HSLA madness & stiffness controversey

[TheTick]

We are building a support frame from tubular steel. Boss is not satisfied with the amount of deflection (no plastic deformation) and wants to address deflection by switching to HSLA.

Everything in my experience tells me there is no difference in stiffness between HSLA and mild steel when operating below yield stress. Have I been deluding myself? I've checked MatWeb, and Young's modulus varies less than ±2% for all the grades I checked.

 

[btrueblood]

Tick,

He probably won't. What he'll do, is bend the mild steel frame by overloading it, and then show the HSLA frame doesn't bend at that load, and then say "that's what I meant all along". Giving you the "wotta dumby" look all the while. Been there, done that, got the heck outta Dodge at next opportunity.

 

[Tmoose]

Maybe some advice from O Blodgett would have been helpful.

http://weldingdesign.com/blodgett/wdf_54866/

 

[TheTick]

This got settled the hard way. Several hundred dollars, dozens of man hours, and one prototype later, I was right.

 

[rmw]

But.... does anyone know that besides yourself?

I spent the better part of last year in a redesign effort that "His Bossness" thought was unnecessary. Fortunately some of his bosses thought differently and initiated the redesign anyway.

Very recently we had a catastrophic failure of one of the original design gadgets which had not yet replaced by the redesign that proved me right when I told "His Bossness" on my first week on the job that the gadget in question was in 'real trouble'. The askance look given to me at the time by His Bossness is still indelibly etched in my memory.

Vindication is sweet.

rmw

 

[Guest102023]

I've fought this one a few times too. As they say, ' a little knowledge is a dangerous thing'. The engineering extension to this is 'and very little is very dangerous'.

 

[Guest102023]

THeTick,

I was half expecting to hear that your boss would insist on PWHT of the welded HSLA to solve the stiffness shortfall ...

Many engineering victories are won with a large bladder and a very hard forehead.

 

[PeterCharles]

WARNING -- WARNING -- WARNING

What is worse than being proved wrong....

Being proved right, so proving the boss is wrong!!