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What do the markings on this steel plate tell me?

J

JimGnitecki

Active Member
Below is a photo of the leftover 3/8" thick 19" diameter steel plate that my local steel supplier sold me to use as a welding table top for small projects.

Steel plate - 19 in dia - 44W - HT#425107 - 1.jpeg


What do the "44W" and "HT #425107 tell me about the properties of this piece of steel?

And, is the surface just a rust layer or something different?

I assume I need to belt sand the surface to get a good clean steel surface ?

Jim G
 
Googling 44W got me this....

"

General Product Description​


The Canadian Standards Association (CSA) specification G40.20/G40.21 covers structural quality steel of a number of different product forms. SSAB produces structural quality plates and sheet in accordance with CSA G40.20/G40.21 with specified minimum yield strengths of 38 ksi to 70 ksi. CSA 44W is a weldable steel with a specified minimum yield strength of 44 ksi for thicknesses up to 2.5 inches and a specified minimum yield strength of 40 ksi for thicknesses greater than 2.5 inches."

CSA 44W

The Canadian Standards Association( CSA) specification of G40.21-13 establishes the requirements for structural quality plates, shapes, hollow sections, sheet, sheet piling, cold-formed channels, Z sections and bars used in general construction. SSAB offers the following CSA steel Types-W...
www.ssab.com www.ssab.com


HT? Heat treated maybe? Maybe a work order number?
 
Thank-you both, Guys! IF the "HT" refers to heat treating, what effects wouldthe heat treating have on this 44W steel? I realize that heat treating is generally done to strengthen and/or harden steel or to give it a tougher surface, but what I am asking is what potnetial effects, if any, would heat treating have when I use the steel piece as a welding surface?

I plan to weld mostly aluminum and stainless steel, so my actual welding table top is aluminum, but I want to be able to weld steel without melting the table under it (since Steel has a much higher melting temperature than aluminum, AND I want to be able to use magnets to position workpieces for welding.

Would the heat treating have any effect, either good or bad in my intended usage?

Jim G
 
JimGnitecki said:
Thank-you both, Guys! IF the "HT" refers to heat treating, what effects wouldthe heat treating have on this 44W steel? I realize that heat treating is generally done to strengthen and/or harden steel or to give it a tougher surface, but what I am asking is what potnetial effects, if any, would heat treating have when I use the steel piece as a welding surface?

I plan to weld mostly aluminum and stainless steel, so my actual welding table top is aluminum, but I want to be able to weld steel without melting the table under it (since Steel has a much higher melting temperature than aluminum, AND I want to be able to use magnets to position workpieces for welding.

Would the heat treating have any effect, either good or bad in my intended usage?

Jim G
Click to expand...
nope, still magnetic unless you hit the critical temperature.
 
44W is the most common grade of mild steel plate/sheet. You can't heat treat it (well, except for case hardening but that is hardly applicable).

dollars to donuts the "H" refers to a Heat number. At the mill each molten ladle of steel is called a heat, and while molten they test the metallurgy and add stuff to it while in the ladle. Its then poured into slabs then rolled into coils....but each is still carefully associated with its heat number so the physical steel can be linked to the mill certificate which records the chemistry from the metalurgy done before rolling.

Some jobs require a lot of traceability. You might have steel from thee different heats say going into a fabrication and the customer wants a schedule of what part was what heat # along with copies of the mill certs.

Long winded explanation of what I'd guess the "H" is for.

As for finish, I've only ever seen it hot rolled, either au naturel with a very hard blackish mill scale or pickeled and oiled (what a metal stamping firm would use). The scale is very durable, not at all flaky. 98% of jobs we do are paint right over the mill scale, 2% would be sandblasted. Not sure what yours is, but I'd be thinking wipe it down (say varsol) and use it. If it does have scale it will be a far better rust protector than then fresh steel you'd get from grinding
 
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If you know who the supplier is you can actually get the MTR's for that particular heat #

But really don't bother, it doesn't do you any good, I'm kinda surprised there are any markings on an offcut that small, must have quite the high end QC Dept at that shop
 
So I should NOT belt sand it? Leave the brown finish layer on it, whatever it is? I just want to ensure that:
- It is non-toxic when heated up
- Not some kind of coating that presents any fire hazard
- Will not contaminate a weld being done using it as a table surface

I'm thrilled to have gotten this piece almost for free. When I look online for pricing for pieces of steel in the 18" x 18" to 24" x 36" size range, I see some BIG numbers. :)

Jim G
 
I can't say whats on that piece, maybe ask where you bought if it was coated with anything?

Just covering my ass....chances are about 99% its just rust in which case I'd wipe with varsol, just clean the worst of it, and put to work. try scraping a bit off it or weld a small bead on it (which you can grind off) if you are concerned. It may be pickled and oiled which rusts easily, but worst you'd get if is a bit of smoke. If its not pickled you'll go crazy trying to sand through the mill scale.

I know what you mean about cheap. I fill a 30 yard bin once or twice a week. It kills me sending out prime steel offcuts for a few cents a pound, but time is money and space is money...it has to go.
 
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The only consideration about leaving the mill scale on is that when I weld a lower voltages, it seems to impede the flow if using the table for grounding instead of connecting the ground to the work..
 
Dabbler said:
The only consideration about leaving the mill scale on is that when I weld a lower voltages, it seems to impede the flow if using the table for grounding instead of connecting the ground to the work..
Click to expand...
THAT's significant, since I had grounding issues before I started to ground directly to the workpiece AND replaced the grounding clamp with a much higher quality one.

Jim G
 
if your going to take the scale off vinegar does a nice job without gouging the crap out of the plate with a grinder, just leave it soaking for a day or so, and off it comes
 
As Mcgyver said HT is the heat number used to trace the composition of the steel. When I was working I had to order material for QA jobs and the HT # was required for tracing. We also required a copy of the mill certificate for our records. These numbers would then be written or stamped on all the material used for the job. It was used mostly on pipe. The info was recorded in a data base, along with date, QA number and PO #
 
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