Stainless Steel Grades & Quality - 316L - ASTM

[ATSE]

To my Metallurgical Expert friends:
1. Is there anything draw-back to specifying austenitic stainless steel simply as SS 316L, and not referencing specific ASTM specifications (such as A666 or A240 or A312 or A276) for the different components (plate, tube, shapes...)?
Or is it more appropriate to specify as:
Plate: A240
Bars and shapes: A276
and so on.
I don't have these ASTM specs in the office so I don't like to spec them (not that I could understand the contents anyway).

2. Should I care if the plate is cold-formed or hot-rolled?

3. Should I care if the material is made in China?

Background info:
a. For design I usually use ASCE 8-02, and use Fy=28ksi & Fua=75ksi for calculations.
b. For fasteners, I specify ASTM A193 Gr B8M Class 1 for bolts (more available than F593).
c. Welding electrode is 316L.
d. The application is usually welded structural steel plate and shapes used for exterior applications (mildly corrosive environments). Mostly small stuff (small beams and columns, angles, embeds into concrete, pipe brackets, plate less than 1" thick).

 

[metengr]

1. Is there anything draw-back to specifying austenitic stainless steel simply as SS 316L, and not referencing specific ASTM specifications (such as A666 or A240 or A312 or A276) for the different components (plate, tube, shapes...)?

Or is it more appropriate to specify as:
Plate: A240
Bars and shapes: A276
and so on.
I don't have these ASTM specs in the office so I don't like to spec them (not that I could understand the contents anyway).

Yes, you should use ASTM or equivalent specifications to ensure correct product form and properties.

2. Should I care if the plate is cold-formed or hot-rolled?

Yes.

3. Should I care if the material is made in China?

Yes.

 

[ATSE]

Metengr, thanks for the reply.
Could someone point me to a resource(s) for items 2 & 3 above.
For item 3, what usually happens is that the contractor tells the owner:
a. he can save X% and there's no difference between Chinese steel and Australian / American / Japanese steel,
b. the Chinese steel mill certs prove they comply with all ASTM requirements,
c. the structural engineer blindly put a "buy American" type clause in the spec and really doesn't know what he's talking about.
Some Chinese metals are probably excellent quality, and there's probably melamine in some other Chinese stainless steel. I need a good technical argument to answer the owner when he thinks I'm wasting his money.

 

[cloa]

How about a good legal argument- if the Chinese stuff up you can't sue them.

 

[metengr]

ATSE;
Here are some replies to your statements. Also. when others have been down this path before, it would be wise to take advice. Otherwise, you can go down this same path and learn lessons the hard way;

a. he can save X% and there's no difference between Chinese steel and Australian / American / Japanese steel,

If the above steels are made and certified to the same ASTM specification, this is basically a correct assumption. Otherwise, simply ordering grades of steel and assuming them being equal is an incorrect statement.

b. the Chinese steel mill certs prove they comply with all ASTM requirements,

Really. There have been problems with fraudulent material test reports from certain mills in China. Unless you or someone that represents your interests goes over to the mill and audits the mill to satisfy themselves that what is being produced indeed meets ASTM specifications, is a poor assumption.

c. the structural engineer blindly put a "buy American" type clause in the spec and really doesn't know what he's talking about.

I would not use blindly. I have various company engineering specifications that require our review and approval for ANY foreign sourcing of material. This is what should have been stated.

Look, the bottom line is this, tell your owner that sourcing steel from China requires active involvement on their end to have audits conducted and to park an inspector in the mill to watch your material and to verify compliance with a known product specification. Now, one can make an informed decision.

 

[EdStainless]

If you just call out a common grade name there is no legal basis for the chemistry or properties. They could literally supply you anything.
You could at least use the UNS number and then the chemistry would be specified.
But unless you call out a specification you have legal basis for the contract.

The form and history of the plate depend on what you expect it to do. If you care about strength and distortion during welding and you want two pieces to behave the same then you need to require a specific product.

The issue with Chinese (and India, Pakistan, and a couple of others) is the lack of oversight. By the time that you get your material it has been through the hands of 4 or 5 intermediaries. Just knowing which mill made it may be imposable. If someone tells you that they can save money you need to ask what a failure will cost.

Buy the ASTMs. They can be purchased one at a time and are not that expensive. If all you use is steel and stainless plate then join ASTM for $85 and get the 'free' volume that has those specs.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[ATSE]

Gentlemen,
Thank you for the input.
Just for the record, the "objections" and questions I stated were not my own - just trying to play the devil's advocate and develop rational (and brief) responses to general contractor and owner complaints. Good comments.

 

[Duwe6]

In the last 2-3 years the pipe-spec Chinese stainless has been excellent. Couldn't say that 15 years ago. I would insist on Positive Material Identification - PMI - of any non-domestic/non-1st-world country material. Especially Pakistan and Malasia. PMI using X-ray Fluorescence is cheap -- $300 per half-day, or less. Very cheap insurance.

Also, are you sure that you are using the 316L [low-carbon] strength table for design? Most of 316 [and 304] material is dual-certified; 316/316L - meaning that the chemical analysis shows low Carbon, and the Physical properties show the strength of 316 plain. Always buy the dual-cert'd stuff if available. Two for the price of one.