Canadian Steel Standard 1

[dozer]

If someone specifies steel to be CSA G40.21 Grade 300W and the mill gives you steel meeting CSA G40.21 Grade 44W are you getting exactly the same thing or just pretty darn close? I don't have CSA G40.21 but I know 300W is 300 MPa minimum yield strength steel. I assume from context that 44W is 44 ksi steel. Now I know that doesn't make a bit of difference and it should be fine but client's can be a strange breed that just love to be irrational. He wrote Grade 300W in his spec and that's probably what he wants to see on the mill test report.

Can anyone give me some insight into CSA G40.21 and let me know if this will be an easy sell to our client or should we go back to the steel distributor and say we need a piece of paper that actually says it meets CSA G40.21 Grade 300W?

 

[jayrod12]

It's unlikely you'll fine a MTR with 300W if it's american steel. However that being said, you are getting the exact same steel.

 

[dozer]

I read in another post on this site that there are essentially no mills in Canada that roll steel. Is this true? If so, why do our Canadian brethren (I'm in the U.S.) spec Grade 300W instead of 44W (or any metric designation instead of US customary)?

 

[jayrod12]

Because we work in metric?

There is also an abundance of steel coming in from overseas where they are operating in metric as well.

In the end, 44W converts to 303MPA. How does this cause issues at all? It's literally a straight conversion. Do you expect the rest of the world to start specifying temperatures in Fahrenheit as well?

 

[dozer]

Whoops, didn't mean to rile you up. Just curious why the engineer didn't put 44W in parenthesis to avoid any confusion. The drawings he prepared are in feet and inches and the loads he gave or in kips. My concern doesn't stem from my own preferences. I would certainly have no problem with this if I were the engineer of record. I've just been burned too many times by people who don't understand basic principles but have been given some modicum of authority. "I spec'd Grade 300W, and by gosh, I want 300W not any of this 44W crap." You and I know a statement like that would be asinine but I've seen stranger things.

Maybe this stems from my lack of knowledge of CSA G40.21 and if I read it I would say, "Oh, everybody but me understands they are the same thing." Thanks for your response.

 

[jayrod12]

Didn't mean to come across harshly.

Essentially our G40.21 is extremely similar to ASTM A572 gr. 50 and A992. Most steel that meets one spec, meets the other.

On the topic of notes showing 300W and plans in imperial. This happens quite frequently unfortunately. People use general notes and only slightly modify them regardless of units used on the drawings.

There are still a significant number of jobs done in imperial up here mainly because the construction (Buildings specifically) industry didn't want to buy new tape measures and never really let it go. To be honest, my brain works a lot smoother in imperial.

 

[TheoreticalHope]

CSA G40.21 provides "Table 7: Mechanical properties of rolled shapes and sheet piling"

Table 7(a) is Metric and lists Tensile Strengths of Grade 300W ranging between 450 MPa and 620 MPa. (300 MPa yield)
Table 7(b) is Imperial and lists Tensile Stengths of Grade 44W ranging between 65 ksi [448 MPa] and 90 ksi [621 MPa]. (44 ksi [303 MPa] yield)

So therefore,
44W is a legitimate CSA steel grade (And does not necessarily imply ASTM grade conformance)
44W and 300W are not exactly equivalent, but the deviations between grades is within 1% of each other.

Hopefully your client recognizes that 1% is a rather small number.

 

[TheoreticalHope]

Also,
Clause 4.1 "Materials conforming to ASTM A 992/A 992M conform also to this standard.
But continues to note that ASTM includes additional requirements not addressed by CSA G40.21 (max. yield, max. yield/tensile strength ratio, max. carbon equivalent and max. nitrogen)

So all ASTM steel is okay for CSA, but some CSA steel may not conform to ASTM.


With regards to units, the Preface states "While the technical requirements of the metric and imperial versions are virtually the same, some differences do occur. Either the SI or the imperial units must be used, and any attempt to intermingle the two systems of units on any specific purchase of material may result in nonconformance with the Standards."


Hope that helps!

 

[dozer]

Trundle, yes that does help. Thanks.