.It is often possible to cut softer materials with a metal blade, but difficult to cut metal with a wood blade.
Hacksaw blades only cut in one direction. The blade in the image only cuts when moving from right to left. Don't try to cut in both directions by really bearing down on the blade; you can damage your blade that way.
Cut the material with even strokes and slight pressure against the material (use a reasonable amount of pressure along the direction of the cut).