softening a industrial hacksaw blade

[woodsman1031]

Hello,

  I have saw blade that is 14" long 1 1/2" wide and a little over 1/16" thick. I cut a blank out of it and I ended up using 3 reinforced disks just to get it cut out. It is carbon steel.

I have heated it to non magnetic and allowed it to cool very slowly, but It will not soften. Any suggestions?

Thanks

[Lin Rhea]

How slowly did you cool it? This is an honest question and I may not be able to help. I cant imagine it not annealing to some degree if it's carbon steel. Lin

[tippit]

I agree with Lin, you need to bury it in something to allow for the slow cooling...wood ash or vermiculite.  Air cooling will still keep it very hard...tippit

[Lin Rhea]

I would not know what steel these blades could be. At first, I would think 1095, but they may be L-6. If it has a high chromium content,as would L-6, it could air harden as it drops below critical and end up quite hard.

Have you tried a sharp file on it?
                                      Lin

[robtattoo]

Could be M2. I believe this is commonly used for power hacksaws, but I couldn't tell you how to deal with the stuff, if it is.

[woodsman1031]

I fold it in a fire blanket. It has 3" of the material surrounding it. I am able to immediatly put it in there while it is still red. every time I have done it this way I can still feel heat in the blade about 6 hours later. It has worked for me in the past.

I have tried a file on it. It skates across the steel as much as the original piece I cut it out of.

I have worked with a carbon steel saw blade before. I annealed the exact same way and it softened it. I was thinking this may have been some type of uncommon steel steel used in this blade. This is some tought stuff! I would love to get a blade out of it!

Thanks

[Todd Robbins]

Most industrial hacksaw blades are bimetal with a HSS edge, probably M2, and a body of 1045-1050.  The ones that aren't bimetal are usually all HSS.  The reason for this is that the friction of cutting metal in an industrial shop will commonly cause the blade to get hot enough to soften a simpler alloy.  The high speed steels can hold upper 50s Rc hardness up into the glowing red color range.  If you can grind it in the hardened state, it holds an edge practically forever, but it takes alot of patience and grinding belts to do.

Todd

[woodsman1031]

Todd,

  Thank you so much! I plan on making a knife from it, I will just plan on taking my time. It will be worth it to have a knife that will hold an edge like that.


Tommy