Hi there friends i have a case study in my university and i cant find the answer after two days and lots of reading im not even close. I want to know if anyone has any thoughts about whats going wrong in the below matter:
PROBLEM
Examination of Spot Weld Heat-Affected Zone Stainingin 1010 Sheet Steel For a Tool Chest Manufacturer
Overview
A company which makes mechanics tool chests out of cold rolled 1010 steel is having quality problems. They electric resistance spot weld the cabinets together and then paint them red. After the paint has dried, there is a dark stain around each weld in the heat-affected zone of each weld. The company is requesting help to determine what is going wrong.
The Tool Chest Manufacturer buys cut lengths of cold rolled steel from a warehouse. The steel is commercial .034 gage 1010 cold rolled steel strip supplied to the warehouse as coiled product. The warehouse uncoils and shears to length for the tool chest manufacturer.
The steel mill starts with commercial hot rolled coil of approximately .150 gage, cold rolls this steel to .034 gage, coils the cold roll product and tempers it in a temper furnace where at least 3 coils are stacked upon each other. A fairly tenacious oxide layer occurs after tempering, so the steel mill uncoils and pickles the cold rolled sheet in a hot acid bath, oils it to prevent further surface oxidation and recoils for shipment to the warehouse.
The tool chest manufacturer makes the weld using a series electrode arrangement with a large backing block. The welding conditions used vary somewhat throughout the day but are typically the following:
Line Voltage: 470 Volts Up Slope: off
Tap Setting: Low 2 Down Slope: off
Squeeze Time: Max Hold Time: 10 cycles
Heat Time: 10 cycles Electrode Force: 600 lbs.
Current Control: 85% Temper: 30-60%
What do you think went wrong? How are we going to prove it?
Now that we know what went wrong, what recommendations are we going to make to the tool chest manufacturer? to the warehouse? to the steel mill?
If anyone has any thoughts about this stain please hit me, thanks in advance.
Send me an e-mail: mdgwelding@yahoo.com
We work on many automotive resistance welding systems, many for door and body panels with class A surface requirments. I would like to get some more information about the processing of the steel and also the paint specs too.
Maybe we can help.
Mark
An sou dwsoun tin apantisi den tin anakoinvneis edw? Kai egw psaxnw edw kai dyo vdomaes jai den vriskw tpt.
That cleared it up.. Thanks
Rander,
I agree!
Absolutely! :-)
This is Greek. Apantisi means answer, but I can't figure out what the question is. Google translation only gets bits of it. Anybody know anyone who knows Greek?
Ross
AWS Marketing
Ross,
I'm sorry I didn't want to offend a foreign colleague or anybody else!
mc02664 please take my apology!
Best regards,
Stephan
Edit:
We have at least one Greek forum member. When I remember correctly it is "WeldAddict" (Dr. Stavros Chionopoulos).
Perhaps he could translate it...
No offense taken.
It is Greek but the sentence is not right. It seems that I am studying at the same university with the guy who send the original message.
So I requested that if he finds the answer to his problem if he could send it to me too.
mc02667,
thanks a lot for that!
And please convey my best regards to the fellow!
Stephan
LOL at Rander.
John,
me too!
He truly made my day..!
Sorry,
I just had to come back, having a short look at the "Klingon-post" and the excellent response on it!
This is so good, for me it deserves :-):-):-)
No offence though!
Translated greek to english,still dont make any sense!
If sou dwsoun the answer anakoinvneis here? Kai egw psaxnw edw kai dyo
vdomaes jai den vriskw tpt.
Was the corrosion inhibiting oil removed prior to welding?
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