Hard to Believe!

I am no Metallurgist ether but I think Armour plate also has other minerals mixed in as well as tempering to give it its strength so if they did melt it down and mix it in with regular mild steel then that would cause some problems I.E The two not mixing and causing corrosion and internal cracking.

I read it too and found it hard to believe, High carbon or tool steel maybe but armour plate don’t think I believe that.

Have a look HERE

There is a comment on machining, preferably at 50% of the normal machining speed for regular carbon steel, using high speed tool steel(what all reasonable bitd should be made from). Once blended, I can't see a reason for it presenting too many problems with regard to drilling.

I however am also not a metalurgist(sp?) so I can't make a definite statement.

Maybe they were not properly molten and then shaped?
we had some imported star pickets recently and in some parts of the picket not one screw or bit could get through it.

bourbon logic was involved in later scientific evaluations on a theoretical level.

This also happens regularly in Grade 250 Mill Steel Bar from Bluescope.

Sometimes you will hit a hard patch, and do in a drill bit. It not only depends upon carbon ratios, but also cooling rates, especially localised cooling.

At One steel in Whyalla, I had to supply signs for their outside cooling area. Billets took one week to cool in an outside environment, so as you can see, there is not a lot of control.

This process will also hasten the autensite - martensite ratio as well, if cold spots are allowed to form. Welding in localised areas also always does it.

Cheers Wolfie

Yes, there are obviously conditions whereby hardspots may occur in the finished product, BUT none of that has anything to do with the fact that the source material was "armour plate" and that it "survived" a blast furnace without altering its molecular structure. Hmmmm.

Sand Man,

Armour plate is not spring steel and if any body buys these cheap springs they will getting mild steel springs at best and wounder why they sag after a few months.

Spring steel has more carbon in it than mild steel and to be a good spring it has to be harden and tempered. The springs would only be 40RC. (RC stands for Rockwell on a C scale this is a measure of hardness. Mild Steel is about 5RC and tool steel 60RC)

If the steel is not annealed properly it can have hard spots that work harden when subject to heat and pressure. Trying to drill a hole with a dull drill will do this, and the more you try to push the drill through the harder the steel gets.

Steel is supplied in a soft state so that it can be machined or worked, once this is done it then heated up to its critical temperature which is any where from 800c to 1000c. It is then tempered or annealed back to the required hardness. In the case of springs the good ones are shot peened to give then the hardness or toughness that is required.

I also am not a metallurgist but have pick up a few thins over the years about steel.

Wayne

Was that in the december 2028 issue.

All the best
Eric

Trailer springs..Indian..Drama!..During our last dry spell I was carrying 1000 litres of water in one of those plastic containers with steel frame,home 16k on a N***** trailer rated at 1100kg..Running along nicely pulling the One Tonne load with my 1980 Diahatsu F-55 with my dog in the back..Went over a slight bump,hardly moved the rig,then,BANG !..All off a sudden some mad-man was at the wheel..All over the road..From table drain to table drain..Trees well off the road looked threatening..Although I was wildly fighting the wild zig-zags,I kept thinking,this is gonna hurt..Then,all of a sudden,I regained an element of control,the rig was now starting to respond to my action..How nice!..We stopped..So quiet!..No blood..No damage to my truck..Bet my old mate,Harley thought "dad's gone crazy"..Got him off the truck..Went round the back..Disaster!..Right trailer spring had broken at centre bolt hole..Rust showed it had been cracked for a while..The 2" sq axle as badly bent and had become a "steer" axle..R/H wheel was now in the centre of the tailgate,causing the trailer to try and pass me..Give you an idea how wild it was..The 1000Ltrs of water in plastic container had jumped out of the trailer,wiped my neighbours electric fence out and rested there,battered but not a drop of water was lost..Hurt me to let it all out to "drag" trailer home..Found out that brand trailer use some Indian springs..A man in Barcaldine/Alpha rang us up for one mudguard for his trailer..Hmmm! Sounds like he had our trouble..Sure enough..Same brand of trailer..Broke same place..Melted down ships ??? !MPG:6!