0
$\begingroup$

I would like to weld a piece of hardened steel but i don't want to ruin the treatment on the tip of the piece. Can i put some ice in the middle of the shaft so the heat generated from the welding (SMAW DCEN) doesn't temper the tip? Thanks in advance.

$\endgroup$
  • $\begingroup$ If you post a photo or mech dwg of the piece in question you may get more useful responses. $\endgroup$ – Carl Witthoft May 30 '18 at 17:55
  • $\begingroup$ I think the heat is going to be too localized that it won't be conducted well to the ice. Maybe better would be to cool the part before welding? $\endgroup$ – user10585 May 31 '18 at 11:28
  • $\begingroup$ Combined, final answer --- NO ! $\endgroup$ – blacksmith37 Jul 29 '18 at 17:20
1
$\begingroup$

It will reduce the weld HAZ some , but not much. It depends on the dimensions and the heat input of the weld, the alloy , the original hardness , and the original heat treatment. The primary cooling is by conduction which is affected by the temperature difference. So the temperature difference will be 75 F / 2800 F , or 32 F /2800 F , not much of a difference. And, if the steel has much carbon ( eg. over 0.15% ) , the weld HAZ will contain some hard brittle zones with a significant chance of cracks.

| improve this answer | |
$\endgroup$
  • 1
    $\begingroup$ Could you please combine and edit your answers (maybe in the form of a paragraph for the general case and a paragraph for the specific case). This is useful information, but it's not clear what "is not, can not be welded" (="cannot be welded"?) means, for example. In addition, no space is used before the comma or within parentheses (e.g., "(I have seen recommended up to 600°F.)"). $\endgroup$ – Chemomechanics May 30 '18 at 17:04
0
$\begingroup$

Second, more planned answer . Hard steel ( Rockwell C 35 +) is not, can not be welded. In an unfortunate situation where it must be attempted ; 1 - Soften at about 1300 F , one hour . 2 - Preheat to 400 F ( I have recommended up to 600 F) . 3 - Weld. ( maintain preheat ). 4 Inspect for cracks. 5 - Soften the weld HAZ at 1300 F. 6 Heat-treat , quench and temper, according to the alloy.

| improve this answer | |
$\endgroup$
  • $\begingroup$ Thanka for your answers. The piece is a HSS 12 mm drill bit. I can't reharden it properly, so you think that preheating and welding the shank keeping the tip cold could cause cracks? $\endgroup$ – Tommaso Lencioni May 31 '18 at 16:58
  • $\begingroup$ High Speed Steel is a very different type of steel , it can maintain hardness up to 1200 F. When i worked in a drill bit heat treat lab , the shanks were clamped in tongs. Then most of the bit was put into a slot furnace at about 2150 F for a couple minutes. The shanks did not get hot enough to harden when the bit was quenched into oil. So the shank is not as hard . HSS is tempered at temperatures like 1200 F .. The point is even most commercial heat-treat shops can not harden HSS. Also , I can't guess what would happen in a weld on HSS. $\endgroup$ – blacksmith37 Jun 1 '18 at 3:21

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.