ASTM B631 class B and PTFE belong to fundamentally different material chemistries. ASTM B631 class B is a metal, while PTFE is a polymeric material. Therefore, their performance will be even more dissimilar than would be suggested by the difference in properties. There are 3 material properties with values for both materials. Properties with values for just one material (29, in this case) are not shown. Please note that the two materials have significantly dissimilar densities. This means that additional care is required when interpreting the data, because some material properties are based on units of mass, while others are based on units of area or volume.
For each property being compared, the top bar is ASTM B631 class B and the bottom bar is PTFE.