Boiler plate?

[Shedendman]

Dug some plate out of my normal surpliers skip and found 10 of these,all but one side has in the 1st pic this cast/pattern effect the other side smoothish dimple effect,they all had surface rust on and a grey ash covering on one side,mate of mine surgested it was boiler plate i always thought that boiler plate was a lot thicker these are 4.5mm thick.
Just like to know could it be BP,whats that effect on one side and hows it caused?
In the second pic that little cut out they've all got it,why?
Any ideas would be greatfull,cheers
Oh they're steel not cast iron

 

[Welderpaul]

Looks like rusty old pitted sh1te

 

[Hitch]

Looks like its just some old plate thats been kicking around for a while, pitted with rust

 

[Steve182]

Wouldn't make it onto one of my boilers

Takes a while to pit that bad plus the thinnest boiler plate we use is 6mm

 

[pidgeon chit welder]

That little punch out may be an arrow pointing to a direction of rolling so that plate may well be something that was to be heat forge welded to make a cross grained sheet such as a light armour gun shield .

When grinding with a decent wheel , what sort of spark do you get ?
Dull red blobs , orange blobs with a few sparks , yellowish small sparks or or bright yellow almost white like a sparkler with large long tailed many armed star type sparks ?

 

[richy_B]

I was told the marks in the first picture are caused by mill scale, being blasted off by the cooling jets at the rolling mill. The little mark could be a gob of something stuck on the rolllers either at the mill, or where the plate was decoiled. Probably totally wrong.
Rich

 

[pedrobedro]

Looks like rusty old pitted sh1te

I'd go with this description. I dug some up in the garden in similar condition after it was cleaned up with a fibre disk.

 

[gridley51]

Looks like rusty old pitted sh1te

Just got to decide whether Grade 1 or 2.

 

[NigelAylesbury]

Not good enough for boiler usage. Ok for simple brackets and the like. Oh yes, and for welding practice

 

[Shedendman]

Thanks guys,i was just curious thats all,anyway i'll find a use for it somewhere seeing as its for nothing.
Regards