ASTM A194 '2H' Nuts not meeting spec?

[NickelMet]

Has anyone else noted a change in the quality control of these type nuts ('2H', ASMT A194) over the past couple of years?

In this ever-changing world of quality control and quality assurance, we have started digging into this topic. It all started with several field failures when the nuts were torqued down. From that, it grew into random sampling of various manufacturers' nuts that we use (over 30 different ones). And now, based on the analyses, we have found 6 manufacturers that have had consistently provided '2H' nuts that do not conform to the requirements of the specification. The failures to conform have been in chemistry, microstructure, hardness, and tensile testing.

Does anyone have any information or a similar story?

Thank you for your thoughts and replies.

~NiM

 

[HgTX]

Haven't noticed anything with bolts, but plate's sure gotten worse the last couple of years.

Hg

Eng-Tips policies: faq731-376

 

[dbooker630]

This is a real sore subject with me right now.

I can't speak directly about 2H nuts, but over the past year with SAE J1199 class 10.9 and 12.9 fasteners I have seen a deterioration in material selection, heat treatment, and rolling quality. I get more reports of stripping or necking under torque. I used to be able to assume that this class of fasteners was made from 4140 and heat treat would not be an issue.

In the effort to reduce alloy content I am seeing more 4037, 5046, and 10B30, often for sizes that exceed the hardenability. The definition of an alloy steel is so broad that all sorts of steels are being used. I often run tempering audit tests to make sure that draw temps are not being lowered. Now I'm seeing rolling laps and seamy steel so I'm deep etching parts to confirm surface integrity.

Bottom line is that I am seeing the same things that you are and its resulting increased inspection levels to keep out of trouble.

 

[NickelMet]

I don't know if you've looked into the country of manufacture, but the vendors we have banned from use hail from China and Germany.

And, we are looking at all metals products from Asia and Eastern Europe under a fine-tooth comb. We have gotten rotten castings from Eastern Europe that were supposedly checked and approved per ASME code, only to have them fail a test hydro upon arrival.

As a former melting/casting/rolling engineer, I find this very distasteful to the industry. Much more, how aggravating it is to have sub-standard materials purchased just because they are less expensive with no check of quality up front.

OK...I'm sure you can see where this soapbox is going. And for those peers and colleagues that are overseas, I apologize if I insult your professionalism and commitment. But truly, something needs to be done to curb a lack of honesty in the world market. Maybe I'm an idealist, but I firmly believe in giving the customer what they order and what they expect...nothing...nothing...NOTHING LESS.

Just venting a bit...

~NiM

 

[arto]

remember John Ruskin?
"There is hardly anything in the world that a man can not make a little worse and sell a little cheaper. And people who consider price alone are this man's lawful prey."

"It's unwise to pay too much, but it's unwise to pay too little too. When you pay too much, you lose a little money.....that is all. When you pay too little, you sometimes lose everything because the thing you bought was incapable of doing the thing it was bought to do.

The Common Law of business balance prohibits paying a little and getting a lot...it can't be done. If you deal with the lowest bidder, it is well to add something for the risk you run, and if you do that, you will have enough to pay for something better."

...there ain't no free lunch ;-)

 

[HgTX]

What arto says is only relevant if the vendors are offering good bolts at a high price and crappy bolts at a low price.

This is not the case.

Everyone is selling product that's supposed to meet the standard, and it doesn't.

The problems that I've seen with steel plate are from every single mill. Steel products are a seller's market right now and they can do whatever the hell they want.

Hg

Eng-Tips policies: faq731-376