Welding with old steel 1

[ape2010]

Hi,

I come across lots of old steel where I work. The time ranging from 1928 to 2013. The very old steel which I cannot find the proof of the strength, I use 210MPa yield strength. Most of the connections are riveted but I see some welding as well. I heard the welding is not effective for 210MPa or riveted steel. If it is true, is there a specific procedure to weld that kind of steel. And how can I quantify the strength of weld at a connection.

Thank you for your time

 

[berkshire]

There was a related thread on the strength and weldability of old steel on one of these forums some 3 or 4 years ago.
Try using the search feature to see if it shows up.
B.E.

You are judged not by what you know, but by what you can do.

 

[metengr]

The 210 MPa limit and weldability is not true. Weldability is governed by chemical composition and original heat treatment of the steel. The real concern with weldability of older structural steels has to do with elements like carbon, sulfur, silicon, and phosphorus, assuming your reference applies to old structural steels.

If the older structural steel has been welded, you can use conventional welding (SMAW) with E7018 weld rod and weld a small tab of A 36 steel to the original steel member using a fillet weld. Once this is completed, take a chipping hammer and see if you can snap the tab off with a hammer blow. If the tab bends versus fractures at the fillet weld, you know the older structural steel is weldable. Your other option is to use PMI to determine if elements I mentioned above are present and in what quantity.

 

[fegenbush]

metengr,

I just wanted to add that, if you use PMI, you should ensure that the technology you are using can measure carbon content. Many of the X-Ray Fluorescence devices are intended for alloy steel (read: not carbon steel) and will provide less useful information.

 

[weldstan]

As metengr stated, base metal chemistry may well be a problem regarding impact toughness in the HAZ. Welding residual stress in combination with very low toughness (< 5 ft-lbs) at temperatures well above 100 F may limit the use of welding, depending on applied loading in service. Think of the brittle failures in weld constructed Liberty Ships during WW II.

 

[boo1]

why not just bolt it?

 

[msquared48]

And "PMI" refers to ????

Mike McCann
MMC Engineering

 

[fegenbush]

Positive Material Identification, in this case.