Professional Soldiers ® - View Single Post - Knife Steels-Material Science

**Bill Harsey** · 05-16-2006, 20:16

Guys and Gals,
We've laid down enough stuff so far to make common folk hate reading about steel.
Good thing we don't have any common folk around here.

You've noticed in this thread that a concern when heat treating hardenable steels is cracking if we cool it too fast from the initial hardening temp. Welding heat can cause this too.

Here is a tip to lock down and print out for any of you guys and gals are out in the field that might have to make an emergency weld on unkown steels.

Pre-heat your weld zone (the steel) to 300 degrees F. Use your best judgment. Make the weld and if possible, post heat for a couple minutes with the same torch or heat source. DO NOT COOL WITH WATER!

This will greatly increase the chances of the weld not cracking on castings, shafts, springs, etc. Use 7018 Low Hydrogen rod on DC Reverse polarity of possible. If your welding on cases or around things that have bearings in them, place the ground clamp within 6 inches of the weld, either coming or going as the magnet will deflect the arc.

This stuff is so good I should charge money for it.

Edited to add:
AmbushMaster, I have no technical data on using various and interesting alternative heat sources for a controlled pre-heating of steel that may be readily available to the Special Forces Soldier.

05-16-2006, 20:16	#101
Bill Harsey Bladesmith to the Quiet Professionals Join Date: Feb 2004 Location: Oregon, Land of the Silver Grey Sunsets Posts: 3,886	A Breather! Guys and Gals, We've laid down enough stuff so far to make common folk hate reading about steel. Good thing we don't have any common folk around here. You've noticed in this thread that a concern when heat treating hardenable steels is cracking if we cool it too fast from the initial hardening temp. Welding heat can cause this too. Here is a tip to lock down and print out for any of you guys and gals are out in the field that might have to make an emergency weld on unkown steels. Pre-heat your weld zone (the steel) to 300 degrees F. Use your best judgment. Make the weld and if possible, post heat for a couple minutes with the same torch or heat source. DO NOT COOL WITH WATER! This will greatly increase the chances of the weld not cracking on castings, shafts, springs, etc. Use 7018 Low Hydrogen rod on DC Reverse polarity of possible. If your welding on cases or around things that have bearings in them, place the ground clamp within 6 inches of the weld, either coming or going as the magnet will deflect the arc. This stuff is so good I should charge money for it. Edited to add: AmbushMaster, I have no technical data on using various and interesting alternative heat sources for a controlled pre-heating of steel that may be readily available to the Special Forces Soldier. Last edited by Bill Harsey; 05-16-2006 at 20:28.
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