal that is crushed over the pores. Stoning and polishing, up to about a number 800 stone/paper finish, is possible. During the stoning and polishing process, it is important to occasionally flush the pores at the surface to prevent packing the pores with debris.

Electric Discharge Machining is the best way to re-establish permeability. This method will burn away the metal fragments that are crushed over the pores by milling and/or grinding. Because of its powdered metal origin, when using a wire EDM machine, it is important to increase the wire speed about 10 % to prevent arcing from the particles produced. Because a wire EDM machine uses water, the insert must be dried in an oven after EDM, or rust and pore closer will ensue.