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Roger Rapid

Shotgun splatter??

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10 hours ago, Roger Rapid said:

Lead could probably be most safely removed by melting it off, but since lead melts at 621°F I'm not sure what affect that heat would have on AR500 steel. 

Most bullet lead is alloyed material and eutectic alloys will melt somewhat below 621 d.   But that is still plenty of heat to modify the heat treatment on any of the AR steel alloys.  It is not hot enough to anneal them, but it is hot enogh to temper and make them more brittle, depending on the heating time and cooling regimen involved.  

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I provided a Road Map of the causes of Splatter.  It's really simple.  Simple Physics.  Eliminate Right Angles to the trajectory of the shot.  Eliminate the Angles and Dangles of Rebar.  Pad your gravel Bay surfaces.  Negative toe angle on all targets.  No Splatter no matter what you shoot nor how far.

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Quote

lead could probably be most safely removed by melting it off,

 

There really is no need to remove the lead from the surface of targets.  Thin spots will just get knocked off safely.   Thick deposits that affect the operation of a KD target can be peeled off with a dull chisel shaped tool.

 

The temperature of molten lead WILL NOT affect the heat treatment of AR steels.

 

End of physics/metallurgy lesson. :lol:

 

What you need is to flatten the STEEL surface.   That is what is strong enough for craters to deflect shot in random directions (not any lead coating).

A good metal working shop's procedure would be to cabinet sand blast the steel (removing lead and rust and paint) before doing any work on the steel.   Safely discard the sand blasting residue.   Then you could grind or weld on steel targets without having to have unusual levels of ventilation during such work.

 

Good luck, GJ

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5 hours ago, Garrison Joe, SASS #60708 said:

The temperature of molten lead WILL NOT affect the heat treatment of AR steels.

Your discussion on lead removal is excellent.  Cabinet blasting with sand or beads and careful disposal of residue is clearly a very good way to remove lead-- if removal is desired.  And I agree that the lead deposits are probably not the real problem causing ricochets.  

 

Regarding the metallurgy discussion:

After initial thermal soaking at the annealing temperature (usually around 1,800 F.), the steel being treated to AR is quenched in air (preferable), oil or water, depending on the parent steel in use.  Quenching makes the material brittle, due to Austenite crystalization.  When it cools to about 125-150 F.  it must be immediately tempered/drawn at temperatures usually between 

325 F. and 950 F. for varying time, depending on the final tool application.  Tempering relieves the brittleness,  and strengthens the crystalline structure.   The higher end of the tempering temperature range, applied for a shorter time will produce the harder surface that characterizes Abrasion Resistant (AR) steel.   

It is true that after full cool-down following quenching, the tempering heat has a much lessened effect, but it will still alter surface hardness if the exposure is long enough.   

 

I'm taking most of this from Bill Bryson's 1997 book,  "Heat Treatment, Selection, and Application Of Tool Steels". 

 

 Obviously there is much more to AR steel treatment, but my only point here is that lead melting Temps (650 F., give or take) for extended time coulf affect AR steel surface hardness.  

 

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1 hour ago, Dusty Devil Dale said:

It is true that after full cool-down following quenching, the tempering heat has a much lessened effect, but it will still alter surface hardness if the exposure is long enough. ... my only point here is that lead melting Temps (650 F., give or take) for extended time could affect AR steel surface hardness. 

 

So why would you ever want to expose armor plate to lead melting temperature for more than just a minute or so?   But if one was to do that,  that temperature is, from the numbers you quoted, well within the draw range, so it should simply "redraw" the plate back to original hardness and ductility specs.   Some folks weld on cold AR500 and never re-heat treat their targets.   A much worse metallurgical practice than just heating up a plate.

 

Anyways, just don't heat your target plates to try to "melt off" lead.  It's unnecessary and "fuelish".  

 

Good luck, GJ

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9 hours ago, Garrison Joe, SASS #60708 said:

Anyways, just don't heat your target plates to try to "melt off" lead.  It's unnecessary and "fuelish".

Totally agree - - and it's foolish too.  :)

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i am with coffinmaker on the setup - its just a fact that every range terrain is different and some work better than others , i keep my eyes safe and am not surprised by the splatter that comes with close steel targets and lead shot/bullets , we all strive for perfection , not always achieved , but most every range i shoot at did put forth the effort and will correct a defect when pointed out - i did not intend to cast a bad light by my previous comment only to point out the obvious - i do not believe i have ever experienced a safety issue at a single range 

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