I think cracks in that region are fairly common. Assuming this K-Member isn't bent I don't think this K-Member is junk.
Firm Feel welds in reinforcement plates on their reinforced k-frames in this area.
While that weld looks like crap, I think a little investigation and effort will determine what if anything you need to do to the k-member.
Use paint remover to remove the paint and then do a thorough visual inspection looking for cracks, thoroughly inspect the weld to insure that it has good penetration. If you think the weld is suspect, grind out the weld and have it welded again.
Here's a picture of the Firm Feel Reinforced K-Member.
http://www.firmfeel.com/reinfkfram_e.htm
Hope this helps,
Regards,
Joe Dokes
